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Valve Clearance Questions

5K views 13 replies 4 participants last post by  Vince Accardo 
#1 ·
I am currently tearing down a 2007 Daytona 675 for track purposes. I am checking the valves and found the intake to be within spec of .14 and .15mm. On the exhaust side I am finding the clearances way too tight all at around .20mm. The service manual calls for .275-.325mm. I pulled the cam followers and they all have fairly typical shim sizes from my minimal knowledge. They are .258, .260, .265 and .270mm. Now, doing the math means that I would be getting shims in the .158-.170mm range roughly. Does that sound strange to anyone else?
 
#2 ·
They are .258, .260, .265 and .270mm. Now, doing the math means that I would be getting shims in the .158-.170mm range roughly. Does that sound strange to anyone else?
It is normal for them to tighten up over time, especially the exhaust valves since they are subjected to a very hostile environment. The repeated opening and closing slowly deforms the face of the valve and seat in a way the tightens clearance. How many miles does the motor have on it?

Since you have it apart, I would run a compression test or better yet a leak down test to check to see if any are burnt.
 
#3 · (Edited)
It has 14k on it. But that is what I have been told by a seller so who knows. I bought it under the impression that it had an air leak at the throttle body boots. The seller had a low side crash and lost interest in the project. It started up fine when I went to pick it up but it was a little rough. I took his word for the leaky throttle bodies. I got it home and it started but stopped running after three seconds. Then started and ran for two seconds. Now it won’t start so I’m tearing it down. I bought a Motion Pro compression test kit which I was told would work, but the brass hose crimp doesn’t allow the o-ring to seat and create a leak free union. So I’m only getting 50psi per cylinder. I am going to make a custom fitting today to remedy that and get a good reading. In the meantime I started looking at the valves, etc.
 
#4 ·
That seems really low mileage to have the exhaust valves that tight. Mine were in the same range, but my bike had about 55k kms on it when they were that tight. And mine does more track time than street time.
 
#5 · (Edited)
That’s what I thought also. I was able to modify the compression test kit to work. They are all in the 190’s. So now I need to determine why the exhaust valves are so far off. Everything looks clean, no mushroomed heads, etc. So the question still remains, why in the world are they so tight already? I am going to pull the head just to double check that it is seating correctly, etc.
 
#7 ·
I wanted to pull the head off mainly to just be completely sure that there were no underlying issues. I won’t be taking this bike to a track anytime soon, but when I get there eventually I want to be confident in it. Especially with the hard starting issue it had. I was concerned there may be a cracked valve or something worse. For the $66 head gasket I can rule these things out for now. And now check the bottom and top end off of the list of potential problems. I’m going to strip the majority of the engine down while I’m at it and replace all of the seals, etc. I might even keep my eye out for a 2009+ oil pump while I’m in here. The billet oil cooler is on order from England so I’ve got a little time to play.
 
#10 ·
For the $66 head gasket I can rule these things out for now.
Technically you need to replace the head bolts as well according to the service manual.

And now check the bottom and top end off of the list of potential problems.
Great idea.

I'm going to strip the majority of the engine down while I'm at it and replace all of the seals, etc. I might even keep my eye out for a 2009+ oil pump while I'm in here.
I would definitely update the oil pump, pressure relief valve and pan gasket/baffle.

The billet oil cooler is on order from England so I've got a little time to play.
Unless things have changed that is not an oil cooler. Please see following thread for discussion:

https://www.triumph675.net/forum/showthread.php?t=85225&page=3
 
#8 ·
You are right to think that a ~160 shim is way off. But I think the shim you're coming up with is incorrect; your math is wrong and your shim number vs. thicknesses is also off. e.g. a 260 shim is not .260mm, it is 2.60mm. Could have been a typo tho.

If measured exh clearance is 0.20mm, target (avg) is 0.35mm: the difference is 0.15mm. If you currently have a 260 shim (2.60mm), then your new shim is 245 (2.45mm). e.g. 2.60mm - 0.15mm = 2.45mm.
 
#9 ·
One more thing: Triumph's EXH spec range is narrow compared to most bikes. As a result, Triumph has intermediate sized shims which you won't find in the usual kits like HotCams. Just something to be aware of. No idea if you can get them anywhere other than Triumph.

255 (2.55 mm) Normal increment
258 (2.575mm) Triumph half size
260 (2.60mm) Normal increment
etc...
 
#11 ·
Triumph also does their increments in 0.05mm, it's just that their increments are directly between common shim sizes. If you really want to be precise you would need both common and Triumph shims.
 
#13 ·
Lots of good info here. And you are correct, I did my math wrong. I figured it out a few minutes later and tried to edit the post so that I didn’t add any confusion. I ordered the shims from Triumph on Friday morning along with the head bolts.

The heat exchanger is definitely a preventive measure item because I had read about the nightmares of coolant mixing with oil in track applications. I’ll do some more research on them before I run it. I am a rookie track rider coming from a dirt background and just want to build something reliable to test the waters on the track.
 
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