Scooterotica

Needing advice here I'm assembling an engine using a new SIL 200 case. Assempled the gearbox with no problems but when I tightened the clutch center nut the inner basket locks solid with the outer sprocket. I've stripped it all down several times now, the shims are all in place and I've checked them against the profiles in Stickies book. I'm using a new 47 tooth outer basket but if I try another (46 tooth) it is fine.

The only thing I can think of is that the new clutch sprocket is slightly deeper, anyone ever come across this?

The other though I had was that the clitch shim is quite large in diameter and it's probably that which is binding on the outer edge of the boss which holds the clutch bush, maybe if it was the same diameter as the bush??

Cheers in advance

Colin

coaster wrote:The only thing I can think of is that the new clutch sprocket is slightly deeper, anyone ever come across this?

more than once... compare the height of the centre of the crownwheel on both the 46 & 47. You'll probably find that the 47 is deeper, so when you're tightening the centre nut, the spider is locking down onto the crownwheel, not allowing this to be spin freely...
solution is to take a bit off the back of the crownwheel, obviously keeping it square, and probably not that much..
the shim is nothing to do with it, if it's the right size, all it does is move the whole assembly in or out to align the chain with the front sprocket.

btw, should be a few scooters in quidenham mon pm, then stop at wymondham on the way back, be good to see you if you have the time

actually the shims can have quite a lot to do with it...
always rebuild and set up with a new one ,cos old /worn and grooved ones can make all the difference ..
as per stickys book..the inner spider boss should protrude through the bell by approx .1mm.
a worn shim can certainly cock this up...

sean brady scooters wrote:as per stickys book..the inner spider boss should protrude through the bell by approx .1mm.
a worn shim can certainly cock this up...

That confirms it, the inner spider boss is flush with the outer sprocket If I try it with a spare 46 spocket it protrudes very slightly.....I couldn't see any reference to it in Stickys book or the LCGB workshop section. They both mention shiming for chan alignment though.

Do the spiders come in different lengths too? only this sprocket has been used before although not on my scoot.

Cheers

Colin

i had a simular problem with a new crown wheel and it was the shoulder that the bush sits in,it was 1mm too high, my mate pulled his hair out for weeks over that,supplied by resurection scooters!. took john from JB to finaly work out what was wrong!! put a new SIL one in problem sorted.

Update, I filed the center boss down untill I had 1mm of inner spider boss protruding and it still locked up. After much head scratching I deduced that the phosfor broinze bush was too long so filed that down as well and the jobs a good'un :bouncyeng: I think what was happening was that as the nut was tightened the bush distorted and squeezed the spider boss that runs in it.

Anyway thanks for your help guys it pointed me in the right direction

colin

coaster wrote:... 1mm of inner spider boss protruding.

1mm is quite a lot colin, as sean says

sean brady scooters wrote:...the inner spider boss should protrude through the bell by approx .1mm.

0.1mm is nearer...
too much and the crownwheel will rock, and cause unnecessary chain/sprocket wear...

onwards to the next issue now...

byron wrote:

coaster wrote:... 1mm of inner spider boss protruding.

1mm is quite a lot colin, as sean says

sean brady scooters wrote:...the inner spider boss should protrude through the bell by approx .1mm.

0.1mm is nearer...
too much and the crownwheel will rock, and cause unnecessary chain/sprocket wear...

onwards to the next issue now...

Yes, cheers Jarv, the next issue is figuring out what's missing from the kick start so that I can get it ordered with some chance of it being here for Friday then I should be able to gert it running, sort the wiring and get it mot'd. THEN I get to find if it will pull the gearing

I had hoped to have it running this weekend but it's been one problem after another, stator wires had melted, the new indian fan cowl fouled on the new indian fan I'm goiung to bve running in on the way to thge ferry at thgis rate

coaster wrote:...the next issue is figuring out what's missing from the kick start so that I can get it ordered with some chance of it being here for Friday

use Scooter Restorations, they deliver on time.
If you have no luck, give me a shout and I could bring some bits to you on saturday if you're about.

byron wrote:

coaster wrote:...the next issue is figuring out what's missing from the kick start so that I can get it ordered with some chance of it being here for Friday

use Scooter Restorations, they deliver on time.
If you have no luck, give me a shout and I could bring some bits to you on saturday if you're about.

Yes SR will have most of the stuff I need but not all more's the pity. I'll certainly give you bell if I forget something, I already raided Jon's shed on Saturday. I'll be in next Saturday working like fek on the scoot and hopefully having it running, visitors very welcome with or without parts