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Royal Enfield Motorcycles => Vintage Royal Enfield => Topic started by: High On Octane on May 08, 2013, 10:51:39 pm

Title: Lame Top Speed - Lean Condition???
Post by: High On Octane on May 08, 2013, 10:51:39 pm
I strapped my phone to my gas tank today and tried out the GPS speedometer app I downloaded yesterday.  I tested the app in my truck 1st and it is VERY accurate.  So, I headed out to the back country roads to see what was going on.  I immediately noticed that the Smiths speedometer is pretty much 15mph fast throughout the range of the speedo, starting off at 15mph (30mph indicated).  It stayed consistent and true to this all the way at least 55mph (70mph indicated).  Unfortunately I forgot to compare the GPS to the speedo at 75mph.    :-\

I got out into the country a bit and from 45mph in 4th gear I rolled WOT.  It took about 3/4 of a mile to reach a top speed of exactly 75mph.  I know this bike is capable of at LEAST 95-100mph and I wasn't even close to red line, (working, but not red lined) but it just had nothing left.  I noticed that the bike isn't accelerating as quickly as I thought either.  I also know it's not the timing, I hit that shit with a digital Snap On light and I KNOW it's correct.

I got home and pulled the #1 plug.  I have brand new E3 plugs with about 3 hours on them and it was completely dry.  It seems like it's running WAY TOO LEAN.  Lack of power and acceleration and absolutely no carbon on the plug.

(http://i6.photobucket.com/albums/y217/lethalinj/E3Plug3HrsRunTime_zps25a84e14.jpg) (http://s6.photobucket.com/user/lethalinj/media/E3Plug3HrsRunTime_zps25a84e14.jpg.html)

Here's what I have set up right now:
Carburater: Amal 930 Concentric
220 Main Jet
3.5 Pilot Jet
106 Needle Jet
Needle clip in lowest of 3 positions - Air Screw only about 1/8 of a turn out

Someone please throw me a bone here and tell me what changes I need to make to the jetting to get better throttle response and actually get everything out of the motor.  Thanks!

Scottie
Title: Re: Lame Top Speed - Lean Condition???
Post by: ace.cafe on May 08, 2013, 11:36:04 pm
I don't know Amal tuning, but if it's lean and weak at wide open throttle you should try some bigger main jets.
You already have the needle all the way up, so you can't do much with that unless you get a richer needle.
Title: Re: Lame Top Speed - Lean Condition???
Post by: High On Octane on May 08, 2013, 11:39:22 pm
Ace - Maybe try 2 sizes bigger on the main and 1 size bigger on the needle?

Scottie
Title: Re: Lame Top Speed - Lean Condition???
Post by: ace.cafe on May 09, 2013, 03:02:58 am
Ace - Maybe try 2 sizes bigger on the main and 1 size bigger on the needle?

Scottie

I usually like to move one step at a time.
The main jet will primarily be for WFO.
The needle will be for a wide range at medium to large throttle openings.
But the main jet is the limiting factor for how much fuel can move thru the jet system.
Title: Re: Lame Top Speed - Lean Condition???
Post by: Bullet Whisperer on May 09, 2013, 09:11:48 am
A 220 main jet is what I would use in a 350. I would go for 250 - 270 in that carb for a 500, especially if the engine is tuned in any way. The MK I Concentrics are not very good in my opinion, the Monoblocs and MK II's are much better by comparison and what I usually fit to my tuned Enfields. I have recently worked on two separate MK I equipped machines which have suffered from fuel starvation, due to the float needle seating being too high in the float bowl - one even needed me to blow into the tank while I held the tickler button down to flood it for cold starting  ::)
 The float needle seating can be moved in the float bowl by tapping it with a suitable drift. The float needle wants to close, just as the top surface of the float becomes parallel with the top edge of the float bowl - many I have seen close well before this level is reached.
 B.W.
 B.W.
Title: Re: Lame Top Speed - Lean Condition???
Post by: High On Octane on May 09, 2013, 02:35:50 pm
This a is a brand new Premier 930 concentric with maybe 5 or 6 hours on it.  It's just that I haven't had a chance to diagnose the the jetting until yesterday.  Originally the bike had a 30mm Monobloc, but that carb is 55 years old and the and the sleeve is so worn out that the slide was getting cocked and stuck between half and WOT.  I have a local guy that sells the new Premier 930s for $190 USD, so it was hard to pass up.

