[LJRead]

Have a small problem with a slight smoke coming from the exhaust at idle.  Have adjusted the idle mix, turning in the screw almost all the way and backing off the gas supply screw, but still the slight smoke.  If I do a plug check it shows me that the temperature range of the plug is about right, and the color is good just in the area of the ground strap and the plug tip, but the rest is sooty.  I am hoping it won't carbon up too bad, but can't think of what more to do.  I blew out the little air orifice for the idle circuit and a couple of drops of water came out, so I cleaned the carb, finding a small pool of water in the float chamber.  Otherwise, the bike runs very well, is responsive with no flaws I can detect in the throttle range (up to the 40 mph max driving speed). Today I put in a small settling bowl to keep the water out of the carb.

Carburetor  is a Dell'Orto.

What is normal for idling in an as yet unbroken in bike.  Any chance the smoking will cease when it gets broken in?  Has about 500 miles on it now (850 km)

Thanks for any suggestions.

LJ

[petefletcher]

I wouldn't worry about a wisp of smoke if the engine is still  breaking in.
Is the plug really sooty round the edge? if it's just black that's OK - if really sooty it does show it's running rich but if the centre is the right colour I think it's OK

[clamp]

Did you change the oil at 300? What did you use ?

   Mine don't smoke --not a wiff of it.

    Give it some stick at intermediate RPM, don't rev it or let it labour but start putting some power on and get those rings bedded in.

    Check oil level before and after a run, in other words look for something out of the ordinary to gives us some ideas.

      What colour is the smoke,--blue?
     

[hutch]

LJ, my 2005 Bullet smokes at an idle if I dont park it with the motor at TDC. Running down the road there is no smoke after it has cleaned out. Blue smoke will start to show up again if I let it idle for a long time, but long idles are not good for air cooled motors any way, and I try to avoid doing that. My plug looks good also, and oil consumpion is very slight with about 3200 miles on it. It runs like a top, so I don't worry about it for the little bit it smokes. It is usually my fault for not setting it at TDC when parking the bike. Kevin says the newer bikes like mine don't need to be set at TDC when parked, but my bike didn't get the memo. It works every time for me. I really wouldn't worry to much with it only having 500 miles on it. The rings are probably not fully seated. Keep an eye on it though. I know how long you waited to get the bike, and it would be a bummer to have a major malfunction.    Hutch

[clamp]

Ive heard this parking the motor at TDC before .

    Can you explain just  what and why this does anything?

[LJRead]

Thanks guys, the smoke is black and it isn't using oil at all.  I learned how important having a settling bowl between the fuel tap and carb and maybe that will help some.

The TDC thing is to prevent wet sumping which has to do with the oil draining down where it isn't supposed to be during storage, then being burned off during start up.  I haven't been doing that, so maybe that is part of it.  I'll give it a try.

Anyway, many thanks,

LJ

[Kevin Mahoney]

Correct float bowl setting and a petrol filter are mandatory things to prevent black smoke. REM didn't start lining tanks until the early 2000's. Before that they were prone to rust if they weren't kept filled. Cleaning the tank was a standard dealer PDI item in those days.

[Kevin Mahoney]

