Calling All Gearbox Gurus . . . .

[Rob Farmer]

Hookster posted this in one of the other sections today. Very appropriate for this thread.

http://www.gunsmoke.com/motorcycling/r100gs/tranny/index.html

 

[BillN]

Why do you want to change what God has created?

 

[seancb]

had a look at hpn website and it was that no change is needed on all gses made after 82 so no other bits are needed Sean

 

[Voyager]

Hookster posted this in one of the other sections today. Very appropriate for this thread.

Thanks Rob, very interesting.

I suspected that they were playing with tooth design in order to produce one tooth less on the output shaft whilst keeping all other dimensions the same. Cunning stuff.

It didn't make much sense to me at the outset and I was wondering if the 'explanation' on the HPN site had lost something in the translation !

I'm glad I don't have to change the gear on the layshaft . . . I don't have a 30 ton press either (though I have been coveting a 50 ton press in my local Engineering Supplies Store ).

I don't follow your logic re. the size of the layshaft gear when driving fifth gear . .

Its simply a 'pass-through' as the layshaft speed is irrelevant.

one tooth on the input turns one tooth on the layshaft which turns one tooth on the output shaft. As only the input shaft speed (= engine speed) and output shaft speed (= drive shaft speed) matter, the layshaft gear could be any size.

It does matter on gears 1 to 4 as the drive is via the layshaft . .

Input shaft to layshaft = a fixed reduction.

Layshaft to output shaft = a further reduction depending on which cluster is engaged.

Or is there something else I don't understand ?

Thanks for all your help, its been very educational.

I hope all the others think so too

Bob.

 

[Voyager]

A Conclusion:

Well, 'Seancb' turned up at my place today and we swapped his re-built gearbox back in.

All looking good, so he had a quick bimble around the yard . . . .

The box seemed fine - but his exhaust was shot .

Fortunately I had an old silencer in better condition than the one on the bike so a bit of 'fettling' was done.


So at 17:00 he was off, back to 'The Borders'. Hopefully he got home safely.

I'll be interested to hear how he gets on with the tall fifth gear.


I've now got a spare (tested) Paralever box again




Bob.

 

[seancb]

gear box

just like to say that the taller 5th gear works well you can now sit at 80 with last less revs and i got back fine Thanks to bob for the works