Valve clearances - race bike

[StrayAlien]

Hi all,

Just got the heads back on the engine after top end refresh - time to check clearances.

I was all set to go then something struck me ... are the clearances the same for a race bike vs a street bike?

[CMSMJ1]

The HRC manuals have them a smidge loose than std clearances..

[StrayAlien]

Doh! Thanks. RTFM. I have the translated-to-English manual, but at midnight last night after an evening in the garage and a few sherberts I didn't thihk of that!

Cheers.

[dobbslc]

I set my clearances a bit looser and all seems fine.
I think as things get hotter when thrashed the clearances can tighten up so I set mine slightly loose.

[StrayAlien]

..... the HRC manual has EX clearances tighter than the Honda manual -

HRC is 0.20 +- 0.02 ... vs Honda 0.21-0.27

Any thoughts?

Also, my EX where all okayish (0.20-0.23). However, all except one IN was waaay to tight. Most were 0.10 or 0.11. I have no idea when they were last done (I have not had it that long) .. but their consistency either means a) they were done like that on purpose, or b) they've all worn at the same rate.

Again, any thoughts?

[Neosophist]

..... the HRC manual has EX clearances tighter than the Honda manual -

HRC is 0.20 +- 0.02 ... vs Honda 0.21-0.27

Any thoughts?

Also, my EX where all okayish (0.20-0.23). However, all except one IN was waaay to tight. Most were 0.10 or 0.11. I have no idea when they were last done (I have not had it that long) .. but their consistency either means a) they were done like that on purpose, or b) they've all worn at the same rate.

Again, any thoughts?

Too sleepy to think now but the HRC bikes have different cams and internals, perhaps somethign to do with the duration of the cams, could probably be wildly wrong

[magg]

Agree with Neosophist, you are comparing apples and oranges. IMHO would only use HRC TT F3 figures if I was using all the HRC stuff.

As for your inlet figures, may be they were all done wrong.

Interestingly from info I have, only the HRC F3 TT uses special cams and clearances, all the other HRC hot rod versions of the NC30/35 do not list special cams or clearances.

[StrayAlien]

Thanks, I suspected it might be as such. Next question the ... !

The part catalogue shows two part numbers for each shim size (bike is a '93). For example, the following parts are both 2.425mm shims.

14950-KT7-000
14950-KT7-013

And all sizes have that pattern. A 000 and a 013. Are they both the same?

[Yakama]

I think a change in the end of a part number like that usually means the supplier has changed

[magg]

Bought my shims from Precicion Shim Melbourne 97230199 for $6 ea in 2011 about half then Honda prices.