Jump to content

Why is rocker-arm end play such a revalation?


Huzband

Recommended Posts

I've seen this come up up occasionally in valve adjust threads, & it always seems to be a new concept to Boxer owners. It really came to light with me Sat. at Chris & Randy's Atl Tech Daze.

 

In the mid-late 70's, when I attended BMW Tech School at Butler & Smith, I learned the secret to truly quiet valves was getting the end-play correct. Since then, I've attended many rallys & events, & have met countless riders that have expressed, " I just did a valve adjust, & they're still noisy".

 

This has been going on for more than thirty years in my experience. Why?

 

I know I'm not the only one to know of this particular brand of tweaking. But at the Atl. Tech Daze, there were two Boxer owners that had never heard of this. I can only imagine how quiet their ride home was. :)

 

Anyway, why is this such a mystery to Boxer owners after all these years?

 

I know BMW has specs for this, but I've always disagreed. I'm sure I'll get flamed for this, but so what. Argue with experience all you want, if it makes you feel better.

 

BMW specs are too loose. You'll still sound like a mid-sixties VW going down the road.

 

Set your end-play to .002-004, & you'll live happily ever after with a quite motor.

 

If you need instruction, PM me. I'll gladly walk you through it.

 

I posted this here only because there are more Oilhead riders on this board than the other variations. This end-play adjustment is equally critical to Airheads & Hexheads.

Link to comment

You know you're pissing in the wind right?

When dealing with BMW kids it's all BMW specs or nothing.

Very few deviate from the directive. I think a lot of it comes from paranoia of the initial high dollar investment and the finger wagging of dealer servicing.

 

By the time the bike is out of warranty the directive has been firmly engrained in the psyche.

 

Momma would be proud of how well BMW holds the child under its thumb.

Link to comment

When dealing with BMW kids it's all BMW specs or nothing

 

You have a point. It was amazing to me to see the degree to which some of the guys at the Tech Day would go to to get a torque value on a fastener.

 

4nm for the ABS sensor on an R12 final drive? Two guys torqued theirs, I didn't. Guess who's didn't leak. :/

 

As for pissing in the wind, it won't be the first time. :grin:

Link to comment

I may be wrong (would not be the first time) but I think the specs. call for a min. of

.002".

How ever the max. (allowable) is substantially greater then .004".

 

When I adjusted mine, I set them to .002".

Link to comment

And I think the fault lies in the "greater" of the tolerance. As I opined yesterday, given that this is such a tedious process, if a dealers shop charged by the hour to perform the task to the minimum tolerance, we'd SCREAM at the cost. But it's one of those operations that, once done, it hardly has to be done again. I check end-play at every valve adjust, but rarely have to change it after the first time.

 

For the record, I don't check end-play with a feeler gauge. I go by "feel".

 

As long as I can feel them move, & see oil squish at either end, I'm good. If I hear a clunck, it's too loose. This weekend was the first time someone stuck a feeler gauge in there to see what the final result was.

 

A snug .003 was the tightest, & a loose .004 was the loosest. Outside .004 you could hear a clunck.

 

As for my bike, I still won't measure it, I'll just go by feel.

Link to comment
Anyway, why is this such a mystery to Boxer owners after all these years?

Well probably because as long as it is within BMW’s (admittedly very wide range) specification; it has no effect on the bike’s running, performance, life, etc. The noise is a subjective thing only.

 

This end-play adjustment is equally critical to Airheads & Hexheads.

What makes you say it's particularly critical on hexheads? The spec is the same. 0.05 - 0.4 mm.

 

And I think there is a real danger of getting the end play too tight. A hot engine if the gap closes too much and a rocker was to seize with a valve pushed open it would not be pretty.

 

It's only of late (last couple of years) that this whole thing of trying to quite a boxer valve train that was never designed to be quite to start with, has come into vogue.

 

 

Link to comment

Danny,

I don't know 'why' it's such a mystery. It is officially part of the 600mi checks but very few dealer techs even bother. I wrote this procedure up in 1995 for the IBMWR Oilheads tech pages.

 

Mick

Link to comment

What makes you say it's particularly critical on hexheads? The spec is the same. 0.05 - 0.4 mm.

 

I suppose critical is a subjective term here. Your correct that it has no effect on running, etc. But I consider it at least important to a quite motor.

 

And I think there is a real danger of getting the end play too tight.

 

Right again. And I have seen a few that were too tight. But, as a general rule, nearly every valve cover I've removed has revealed clattery rockers. And in doing this for more than thirty years, I've never had my adjustments cause a problem.

 

It's only of late (last couple of years) that this whole thing of trying to quite a boxer valve train that was never designed to be quite to start with, has come into vogue.