I cannot explain the TDC parking thing, but it does work or at least is helpful. There are several reasons for a bike to smoke when it is first fired up. The smoking is a sign that there is excessive oil in the crankcase when the bike is started. As it runs the front pump clears out this oil and the smoking stops.
1. The front oil pump is twice the size of the rear pump. This means that it should be able to remove twice as much oil from the crankcase than the pressure pump can place there. If the front pump cannot keep up for some reason excess oil will end up in the crankcase and the bike will smoke. In this situation the bike will smoke all of the time. This condition is unusual.
2. It did happen in the 1990's and occasionally in the early 2000's because the surface of the timing cover that the pump operated against was not perfectly smooth. This is why we sell oil pump lapping tools. The pumps require a good fit between the back of the timing cover surface that they rub on for proper operation. After this was discovered as the cause the factory then started to lap them with a machine. They now just use better cutter tools. This can also happen if the pump is worn out. To test for this condition when you are finished riding for the day, park the bike and then drain the crankcase (not the oil tank, the crankcase is usually the forward most drain bolt underneath the engine). Measure the oil that comes out. It is important to measure it and not just eyeball it. An ounce of oil on the floor looks like a quart. You should not have more than 1-2 tablespoons. A worst case scenario is constant smoking and oil disappearing from the oil tank. This can be a bad gasket between the two engine halves. Very very rare, so don't panic.
3. A far more common problem is the bike smoking when it is first started up and then disappearing. This is due to excess oil draining into the crankcase while the bike is parked. As soon as you start it the front pump starts to evacuate the excess oil and it stops smoking. This is generally caused by one or more of three problems. By far the most common is a worn worm nut seal or cork. When the bike is parked the timing chest is full of oil. If the worm nut seal is bad it will allow oil to seep through the seal and then drip into the crankcase. It is this condition that is the most common. This seal is a wear item. If you have an older bike the seal is nothing more than a cork with a hole in it. http://www.royalenfieldusa.com/royal-enfield-bullet-motorcycle-cork-retainer-feed-plug-p-38.html
NO bikes ever imported into the US use a cork. (We started in 1995). All modern and all US bikes use a rubber seal which is molded into the worm nut.
http://www.royalenfieldusa.com/royal-enfield-bullet-motorcycle-worm-gear-rubber-seal-p-81.html You can replace the cork seal with one of these modern more reliable seals.
Other reasons for this condition are a bad engine seal on the right hand side of the engine or a bad crankshaft bearing (rare). To test for this condition when you part the bike for the night, open the crankcase and drain whatever oil is in it. Then either place a measuring cup underneath the hole for the night, or seal it back up and re-open it in the morning. After sitting all night it should not have more than a tablespoon of oil in the crankcase. Any more and it is getting into the crankcase in one of the three ways mentioned above.

Smoking bikes that have the more modern crankcase breather system may have other issues.
1. If you have a bike with the breather hose on the rear of the crankcase and not on the left hand side of the crankcase below the cylinder, it is possible that one of the hoses are full of gunk, kinked or the catch can behind the battery is full. Also check the hose from the catch can to the air cleaner and make sure it is not kinked.
Hope this helps.
2. It is also possible that oil is moving backwards through the line from the back of the timing chest to the catch can. Sometimes this manifests itself by oil coming from the air cleaner.  In this case we have an alternate hose with a one way valve in it. This is uncommon but it happens.

Bad rings and/or bad valve guides are other reasons the bikes can smoke

[LJRead]

I have AVL so some of the above probably doesn't apply, but thanks for the information, Kevin.  The air breather starts out at the intake valve cover, which is different than any other AVL, as this was one of the first years for the engine (2002 Machismo A350). I did away with the catch can and carefully routed the hose out the back with no low places in the hose to collect the breather stuff.   It could just be that it still has some break in to do as it now has only 500 miles on it.  The soot on the plugs is just that, a powdery soot which is easily wiped off.  The bike starts first kick and runs very well.  I'll just keep an eye on it and see if it improves.  The smoke is very light, almost can't see it unless you look, but the black plugs and possible carbonizing up is what would concern me.

Problem is that I just didn't know what similar bikes are like at first.  I have nothing to compare it to except my Thunderbird which burns clean and has the CV carb instead of the Dell'orto.  I've been running it so slowly maybe Clamp is right an it needs to have a little more revs put on it.  The exhaust pipe has no color at all on it - it doesn't run hot except when setting at idle, a practice I've discontinued.]

Some of this may just be paranoia at having a new bike.

Thanks again,

LJ

[Jerry]

I don't know anything about a Dell'Orto carb but on some brands the "idle mixture"
screw is an air jet.  If you have it all the way in (closed) it would be too rich and you would get the soot and black smoke symptoms.  Opening the screw leans it out.

Just a thought.

Jerry

[LJRead]

Thanks Jerry,

Dell'Oro made two versions, one with an air enrichment screw back near the intake of the carb, the other with a mixture screw to the front.  The pdf manual says to turn the screw in to lean out (mine is the mixture screw type).  But now that you mention it, it shouldn't hurt to try turning it out to see what happens.  I'll try that in a while and see if it helps.  It was further out when the bike came to me so that could be. 

The float level is fixed by some plastic tabs that control the needle valve so I don't think that is an issue.

Oh and I changed the oil during servicing at 300 miles.

[cyrusb]

Good information,I wrongly assumed a smokey startup was right after sex.

[petefletcher]

The "parking at TDC is simple really.
The oil has a tendency (on some engines) it find it's way through the big end bearing and into the sump. Leave the engine at TDC and the big end is above the oil level.
It's nothing to do with compression and TDC between exhaust and intake would work just as well if you could find it. Too much oil in the sump gets splashed around by the crank so you get too much on the cylinder walls, the rings can't cope and it gets into the combustion chamber. It gets into the breather as well and hence to the air filter if you haven't altered the breather arrangements.

