Bonneville America Forums Forums Technical Forums General Tech correct me if i'm wrong...

...but over time our valve clearances get smaller (closer) due to valve stretch and face:seat wear... right?

sooooo if i have one valve clearance that's .003mm over, it will soon close that gap and bring itself within tolerances... right?

Well, at .003 over, you are not getting the valve to open as far or as long as it should, so you lose some performance. I have no clue if the situation will heal itself over hours of runtime. I think not. Just me.

yeah, i get that. but the difference between putting it back together and riding or having it down another week waiting for parts depends on where it's doing its wearing.

I see where your coming.

It's gona bug you untill you get it corected,wait for the parts so you don't have to do it all over again.

I buttoned mine back up because of the length of time it takes to get the parts.It's goin in this week.No crush washers or o rings in western canada,can you belive this?I would think that they should have all parts on hand to do a simple valve adjustment on a 865 thriumph.They tel me that they haven't ordered these in over two years.I'm getting the idea that they just want the work.It's crap!

Makes you wonder if corporate Hinckley Triumph even cares about us purists any more as they market to mainstream motorcyclists.
I did my own shim service at 20,000km a couple of weeks ago and when I asked for the crush washers and o-ring for the oil feed line I was told by my local dealer that they didn't stock those o-rings.
I challenged him by asking - "so you don't replace those o-rings as Triumph recommends when you service customers shims?" His reply was he don't want to go there.
btw I got the right sized o-ring from my local bearing supplier for free and the crush washers for that oil line are simple over the counter copper washers available at any automotive parts shop. The copper washers my local Triumph dealer supplied were the wrong size anyway so I guess they aren't used to seeing them very often when they service customers bikes.
I now know that my valve clearances are correct and my bike hasn't been screwed around with by some pimply faced second year apprentice.

Oh, we are supposed to measure them??? I was waiting for mine to stop ticking when its hot and at idle Lose is good tight it bad. They are pretty hard to hurt though.

If there is a big wait ride it. You won't hurt it.

You also have shim wear, seat wear, and the top of the valve can wear as well, along with many variables. In short, No. It will not fix its self. .003 however is an extremely small amount, so if you decided close enough you are not hurting anything. .003 mm lager gap simply means tht the valve is not opening that same .003 mm at the maximum open possition. I suggest looking at the .003 mm feeler thickness, and ask your self how high performance is this motor? What am I attempting to accomplish? Am I going to be able to sleep if I leave it? (ocd question)

If you were too tight I would be concerned more because not closing can cause more problems; burned valves being the worst.

i actually replied to this yesterday, but apparently i forgot to click the continue button. i buttoned everything back up. i'll give it a few more thousand miles and i'll sleep just fine.

With the tolerance range 0.15 to 0.20 are you saying one cam is 0.203? Because the shims are sized .025 apart and .003 isn't far outside the margin of error.

But it ain't going to fix itself.

so those tolerances will increase over time rather than decrease. this is what i was looking for.

not necessarily, Lots of factors go into presicting what will happen. Could get better could get worse. I have done this several times, and have not ever seen a pattern. I have seen the exhaust on one bank need thicker shims while on the other need thinner, and the exact opposite for the intake on the same bike. There are far too many variables to take into account.
I always shim to the middle of the road as possible.

okay, thanks. that's what i needed. i'm close enough to being within tolerances that i'm not going to worry about it. absolutely when it's needed my goal will be dead center of the tolerances.