S2R g/box sprocket realignment?

Bitza · 31-03-2019, 06:51 PM

Hi all, OK welcome to my latest nightmare, I'm fitting a S2R 1000 lump to my 1994 bike and have a bit of a problem with the sprocket alignment, which basically stems from the original offset of the rear sprocket to wheel centreline of the respective original wheels. The result is that the situation I now have is that the gearbox sprocket is 5mm outboard of the rear wheel sprocket, and there seems little opportunity to alter the rear sprocket, which leaves the the g/box sprocket. Has anyone out there any experience they can share? I'm wondering if the spacer inboard of the sprocket could be shortened by 5mm to bring a standard sprocket in by the same amount (so that subsequently replacements can be the standard item). All thoughts welcome, Bitza.

Mr Gazza · 31-03-2019, 07:13 PM

Not sure if you have the same kind of sprocket retainer as a 900, but you probably know that the 2000 M900ie has a unique sprocket for that year. It has bosses on both sides and I believe it sits 5mm further inboard than the other 900s.

I couldn't get the right sprocket for mine when I last changed sprox and chain, so I made a 5mm spacer for a standard sprocket and it works fine.
It was simple to make by just cutting a ring out of 5mm ally sheet with two hole saws of appropriate size . I used 5mm longer screws too.

Sounds like there is a spacer stopping your sprocket from moving closer to the engine?
Do you mean the boss on the sprocket?

I still have the proper y2000 worn sprocket somewhere if you'd like me to measure it... They are available, I was just lazy!

utopia · 31-03-2019, 07:23 PM

My experience is limited to a double sided swingarm but I dont think it makes any difference here.
The sprocket can be moved inwards simply by fitting a spacer between the sprocket and its splined retainer ... along with some appropriately longer bolts.
The spacer can be a simple washer .. it doesn't need the splines.
Though obviously it needs holes for the bolts.

There are also sprockets available with different thickness bosses on them.
I think 5mm or 10mm are available as std fitment on various different monsters.
And some have no boss on one side. They can be fitted "boss outwards" or "boss inwards", so they can give a third, 0mm option.

The above is typed from memory following the fitting of an ally swinger and wider rear wheel/hub to my M750, about 2yrs ago.
Its accurate .. as far as my memory can be relied on.
If there's no confirmatory post from anyone else, I'll nip and check what my current set-up is and generally verify the info.
I think Mr Gazza has some experience of this area too .. he'll probably post up.

ps. Ha .. there you go, he already has.

Bitza · 31-03-2019, 10:08 PM

Ok thanks for the comments, but I think you'll find that the 1000s have a different sprocket set up to the 900 era engines, certainly this one just has a single nut holding the sprocket in place. Sorry for the vagueness but I haven't actually taken the sprocket off yet, so am relying on views from the parts list, It basically goes securing nut, lock washer, sprocket, a spacer and then shims (0.7 - 1.1) before hitting the shoulder of the sleeve which in turn fits onto the shaft. So what I'm hoping is that I can take 5mm off the spacer, to get the sprocket moved inboard. But of course this relies on there being enough splines & thread etc. to make it a possibility. I know its possible because a few people have done similar engine swaps for classic racing prior to the 1000,s being outlawed.

Well apart from this, and the petrol tank not fitting over the the revised battery/air filter, the jobs going a breeze, well no actually all the final bits are proving a real struggle, but it looks almost complete?!&%^* Bitza.

utopia · 31-03-2019, 11:05 PM

Ah yes, sorry, I think I have heard of that type now you come to mention it.

Stafford · 01-04-2019, 06:32 AM

Flip the sprocket and/or adjust the spacer behind to suit.

Bitza · 01-04-2019, 08:23 AM

NOW THAT'S THE TYPE OF RESPONSE I LIKE!!!! Thanks Bitza (assuming it works).

Bitza · 01-04-2019, 05:14 PM

Have just flipped the sprocket and bingo, I've still got a few more checks to do but all seems bang-on. Thanks to all for your suggestions Bitza.

