Saturday, March 28, 2009

Finally, no subjective "slight drag" when doing valve clearance checks!

My beloved Beemers, require that I check the clearances for their valves at set intervals. Every 5000 miles for Brigitta, my 1987 R80and every 6000 for Maria, my 2004 R1150RT.

I was first introduced to this maintenance task by Mike O, he was a mentor to me in such matters when I first got Maria and she was my only motorcycle. He taught me what to look for in terms of "a slight drag" when measuring the gap for the valves. Since then I'd done several valve checks, always thinking I'd retained the memory/feeling of "a slight drag".

Well, that proved wrong recently. I had taken Maria in to Pete Homan's indie workshop for surging issues and he informed me I was setting the valve clearances way too lose! I know, some of you will have heard or believe that "loose valves are happy valves" but the loud clicking noise does tend to prey on your mind. Not being the anal kind of wrencher, I'd put up with the clicking thinking or rationalizing acceptance of it under the "loose valves are happy valves" mantra.

Too loose though, and your subsequent throttle body syncs will be off as well. Not to mention, failing to check the end rocker play before even dinking with the valve clearance checks! Oh well, it was a lesson with a cost (Pete's fees) but well worth it and not too expensive.

So, back to the conundrum of defining what is "a slight drag". The objective is to adjust your valves so that the correct clearance is reported by the right feeler gauge but it's not too loose. So I'd done things where I'd feel just a slight rubbing feeling of the feeler gauge as I slid it back and forth in the valve gap. Very, very subjective.

Then I read online one method used by a fellow wrench: Measure your desired gap, then see if you can insert and move back and forth the next higher up feeler gauge! Its so simple, why didn't I think of that? Why didn't the guys whom created the online guides mention that? A slight drag is too subjective. Using the next higher gauge, quantifiable!

So this morning, I took the valve covers off Brigitta who's always had what seemed to me a loud ticking noise from her valves. In fact, Matt Parkhouse, the air marshall for Colorado Airheads had described it as " a bit clattery".

Sure enough, I found that I could insert the next higher gauge into the valve gap! For instance, on the intake valves, you're supposed to have a gap of .10mm, I could insert a .127mm feeler gauge! This was the same for the exhaust valves where you're supposed to have a .20mm gap, I could insert a .229mm feeler gauge! Arrggh.

So I undid the retaining bolts, adjusted the valves again so that the intake valves would allow a .102mm feeler gauge to move back and forth (a bit tighter feel than what I'd used before) but I could not now insert the .127mm feeler gauge!

Same thing for the exhaust valves, I adjusted the gap so that my .203mm feeler gauge could move back and forth in the gap but my .229mm feeler gauge could not even be inserted! I was much more certain, by using this method, that my gaps were correct!

I buttoned Brigitta back up and fired her up. She sounded as sweet as ever and I could just barely hear the valves ticking! Yes, they do tick, but this time she was not as "clattery" as before and I had to really listen for the ticking noise. Brigitta now sounds as "quiet" in terms of the valves moving back and forth as Maria does!

Took her out for a test ride, I could not hear any "clattery noise" as before and she rode sweetly through my usual 12 mile test ride course. Got her home, put the engine guards back on, this time using a bit of red loctite threadlocks since I keep finding the right side engine mounting bolt loose.

Did some cleanup that I'd missed from yesterday, and wiped her down. I'll be going for a ride in the afternoon after lunch. Quantifiable valve lash clearances! I am a happy wrench!


Jack Riepe said...

Dear Charlie6 Dom):

There is a reason why I ride a "K" bike. No valve adjustmets every 15 minutes! But my friend Dick has an "R" bike now. I will be able to enourage him in this new requirement.

But I will forward him this data to make things easier for him.

Fondest regards,

Charlie6 said...

I didn't realize K Bikes don't require valve adjustments....up until today's discovery of how to do them right, I would have considered going over to the "dark side" of beemers.....

gate valves said...

great blog. im glad i dropped by here.