[LJRead]

Today I ran the bike for maybe twenty minutes in all at about 40 mph and on return home, still a slight amount of black smoke, indicating that it isn't oil being misplaced before startup.  Odd thing is that when I adjust the mixture screw all the way in, it still runs fine, only again with the slight smudge.The idling itself is smooth, and I can reduce it down to just a slow thump, so it isn't getting too much fuel, but just isn't getting quite enough air, so it isn't burning the fuel it gets efficiently (too rich in the fuel/air mixture).  The air input at idle normally isn't enough (according to the Dell'Orto manual) to give a lean enough mixture, so there is a small orifice that supplies air at idle, even before the main jet is opened.  I would have thought that screwing the mixture screw all the way in would have cut off, or at least down, the fuel supplied, but for some reason that isn't the case.  I'm wondering if enlarging the air orifice just a tad might increase the air flow enough.Easy enough to do because there is a plug in the float chamber, and when you remove the plug, you can see light coming in from the small opening in the main air channel itself.  Kind of scary to do that, but I can't see that it would do any harm, especially if I did the drilling out in small steps, testing between each drill out.

The dense air here (high humidity) might also have an effect such that a carburetor designed for dryer conditions might need a larger air orifice with denser air.   Or maybe some slight condensation occurs which occludes the air passage with beads of water (vapor lock).  But I would have thought that in Italy, home of the Dell'Orto, some places would have high humidity along with heat.

I'm also wondering if the small channel leading from the air opening to the gas mixture chamber might be occluded, possibly by the water and rust particles in the carb initially (it was stored for six years and had water in the bottom of the fuel tank).  I'm not sure how to open that chamber up if there is some particulate matter in there.  It wouldn't be a varnish which could be removed using varnish thinner, but what else would dissolve it without harming the metal in the carb.  Maybe a vinegar solution and flushing.  I can blow through it with seemingly no restriction, but that doesn't assure me of no occlusion.  Just cutting down the size of the mixing chamber might be enough to throw off the balance, even though the pathways seem to be open.

Apparently the idle circuit and the main throttle circuit work together until about quarter throttle, and throttle response is so good, I'm thinking that going down in idle jet size wouldn't be good.

One interesting thing I've come to realize is that it may not be such a good thing to have a tank reserve in that it would be rarely that any water settling in the bottom of the tank would be drained out.  I suppose now that they are coating the inside of the tank with something, this isn't a problem, but I could see that if enough water from condensation or other sources got in there, it could cause some problems, especially as fuel levels got low and some mixing of gas and water occurred. due to vibration.

[baird4444]

Ljr- I can't believe I'm saying this but ya gotta relax...  you are til running it in....   so long as you aren't too lean you are OK...  riunn'n  rich will only foul a plug.  You've got a long way to go and your machine will change a lot as it matures. ...   just make mental notes and small changes...
               - Mike

[LJRead]

Yeah, I know you are right, Mike, but it is like a new baby to me.  I have these visions of the head and upper cylinder carbonizing up and having to tear it all down to get the carbon out.  Pete Snidal said an interesting thing, that if it is a soot and not a wet carbon deposit on the plug, it is likely that the spark pug isn't firing strongly enough at idle.  But since it is CDI electronic ignition, there is no adjustment.  I can, however, check the contacts and make sure they are good.Already, gas mileage seems to be improving and today I was looking at the smoke and it isn't much.  My manifold opening is 28 mm by the way and not 26 which is the opening of the 350 Bullets.  I take it you're still cranking on the mileage Mike  Way to go!

LJ

[clamp]

I hear exessive oil in the crank case when starting up will cause the smoke?

    How does it get up into the combustion chamber? isnt a cars wet sump crank case full of oil too.

   You are assuming that parking the engine at TDC will stop any syphon effect of oil into the crank case from the timing case, but  the main bearings are oil fed too!!  dont you think that oil will more likely seep down the timing  gears into the crank shaft bearing and into the crank case.

        Any way the problem is none of that because the smoke is black. I would have thought that running that rich would mean a fowled plug every 10miles if you lucky.

   How come you got a Dellorto carb on anyway.

[baird4444]

Yeah, I know you are right, Mike, but it is like a new baby to me.Already, gas mileage seems to be improving and today I was looking at the smoke and it isn't much.  My manifold opening is 28 mm by the way and not 26 which is the opening of the 350 Bullets.  I take it you're still cranking on the mileage Mike  Way to go!