Scottie
Title: Re: Lame Top Speed - Lean Condition???
Post by: ace.cafe on May 09, 2013, 02:54:21 pm
I think I'm a little leery of that E3 spark plug.
It looks to me like it's blocking 2/3 of the flame path with all those ground straps.
At the very least, please index that plug so that the open side is facing toward the center of the chamber.

I really think that a regular spark plug would do better.
Title: Re: Lame Top Speed - Lean Condition???
Post by: High On Octane on May 09, 2013, 03:20:18 pm
Here's the deal.  I had to run 5K ohm resister caps with the Sparx battery eliminator.  The only GOOD 5K ohm resister caps I could find are the NGK 8031, and they only accept spark plugs with a threaded nipple.  THE ONLY PLUG I could find with a threaded nipple for my bike was the E3 plug.  And I checked, the spark comes right out the center of the ground strap.  I'd also like to add that I have a friend that has a '83 S10 and a '91 IROC Camaro, both street/strip set ups with 400hp 383 strokers.  He runs nothing but E3 plugs in them and swears by them.  And I feel his word is worth it's weight in gold.  He's been building high performance small block Chevys with his Hot Rodding dad since he was 8 years old, and was working as an engine machinist while he was still a senior in high school.  Maybe it's possible they are good for cars but not motorcyles, I don't know. 

I will try to index them, see if it makes a difference.  I'm in doubt of it, but hey.  Here's my concern, the plugs were 100% dry with absolutely no carbon build up after running cranked at full throttle for almost a mile, and various throttle positions throughout, and it just doesn't feel like a spark issue.  It runs and idles fine, just has no accelerating power.  Even if the bike's not under load just revving it up, just doesn't seem as crisp as it should be.

Scottie
Title: Re: Lame Top Speed - Lean Condition???
Post by: Bullet Whisperer on May 09, 2013, 04:00:33 pm
O.K., I stand by what I've said already, but you could try a 107 needle jet, this might help, my own Indian 350 has one in its' well used 389 Monobloc, along with a 230 main jet.
 We also have two Enfield racers here, 350 and 500 [Redditch], which produce up to 37 and 46 bhp respectively, neither of these has fancy spark plugs in - just boring old NGK B7/8 E/HS with their twin spark PVL ignitions. Both machines have won numerous races in the 8 years they have been around since I built them. You need to get more fuel into the cylinder, I.M.H.O.
 B.W.
Title: Re: Lame Top Speed - Lean Condition???
Post by: High On Octane on May 09, 2013, 06:08:11 pm
I'm beginning to wonder if this bike had the wrong plugs in it when I got it.....

Does anyone know what plug a '58 700 twin is SUPPOSED to have? ???

Scottie
Title: Re: Lame Top Speed - Lean Condition???
Post by: ace.cafe on May 09, 2013, 06:40:01 pm
I'm beginning to wonder if this bike had the wrong plugs in it when I got it.....

Does anyone know what plug a '58 700 twin is SUPPOSED to have? ???

Scottie

According to the info that I found, if your engine number is prior to SMQA 4687, then it should have a short reach plug which would be a Champion L7 or equivalent. NGK cross reference would be B6HS.
If your engine number is SMQA 4688 onwards, then it should have a long reach plug which would be a Champion N5 or equivalent. NGK cross reference shows B6ES.

I would recommend checking the heads for plug reach dimension, because on an old bike there may be parts put on there from a different engine over the course of the years, and I don't know if the other heads are interchangeable or not. It won't hurt to verify the plug reach dimension.

Here's a link that should be very valuable for you. I would recommend downloading this and keeping it, and maybe print off a copy or two for your workshop.
http://www.pearsy.co.uk/Manual/RoyalEnfieldMaintManual.pdf (http://www.pearsy.co.uk/Manual/RoyalEnfieldMaintManual.pdf)
Title: Re: Lame Top Speed - Lean Condition???
Post by: High On Octane on May 09, 2013, 07:01:30 pm
Ace -  I pulled out the repair manual, it calls for a Champion L10.  I called NGK directly and you are right.  The correct plug for this bike is the B6HS, which does in fact have the threaded terminal.  Horray!!!    :D   I think I may have solved half my problems right there.  I'm picking up bigger main jets tomorrow after work, hopefully hit The Ton this weekend.

