Topic: Transmission Rebuild - How much play is OK?

[odin836]

I'm rebuilding the transmission on my bike, all parts look good with little wear.
I am however a little concerned with Part Number 8 in the image below...

All components except this feel snug, with very little play / side movement.
I realise this is the only free spinning component, I'm just not certain...

The manual states very little about the tolerances.

Internal diameter of the cog is 24.73mm, external diameter of the shaft where the component spins is 24.97 (give or take my unsteady hand). 

Whats the general consensus on this??

[mystic_1]

Internal diameter of the cog is 24.73mm, external diameter of the shaft where the component spins is 24.97

24.94mm - 24.73mm = 0.21mm total clearance
0.21mm / 2 = 0.105mm clearance each side

0.105mm ≈ 0.004 inches

Sounds right to me on paper.  Does it feel loose on the shaft?

mystic_1

[odin836]

There is a little bit of play, but not much...
Its possible I am use to the solid feeling of the other components.

I think I have a used spare somewhere, but finding it will be another story...
If this one is within tolerance I'd prefer to not have to look through the spare's boxes...




Also, in regards to measuring the gear shift forks the manual states that the "fingers" can not be worn beyond 6.1mm.  Which finger?  Top and bottom?  Obviously in the photo below there is a big difference with K when compared to J and L.
Is this normal?

My understanding is D, E, F & J, K, L need to be 6.1mm+.  M, N, O needs to be less than 13.03.

[mystic_1]

See page 57 of the following PDF:

http://www2.tech.purdue.edu/At/Facstaff/mleasure/Personal/HondaCB750.pdf

Standard clearance is 0.04mm to 0.082mm (0.0016in to 0.0032in).  Replace if over 0.182mm (0.0072in)

If those values are total clearance (as I suspect) then your gear is out of spec.

I think your understanding of the shift fork tolerances is correct.

mystic_1

[odin836]

Is "K" meant to be less than "J & L" as per the above photo?
The manual makes no mention of difference betweek one fork to the next...
 

[mystic_1]

Is "K" meant to be less than "J & L" as per the above photo?
The manual makes no mention of difference betweek one fork to the next...
 

I don't know the specific answer to that, but I can say that based on the pics I think your shift forks are OK.  When they're worn you can see it pretty easily.

mystic_1