LJ

I haven't been on for 10 days...   maybe by the end of the week.
I had one of those hernia things fixed with a screen on the 18th. There is
NO WAY I'm going to stay off for 8 weeks... I'm thinking 2 or 3 but I'll just
have to see how it feels the first time I put it on the center stand.
I've got a list of things that I'm doing to it, it's not as good as riding
but the daily contact is good for BOTH of us!!
              - Mike

[LJRead]

West sumping is something I can never quite get a handle on either, but has something to do with the way the oil is channeled when it leaves the main oil chamber, running down through the crank at its low position and into the sump.  It causes a cloud of smoke on starting.  Mine has a slight smoke even after a ride, so it isn't wet sumping.  And it is so slight that when I accelerate I guess most of the soot burns off.  The plug has only fouled once. The Del'Orto was manufactured under license to the Italian company by and Indian one called Spaco.  It was only used on my year model of Machismo, then discontinued for the CV, which is more fuel efficient.

Mike, sorry to hear of your reduced riding, but I think those things heal up real well.  My next door neighbor growing up had a screen put in and I think it was a done issue once it was put right.  He got it pushing my old hot rod trying to get it started.  Always felt a little guilty about that.

[clamp]

I think this is something to do with the rings and the way they bed in. I have nursed mine through 1000Kms as told to do buy RE and by many web sites.

  However I found a web site that says do not do this , the rings must be bedded in and this means thrashing it from day one. Now as a mechanic all my life till retirment I know from experience that an engine that has been used hard from day one is better than one run about by an old lady.

       I am riding mine hard now and purposely heading for the hills to give it 1-2 minutes of hard pull.  It does nt smoke at all,--ever.

    I have also used a whole tin of Wynns friction crap. Half in the engine 1/4 in the  chain case and 1/4 in the gearbox.   I got a real nice bike.

   PS  I do not mean racing 1500rpm to 2500 RPM give it some.  Ille try to find that web site.

[clamp]

http://answers.yahoo.com/question/index?qid=20080407130440AAYP4fO

   A lot of different opinions , but this is the one I wanted to show you.

http://www.mototuneusa.com/break_in_secrets.htm

[LJRead]

Couple of things about this, Clamp.  First, the last article you cite is distinguishing between old technology bikes and new ones, and says the window of opportunity to use the honing lines is in the first twenty miles when you use hard riding tactics.  I'm not sure what technology was used in creating ours. Well, my bike came with 19 km on it, so the window was already pretty well closed.  Then you have to remove the cylinder, rehone, and hard ride for twenty miles.  Second, mine doesn't use any oil and the plug soot is just that, a light soot which Pete Snidal says may be due to not hot enough spark at the low RPMs, or a too rich idle circuit.  However, because it is dry like this, it may be the former, not hot enough spark at low RPMs

Pete also says, and has said for years, not to hone an engine on rebuild, that it isn't necessary and may not be good.  I think, now that I have 850 km on it, I will open it up a little and see how it goes.  I can't go very fast, but I can get the revs up by staying in a lower gear.

We have had one forum member, Dewey, who advocated hard break in and seems to have had good luck with breaking his in like that, so he would be in your circle of agreement.

I still have more reading to do in what you have presented ...

Thanks,

LJ

[clamp]

Honing on a rebuild is very important, I cant believe someone would say that it was'nt.

     Even if you don't call it honing which is actually taking it right down to size to the thou.  Glaze busting  is very necessary to get the worn cylinder ready for new rings.

[LJRead]

It is sort of like the break in hard or soft controversy.  I'll see what I can find on the honing controversy, but those who say don't do it have their reasons and are pretty adamant about it.  I think they are saying it makes the cylinder worse instead of better.  I was a bit surprised too, but their arguments seem clear enough, and on the practical side, many, including Pete Snidal, have been rebuilding without honing for years with no problem.  I think what they say is like your reference says about honing, the honing is to smooth off the ridges but the rings will do that better themselves., but it has been a while since I read their ideas, so maybe there are other reasons as well.

Anyway, when I find something for you to read I will let you know.

[LJRead]

Yeah clamp, I found it in his manual (it was also on some websites but I don't have links to them). Here is what Pete says:

"When fitting new rings to a used bore, ALWAYS be careful to use only cast iron rings.  Chrome-Moly rings, although often used in new installations, will not seat on a used bore, unless the bore is throughly scratched up with a hone, or, as it is often mistakenly called, a "de-glazer". 
The rapid wear associated with the practice, as the scratches in the cylinder wear down and the cylinder wears to a large size, obviate most of the good done by re-ringing.For this reason, honing a used bore should not be considered, and only cast iron rings, which will seat on a worn bore, should be used in a re-ring. ."