Scottie
Title: Re: Lame Top Speed - Lean Condition???
Post by: Bullet Whisperer on May 09, 2013, 08:16:44 pm
Sorry, Scottie - I misunderstood and thought you were talking about a 500 Bullet for some reason, but even so, try jets around the size I stated, they should help you. A late '50's Big Twin should be good for around 110 mph in tip top order. What gearing have you got - if you have 46t on the rear wheel, you need at least 20t on the front [gearbox]
 B.W.
Title: Re: Lame Top Speed - Lean Condition???
Post by: High On Octane on May 09, 2013, 09:46:28 pm
I never counted the gears so I'm not sure what's on there.  Good news!  Got to work and I have the plugs I need on the shelf.  Score!   ;D

Scottie
Title: Re: Lame Top Speed - Lean Condition???
Post by: Arizoni on May 10, 2013, 12:55:48 am
I was looking at some of the photos you've posted of your "Indian" and had a thought.  (Scarey, I know.)

Just looking at it, it looks like the pancake air filter you have mounted could be pretty restrictive.
While your out testing your bike the next time, you might remove the air filter and give it another try to see what happens.

I would be the last person to recommend running the bike without a air filter for very long but it would be okay for a one run test to see what happens.

If some noticeable gains in speed are found, one of the thicker filters (more depth between the back plate and the mouth of the carb.)  might be the answer to your lack of power.
Title: Re: Lame Top Speed - Lean Condition???
Post by: High On Octane on May 11, 2013, 05:41:17 am
Stopped at The Bonneville Shop on my way home from work today and picked up a #3 slide to replace the 3 1/2 and also picked up a 230 main jet to replace the 220.  Got home and slapped them in and was having trouble getting it to run right.  I so move the needle from the bottom notch to the middle and was better but idling high.  So I made a timing adjustment of about 2 1/2 degrees retarded and had it running, but it still wasn't running right.  But it's Friday night and I wanted to go to the Friday Night Hot Rod meet.  So I headed down the road, rode around for a bit and then stopped at the meet and hung out for a while and said hi to some friends.  When I went to leave, I damn near couldn't get the bike started.  It was spitting and popping and running like total shit to where I barely made it home.  WTF?!    >:(   "Thanks for making me look bad in front of all the Hot Rodders admiring you.  Stupid bike."  LOL  In all reality, stupid ME.

I get home and pull the plug and it looked like a good clean burn.    ???   Pull the drain on the carb to see if there was dirt, and it was clean.  WTF?????  Come to the conclusion that it's got to be timing.  Thankfully when I timed the bike dead nuts with the light I made timing marks on the rotor and trigger plate for the Thorspark ignition as well.  Get out my handy TDC tool (a section of coat hanger bent over with TDC and 3/8" Before TDC marks) and bring the piston up to 3/8" before TDC, look at the rotor AND I'M LIKE 20 DEGREES RETARDED!    >:( >:( >:(   The stupid auto-advance must of gotten stuck in the advanced position with out me catching it when I made my change, and then after warming it up and riding it and must of returned back to the normal position retarding it the 20 degrees or whatever it was.  Then after hanging out for a while the bike cooled down and when I went to go leave the bike said "screw you dumb ass"  and was just never able to get going fast enough to get the auto-advance to actually move forward.

So I moved the timing back to 3/8" Before TDC, but it was getting too late to be firing up the bike and pissing off the neighbors.  So tomorrow morning I'm going to go back out and play with the carb some more and see where I'm sitting.

ALSO, here's a pic of the spark plug situation.  The plug on the left is an Autolite 85 which crossed over from the Champion that was in there.  The plug on the right is the NGK B6HS that is correct for this motor.  Note the difference in thread length 3/8" compared to 1/2".  I also decided to change to a B5HS as the resister caps have reduced my spark considerably and needed a little more oomph from the plug.

(http://i6.photobucket.com/albums/y217/lethalinj/PlugDifference_zps7e97dbd1.jpg) (http://s6.photobucket.com/user/lethalinj/media/PlugDifference_zps7e97dbd1.jpg.html)

Scottie
Title: Re: Lame Top Speed - Lean Condition???
Post by: ace.cafe on May 11, 2013, 01:22:38 pm
Keep an eye on that B5HS hotter plug.
"Hotter" heat range does not mean "hotter" spark. All it means is that it is less capable to dissipate heat, and runs at a hotter temperature.
It could cause pre-ignition.
Title: Re: Lame Top Speed - Lean Condition???
Post by: ERC on May 11, 2013, 02:08:38 pm
Ace is correct, especially if your going for top speed then you probably want a B9ES.  ERC
Title: Re: Lame Top Speed - Lean Condition???
Post by: High On Octane on May 11, 2013, 02:53:06 pm
So are you guys saying that even though with the B6HS I could barely see a spark forming is irrelevant to how the bike is going to run?

