Changing front sprocket on 748s
 

I've got a 13t front which I want to swap with the standard 14t.

Getting the old one off is proving to be a complete nightmare! I am following the Haynes manual which makes it sound pretty simple - yeah right.

I have removed all the front sprocket bolts etc, slackened the chain to its fullest extent but it's nowhere near slack enough to take off the rear sprocket and in turn get the front out.

Am I missing something here guys?

Failing that, anyone got AJR's number....:(

Cheers for any advice.
Jacko.

have you taken the clutch slave cylinder off?

if i read correctly you are changing the standard 14 tooth front sprocket for a 13 ??? this is not really a good idea as a 13 tooth sprocket will place more stress on the chain (something to do with the angle and pitch of the chain i think) best to up 1 or 2 up on the back

Nige, cheers for the advice - much appreciated.

I took the slave cylinder off but still nowhere near enough slack there. When pulling the sprocket off, the frame was restricting complete removal.

I posted previously about the merits of doing this and most replies advised either going down 1 on front or up 2/3 on rear. Didn't seem to be any probs taking one off the front by the sounds of it.

Just had a new set put on the bike but they couldn't get the bigger rear in time - gutted now!!! That's why I went for the front option as it appeared to be an easier job for the more mechanically challenged (i.e. me).......

Anyone else out there help out???

Thanks.
Jacko.

Go back and read thread again, specifically my post ;)

Just re-read my original post and I AM knocking 1 off the front as suggested (748s is 14 tooth as standard).........

Anyway, I take the point that a 13 is too stressful on the chain - looks like I missed the opportunity when I had the new set put on.

Soooooo, anyone want a 13 toother FOC? Give me a shout.

P.S. Can anyone enlighten me why I can't get the original off????? Not that I need to now anyway. :flame::flame:

Cheers

Jacko.

try getting the shop to swap it..if it isnt used its worth a go. Isnt there a retaining clip on it? Cant remember for sure but think so, mine came off easy (and you cannot be worse than me!) using a haynes manual so hope its something simple that youre missing/:)

I tried a 13 tooth on my 748e before going the full cost of a rear carrier & sprocket(42 teeth) slackened fully the chain, took off the clutch slave cylinder, & managed to get the chain off the rear sprocket, not easy but found it the only way.
14 front with a 42 rear is the way to go.

Chris. :roll:

If you going for the larger rear (which as already mentioned is the way forward with a 748...not a 13 front!)...then you may well need a longer chain anyhow. The larger rear sprocket will have an effect of shortening you wheel base and increasing the ride height, if you keep the chain the same length, as chain adjustment and these two factors are directly linked due to the hub arrangement.

If you are having trouble removing the chain when fully slackened off, then it may be too short...if so it will definately need changing/more links adding if you increase the rear sprocket.

My advice...fit a replacement rear sprocket, say a 40 or 42 (either carrier+sprocket, or just just plain jobbie depending on finances). If you cannot then adjust the chain to the correct tension, with the hub almost as far back as it will go...then the chain is too short, and you may want to look into getting a new one to the correct length. Mike Davies and Nelly both do Tsubaki chains a v.good prices.

Once you have this sorted its just a case of adjusting the ride height to suit.

[Edited on 17-5-2004 by Harv748]

It wont shorten the wheelbase will it? Doesnt the 748 have an eccentric adjuster? It will alter the ride height though.

Yep...it will shorten the wheel base...the 748/9** series do have eccentric adjusters.

In effect, the chain is tightened by doing just that...pushing the back wheel further away from the sprocket, and therefore the front wheel. Taking it to the extreme, if you want an even longer wheel base, you have to fit a mag swingarm and an even longer chain depending on the gearing.

However, most people new to Ducati ownership don't realise that in adjusting the chain it has a direct effect on the ride height, even if its adjusted only a little.

When I first fitted a new chain to mine...i also changed the steering head angle to the steep setting. The chain that I fitted was a little short, and that, combined with the shorter wheel base and increased ride height made for a very entertaining ride!!! Its worth getting the correct length chain for your gearing...the tranformation in the handling is quite noticable when the hub is posiioned correctly, and the ride height adjusted to suit.

Search Shazzams posts. He has covered the chain length/gear ratios/hub position many times before and posted a great chart covering all combinations some time ago.

Jacko, You can get some additional slack in the chain if you put a jack under the engine (with the bike on it's paddock stand) so that the swingarm drops down a bit. The chain is tightest when the two sprockets, swingarm pivot, and swingarm are in a straight line.

As a guide you want to get the distance from the swing arm pivot centre, to the centre of the hub as near as you can to 1/2 metre 500mm.

This is achieved by having the eccentric hub pointing to about 5 o clock as viewed from the chain side.

Of course with a larger rear sprocket you will need a longer chain..

Oh - thats why I cant touch the floor Harv - maybe I can lift up my own stand next time:lol:

I don't think there is that much adjustment mate:bouncy:

Maybe try the 4stroke scooter tyremans selling in the market place:lol:

OK guys,

Cheers for all the replies. Top blokes one and all!!!

Looks like I'll keep the gearing as standard for now.

After making 2 x 150mile round trips and shelling out in excess of £900 just to get it serviced, c & s, back tyre, I really can't justify to the missus any more expense on the thing....and then there's the insurance re-newell that's just landed aswell:o

Then I find out today that my contract is being ended in 28 days. :flame:

Ah well, it's my birthday tomorrow. :sing:

P.S. That offer of the 13t sprocket is still there for free if anyone can find a use for it - drop me a u2u with your address.

Cheers.
Jacko.

do you think I could use that as a stool then:puzzled: cause I hope your not suggesting i RIDe it;) Then again - might be quicker on it thru the bends....

No comment mate:P