Nw big sprocket fitted

[Lucazade 749s]

Originally Posted by Jyrki

You might be right and maybe if 41 means that the original chain still fits it might make a case, but then again with 43 rear sprocket the kick must be impressive when you are give it full throttle.

Bike is now a bit longer due to longer chain. On original setup you had to help it do a wheelie (I do not know how to do one) I never even managed to do a wee at start.
Now, mind you bike is longer, I do wee's under every hard acceleration by just not leaning forward. If I lined back it would probably wheelie. On 2nd gear boy it responds with a wee as well. On every other gear it responds so much faster. So what that now to have relatively quiet m-way cruising I need to go max 80MPH (anymore and engine gets above 6k). That can only be good. Max MPH dropped, can tell you this without testing. At 100MPH it is 1.5k up the rev range.


I so love it

One bad thing will have to change my rear mud-guard again. It was ok with original sprocket but with this one it makes strange noise around 60 to 80 MPH.

[BaggaZee]

Er, the bike's not longer, or if it is you've done something very scary!
As for the noise, is your chain rubbing on the chainguard due to the larger sprocket?

[JerryXt]

Originally Posted by Lucazade 749s

...I do wee's under every hard acceleration ... On 2nd gear boy it responds with a wee as well.

Luca, if stuff is coming out of your bike, I'd get it seen to. Not being an expert, but I'd say something wasn't right...





I'll get my coat

[rouge brute]

Originally Posted by Lucazade 749s

Bike is now a bit longer due to longer chain. On original setup you had to help it do a wheelie (I do not know how to do one) I never even managed to do a wee at start.
Now, mind you bike is longer, I do wee's under every hard acceleration by just not leaning forward. If I lined back it would probably wheelie. On 2nd gear boy it responds with a wee as well. On every other gear it responds so much faster. So what that now to have relatively quiet m-way cruising I need to go max 80MPH (anymore and engine gets above 6k). That can only be good. Max MPH dropped, can tell you this without testing. At 100MPH it is 1.5k up the rev range.


I so love it

One bad thing will have to change my rear mud-guard again. It was ok with original sprocket but with this one it makes strange noise around 60 to 80 MPH.

That seems pretty drastic to me. I went to a 40t on the rear which made a nice difference.

[hugepiece]

Originally Posted by rouge brute

That seems pretty drastic to me. I went to a 40t on the rear which made a nice difference.

Did you manage to do this without having to get a longer chain?

[Monkeyboy]

Originally Posted by BaggaZee

Er, the bike's not longer, or if it is you've done something very scary!

my inexperience might be beaming through, but surely if he has a longer chain on it then the wheel base must be longer to keep up the tension?

[BaggaZee]

The extra length is to go around the bigger rear sprocket, he hasn't extended the swingarm....or has he?! Are you going drag racing Luca?!

[Lucazade 749s]

Originally Posted by BaggaZee

Er, the bike's not longer, or if it is you've done something very scary!
As for the noise, is your chain rubbing on the chainguard due to the larger sprocket?

Longer chain so need rear wheel a bit further apart from front.
Regarding noise, no sprocket is not rubbing against chain guard, look at pics below. It is more of a whistle noise, it is an air thing as at some angles it does whistle and at some it does not.

Originally Posted by JerryXt

Luca, if stuff is coming out of your bike, I'd get it seen to. Not being an expert, but I'd say something wasn't right...





I'll get my coat

Do get your coat

Originally Posted by hugepiece

Did you manage to do this without having to get a longer chain?

You can fit rear 40T sprocket with out longer chain apparently 41T as well and 41T is recommended for chain life not 40T.
Also it is said that chain and sprocket should be changed not one or the other but who cares.

Originally Posted by Monkeyboy

my inexperience might be beaming through, but surely if he has a longer chain on it then the wheel base must be longer to keep up the tension?

Correct, sad but correct as I prefered shorter wheel base.

Originally Posted by BaggaZee

The extra length is to go around the bigger rear sprocket, he hasn't extended the swingarm....or has he?! Are you going drag racing Luca?!

No swing-arm is not changed.

[moto748]

As for the "making the bike longer" thing:

Obviously a chain with extra links *is* longer, but the questions is, how much of this extra length is used up going round the larger diameter sprocket?

These are my fag-packets figures; if anyone knows better (and yes, I know there are formulae for chain centres, but I CBA with that), feel free.

Chain pitch = 16mm.
New sprocket = 43 teeth
Old sprocket = 39 teeth (that right, Luca?)

Old sprocket circumference = 16 x 43 = 688mm
New sprocket circumference = 16 x 39 = 624mm

But the "wrap" of the chain is roughly 60%* of the total circumference.