Scottie
Title: Re: Lame Top Speed - Lean Condition???
Post by: ace.cafe on May 11, 2013, 03:08:13 pm
So are you guys saying that even though with the B6HS I could barely see a spark forming is irrelevant to how the bike is going to run?

Scottie

No, what we're saying is that the B5HS won't be any better because the heat range of the plug has absolutely nothing to do with the intensity of the spark.
If your spark is weak, you need a better coil, or whatever other part of the ignition system is not working properly.
And on top of that, if the heat range is too hot, the plug will run too hot, and potentially be a cause of pre-ignition in your chamber.
Title: Re: Lame Top Speed - Lean Condition???
Post by: High On Octane on May 11, 2013, 03:38:05 pm
I had great spark until I installed those stupid resister caps that apparently I have to have to operate the electrical system without damage.  What the hell is the point in those damn things anyways?  Maybe if I understood their role it wouldn't be so frustrating.  I just know I went from a fat blue crackling spark to being almost non-existent.

Scottie
Title: Re: Lame Top Speed - Lean Condition???
Post by: ace.cafe on May 11, 2013, 04:05:02 pm
I had great spark until I installed those stupid resister caps that apparently I have to have to operate the electrical system without damage.  What the hell is the point in those damn things anyways?  Maybe if I understood their role it wouldn't be so frustrating.  I just know I went from a fat blue crackling spark to being almost non-existent.

Scottie
The purpose of the resistors in the system is to reduce RF interference radiating off the ignition wiring. If you have a computerized igntion system, it is possible that the RF radiation "could" cause it to malfunction. That is why many electronic igntion systems say they require it.

Now, these resistors can cause a weak coil to seem too weak. It is VERY common on Bullets that have the stock Lucas coil, which is known to be a weak coil. It's not unusual for them to be about 25k volts max, which is okay without resistors in the line, but with resistors in the line it gets into marginal territory. With more than one resistor in the line, it might not work hardly at all.
On the other hand, a good Bosch Blue coil will often have nearly 40k volts max, which will easily overcome any of those resistors in the line, and give a nice spark.
There needs to only be one resistor in the line. If you have a resistor wire, you don't need a resister cap or resistor plug. 5000 ohms is the necessary amount, and that is the amount in each one of these resistor "thingies". So, don't stack them, and just have one of them at the most.

Other possibilities could be poor coil charging which could be linked to a faulty or weak condenser in a points system. Or to a weakness in that area with some other forms of electronic triggers. Or, a bad wire or bad connection somewhere. Or even poor alternator charging.

You might try using no resistors, but I have no idea if your electronic ignition system can handle no resistors in the system. It might cause intermittent faults or even failures. I have no experience with that ignition system that you have. I know that the Boyer system wants a resistor, but we have tried without it, and it worked.
So, it's up to you. I can't be sure what will happen with your electronic system.

Title: Re: Lame Top Speed - Lean Condition???
Post by: High On Octane on May 11, 2013, 06:54:17 pm
WHOOO!!!  SUCCESS!!!

HUGE improvement with the latest changes.  First of all, ice cold and it started on the 1st kick!   :D  After warmed up, I made some minor changes to idle and air screws and now crisp clean throttle response.  Revs like a champ.  Turned on the GPS speedo and headed out.  Man, the acceleration and throttle response is great!  Pulls hard in every gear regardless of speed.  I was even creeping in 4th gear at 25mph and never choked out when I hit the throttle.    ;)

Now for the fun stuff.  Went back out in the country, rolling at 25mph in 2nd gear I started to hammer on it.  Hit 55 in no time!  Pulled really hard until 75mph when I started to lose momentum.  BUT!  I hit 87mph for about a second!  Yeah buddy!  But basically topped out at 85mph.  Though, the bike pulled and felt great at 75mph without the motor working for it.  Upon return I did another test.  This time rolling at 45mph in 4th gear.  It only took 8 seconds to reach 65mph and hit 75mph within 15 seconds.

