Unofficial Royal Enfield Community Forum

Royal Enfield Motorcycles => Bullet Iron Barrel => Topic started by: jonapplegate on August 20, 2007, 06:13:06 am

Title: 535 bore break-in
Post by: jonapplegate on August 20, 2007, 06:13:06 am
 I am thinking about installing the big-bore alloy barrel. Anyone know what kind of break-in speed and miles we are talking about?

Thanks,
            Jon
Title: Re: 535 bore break-in
Post by: dewjantim on August 20, 2007, 08:29:20 pm
Hey Jon, go to mototune.com and read their break-in procedure. A little controversial, but it works for me......Dew.
Title: Re: 535 bore break-in
Post by: Peter on August 21, 2007, 01:14:51 am
Which piston are you going to use?

Peter
Title: Re: 535 bore break-in
Post by: Thumper on August 21, 2007, 01:43:40 am
I am thinking about installing the big-bore alloy barrel. Anyone know what kind of break-in speed and miles we are talking about?

Thanks,
            Jon

I think a standard break-in would be sufficient. Go easy for about 500 miles, varying the throttle so that you don't hold it at one constant speed for more than a couple of miles.  Increasing or decreasing by about 5 mph for even a short sprint of 1/4 mile is enough to vary it under periods where you're pressured by traffic to go a constant speed. Avoid long, uphill grades.  Keep it under 45 for the first 100, under 55 for the next 400.

You can always be more conservative with the road speeds.

Matt
Title: Re: 535 bore break-in
Post by: baird4444 on August 21, 2007, 05:49:36 am
Hey Jon, go to mototune.com and read their break-in procedure. A little controversial, but it works for me......Dew.
Dew...  did you use this method on your Enfield??  I DO agree with it on a modern engine with real oil pumps with real oil pressure to keep every thing rinsed...
Maybe on a new crotchrocket....
 remember that these 50 year old designed machines don't really carry any measureable oil pressure; just flow...     
- Mike
Title: Re: 535 bore break-in
Post by: FiferWD on August 21, 2007, 05:56:06 pm
I'm also considering the 535 kit, but doesn't it come with a piston?

Referring to  the Freeway thread, would the increased power of the 535 yield higher sustained speeds, or would it just mean you could get to 55 mph faster?
Title: Re: 535 bore break-in
Post by: baird4444 on August 21, 2007, 07:03:13 pm
I'm also considering the 535 kit, but doesn't it come with a piston?
Referring to  the Freeway thread, would the increased power of the 535 yield higher sustained speeds, or would it just mean you could get to 55 mph faster?
ok...  this is fuzzy math but it almost makes sense...
the increase to the 535 is only 7%. Now if you ad that 7% to the 55mph;
 your present happy speed; you are up to almost 59mph...
is it worth it??
Just thinking out loud...  - Mike
Title: Re: 535 bore break-in
Post by: Leonard on August 21, 2007, 11:00:44 pm
ok...  this is fuzzy math but it almost makes sense...
the increase to the 535 is only 7%. Now if you ad that 7% to the 55mph;
 your present happy speed; you are up to almost 59mph...
is it worth it??
Just thinking out loud...  - Mike

Mike,
  I believe it is the increase in compression that gives the 535 conversion the extra ponies not so much the increase in CC's.  I couldn't tell why but I agree, your math is fuzzy  ;)
--Leonard

Title: Re: 535 bore break-in
Post by: RagMan on August 21, 2007, 11:09:03 pm
If you gained the extra ccs with the kit, and put a larger sprocket on, you could more easily sustain an increased top speed. But would the increase in speed be worth the outlay in monies for the 535cc kit and the larger sprocket?

I could see a definite advantage with the 535 kit, if one reduced the size of the sprocket, and hooked up a sidecar - that would give better pulling without sacrificing as much speed.
Title: Re: 535 bore break-in
Post by: Peter on August 21, 2007, 11:51:23 pm
Compression and displacement are different things and the math - well I was never good at that myself.

I have the alloy 535 and the forged 8.5:1 "acralite" piston.
The stock head is lapped to the cylinder.