He goes on to call the idea of the need for honing n "old wives tale" and concludes by saying:

"Those who trust this advice will be repaid by considerably less break in wear, and subsequent tighter clearances once the new rings have worn in."

He says, in effect, that there will be enough friction causing wear to allow the rings to seat without tending to make the clearances excessive by honing, and that excessive clearances will cause oil burning.

There was something said in the links about glazing, but apparently it isn't the problem it is made out to be.

I tend to rely on Pete because he has the experience and I know so little.

LJ

[PhilJ]

When they talk about honing, LJ, their not taking any metal off to speak of. It is just like lightly rubbing with steel wool, only controlled so that every thing is uniform. Over the years my friend and I, mostly him, rebuilt many engines and always used  a hone with no problems. I really think Clamp is talking about what I just described. The roughing up of the cylinder allows a little oil to remain, thereby reducing the friction (read that heat) which is what you want. I think Pete Snidal is wrong, at least if that is a direct quote from Snidal.

[PhilJ]

On my AVL 500 I took it easy for a little over a hundred miles, then started running it up to 50 mph and back down, then to 60 and back, then once to 70 and back. All this through the course of a 100 mile day. Never a hard run up, just medium. I didn't hold at those speeds either, just backed off to 45 or so. I did stop throughout the course of the day. I never discerned any oil usage, the bike runs very well and has given no problems. Now the AVL is CNC manufactured, I'm not sure I would have done the same thing to an iron barreled bike that was brand new. But I don't think I would have babied it like the book say either. There would have been lot more rest/cool down stops.

[LJRead]

I haven't done a lot of honing, just on an old Volvo marine engine I have, and in that case, I rented a honing system from a machine shop (in the U.S.) and it scratched it up pretty well, and I think this sort of thing is what Pete refers to (yes it is a direct quote from his manual).  And, when you read the link clamp refers to they are talking about actually grooving the cylinder to provide ridges to wear the rings in.  It is controversial however, with strong supporters of both sides. Pete feels there is enough friction in installing the iron rings to allow them to seat in.  And he is definitely referring to the iron cylindered engine.

I hope I never have to do a rebuild so much of this is just talk with me, but I enjoy that too!

My bike is running so well and not burning oil so I will take Mike Baird's advice  and just ride.

[PhilJ]

Yes I understood the bit about the friction. That was my point friction = heat, but no grooves or the like would I do. However, with fine or very fine honing pushed back and forth for just a little you get the gentle scuff that will hold the oil and prevent excessive friction. I doesn't take log for rings to seat if it did there would be a lot of complaining about oil consumption. Rings are by their very nature are springy, their gaps overlap preventing oil usage and expand as the cylinder hones in to a mirror finish. The increased size of the bore is almost immeasurable.

[LJRead]

I'm sure that what Pete is talking of is a far more abrasive system than you use, Phil.  The honing system I rented was used with an electric drill and consisted of abrasive balls, as I recall, on the end of wires or string and they would spin around and do the abrading.  I too doubt that they went that deep, and your system seems fine, and, like you say, would hold a bit of oil for the process.  Some of these controversies do seem like a lot of hot air (from friction?) and honing is tried and true. 

I think roughing it up just a bit would be a good idea.

[clamp]

Abrasive balls on  springy wires is a glaze buster.

  How can that accurately hone a cylinder.

    A honer is done with a similar  machine to the borer.  It has 3 straight stones that go almost full length of the cylinder and will finish the cylinder after boring.

   Some boring machines are better than others. The portables are good but not as good, and some take the last bit out with a honer. when the piston drops through the cylinder without sticking its done.

       With the 3 stone honer you can actually see where the stones hav'nt touched the cylinder such as just below the ring wear ridge.

    Springy balls will go every where.

     

[baird4444]

Glaze buster.......
   explain glaze...   what causes it....   effects of glaze....
                 - Mike

[LJRead]

Well clamp I think Pete is talking about something like the balls on a string because he refers to putting new rings with an old cylinder bore.  Probably means over sized rings  He is talking about a "used bore", meaning, I suppose not a rebore.  He is talking about reringing to an old bore which is still within tolerances so that a complete rebore isn't necessary.  The honing instrument I used required that cross hatch marks be made at which time you knew the balls had done their job.  It warned against excessive use of the instrument.  But he could be talking about honing a cylinder without a rebore using something like you suggest - he calls it a deglazer.