31-03-2019, 06:51 PM	#1
Bitza Bronze Member Join Date: Jul 2006 Location: Poole Bike: M900ie Posts: 468	S2R g/box sprocket realignment? Hi all, OK welcome to my latest nightmare, I'm fitting a S2R 1000 lump to my 1994 bike and have a bit of a problem with the sprocket alignment, which basically stems from the original offset of the rear sprocket to wheel centreline of the respective original wheels. The result is that the situation I now have is that the gearbox sprocket is 5mm outboard of the rear wheel sprocket, and there seems little opportunity to alter the rear sprocket, which leaves the the g/box sprocket. Has anyone out there any experience they can share? I'm wondering if the spacer inboard of the sprocket could be shortened by 5mm to bring a standard sprocket in by the same amount (so that subsequently replacements can be the standard item). All thoughts welcome, Bitza. __________________ Bitza

31-03-2019, 07:13 PM	#2
Mr Gazza Lord of the Rings Join Date: May 2013 Location: Norwich Bike: M900sie Posts: 5,790	Not sure if you have the same kind of sprocket retainer as a 900, but you probably know that the 2000 M900ie has a unique sprocket for that year. It has bosses on both sides and I believe it sits 5mm further inboard than the other 900s. I couldn't get the right sprocket for mine when I last changed sprox and chain, so I made a 5mm spacer for a standard sprocket and it works fine. It was simple to make by just cutting a ring out of 5mm ally sheet with two hole saws of appropriate size . I used 5mm longer screws too. Sounds like there is a spacer stopping your sprocket from moving closer to the engine? Do you mean the boss on the sprocket? I still have the proper y2000 worn sprocket somewhere if you'd like me to measure it... They are available, I was just lazy! __________________

31-03-2019, 10:08 PM	#4
Bitza Bronze Member Join Date: Jul 2006 Location: Poole Bike: M900ie Posts: 468	Ok thanks for the comments, but I think you'll find that the 1000s have a different sprocket set up to the 900 era engines, certainly this one just has a single nut holding the sprocket in place. Sorry for the vagueness but I haven't actually taken the sprocket off yet, so am relying on views from the parts list, It basically goes securing nut, lock washer, sprocket, a spacer and then shims (0.7 - 1.1) before hitting the shoulder of the sleeve which in turn fits onto the shaft. So what I'm hoping is that I can take 5mm off the spacer, to get the sprocket moved inboard. But of course this relies on there being enough splines & thread etc. to make it a possibility. I know its possible because a few people have done similar engine swaps for classic racing prior to the 1000,s being outlawed. Well apart from this, and the petrol tank not fitting over the the revised battery/air filter, the jobs going a breeze, well no actually all the final bits are proving a real struggle, but it looks almost complete?!&%^* Bitza. __________________ Bitza

01-04-2019, 06:32 AM	#6
Stafford P3, nice. Join Date: Jun 2006 Location: Calne Bike: S2r 1000 Posts: 2,145	Flip the sprocket and/or adjust the spacer behind to suit. __________________ celeres-racing.blogspot.co.uk/ The probability of survival is equal to the angle of arrival. Last edited by Stafford; 01-04-2019 at 07:05 AM..

01-04-2019, 08:23 AM	#7
Bitza Bronze Member Join Date: Jul 2006 Location: Poole Bike: M900ie Posts: 468	NOW THAT'S THE TYPE OF RESPONSE I LIKE!!!! Thanks Bitza (assuming it works). __________________ Bitza

31-03-2019, 07:23 PM	#3
utopia No turn left unstoned Join Date: Jun 2010 Location: leicester Bike: M750 Posts: 4,545	My experience is limited to a double sided swingarm but I dont think it makes any difference here. The sprocket can be moved inwards simply by fitting a spacer between the sprocket and its splined retainer ... along with some appropriately longer bolts. The spacer can be a simple washer .. it doesn't need the splines. Though obviously it needs holes for the bolts. There are also sprockets available with different thickness bosses on them. I think 5mm or 10mm are available as std fitment on various different monsters. And some have no boss on one side. They can be fitted "boss outwards" or "boss inwards", so they can give a third, 0mm option. The above is typed from memory following the fitting of an ally swinger and wider rear wheel/hub to my M750, about 2yrs ago. Its accurate .. as far as my memory can be relied on. If there's no confirmatory post from anyone else, I'll nip and check what my current set-up is and generally verify the info. I think Mr Gazza has some experience of this area too .. he'll probably post up. ps. Ha .. there you go, he already has.

31-03-2019, 11:05 PM	#5
utopia No turn left unstoned Join Date: Jun 2010 Location: leicester Bike: M750 Posts: 4,545	Ah yes, sorry, I think I have heard of that type now you come to mention it.

01-04-2019, 05:14 PM	#8
Bitza Bronze Member Join Date: Jul 2006 Location: Poole Bike: M900ie Posts: 468	Have just flipped the sprocket and bingo, I've still got a few more checks to do but all seems bang-on. Thanks to all for your suggestions Bitza. __________________ Bitza

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