There are several benefits: better heat dissipation, more torque and power, I would be surprised if I would see the need to decoke as much as with the standard setup.

Downside is that I need premium gas and had to fettle with the clutch.

As it is a forged piston, I just broke it in quickly and switched to synthetic oil after about 700 miles. I was also breaking in a new head otherwise I would have switched after 300-400 miles. I do an early (50-100 miles) oil change though, to get the inevitable shavings out as much as possible.

As far as I understand, cast pistons are a different matter for various reasons.
But I don't have any interest in these so I never bothered to find out the gory details.


Peter
Title: Re: 535 bore break-in
Post by: jonapplegate on August 22, 2007, 04:00:59 pm
Yes, I was thinking of the high compression 535 alloy piston and barrel set-up. I realize compression equals more heat but the alloy heat dissipation is better. I would probably add hi-po oil pumps before any big changes. I would think bigger bore and compression would improve top-end more than bottom end torque.   
Title: Re: 535 bore break-in
Post by: Peter on August 22, 2007, 06:48:22 pm
.... I would think bigger bore and compression would improve top-end more than bottom end torque.   

It's not that simple. There are many variables going into a well tuned, nice ride.
Higher compression and more displacement help out in a more general way.

Let's just say that the performance results are satisfying all around.

Peter
Title: Re: 535 bore break-in
Post by: dewjantim on August 22, 2007, 07:27:55 pm
Hey Jon, go to mototune.com and read their break-in procedure. A little controversial, but it works for me......Dew.
Dew...  did you use this method on your Enfield??  I DO agree with it on a modern engine with real oil pumps with real oil pressure to keep every thing rinsed...
Maybe on a new crotchrocket....
 remember that these 50 year old designed machines don't really carry any measureable oil pressure; just flow...     
- Mike
Even though our engines are 50+ year old designs they still have modern metals in the rings and bearings. And, yes, I did use this method. Have almost 6000 miles on my bike and it still runs like a top. Many top engine builders disagree with this method. The couple I have talked to (on the net) say to break-in every newly rebuilt motor easily. Even though they say that,  they wont answer when I ask them how they break in their race motors. Obviously, they must be talking out of both sides of their mouth. Saying break-in slowly, but knowing that isnt possible with a race engine. Only one time did I follow proper break-in procedure. In 1981 I bought a Honda 750F and broke it in per owners manual. It smoked for 2500 miles until the rings finally seated........Dew.
Title: Re: 535 bore break-in
Post by: Peter on August 22, 2007, 11:52:43 pm
Hey Jon, go to mototune.com and read their break-in procedure. A little controversial, but it works for me......Dew.
Dew...  did you use this method on your Enfield??  I DO agree with it on a modern engine with real oil pumps with real oil pressure to keep every thing rinsed...
Maybe on a new crotchrocket....
 remember that these 50 year old designed machines don't really carry any measureable oil pressure; just flow...     
- Mike

If your oil pressure is low, you must have one of the engines with a pressure relief valve (PRV) in the crank and it has failed. You will hear from your big end bearing shortly.
The Bullet big end bearing is a floating bushing bearing and critically dependent on oil pressure.
The correct opening pressure of the PRV is 35PSI (I heard) and everything would be fine if they wouldn't fail open (bad spring). Mine opened at 25PSI and I disabled it with a JB weld injection.
These valves were put in the 2001 to 2003 years and were subsequently abandoned.
You can check if you have one by taking out the oil feed quill bolt and gently pushing against the ball at the end of the hollow crankshaft (you need a stick). No give = no valve or failed valve maybe.