So clamp, I think you are talking about proper honing after reboring and Pete is talking about de-glazing., but maybe I can find out.

Glaze is a sort of varnishy look to the cylinder wall instead of the metal look of a new cylinder.

[clamp]

First of all we are not removing metal here ,--well microns.

  You would not ever put oversize rings into a old bore. 

     If you are fitting new parts to old surfaces you are asking for trouble. Such as cam followers to new cams or new bearings to old cranks, Sometimes it works but I would never do this to an engine of importance such as a marine engine.

     But new Std rings in old Std cylinders can be done if the cylinder is cylindrical. 

     This is where they will be controversy, its up to you ,its your engine ,but if you can feel a ridge on the top of the cylinder it needs a bore,--But if you've no money and you've just got married and you need to get to work yes it will work.
 
   You can buy rings for old bores, the top ring is called a ridge dodger and has a cut out to dodge the ridge which would knock like hell if it had'nt.

     It is important you bust all the old surface off, or rough it up to bed in the new ones.

   We are talking sandpaper,-- not metal removing or resizing.  How deep is a scratch? in metal  with sandpaer? its not measurable.

   I too am not too sure if we are talking re bore or fitting new rings in old bores.
 

[LJRead]

What we are talking about is a new engine and the thought that it needs to be broken in during the first 20 miles when the honing is fresh, and the window of opportunity to bed the rings in is only twenty miles worth. 

So, according to your reference, if you miss the window, you have to rehone or the rings won't have anything to abrade (i guess) the rings down so they will bed in.

But I suppose Pete would come in with the idea that in a new engine there is plenty of ring to bore abrasion going on during the what? Maybe first three hundred miles.

But then this whole mess of boring, reboring, honing etc. got started and we got off track.  But then I'm learning something, so offtrack is good!

What I will have to do, and I will do it, is reread all the info about the controversy.  Seems though you understand what should be done very well.

With my verticle mill (Clausing) I think maybe I could do a rebore if I took my time and got the setup just right.  But then, I'll try anything at least once!

[clamp]

As I was just riding my mountain bike down to the bank and pay the Astro bill I was thinking.

      If this was a 2 stroke it would be extremely critical,   a slack piston would destroy itself as the rings would pick up on the transfer port and break. The consiquences can be imagined.

  Either total siezure or it would blow all the land out of all 3 rings,-- compression as we know it would not exist.

    Ahem,-- done this quite a few times.

      But yes back to breaking in procedure of a 4 stroke that has rings that are allowed to rotate and do. A 2 strokes rings are pegged and therefore stationary meaning the rings gets it own bit of cylinder and stays there.

      I have experienced some fantastic compression on 2 strokes.

   It is rumoured that old Silver Ghost RR would hold compression overnight. Moving the advance and retard lever on the steering wheel would open and break the points causing a spark and the engine would start.

[PhilJ]

Larry,

I just can't see the need to "rebore" your engine. Let's say that your rings didn't seal / break-in properly. That doesn't mean you must rebore. Maybe running the bike a little harder could bring them in. At worst all that would be needed is new rings of the same size and the three pronged honing instrument that Clamp referred to (which is also what I was referring to but didn't do it as well as Clamp) to scuff up to bore and go again at the break-in, It wouldn't be like a totally new break-in. And just running it a little harder this time. Which for your situation is difficult but doable.

Those honers are usually used in a hand held electric drill. But I would first try running the bike a little harder first.

[clamp]

Oh absalutely. I was'nt aware that we we considering a rebore on a 1000km engine to cure the smoke.
 I guess I got so far off topic I forgot what the original question was.

         would'nt worry about it at the moment --no way. I would exhaust every avenue before doing that.  Change your gas station for one, --just to see if!!

     What is it like when you slowly turn the engine with the kick start?  I mean does it hold compression. Then put some oil in the cylinder and try it again. Kinda like  compression check wet and dry,--

        I know I know some one will say a compression check is not necessarily an oil control problem, but the results would be interesting.
     

[LJRead]

My goodness, I haven't even come close to saying I needed a rebore.  I only responded to clampt's link saying that if you didn't get the rings seated by hard break in tactics within the first 20 miles of breakin, then the link suggested rehoning and a new 20 mile break in, which seems absurd to me. 