Conclusion:  The bike pulls great at all speeds and gears, and most importantly, I'm leaving the timing the fuck alone.    8)   The #3 slide and moving the needle to middle position made a huge improvement in idle and low and mid range throttle.  I'm good in that department and won't be making any changes there until I get a another hour or 2 on the bike and I will check the plug again.  Lastly, increasing the main jet from 220 to 230 definitely helped out the WOT and top end speed, but I think I still have room for improvement.  In theory, increasing the the main jet 1 size increased my top speed by 10mph, knowing my bike is capable of at least 95mph with age and altitude (110mph when it was new), I think I might try a 250 main and see where that gets me.

I will keep you updated when I make more changes.  Thanks everyone for you input and help!  I love this forum!

Scottie
Title: Re: Lame Top Speed - Lean Condition???
Post by: ERC on May 12, 2013, 08:11:22 pm
Was wondering Scottie if it runs after you charge the battery. You mentioned your alternator crapped out could be it will run lousy when the battery goes low and with the ignition you have I think it needs a battery to work properly? Glad it's running well now.  ERC
Title: Re: Lame Top Speed - Lean Condition???
Post by: High On Octane on May 12, 2013, 09:53:56 pm
The system seems to still be charging slightly at higher RPMs.  The last few time I've come back from a short highway ride the battery had had at least 13v when I shut it down.  Other than the first time it died on me I haven't let the battery drop below 12v and have only ridden about 45 minutes at a time.  The bike actually ran BEAUTIFULLY on  my way into with this morning. 

Scottie
Title: Re: Lame Top Speed - Lean Condition???
Post by: High On Octane on May 13, 2013, 12:12:43 am
So, here's the deal with the alternator.  The last couple times I drove to work, the battery dropped from 12.8-13v upon departure to 12v upon destination.  Though the last few times I jumped on the highway right next to my apartment, when I came back my voltage was about 13.2v      ???    So I topped off the charge at work before I left and headed home, knowing that if I stayed on city streets my voltage would again drop to about 12v by the time I got home.  Rather than taking city streets all the way, I detoured out of town and took the highway (back way) home for about 7 miles.  Got home, killed it, and Viola!  13.46 volts!  So as long as I keep the motor up at, oh say, around 3K RPMs (basically stay in a lower gear) the charging system does seem to be working.  I'll do a run or 2 with the head light plugged back in and see if anything changes.  Regardless, I still need to replace that alternator and rotor, the sooner the better.

I can't wait to have everything dialed in and ready for an actual ride.  Still having a lot of fun just rolling around town.

Scottie
Title: Re: Lame Top Speed - Lean Condition???
Post by: Bullet Whisperer on May 13, 2013, 07:55:48 am
Hi Scottie,
 If it is a Lucas alternator, chances are you have green/white [light green], green/yellow [mid green] and green/black [dark green] wires coming from the alternator. If you have and they are connected to the bike's wiring loom colour to colour, try swapping the mid and dark green wires around - this will give you more charge at lower engine speeds, but no extra charge at higher engine speeds. I suspect, though, that you don't have three separate wires anymore, as you say it is a 12 volt system.
 If you have a Boyer 'Powerbox' fitted, make sure the mid and dark greens are joined together and treated as one wire, the light green being the other, both of which connect to each of the two yellows from the powerbox.
 B.W.
Title: Re: Lame Top Speed - Lean Condition???
Post by: High On Octane on May 13, 2013, 05:48:29 pm
BW - It's the factory 3 wire hexagon stator wired up to a Sparx rectifier/battery eliminator.  I have it wired as you stated (and also the instruction that came with the Sparx) with the 2 darker green wires connected together to 1 yellow wire on the Sparx and the other lighter green wire connected to the other yellow wire.

But while were on the subject...  Does anyone know the difference between Lucas part # LU/47205 and part # LU/47205A???  Hitchcock's told me I need LU/47205A.  Roger at The Bonneville Shop told me he sells the LU/47205 and the rotor.  All I'll need to order from Hitchcock's is the adapter bracket.  That should save me a crap ton of money on shipping from having to have the alternator AND rotor shipped over seas.

