A forum for owners of Yamaha TTR250 trail and enduro bikes!

yamalama · Veteran Member

Can front sprocket be changed without splitting chain?

Cubber · Super Guru

At a guess, though I've never tried it, I reckon so. blankstare

If you remove your back wheel first there may be just enough clearance to pull the chain clear to remove the gearbox sprocket.

I'd undo the gearbox sprocket nut first - BEFORE taking the rear wheel out though. wink

Don't blame me if you can't do it!.

Will you not need to shorten the chain to accomodate the reduced size sprocket? confuse

Martyn

barra8 · Guru

yamalama wrote:
Thanks for your reply Martyn.
I am fairly sure that I can accomadate a 1 tooth less front sprocket without removing links from the chain, and that just moving the rear wheel back in the swing arm to get the correct chain tension will be OK and still have some possibility for future chain tensioning. Whai I am less sure of is where I can buy Tsubaki x-ring chain split links if I do split the chain.
Has anyone actually changed a front sprocket without splittin the chain?
Thanks
Lama

I have done what you are trying to do no with no problem. The thing is that i can't say how many links i used so...

If your rear wheel axle sits a little to the front & not right at the back you should be fine.

......................

Jarrah.

-- Edited by barra8 on Tuesday 29th of January 2013 01:02:02 PM

yamalama · Veteran Member

Thanks for your reply Martyn.

I am fairly sure that I can accomadate a 1 tooth less front sprocket without removing links from the chain, and that just moving the rear wheel back in the swing arm to get the correct chain tension will be OK and still have some possibility for future chain tensioning. Whai I am less sure of is where I can buy Tsubaki x-ring chain split links if I do split the chain.

Has anyone actually changed a front sprocket without splittin the chain?

Thanks

Lama

barra8 · Guru

So you have a better understanding on how it works....

The front sprocket will have an effect on torque. I like to call this bottom end. If you have enough torque than there is no need to change the front. This will only have a minimum effect on top end speed.

The back sprocket will change top end speed more dramatically.

If the front reaches it's top speed ie. maximum torque. It will not be able to pull harder on the back sprocket so therefore not going any faster.

If the back reaches it's maximum ie.top speed...& the front still has more torque (bottom end) then it will still have torque at top speed but this would in turn lower your top speed.

Hope that makes it more understandable & the way i wrote it makes sense? confuse

.......................................

Jarrah.

-- Edited by barra8 on Wednesday 30th of January 2013 12:23:11 AM

yamalama · Veteran Member

Thanks Jarrah, that is good to know.
Gives me the confidence to begin without having a spare split link to hand.
Next think that I need to find out is whether going one tooth less on the front will be roughly offset by going 3 or 4 teeth up on the back from a chain length point of view.
Any thoughts anyone?

Thanks

Lama

barra8 · Guru

yamalama wrote:
Thanks Jarrah, that is good to know.
Gives me the confidence to begin without having a spare split link to hand.
Next think that I need to find out is whether going one tooth less on the front will be roughly offset by going 3 or 4 teeth up on the back from a chain length point of view.
Any thoughts anyone?

Thanks

Lama

The 13 will give you more bottom end but if you like top end more i'd be going the 14T.

I found that the 14 was better but that would be up to you as to whether you need the extra bottom end or top end.

...............................

Jarrah.

barra8 · Guru

barra8 wrote:
yamalama wrote:
Thanks for your reply Martyn.
I am fairly sure that I can accomadate a 1 tooth less front sprocket without removing links from the chain, and that just moving the rear wheel back in the swing arm to get the correct chain tension will be OK and still have some possibility for future chain tensioning. Whai I am less sure of is where I can buy Tsubaki x-ring chain split links if I do split the chain.
Has anyone actually changed a front sprocket without splittin the chain?
Thanks
Lama
I have done what you are trying to do no with no problem. The thing is that i can't say how many links i used so...
If your rear wheel axle sits a little to the front & not right at the back you should be fine.
......................
Jarrah.

-- Edited by barra8 on Tuesday 29th of January 2013 01:02:02 PM

Oh i relized i was meant to write......If your rear wheel axle sits a little to the *BACK & not right at the *FRONT you should be fine.

I'm pretty sure i was using 108L chain.

...............................

Jarrah.

TT-R250M · Super Guru

Thanks for confirming this & it's as I said at the start. It then had me wondering whether or not 106L would work. I knew how close it was from my calculations (not the best at maths but ok) so I said 108L. At least i know that i was close & helps me to find what size is best for that sprocket set-up.

Cheers Lama

yamalama · Veteran Member

Hi, Just thought i should confirm that i was able to change the front sprocket without splitting the chain (or even moving the back wheel forwards, though I will obviously have to adjust the chain tension now). I just removed the case guard that sits around the front half of the sprocket, pulled the chain and front sprocket to the left and off its shaft, and then with a bit of wiggling was able to gat the chain off the sprocket. I'm not sure yet how much this will affect where the rear wheel sits in the swing arm. Hopefully will adjust chain tension this weekend and report back Lama

Nomada_Firefox · Veteran Member

Just read this thread now and the answer for me is yes, the front sprocket can be changed without cut the chain, I have made it at least two times with a chain of 112 links.