As already stated, the minor smoking isn't rings not seating but probably a too rich carburetor idle circuit or else a weak spark at idle.  When I opened up the air flow by taking out the air filter and doing a plug check without, there wasn't the soot problem but it ran a little lean.  Last night I managed to modify a new K & N filter that was designed for an ATV and make a perfectly acceptable smaller filter (actually I got two filters out of the one, the second I will use on the other bike) which I will try today.  I want to increase air flow to the idle circuit so I will be in a range to tune it.  Right now I can turn the mixture screw all the way in and it still soots up the plug.

No, I'm not planning a rebore, the thread just got a little off track.

Anyway, I find all this interesting.  Now that I know more about these honing devices you are talking about, I must say I think Pete is right.  If one were to put new rings in an untouched cylinder, the rings would seat in if within specification, if you rebored and used rings withing the rebore specs, I'm pretty sure there would be enough roughness to the cylinder to provide good ring break in.

[PhilJ]

One thing I was wondering about LJ, if you 350 AVL has an catalytic converter in the end of the down pip right before the muffler?
If it does (having seen automobiles do this) could this be causing the "white" smoke you describe? Since you ride so slow and shorter distances your engine may not be getting to a normal operating temperature and just steaming off the water instead of vaporizing it.
Just a thought, maybe Clamp or someone else might know.

Phil

[PhilJ]

With my verticle mill (Clausing) I think maybe I could do a rebore if I took my time and got the setup just right.  But then, I'll try anything at least once!

This is the quote that made me think you might be considering a rebore.

Phil

[LJRead]

Yeah, I shouldn't have stuck that in about reboring, just that all this has that on my mind.  I doubt if my bike has a catalytic converter since it isn't really to U.S. specs and the exhaust seems loud and unrestricted and the smoke is black, but only a haze, though enough to soot up the plug. 

As I mentioned, no oil usage at all so I'm sure the rings are alright.

It is Coronation Day here, and a national holiday as the new King gains his crown.  Yesterday he announced that the country will be converting more to a constitutional monarchy, with a lot more of the democratic aspects involved.  Up until now it has been pretty much in the hands of the nobility.  I'm in the middle, my wife is noble, I am quite common!

What this means is I don't feel like working in the normal way, but instead will tinker with the bike and go for a ride later on in celebration of our new King.

[PhilJ]

Here in the states we have been dabbling in a monarchy for the last eight years.  

[LJRead]

Last night I took a new K & N air filter I had bought but which was too large.  I sawed it in half and put a round disc of wood on using a thick bead of Goop.  The goop worked very well and the wooden lid was firmly in place with no gaps.  Then I cut a hole in the other end and used this in place of my OEM air filter.  The other half I will use on the Thunderbird later. 

The problem was that with an OEM filter it wasn't getting enough air even when I had the main jet's pin at the highest notch.  It was running too rich.  Without an air filter it was running too lean in the mid range and still a little sooting up at idle.  But with this new filter setup it is just right.  I took three new plugs out to do some plug chops and only had to use one - it was right on.  Smoking is almost gone as well.  I did about 50 km today and the bike performs as good as I could wish and the one plug chop showed a nice tan color. 

I always knew I had a rich running carb in the De;;'orto which isn't a bad thing because I don't need to change jetting to use a more open filter.  I believe, as I said above, that the exhaust isn't bad either.

Here are a couple photos of the filter alteration and the one installed in the side compartment.  The other still has its hose and I will use it on the T-bird when it becomes a rickshaw.  Thanks for all the interest you all have shown.

With regards,

LJ

[petefletcher]

If you really can close the mixture screw all the way you will not be getting fuel through the pilot jet so where is the engine getting fuel?
Check float level / float valve??

[LJRead]

The idle jet has a small opening in the bottom which is below the level of the fuel in the float chamber, so the mixture screw wouldn't cut off the fuel completely as the idle jet is continuous with the air inlet orifice for the idle circuit.  I guess some fuel is being sucked up through this small hole by air passing over the orifice.    When I turn the idle mixture screw in, it will speed up the idle as the fuel becomes richer in air, but it never reaches a stutter phase, so maybe you have something that I should check.  I probably should check the fuel level, but as I recall this is fixed by the plastic tabs connecting the inlet needle valve with the floats and wouldn't appear to be adjustable.  I will check it though.  Problem might be that I have no data on what the chamber level should be.

[clamp]

The fuel mixture setting screw for the pilot jet may not necessarily be fuel ,--it can be an air screw that controls air into the emulsion tube.