Scottie
Title: Re: Lame Top Speed - Lean Condition???
Post by: Bullet Whisperer on May 13, 2013, 05:59:29 pm
Hi Scottie,
 I don't know what those different part numbers relate to, but, assuming the rotor you have is a Lucas [or Wipac] and still has strong enough magnetism to support itself and not drop, if you try to lift it by a spanner or screwdriver stuck to it, it should be O.K. - you could consider fitting an Indian Bullet stator, as these are O.K. [the rotors are crap, mind] to get the job done well and for less money than a new Lucas one.
 B.W.
Title: Re: Lame Top Speed - Lean Condition???
Post by: ERC on May 13, 2013, 08:14:25 pm
Same the 47205 is just cheaper than the A. What the bonneville guy said will work.   ERC
Title: Re: Lame Top Speed - Lean Condition???
Post by: ERC on May 13, 2013, 08:23:08 pm
Make sure you order all the screws nuts etc. when you order the adaptor bracket.  ERC
Title: Re: Lame Top Speed - Lean Condition???
Post by: High On Octane on May 13, 2013, 09:02:11 pm
Make sure you order all the screws nuts etc. when you order the adaptor bracket.  ERC

Thanks for the heads up, I would have assumed they came with.

Scottie
Title: Re: Lame Top Speed - Lean Condition???
Post by: High On Octane on May 18, 2013, 06:26:12 am
Round 734...

With my last carb settings I was able to achieve a best ever top speed of 87mph.  I know bike is better than that, so yesterday I picked up a 260 main jet to upgrade the current 230.  Bike was running really rich and was loading up so I dropped the needle to the lowest position and it was running better so I took it out for another top speed run.  Results were saddening.  Not only did I lose power but my top speed dropped to 84mph, and it took longer to reach that than it did to reach 87mph previously.  So I went back to the garage, made a quick $40 doing the rear brake pads on an '05 Hardley Ableson that took 20 minutes,    ;D ;D ;D   and went back at the carb.  I pulled out my manual that came with the new Amal and determined that the best move would be to replace the new #3 cut away slide and put back in the 3 1/2 cut away.  Did that and put the needle in the middle position and threw it back together, played with the screws for a few minutes and it was revving real strong.  Didn't have time to take another top speed run because I had to get to work, but it sure was running good on my way to and from work.  My butt dyno said that the acceleration felt the strongest yet, so I went on a side street close to home on my way back and opened it up a little bit.  Hit 70mph really quick, and then some asshole made a sudden lane change 100 feet in front of me with out a signal.  BRAKES WORK!!!

Talking to my local Brit Bike Pro today, Roger, I need to drop my needle jet from a 106 to a 105 and play with needle positions a little bit and I should be pretty damn close to where I need to be.

What and exciting adventure this is!!!

Scottie

P.S.  I had a customer come up to me today and say "Wow, it's been a long time since I've seen an Enfield /Indian."   Boy did that put a smile on my face.    :D  Also, I find riding my Indian to work is taking away from sales.  Every 10th customer or so "Hey!  Is that your Indian out there?!  That is a beautiful bike.  What year is it?  What size engine?  Blah blah blah........."  My co-workers give me so much shit about it.  LOL
Title: Re: Lame Top Speed - Lean Condition???
Post by: Bullet Whisperer on May 18, 2013, 10:06:31 am
Scottie,
 Please don't go for the 105 needle jet, I really doubt you need it and it may cause very weak, hot running, pinking [pinging] and even holed pistons and / or sieziure. If you must, try it and hopefully you will notice right away that it is too small and switch back to a larger one. As a yardstick, I am also heavily into Triumph Tiger Cubs and only some of the softer tuned later ones ran a 105 needle jet in their very small 375 Monoblocs, most Sports Cubs had 106 in a 376 size. I still would not rule out a 107 improving things for you.
 B.W.
Title: Re: Lame Top Speed - Lean Condition???
Post by: ace.cafe on May 18, 2013, 12:11:09 pm
Scottie,
 Please don't go for the 105 needle jet, I really doubt you need it and it may cause very weak, hot running, pinking [pinging] and even holed pistons and / or sieziure. If you must, try it and hopefully you will notice right away that it is too small and switch back to a larger one. As a yardstick, I am also heavily into Triumph Tiger Cubs and only some of the softer tuned later ones ran a 105 needle jet in their very small 375 Monoblocs, most Sports Cubs had 106 in a 376 size. I still would not rule out a 107 improving things for you.
 B.W.

