Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > Monsters > Fitting front sprocket to S4R

[webbyc]

I've now obtained a 14T front sprocket fit my S4R courtesy of Nattyboy. Anyway is it easy to fit? Do I need any special tools?

[antonye]

If it's the same as all the other Ducati ones - ie, it uses the locking plate with two bolts - then it's really easy.

You'll need to slacken off the chain a bit first, so get it on a paddock stand if you've got one.

Remove the sprocket cover and you'll see two bolts that go into the sprocket, which hold the locking plate in place.

Undo these two bolts - put the bike in top gear and it should lock the drive train enough to allow you to do this.

The locking plate should sit in the grove in the output shaft, but won't come off when it's aligned with the holes in the sprocket. The trick is to rotate the locking plate to align the splines and then remove it.

You should then be able to unhook the chain and slide the sprocket off.

Simple as that.

The workshop manual says 45-50 Nm of torque when you put the two sprocket locking plate nuts back in, but check with your own manual if you've got one (or wait for Nelly to correct me!)

If the bike was older, I'd say replace the nuts and the locking plate as well, as it'll cost you about £3, but given the age it's probably not worth it.

[Jools]

As Antony says ^^^^^^^ up there.

I found that I had to remove the clutch slave cylinder to slide my 15 tooth sprocket off (you might be able to wriggle a 14 tooth off without doing that).

Slave cylinder is easy peasy to pop on and off though, so it doesn't add any complexity to the job.

[antonye]

Ah yes - forgot about the slave cylinder!

I expect it's from a 15t to a 14t, in which case you'll definitely need to take it off, or at least undo the 3 bolts and move it enough out of the way.

It's a good chance to clear out all the chain-lube gunk from behind there while the slave cylinder and sprocket are off too!

[webbyc]

Thanks guys sounds nice and easy. I'll give it a go.

[moto748]

45-50 Nm seems a hell of a lot of torque for an M5 (?) screw...

The bearing clamp bolts that you undo when you adjust the chain only go 30Nm, IIRC, and they're much bigger (M8?).

[nelly]

45-50 is way too much. That sounds like the rear sprocket nuts???

Apply a bit of locktite and take them to no more than 10nm. Hand tight with a tee bar............

antonys instructions are spot on. you'll need to remove the slave cylinder to get the sprocket off.
Slacken the chain and put it inboard of the rear sprocket to allow the chain line angle to allow the front sprocket to slide off the shaft.
If it gets tight, use the slack to lift the chain off the sprocket. It's tight but can be done. You'll see what's happening as you work the sprocket off the shaft. It can be fiddly first time but you'll crack it.
remember to fit the front sprocket with the raised boss facing inwards!!

[Nattyboy]

I also find a nice cold bottle of Corona Extra always helps when doing little jobs like that mate...otherwise the kids get shouted at when I go back in and its all gone wrong ...

Dont forget to araldite some lead under the front mudguard like I told you..... Wheelysville arizona..yipeeeeeeeeeeee..!!!

Cheers !

Nat

[antonye]

Originally posted by nelly
45-50 is way too much. That sounds like the rear sprocket nuts???

Yeah, I knew that figure didn't sound right, but it definitely says "front sprocket nut" in the torque settings part of the (multi-language) workshop manual. Maybe I just read it wrong.

I've checked the Haynes BoL and it's not even in there, it just says "tighten" but certainly tight by hand and Loctite sounds good enough as the stress is rotational from the chain and not lateral anyway.

[Rushjob]

Could that be the large nut on the testastretta engines perchance?
That's a big bugger....
As for the earlier ones, my charts say 6nm & loctite 222.
Andy