 

I'll disagree with that statement. My Dad was doing this adjustment at rallies in the early seventies, & I was doing them by the mid-seventies. We also performed this step on every Boxer that came in to our shop for service.

Link to comment

 

And I think there is a real danger of getting the end play too tight. A hot engine if the gap closes too much and a rocker was to seize with a valve pushed open it would not be pretty.

 

 

 

Something to ponder. The whole assembly will heat up, so the whole assembly will expand.

 

I think the rocker shaft assembly is steel, but I'm not sure because I never stuck a magnet on it. The head is aluminum, I believe.

 

The head should expand more than the rocker assembly.

 

 

Link to comment
Joe Frickin' Friday
I may be wrong (would not be the first time) but I think the specs. call for a min. of

.002".

How ever the max. (allowable) is substantially greater then .004".

 

Manual for 1100 oilheads says 0.002" - 0.015". That's quite a range.

 

I think it's not something most people bother to check, for a couple of reasons:

 

-noobs will follow the standard 6/12K maintenance list, which doesn't even mention end play.

 

-experienced mechanics are likely familiar with other engines in which rocker arm end play is not something that's adjustable.

 

The only time anyone is likely to become aware of the end play adjustment is when they're of a mind to make it quiet, in which case they start asking around.

 

The spec is intended to ensure longevity, not quiet operation. But when pursuing that adjustment with the intent of reducing noise, it certainly doesn't make much sense to go for anything other than the minimum clearance, i.e. 0.002".

Link to comment

Danny, first let me thank you for all your help on Saturday. You sure took the mystery out of the endplay adjustment for a whole group of riders.

 

I think part of the problem may be that not all of us have the proper tool that is needed to do this job!

\ tc08%20041.jpg

Link to comment

Hey Chris, I have one of those tools. And here I've been using wrenches and feeler gauges, and all I needed was my old axe... I suspect that a bigger splitting axe would be at the upper end of the specification?

Link to comment

I think part of the problem may be that not all of us have the proper tool that is needed to do this job!

\ tc08%20041.jpg

 

I think danny has got some sort of axe to grind with his BMW!

 

Andy

Link to comment

Given how tricky it can be to set this clearance, how critical is it that both the intake and exhaust sides be exactly the same clearance? Danny/Huzband did the left side, and I don't remember how close they were. I did the right side, and got my clearances to between .002-.003" intake and .003-.004" exhaust.

 

Getting both to exactly the same clearance seems a tad obsessive, but re-reading "Oilhead Rocker End Play Adjustment for Dummies" last night made me wonder if I should go in there again and try to get it even closer. On the other hand, I have a long history of making things worse by trying to go that extra step and make them perfect.

 

My clearances were somewhere in excess of .012" before making any adjustments, and I suspect that the difference between intake/exhaust sides were considerably more than .001"

 

Thanks again to Danny for showing how it's done; I had read OREPAD several times, and was a little intimidated -- especially the part about torquing the stud nut, then giving it another 180 degrees of rotation. Until you've actually done it, that's the sort of thing that has one imagining a loud "sproing" sound.

Link to comment

FWIW,I adjusted the end play for the first time on my R1100 this summer because I was tired of hearing the intermittant clap at slow rpm in parking lots and at idle. Adjusted to .003",world of difference. I had done airheads before so it was easy, I used the C-clamp method.

The adjustment also stopped the short rattle on cold start.

 

Steve

Link to comment
Given how tricky it can be to set this clearance, how critical is it that both the intake and exhaust sides be exactly the same clearance? Danny/Huzband did the left side, and I don't remember how close they were. I did the right side, and got my clearances to between .002-.003" intake and .003-.004" exhaust.

 

Getting both to exactly the same clearance seems a tad obsessive, but re-reading "Oilhead Rocker End Play Adjustment for Dummies" last night made me wonder if I should go in there again and try to get it even closer. On the other hand, I have a long history of making things worse by trying to go that extra step and make them perfect.

 

My clearances were somewhere in excess of .012" before making any adjustments, and I suspect that the difference between intake/exhaust sides were considerably more than .001"

 

Thanks again to Danny for showing how it's done; I had read OREPAD several times, and was a little intimidated -- especially the part about torquing the stud nut, then giving it another 180 degrees of rotation. Until you've actually done it, that's the sort of thing that has one imagining a loud "sproing" sound.

 

what torque did you use on the stud nut...20nm plus 180 degrees?

Link to comment

Selden, I wouldn't worry about getting them exactly the same. I think the clearances you have are fine.

 

Brian, you're correct on the head nut.

Link to comment

Yes, 20 nm + 180 degrees. 10 nm, then 15 nm, then 20 for the three torx bolts and the nut, then another 180 on the nut. It's much easier to do than to describe.

Link to comment

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...