Triumphrat

fridaylover

I have a T100 with 10500 miles on it, doing the service myself, valve adjustment is the only thing that bothers me. I measured the clearances today and all 8 of them were over the limit. These are the readings I got:

Exhaust Left to Right: 0.38mm 0.40 0.42 0.38
Intake Left to Right: 0.28mm 0.28 0.25 0.23

The recommended figures(haynes manual) are: Exhaust 0.25-0.30, Intake 0.15-0.20mm.

Is there something wrong with the valves, shims or my feeler gauges :-)?

What happens if I don't adjust the valves? What are the effects of excessive valve clearance?

My bike backfires a lot( BTW, I have Norman Hyde exhausts fitted with matching jets ) and the MPG is disappointing, 33-35MPG in the city. Is there a connection?

Any help will be greatly appreciated.

raproe

Those are reasonable numbers. When I adjusted my valves at 12000 miles I started out with:

Exhaust Left to Right: 0.36mm, 0.38, 0.36, and 0.46 (yes 0.46!)
Intake Left to Right: 0.25mm, 0.25, 0.2 and 0.25

If you don't adjust the loose valves you get more noise (my engine got a whole lot quieter when I got that .46 exhaust back in line), you reduce the duration the valves stay open (because the cam has to rotate more to pick up the extra slack), and you put more load on the cam and valve train (because you miss some of the acceleration/deceleration ramp on the cam).

The disappointing MPG probably isn't because of the valves but, if you fix them, you can eliminate that issue.

Rich

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sweatmachine

not to mention pick up a few hp!

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CAPTDON

They dont sound too bad to me either? I will adjust wnen the noise getstoo much rythem. My bud w/ BA has exhaust on the left w/ a good rap rythm- both valves. The rest sound ok. Its time then. Dont know when he will get to it?
Still ride all the time. Not too loud - just constant. Doesnt seem to bother him much?? Got 10500mi on it.

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CYNCRZR

The hardest part of the whole process is getting your hands on the right shims. You may get lucky and get to swap some. I have both the Haynes manual and the Triumph and it helped to be able to look at the pics in the Hayne's as well.

Take it slowly and methodically, & search the wiki for the Shim Calculator someone wrote, worked real well.

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ohiorider

Here's my old/new clearance figures. Although Triumph offers shims in .025mm increments, it is also possible to use shims from Honda, Yamaha, etc, that are the same diameter as those used by Triumph.

Since I already had the cams out, I didn't feel like waiting 3-5 days on Triumph shims, so I lived with the resulting clearanges using shims in .05mm increments.

Next time, it'll be easier, because I recorded the thickness of the shims I installed. The valves held their clearances well, in my opinion, for an engine with almost 22k on the odometer. I'd have to think that some of the guys on the Triumph assembly line use shims closer to the tight end of the spec than others.

T100 Exhaust Valves
Current Clearance 0.33 0.31 0.31 0.31
Current Shim 2.75 2.82 2.82 2.85
New Shim 2.8 2.85 2.85 2.9
Calculated Clear 0.28 0.28 0.28 0.26
Actual Clearance 0.28 0.28 0.28 0.28

T100 Intake Valves
Current Clearance 0.254 0.26 0.254 0.2
Current Shim 2.8 2.82 2.86 2.9
New Shim 2.9 2.9 2.95 2.95
Calculated Clear 0.154 0.18 0.164 0.15
Actual Clearance 0.154 0.21 0.18 0.18

Bob

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2003 T100 (790cc) Lucifer Org and Silv: 122/42 jets, TORs, 17T, UNI filter, no AI, Polaris bellmouth, Metzeler ME880 tires, Progressive 440 shocks (105/150 springs),11-1126 fork springs, gaiters, MotoTwin low bars, 6024 lamp, htd grips, 12v outlet.

Anchorbend

I had my shims done by my dealer at 12.500 mi.. He used 8 shims which were all loose. No telling how close they were coming from the factory.

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raproe

I suspect Triumph lets a few get through. When I had the 500 mile check done, the dealer said that one exhaust was already pretty loose and would need to be fixed at 12k. I suspect it was the 0.46 one. Hopefully that one will be settle in and still be OK at 24000 miles since it required the largest shim Triumph has to bring it into spec.

Rich

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"....by its very nature, a single-tracker is in unstable equilibrium, i.e., it cannot, when stationary, stand up by itself."

drlapo

how do valve clearances grow or loosen? in 40 years of working on bikes I have never seen a healthy engine increase its valve clearances; they always tighten as the valve recedes into the valve seat

Boddington

Valves and seats wear usually together depending upon materials, and tighten tolerances. (normal wear and tear of an engine) Going loose vs tight is quite a mystery to me too.

Titatium valves had issues on some dirt bikes. Husky and Honda had these issues, due to using titatium and steel seats. No one knows why Yamaha doesn't have this issue, but they say it could be because of their 5 valve technology putting less stress on the valves.

Our Bonnies are running stainless steel valves? Anyone know?

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