Boxerworks.com

Video here: https://youtu.be/hua1GrpEl7Y

Ignore the visual part, it’s just a darkened ultra-vibration-enabled video of the top of the triple clamp coming down the road.

The sound is super accurate, though. Like, essentially exactly what I heard when revving under load / accelerating.

Is it just rockers that need adjusting? Do you suppose it might be something more?

kmisterk wrote: ↑Wed Sep 08, 2021 2:27 am Ignore the visual part

Real men can't do that.

That's a tough one to un-see.

gspd wrote: ↑Wed Sep 08, 2021 2:36 pm

kmisterk wrote: ↑Wed Sep 08, 2021 2:27 am Ignore the visual part

Real men can't do that.

That's a tough one to un-see.

*shrugs* I tried warning y'all twice lol. Next time I'll just edit out the sound and just add the sound to a black screen.

Thoughts on the rattle?

it doesn't sound like a classic rocker arm excessive play issue, but that's what I would first be looking at.

Rocker arm movement (vertical play) should be around .004" or about that.

Obviously, you need to loosen the valve lash adjustment nuts (check clearances first to see if that's also an issue).

.004" Intake
.006" - .008" Exhaust

kmisterk wrote: ↑Wed Sep 08, 2021 2:42 pm *shrugs* I tried warning y'all twice lol. Next time I'll just edit out the sound and just add the sound to a black screen.

BTW - The audio ain't exactly 'studio quality' either.

RPGR90s wrote: ↑Wed Sep 08, 2021 2:53 pm it doesn't sound like a classic rocker arm excessive play issue, but that's what I would first be looking at.

Rocker arm movement (vertical play) should be around .004" or about that.

Obviously, you need to loosen the valve lash adjustment nuts (check clearances first to see if that's also an issue).

.004" Intake
.006" - .008" Exhaust

I suppose it’ll make more sense when I open it up, but what clearance needs checking with the valve lash adjustment? Just the valve rocker itself?

gspd wrote: ↑Wed Sep 08, 2021 2:54 pm BTW - The audio ain't exactly 'studio quality' either.

Haha yes. Noted. I was using phone mic mounted in the middle of the handlebars. Some wind noise made it through. Hard to get proper sound bytes of it when it only seems to happen under load.

I’ll try and get better sound clips later this evening.

"I suppose it’ll make more sense when I open it up, but what clearance needs checking with the valve lash adjustment? Just the valve rocker itself?"

The rocker arm to valve clearance is separate from the up/down (vertical) movement of the rocker arms themselves.

Rocker Arm to valve stem clearance is .004" for intakes and .006" - .008" for exhausts.

Rocker Arm vertical movement is a subjective clearance but I've found them pretty quiet at no more than .004".

RPGR90s

RPGR90s wrote: ↑Thu Sep 09, 2021 11:11 am "I suppose it’ll make more sense when I open it up, but what clearance needs checking with the valve lash adjustment? Just the valve rocker itself?"

The rocker arm to valve clearance is separate from the up/down (vertical) movement of the rocker arms themselves.

Rocker Arm to valve stem clearance is .004" for intakes and .006" - .008" for exhausts.

Rocker Arm vertical movement is a subjective clearance but I've found them pretty quiet at no more than .004".

RPGR90s

Hmm. Trying to understand what you're referring to here, or at least understand the difference.

The Rocker Arm Vertical Movement seems to relate to the rocker arm itself, obviously. Vertical movement, in how much it moves in relation to its own resting position?

If you have a .004 gap, and only allow .004 movement, wouldn't the movement do nothing?

Vertical movement is along the axis of the rocker shaft. On your bike, there's not much you can do to change it, as the rocker stands pilot on the head. Earlier bikes, particularly /5, need the rocker shaft loosely clamped as the head studs get torqued.

I'm assuming that we're talking about a 1980 R100T here (a plea... please put the model and year when you ask a question so I (we) don't have to search back through previous posts to see what you ride... ).

On 'Rocker Arm Vertical Movement'... This is normally referred to as axial play or float in the rocker and refers to the rocker moving axially on the rocker spindle. I has little or no bearing on valve clearance. If excessive, it causes a rattling noise from the relevant heads.

On early (247 series) airheads, the play can (and needs to be) be set whenever the head studs are loosened... which is to say that there is a certain amount of adjustment available. On later (including 1980) models this ability is much reduced because the rocker pillar blocks are positively located in the head. There was a further change in (I think) 1985 where the rockers are fitted with a nylon washer to reduce noise and axial play is adjusted by the use of shims.

According to BMW the acceptable play for the first two rocker types is zero with the rider that the rocket must move freely. For the final type the float is quoted as 0.03 to 0.07mm.

So what do you do if you have the interim type which has virtually no adjustment? There are basically two approaches. BMW and the dealers would advise that you replace with the final type of rocker gear as used from 1985 which is designed to be shimmed... but... there is an alternative. If the interim type rocker isn't to badly and unevenly worn, it is quite possible to fit the shims from the final type of rockers to take up any excessive play without replacing the rocker arms, spindles and piller blocks. This represents an enormous saving money but it may not be quite as effective in reducing noise.

Rob