Offset Front Sprocket (In Search of...)

Started by junior varsity, June 23, 2011, 01:59:47 PM

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junior varsity

not clear on how to measure outward to find the needed offset distance since there's no common reference point...

and I don't own no fancy lasers that aren't already attached to zompocolypse rifles.

ducpainter

Quote from: j v on June 23, 2011, 04:47:37 PM
not clear on how to measure outward to find the needed offset distance since there's no common reference point...

and I don't own no fancy lasers that aren't already attached to zompocolypse rifles.
A straight edge from the rear sprocket to the standard front...

measure the distance it misses by. ;)
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stopintime

Quote from: j v on June 23, 2011, 04:47:37 PM

and I don't own no fancy lasers that aren't already attached to zompocolypse rifles.

They are quite affordable. Batteries ARE included ;D
252,000 km/seventeen years - loving it

junior varsity

Quote from: ducpainter on June 23, 2011, 04:53:53 PM
A straight edge from the rear sprocket to the standard front...

measure the distance it misses by. ;)

guess my warped ruler is not going to be helpful. Time to invest in a quality steel rule more than a foot long.

I suppose the rear sprocket will also need to be bolted to the sprocket carrier, cush drives installed, and everything tightened up correctly... drat. I don't have cush drives yet.   Had thought about waiting until i knew whether or not the rear sprocket was the same as a 748/996 or also "unique". hmm....Can't exactly walk down the street asking folks if they'll sell me some cush either...

ducpainter

Quote from: j v on June 23, 2011, 05:29:06 PM
guess my warped ruler is not going to be helpful. Time to invest in a quality steel rule more than a foot long.

I suppose the rear sprocket will also need to be bolted to the sprocket carrier, cush drives installed, and everything tightened up correctly... drat. I don't have cush drives yet.   Had thought about waiting until i knew whether or not the rear sprocket was the same as a 748/996 or also "unique". hmm....Can't exactly walk down the street asking folks if they'll sell me some cush either...
Yup...all that...and the swinger needs to be shimmed to align the front and rear wheels too.
"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."



junior varsity

sumpregnant dog. that means the motor needs to go into the frame. and the triples need to go into the frame. and the forks need to go into the triples. and the front wheel needs to go onto the forks. and and and and and... *forehead smack*

Speeddog

#21
Quote from: j v on June 23, 2011, 06:02:02 PM
sumpregnant dog. that means the motor needs to go into the frame. and the triples need to go into the frame. and the forks need to go into the triples. and the front wheel needs to go onto the forks. and and and and and... *forehead smack*

Welcome to custom motos.  [bang]

Give Jeff at Monsterparts a call, I think his wife has an M750 with the Febur kit on it.
You may be able to find the original source that way.

Failing that, a pocket could be cut in a standard sprocket.
But sprockets are generally case-hardened, so the first .060" or so of material doesn't come off easy.

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Desmo Demon

#22
Quote from: j v on June 23, 2011, 03:12:12 PM
It looks just like this little guy:

Looks like the ones that are on the '87-'88 Ducati Paso 750, but they are only offset by 2-3 mm. A friend in Germany had one made with a custom offset, but it cost him about $150.

This is the only picture I seem to be able to find of one, so far...


And this is a diagram of one. I believe this is from somewhere on the JT Sprockets website...




Edit - OK. I just found a picture that my friend had posted on another forum. The sprocket on the left is the stock Paso 750 sprocket, and the one on the right is the one that he had made for a custom application for about $150.


Places I've been on two wheels:

IBA #32735

junior varsity

That JT might just do the trick.  For $22-25 its worth experimenting...

stopintime

I'm having a 4-5mm allignment problem myself.... (Wieres carrier and sprocket)

What decides the offset - where the plate sits or the depth of the sprocket?
252,000 km/seventeen years - loving it

DarkStaR

Quote from: stopintime on June 26, 2011, 11:22:14 AM
I'm having a 4-5mm allignment problem myself.... (Wieres carrier and sprocket)

What decides the offset - where the plate sits or the depth of the sprocket?

The  (surface) plane in which the plate mounts in relation to the teeth.

junior varsity

What carrier is it?  Is there a different output shaft length on the superbikes than on the Monsters? (if so, I'm so very close to already splitting the cases, if one could simply swap the trans for a SBK set to get the proper length and avoid needing oddball sprockets in the future, I'd do it. I've already got all the gears on the LH and RH sides removed...  and they've been that way for some time - I keep thinking ProItalia surely has to have my bearings and such in stock for the driven gear, but apparently I'm a very low priority...)

DarkStaR

Will the BIG nut (1KDS) output shaft fit? Seems easier to shim out a sprocket with that set-up.

junior varsity

I'm not in the garage currently, but iirc the output shaft is not threaded on this bike, but I will look at the 02 900 trans shaft I have to see what its configuration is (sure would be neat if I already had it...)

stopintime

Quote from: stopintime on June 26, 2011, 11:22:14 AM
I'm having a 4-5mm allignment problem myself.... (Wieres carrier and sprocket)

What decides the offset - where the plate sits or the depth of the sprocket?

Forget about it - I just made a fool of myself with the laser tool. The beam exits 5mm from the surface of the rear sprocket, of course it's going to hit the front sprocket 5mm left offset.

A shame really - it would have been cool to fix this with a Paso sprocket and some work on the rear set-up.
252,000 km/seventeen years - loving it