Front sprocket retaining plate

[RossObey01]

So I thought I'd give the chain and sprockets a good clean before the MOT tomorrow. Whipped the sprocket cover off and there's so much grime built up in there, the chain is running through it constantly. I thought it would make it easier to whip the front sprocket off, but noticed the retaining plate is cracked near a bolt hole and was badly worn.

http://i1195.photobucket.com/albums/aa397/RossObey01/b21db873-dbba-4452-ad48-6d475dc83d22.jpg (http://s1195.photobucket.com/user/RossObey01/media/b21db873-dbba-4452-ad48-6d475dc83d22.jpg.html)

It was a real pain in the arse to get off, none of the teeth seemed to line up to slide it past the shaft, which is perhaps why it was broken in the first place.

Anyway, new one if on the way from Moto Rapido before tomorrow, but can anyone tell me if these are fitted a specific way? Without a new one here to compare, I'm not sure if they're the same both sides? My old one has two sets of teeth/grooves worn into it, I assume the new ones are not like this?

Does it work by just offsetting the teeth enough when bolted to the sprocket, to stop it coming off?

Thanks,
Ross

[Mr Gazza]

funnily enough I've just been talking to Utopia about sprockets, and I had my cover off yesterday to clean out last years chain goo.

Your new retaining plate will fit the splines much better. It will slide down the splines a treat, then when you rotate it in the groove to line up the screw holes you will get spline to tooth alignment so it can't come off the shaft.....Change the screws at the same time.

[RossObey01]

Thanks Gazza,

I'll be fitting a new chain and sprocket set in the not too distant future, but this should see my fine for a couple of months.

[Flip]

All of the above and while you're about it, it's not a bad idea to fit a case saver. Then should the worst ever happen and a chain does break you should still have a useable motor.

I'm also a fan of making sure things that you don't want coming undone without you behind a spanner don't.

http://i1372.photobucket.com/albums/ag329/fluke900/Slave%20Cylinder_zpsamydhlck.jpg (http://s1372.photobucket.com/user/fluke900/media/Slave%20Cylinder_zpsamydhlck.jpg.html)

[RossObey01]

Thanks Flip, already thought about that - Steve @ BBB will be making me a case saver as soon as I get paid!

[DrD]

Oh and use shouldered bolts (with loctite) on them if not wiring them up like Flip.

[utopia]

Case saver will be a tight fit in the 750 cases if they're the same as mine, and if you still have the std 15T sprocket (which you do, I've counted).
It can be made to fit though.
Its tempting to try a 14T sprocket (as many people fit for improved low speed running) since this gives a little more clearance for the case saver.
My advice is, don't do it, at least not on a 5 speed 750.
I tried a similar but less extreme gearing change (couple more teeth on the rear sprocket) and found that it just made the bike rev too high at fast cruising speeds.
In fact, I've gone a tooth the other way now.

......just in case you were wondering.

[RossObey01]

Utopia, not something I'd thought of doing any time soon but it's good to know - thanks. I'll try and squeeze the case saver, but I imagine it's not going to go on until I get a chance to properly de-gunk behind the sprocket. Will update how it fits.

[Darren69]

Jeff's right of course the gearing on the M750 if its the same as the 750SS is pretty good. You shouldn't mess with it. First is a little tall but otherwise I had no issues and with a a wet clutch it is a lot easier. Its when you get to the 6 speed bikes and 6th is really just an overdrive gear on standard gearing that people get tied in knots. Sure 1st is tall again and town work is more work so a 14t front would make sense if you do mostly town work otherwise its best to leave it alone and avoid town riding as much as possible. Dropping a tooth on the front willl stress your chain more as its a much tighter turn

Well the 900 gearbox is not perfect but at least with the S4 it got the better 748R close ratio jobbie so its just right for the open road, still feels like an overdrive in 6th and if you avoid city riding its great fun.

Ducatis are not really commuting bikes, nor should they be!

[Dukedesmo]

I had the retaining plate come off on my 916, no idea how long it was off as I only discovered when cleaning the chain crud out but the whole thing including both bolts were gone, but despite gouged grooves on the inside of the sprocket cover there were no ill effects.

I fitted an 'open' cover after that so I can see what's going on.

They're cheap enough to change regularly though and I keep a spare just in case.

[RossObey01]

Oh and use shouldered bolts (with loctite) on them if not wiring them up like Flip.

DrD can you please tell me why I should be using shouldered bolts?

[DrD]

DrD can you please tell me why I should be using shouldered bolts?

From my experience, they stay there, I have had internal hex and hexagonals come loose.

[Mr Gazza]

I put a little drop of medium locktite on the screws myself.

I would also smear a bit of coppaslip or moly grease round the shaft groove to try and stop the retainer plate wearing away again...Well more to preserve the shaft actually...It all looks rather dry round there.

[utopia]

I have spring washers on mine.
I was thinking that I'd added them myself but in fact they're listed as standard.
I guess I've got used to thinking that this was adequate on its own, but .......
My workshop manual specifies Loctite 222 on those screws ....which is not a number that I'm immediately familiar with, so I googled it.
Also, I would be sceptical about Loctite being reliable on those particular threads due to the amount of oil and gunk around.
Lo and behold, Loctite 222 is suitable where there is "minor oil contamination".
I didn't know such stuff existed, but I will be ordering some.
Its purple too !!!

And seconded on the moly grease on the shaft .... I've just redone mine the other evening, as it happens.

Can't quite work out how your retainer plate has got into such a condition.
Mine is 20k miles old, but still looks virtually unmarked.

[RossObey01]

New plate arrived this morning, indeed I did put some coppaslip on the shaft and some thread lock on the two bolts before nipping them up.

No idea how the plate got in that state either, but from the bit of research I did yesterday it's not uncommon. Rest assured, it will be maintained slightly better now it's mine!