Gearbox spacer LC v YPVS

[andybush]

Hiya

Does anyone know the difference between a LC gearbox spacer compared to a YPVS

from memory the LC one is narrower because of the difference between a 530 chain and a 520 one.....but how much narrower is it ?

Thanks

Bushy

[rich]

Bushy, I think the YPVS spacer is nearer 5-6mm wider than the LC. The width difference between 520 and 530 sprockets is only 3.15mm but the YPVS chain run is also further away from the motor.

I had to fiddle with the chain run on the Yamagamma and used an LC spacer plus an old clutch thrust washer either side of the sprocket to get it right. I was using a Yam wheel though.

[andybush]

Ah cheers Rich.
That news is just as the doctor ordered ....Spondons rear wheel is in and the front sprocket needs to move inward by 5mm to get the chain run bang on..

sounds like a LC spacer will do the trickerty trick

now where can I get a spacer from.?

if I am on 25posts now..then maybe I can post a wanted add

muchos gracias

Bushy

[rich]

No worries, the LC spacer is p/n 90387-25192 and Fowlers (am I allowed to say that??!) are showing it available to order. Only a couple of quid too Or I guess you could get someone with a lathe to shorten a YPVS one? You'll also need a couple of the thick clutch thrust washers to go between the sprocket and nut or it'll bottom out before it's tight.

[bare]

Odd fitment IMO. A Valvie engine in an LC frame using a Bicycle thin (oem) LC rear wheel needs the LC spacer (it's shorter) and a ~3mm spacer on the output shaft to keep the engine sprocket nut from running out of threads before adequately tightening the sprocket down. Its not the chain difference that's the issue... it's that the LC wheel sprocket is further in. Both inner chain plates would be inset to the same distance, regardless if 530 vs 520 was the base issue. Width of a 530 is 1/8" wider than a 520 (30 = 3/8", while 20 equals 2/8" ..do you see the 1/8" correlation as the numbers 30 and 20 ? ).. Measured between side plates of the chain.
Seems your 'spondon' wheel is erm.. Thinner, or at least of notably thinner hub/sprocket dimension than even a Stock LC one then.. ergo the 'odd'.

[rich]

Bare, it also depends on where the engine sits in the frame. My Yamagamma was running a 4.00 rear wheel with 140 tyre and the chain run still had to come inwards to achieve alignment.

[andybush]

The engine sits 11mm off centre, so guess this is why the gearbox sprocket needs to go inward.
Wheel is centred and the cush drive is as far outward as can go. Dictated by the sprocket studs clearance on the swingarm.
This is a 4.00 rear wheel too..

[andybush]

Thanks to Dave MuttsNuttsenhelper, I can now confirm

YPVS spacer 19.3mm

LC spacer 14.3mm

Houston.....we have chain alignment :-)

[rich]

Happy days...............