Gearing/Chain Question

[M5-]

So I picked up a 14 tooth countershaft sprocket today to gear up all across the board and then started thinking. Is 14 17 one of those combinations that can't be done without the 1/2 link BS on the main drive chain?

M5

 

[Ausm7499]

So I picked up a 14 tooth countershaft sprocket today to gear up all across the board and then started thinking. Is 14 17 one of those combinations that can't be done without the 1/2 link BS on the main drive chain?

M5

Completely depends on the bike.

 

[Motogeek33]

So I picked up a 14 tooth countershaft sprocket today to gear up all across the board and then started thinking. Is 14 17 one of those combinations that can't be done without the 1/2 link BS on the main drive chain?

M5

I thought I could go with a 14-tooth countershaft sprocket if I just had a slightly longer chain, but I was wrong. A one-link longer chain (2 rollers) adds a surprising amount of slack -- it will actually droop down and rub on the track. I just ordered a half-link (will only add one roller). I have some reservations about the quality/durability of the half-link I ordered... it's definitely going to be the, uhh, "weak link".

We'll see how it holds up... I guess I'll be carrying the 13-tooth sprocket with me in case the half-link gives out and I have to go back to the stock chain setup.

 

[Motogeek33]

Completely depends on the bike.

FWIW, my experience is based on an 05 WR with a 2012 ST. The stock chain with a 13-tooth sprocket is really tight.

 

[retired motoman]

16 tooth Jack shaft sprocket?

I have had to change the 17 to a 16 tooth Jack Shaft a couple of times to use a taller Counter Shaft.

 

[up-high]

Didn't Alan post a spread sheet of sprocket combinations?

 

[M5-]

Sorry I should have added, 450 KTM bored to 520

M5

 

[M5-]

So after reading posts and working with the gear chart this is what I have decided. The wide ratio tranny has such a granny gear first and even second is low that I think I should be able to pull a 15 on the countershaft. Final drives are as follows:

13/17 17/20 .0304 What I have now which is way too short
14/17 17/20 .0327
15/17 17/20 .0350
12/17 20/17 .0388

I'm thinking the 388 is too tall for my motor/tranny combo but I think I can pull the 350, it should just move me down a gear all across the board. Thoughts?

M5

 

[Motogeek33]

I have had to change the 17 to a 16 tooth Jack Shaft a couple of times to use a taller Counter Shaft.

That makes a lot of sense... so if I went up one tooth on the countershaft and down one tooth on the jackshaft, then I should be able to use the stock chain without an extra half-link? And going one tooth larger on the jackshaft would probably raise the gearing just a bit more, correct? Where do you get new jackshaft sprockets?

 

[M5-]

So here's the deal, 14 tooth and 15 tooth would both need a half link on my bike as it sits, just tried them both. My 12 tooth puts the chain tensioner basically into the track, so the smallest I can go is 13 tooth on the counter shaft. SO after a bunch of Fawking around it looks like I will need a 16 tooth from TS unless somebody has one they aren't using and you want to sell it?


M5

 

[Ausm7499]

So here's the deal, 14 tooth and 15 tooth would both need a half link on my bike as it sits, just tried them both. My 12 tooth puts the chain tensioner basically into the track, so the smallest I can go is 13 tooth on the counter shaft. SO after a bunch of Fawking around it looks like I will need a 16 tooth from TS unless somebody has one they aren't using and you want to sell it?


M5

Another option for you which is what I am doing on my CR500 is run 13/17 - 17/17. This combination was the only way I could get the gearing ration I wanted without running a half-link. Running 17/17 in the chain case requires you to remove the tentioner assembly and the two stand offs on the left side of the chain.

 

[JimBridger]

...
12/17 20/17 .0388

I'm thinking the 388 is too tall for my motor/tranny combo but I think I can pull the 350, it should just move me down a gear all across the board. Thoughts?

M5

Relentless Rider is trying the .0388 combo on a 300exc. You may want to pm him and see what he found.

 

[M5-]

Relentless Rider is trying the .0388 combo on a 300exc. You may want to pm him and see what he found.

My chain has sub 25 rides on it but it has stretched to the point where I don't feel comfortable running the 12 tooth up front so that kinda eliminates that combo for me unless I buy another new chain which will stretch anyways. When tensioned up it is like 1/8th of an inch away from the track.

14/16 17/20 is 347 which is close to where I think I want to be.

That 13/17 17/17 is 357 that's a possibility as well. So you have no means of tensioning the chain case chain?

M5

 

[Ausm7499]

My chain has sub 25 rides on it but it has stretched to the point where I don't feel comfortable running the 12 tooth up front so that kinda eliminates that combo for me unless I buy another new chain which will stretch anyways. When tensioned up it is like 1/8th of an inch away from the track.

14/16 17/20 is 347 which is close to where I think I want to be.

That 13/17 17/17 is 357 that's a possibility as well. So you have no means of tensioning the chain case chain?

M5

I do see that who ever is making Timbersled parts (there is a thread somewhere around here) is making a piece to replace the Timbersled tentioner triangle piece that will allow you to tension a 17/17 combo and 17/16 combo. I don't worry about it there is very little slack left in the chain with a 17/17 combo, less slack then I leave in my chain when riding dirt.