Peter 
Title: Re: 535 bore break-in
Post by: baird4444 on August 23, 2007, 02:58:04 am
Hey Jon, go to mototune.com and read their break-in procedure. A little controversial, but it works for me......Dew.
Dew...  did you use this method on your Enfield??  I DO agree with it on a modern engine with real oil pumps with real oil pressure to keep every thing rinsed...
Maybe on a new crotchrocket....
 remember that these 50 year old designed machines don't really carry any measureable oil pressure; just flow...     
- Mike

If your oil pressure is low, you must have one of the engines with a pressure relief valve (PRV) in the crank and it has failed. You will hear from your big end bearing shortly.
The Bullet big end bearing is a floating bushing bearing and critically dependent on oil pressure.
The correct opening pressure of the PRV is 35PSI (I heard) and everything would be fine if they wouldn't fail open (bad spring). Mine opened at 25PSI and I disabled it with a JB weld injection.
These valves were put in the 2001 to 2003 years and were subsequently abandoned.
You can check if you have one by taking out the oil feed quill bolt and gently pushing against the ball at the end of the hollow crankshaft (you need a stick). No give = no valve or failed valve maybe.
Peter 

Peter- I've got over 20,000 MILES on my 2003 bullet and I've been reading many of these groups for 6 years. The bush needs flow- NOT pressure. the roller bearings need pressure. Have you pulled your tappet cover while running??? Just a dribble...     it has been said that at lower rpms the oil pressure is still to low to measure, But flow or soaking is what proects the bush.
- Mike
Title: Re: 535 bore break-in
Post by: Peter on August 23, 2007, 11:53:06 pm
OK.

I have not measured oil pressure at the quill myself. Others have: about 50-60PSI (no PRV) when cold. Dropping to verrry low when warmed up.
Problem is that the pressure in that location is not the pressure acting at the big end journal oil feed which is dependent on the centripetal acceleration the oil column in the crankarm bore experiences and is conveniently RPM dependent. Devilishly difficult to measure. But one thing for sure: If it's air instead of oil in the crankarm bore, the effect disappears and your bearing goes  :'( The centripetal force is absent in the center of the rotating mass which is where the crankshaft bore (quill bolt!) happens to be. So no more suction from the accelerating oil in the crankarm when it is filled with air. The darn thing will not purge itself nor prime itself. In comes the oil pump which in the Bullet pumps every 8 revolutions (If I remember correctly) resulting in spikes of pressure. If you manage to get a pressure reading, it is because your measurement apparatus is properly damped to indicate something close to the pressure averaged over time.
The oil in the big end bearing constantly flows out into the crankcase and has to be replenished 1:1 or the bearing crashes. The bearing functions as a flow resistor so for any directional flow to occur, there must be a pressure gradient, however small because of: Flow x Resistance = Pressure (assumed an ideal unchanging liquid, same viscosity oil is good enough) Otherwise the oil gets squeezed out in both directions and the bearing crashes.
Apparently, when the Bullet engine is warmed up, measurable oil pressure in the crankshaft goes down rather dramatically because the resistance of the bearing goes down when warm. However, pressure will build up the moment flow through the big end slows down for whatever reason. Here is where a failed PRV comes in: It will prevent the vigorous purging which would inevitably occur in the normal condition. One could say that the original engineers walked a rather fine line and should have provided some excess oil pumping action to keep oil pressure up at all times and not balance oil needs of the bearing so closely with the pump capacity. But: The genius, the genius! The oil feed pump runs with minimal load in a warmed up engine and the correct oil! No parasitic power losses and decreased wear of the worm drive etc.!
I can already hear the devil's advocate: what about the inevitable wear of the big end bearing causing oil starvation by virtue of lowering the flow resistance? A new Bullet engine has the oil pump to nicely match the big end needs and after a few K miles it's no longer good enough? Programmed failure that would be! Ha!
The answer is that floating bushing bearings do not wear. No they don't. No No No They Don't. They operate without wear or fail within a short time. The genius, the genius!

Check this if you want some in depth plain bearing stuff:

http://mototuneusa.com/circular_logic.htm

So, plain bearings are critically pressure dependent to insure oil film thickness via directional flow at all times - not necessarily from the pressure in the supply system but rather on the effective pressure at the journal feed.
And roller bearings? They just need enough oil splashed at them. They also have little flow resistance (forget pressure) so HiVol pumps are probably ok but I'm not sure that they are needed when I'm thinking of my two strokes running fine on 50:1 premix.


Just some musings  :)

Peter