B.W.
Scottie is at nearly a mile high in elevation above sea level in Denver, Colorado..
Title: Re: Lame Top Speed - Lean Condition???
Post by: High On Octane on May 18, 2013, 03:52:16 pm
Scottie,
 Please don't go for the 105 needle jet, I really doubt you need it and it may cause very weak, hot running, pinking [pinging] and even holed pistons and / or sieziure. If you must, try it and hopefully you will notice right away that it is too small and switch back to a larger one. As a yardstick, I am also heavily into Triumph Tiger Cubs and only some of the softer tuned later ones ran a 105 needle jet in their very small 375 Monoblocs, most Sports Cubs had 106 in a 376 size. I still would not rule out a 107 improving things for you.
 B.W.

B.W.
Scottie is at nearly a mile high in elevation above sea level in Denver, Colorado..


I also forgot to add that I have a nasty cackle when closing the throttle, but usually only cackles if I completely close the throttle (like between shifts or approaching intersections), indicating that I'm too rich in idle circuit.

Alright, I need to get some coffee in me and go for another top speed run.    :)

Scottie
Title: Re: Lame Top Speed - Lean Condition???
Post by: ace.cafe on May 18, 2013, 04:44:31 pm
You need to be watching what the spark plug readings are when you are doing this.
Title: Re: Lame Top Speed - Lean Condition???
Post by: High On Octane on May 18, 2013, 06:04:27 pm
Ace - The plugs actually looked great.  Even the right plug was carbon free with a normal burn.  Here's the kicker though, just finished with my latest top speed run, a lame 81mph.   :(   Pulled over to check the plus and make some screw adjustments.  And while looking at the carb and revving the throttle, mother effing puffs of smoke coming out of the bottom of the manifold.  Got home and sprayed some carb cleaner at the bottom of the manifold and it died almost instantly.  Hitchcocks has the gaskets for super cheap so I'm going to order those up and replace then before I make any more changes.

Scottie
Title: Re: Lame Top Speed - Lean Condition???
Post by: ERC on May 18, 2013, 06:21:54 pm
Scotty check to make sure the puff isn't coming from the bottom of the manifold where it bolts to the carb. Most of them have a small hole drilled in that area to drain out any fuel that may leak past the carb and roll into the cylinder when the bike is sitting. this hole keeps it from getting into the engine and washing the cylinder wall down. It could be another problem. If you have the hole drilled there tape it off and try again.  ERC
Title: Re: Lame Top Speed - Lean Condition???
Post by: High On Octane on May 18, 2013, 06:49:25 pm
It was definitely coming from where the manifold bolts to the cylinder.   But I will take a peak just to make sure.

Scottie
Title: Re: Lame Top Speed - Lean Condition???
Post by: ace.cafe on May 18, 2013, 06:52:15 pm
You can very easily cut that gasket out of gasket material.
Cork is a very good insulating material, if you want to cut one out of a sheet of cork gasket material.

Warning!!!!
Do NOT over-torque the nuts on that Amal carb mount, because Amals are known to warp the flange if you even look at them too hard.
Not kidding! Go easy on the carb mount nuts. But make sure that it is sealed and on there well. Just don't over-do it.
Title: Re: Lame Top Speed - Lean Condition???
Post by: High On Octane on May 18, 2013, 10:21:18 pm
Thanks Ace!  I actually keep cork gasket material in my garage, just didn't think it could handle the high temps.  Cool, looks like I'll be cutting new gaskets tomorrow.

Scottie
Title: Re: Lame Top Speed - Lean Condition???
Post by: High On Octane on June 07, 2013, 12:26:04 am
Alrighty!

So I finally have the top end squared away, and for the first time ever actually took a ride on the interstate, and then looped back around thru the country and even did a little dirt.  :D   The bike is running sooooo good.  Nice smooth power and torque as soon as I need it and no more cackling out the exhaust.  It's running so smooth and good I'm having a hard time believing this thing was built in 1958! 

While out in the country I decided it was time to see what it do.  The bike just barked to life as soon as I rolled the throttle open and she just started to rip!  I looked down and I hit an indicated 117mph!!!  I'm pretty damn sure that's good for 102mph actual!!!  I HIT THE TON!!!

AND, my neighbor just stopped by and have me a couple industrial sized bottles of red and blue loctite!

Scottie
Title: Re: Lame Top Speed - Lean Condition???
Post by: ERC on June 07, 2013, 01:17:21 am
You'll need em.   ERC
Title: Re: Lame Top Speed - Lean Condition???
Post by: ace.cafe on June 07, 2013, 01:45:24 am
Congratulations! Sounds like you're having lots of fun!
Be careful, and enjoy!