New wrap = 624 x 0.6 = 374mm
Old wrap = 688 x 0.6 = 413mm

difference = 413-374 = 39mm

but the chain is lengthened by 43-39 = 4 pitches = 4 x 16 = 64 mm

hence amount of excess chain going into increasing sprocket centres = 64-39 = 25mm

But there are two runs of the chain, upper and lower.

Hence approximate increase in wheelbase = 25/2 =12.5mm (half an inch).


I'd be surprised if that had any appreciable effect on handling.



* 60% is a figure I pulled completely "out of the air"

[Lucazade 749s]

Originally Posted by moto748

As for the "making the bike longer" thing:

Obviously a chain with extra links *is* longer, but the questions is, how much of this extra length is used up going round the larger diameter sprocket?

These are my fag-packets figures; if anyone knows better (and yes, I know there are formulae for chain centres, but I CBA with that), feel free.

Chain pitch = 16mm.
New sprocket = 43 teeth
Old sprocket = 39 teeth (that right, Luca?)

Old sprocket circumference = 16 x 43 = 688mm
New sprocket circumference = 16 x 39 = 624mm

But the "wrap" of the chain is roughly 60%* of the total circumference.

New wrap = 624 x 0.6 = 374mm
Old wrap = 688 x 0.6 = 413mm

difference = 413-374 = 39mm

but the chain is lengthened by 43-39 = 4 pitches = 4 x 16 = 64 mm

hence amount of excess chain going into increasing sprocket centres = 64-39 = 25mm

But there are two runs of the chain, upper and lower.

Hence approximate increase in wheelbase = 25/2 =12.5mm (half an inch).


I'd be surprised if that had any appreciable effect on handling.



* 60% is a figure I pulled completely "out of the air"

Look at first picture I posted of new sprocket and the one I posted now of the old one. Have a look at where the wheel alignment thingis are on bought. Now take under consideration that I had to tension the chain twice now a new ones stretch a lot at start. If you count from left chain is on the 4th or 3rd bar. Apparently bike is longer by 8 mm. I did not have handling in mind I did have wheelies in mind

[Ghost]

I run 13/42 or 43 can't recall, standard chain length also, mine handles ok, you need an ar5s like Rossi to feel any difference on the road by moving the wheel back and forth.

It will have a similar effect on sag also as the spring will feel softer or harder but in the realms of 3/5th of F/all.

[Lucazade 749s]

Originally Posted by Ghost

I run 13/42 or 43 can't recall, standard chain length also, mine handles ok, you need an ar5s like Rossi to feel any difference on the road by moving the wheel back and forth.

It will have a similar effect on sag also as the spring will feel softer or harder but in the realms of 3/5th of F/all.

I do not see any handling differnce because bike is longer. I look at it this way. 1mm longer = 1mm further away from wheelie I got this wheelie obsession lately.

[ducbird]

i can see tears at bedtime here...

Wheelies Luca are you on a death wish....

I like technical info but im really lost here now with chain lengths
can someone put it into simple terms...
Has Luca done the right thing or is his chain too long for the sprocket
Has he got enough teeth

[Lucazade 749s]

Originally Posted by ducbird

i can see tears at bedtime here...

Wheelies Luca are you on a death wish....

I like technical info but im really lost here now with chain lengths
can someone put it into simple terms...
Has Luca done the right thing or is his chain too long for the sprocket
Has he got enough teeth

With chain it is like this. Some say I should have 98 links on a chain and bike should be around 4mm shorter. Some sites say I should have 100 links chain and bike should be 6mm longer compeering to standard chain?! (Difference between 4 and 6 mm I have no clue why) If you get 100 links then front, rear sprocket and chain itself will be under less stress (1 tooth will hit the same link less frequently) while 98 link will put minimum strain on rear but max on front sprocket (in this case 1 tooth will hit the same link every revolution which is the same as standard Ducati setup). Apparently in this setup chain has to be of even number. Decision to which chain I get was left with Steve/Craig at MotoRapido he told me to take that extra strong X ring but I never asked how many links. Will count this weekend and report. I have total confidence in MR (well total I did stop very quickly when my new whistle noise arrived ).

No not on death wish but then wheelie is a right of passage, the same as in my old days on bicycle. But then after wheelie ther was the first jump, the frist downhill at 60 kph, the first downhill in the middle of forest at 60 kph and then downhill in middle of forest in the night no speed limit just who gets down first (or at all).

[ducbird]

well lets hope there are no potholes etc to put you off
balance ... there are schools for wheelies Luca