   However being able to move it right in or out without much difference shows something is wrong there. Is there a pilot jet in it.

  Is this a constant velocity or a slide,--has it a diaphragm?

    With a bit of work "Googling" you may well be able to find an exploded view of your carb. If you do , post it.

     A motorcycle carb works in 3 stages , we have to find out which stage is rich then its easy.

[LJRead]

I wouldn't say you could move it in or out (mixture screw) without much difference.  As I recall, it speeds up as you move it in (more air) until you get it right in, then it just stays the same as just before you reached the end.

It isn't really smoking now, just a balck haze really, and if you increase the throttle a bit, there isn't even the hze.  If you tweak the throttle from full off, you get a bit more smoke, then it quits, sort of like blowing smoke rings. 

It is a slide type of carburetor, not a CV.  There are two versions made by Dell'Orto, one has an air enrichment toward the air intake, the other has a mixture screw toward the manifold, mine is this latter type.

I did run it up a bit more yesterday, leaving it in second up to about 40 km/hr, then in third up to over 60 km/hr.  I really can't complain at all about the way the bike is running, in fact I wisdh it would always run this well (never wear out!).

And now it is really idling nicely, very slow without any pause, just thump, thump, thump.  Like that.  I'm thinking just to make sure I blow it out each time I ride by giving it some good revs, sort of blow any accumulation out, but the thing is, apparently the idle stage and the main pilot stage, before 1/4 th throttle sort of work together, and since throttle response is so smooth, I might be loath to put in a smaller idle jet.

Did some more adjusting of a general nature,  I'm becoming sort of a gentleman mechanic - not a serious one yet.  Just polish, then tweak and dither around.

[clamp]

If I move my mixture control screw I have only to go 1/2 a turn and the engine will stop.

     You must have a fast tick over there.

   Or are you increasing the tick over to max and then making final mixture adjustments? .

    If your not ,--you could,--it is a recommended procedure for some .

   Increase tick over to say 1500,- then adjust mixture of primary jet adjustment screw to achieve max RPM., then re set tick over. You should be on the nose there.

[LJRead]

Thanks clamp, I'll give it a try.  Today I'm building shelves.  Lived here for well over ten years and still have stuff scattered around - I'm ashamed.

What I need is a duck that builds shelves.

[LJRead]

Some time has gone by without a cure to my black smoke problem.  I had posted about this on the Yahoo forum as well as this one and received some ideas from people like Pete Snidal,clamp and others but still no cure.  I had sort of given up and since the amount of smoke was slight, had just gotten used to it. Maybe, I thought, it will go away after break in. Then I got a belated personal email from a gentleman named John from India.  He has the same Dell'Orto carburetor and suggested that it might not be clean enough, going through the steps I should take in doing the job properly.  He mentioned that some of the channels are narrow and tend to get obstructed.  Well, I had thought I did a thorough job in the cleaning, although I hadn't taken apart the choke mechanism.  John mentioned this so finally I again stripped the carburetor down and cleaned everything with paint thinner.  While I saw no obstructions, I simply flushed everything out and reassembled.

No black smoke at all !!!!

A couple of lessons 1) Dell'Orto carburetors (and probably others as well) must be kept clean and, probably, the first sign of trouble may mean a dirty carb. 2) I feel it may well have been the so called fuel enricher or choke that was the culprit, maybe a small particle of debris restricting flow at choke-off idle.  This seems logical because it would mean a too rich idle mixture.  Being used to simple choke systems without an orifice like this one, I just didn't suspect it as the problem, but think now it was.

Hopefully, end of story and a big thanks to a man named John from India!

[LJRead]

Here is a photo of the plug taken moments ago.  Before I cleaned the carburetor it would have been entirely covered with soot.  Maybe slightly lean now, but I think I'll run it that way for now and maybe clean out some of the soot residue. The plug temperature seems right on as judged by the heat band on the ground strap.

[clamp]

looks pretty good actually the 4 threads discoloured on the plug show a perfect heat range.

      I have heard tell that modern bio fuels these days make plug reading difficult and if one strives for a perfect straw colour that was once considered perfect one might be too lean.

        I would guess mine looks similar to that and I am happy with it. I dont want a hot engine and since I have raised the needle now to maximum to accomodate for my little mods on breathing, I no longer get tappet noise that I used to get on a hot engine.

     I now ride with my head held high and look at the passing trees instead of head down to the tank listening for noises and feeling temps.