Let's talk Sprockets

So bought my 426 without a manual(I need to order one) and no idea what size sprocket I need for it. My buddy who retired from Mx racing 15 years ago came over and looked at my 426 last night noticed I am running a 35-38 tooth rear sprocket(tiny he says) and saying I need a larger one to navigate the trails easier. So here is my question:


1. What size is stock for front and rear Sprockets?


2. What would be a great recommendation for trails(woods)?

Stock is 50,perfect for wood riding for me

Edited by 67imp

13/50 or 51 is the stock gearing which is best overall

Ya, mine is no where near that size. Thanks guys. I will be swapping those out sometime real soon.


I know Vortex are crap(especially for sportbikes) and any others I need to avoid in the Enduro product world?

Sun or Sunstar are the best by far, for the least, by far, if you you don't care about weight.

I think the one on there is a Sun, It is small.

That is a small rear sprocket. Probably gonna need a chain too, that one will likely be far to small. 

Mine was 42 tooth in the rear. My buddy luckily has a Yz450 and gave me a stock 50 tooth sprocket and a aftermarket 520 Race chain. I am set now.

14/50 or 14/48. I use "Chain Gang" sprockets and chains. Steel sprockets to handle the massive amounts of force being applied. Aussie made products.

I have always pushed the Ironman sprockets but I have recently had very good luck with the Supersprox and it is a middle of the road price point at $80.  And it has a bit of "bling" factor as well.





14/50 is stock. It works perfectly for Michigan singletrack for me. Rarely do I use first, unless it is ridiculously tight. On the other end, 80-85 mph topped out is plenty fast.

Gonna hi jack for a second here. Took my 05 WR450 for it's first and few road trips 80 miles South in a 55 mph zone and less. I changed the sprockets to 15/45 before the trip. I cannot even use 5th gear unless I am above 53 mph or it lugs so hard and vibrates. If you let off the throttle in 5th or get hard on the throttle in 5th, or go faster than 53 mph it quits. But try and hold a steady pace under 53 and it just shakes like hell. Is that normal? 

That's probably just the harmonics on the chain at that specific combo of RPM and wheel/chain speed, like a guitar string. Could also be a combo of harmonics and tire balancing.

Edited by Pooley


Vibration at those speeds I'd say could be wheel related. Maybe chain isn't aligned with sprockets? You did fit a new chain when you changed sprockets?

It's not a vibration, it's a chug really. The entire bike shakes. 


Is like lugging a car or a bike in too high of a gear. the entire bike "chugs". Only in 5th gear under 53 mph does it occur with constant light throttle opening, Lift off the throttle, and it stops. Give it moderate throttle, it stops. Try and maintain a constant speed 53 mph or below in 5th gear, it chugs. Everything else in every gear and speed is smooth all the way up to 70 mph which is fast as I went,... well as smooth as knobbies can be, 


I buy the harmonics things and don't see how it could be chain or sprocket related.

Front sprocket has about 1K miles, chain has about 2K miles, rear sprocket new. It was ridden by a 59 year old previous owner who kept it well maintained.

Edited by DonnieD

Aaaah, constant throttle around 1/4 open?  That would be the TPS (throttle position sensor).  You can adjust the TPS following the procedure that has been posted on one of the stickies.  That should help.  The bikes aren't really meant to be run at constant throttle, unless it is WFO :).

Aaaah, constant throttle around 1/4 open?  That would be the TPS (throttle position sensor).  You can adjust the TPS following the procedure that has been posted on one of the stickies.  That should help.  The bikes aren't really meant to be run at constant throttle, unless it is WFO :).

I'm familiar with the TPS issues too but here is the way I understand it. In the higher RPMs at constant throttle the bike would hic-up (skip). Mine did that so I unhooked the TPS. So does the TPS affect constant throttle at 1/4 openings too and only 5th gear, You know anything's possible, I'm almost tempted to unhook it and ride it in my PJ's. Ahh, I will just wait till tomorrow. When my cush hub gets here I am tempted to go back to a 50 rear, I didn't have the problem then. 

Screw it, I'm getting dressed. Gonna find out if the TPS is naughty or nice. 


EDIT: Nope. Disconnecting the TPS didn't fix it.  The chatter feeling I'm talking about is  like if you short shift and the bike chugs until the RPMs get up higher. Same thing here. The only way around it is to shift from 4th to 5th at 54 mph, then it stays smooth as butter.

Edited by DonnieD

You sure it isn't the chain slap coming from the chain slide that goes around the front of the swingarm?  Does your chain guide on top have play in it?  Put some thin weather stripping underneath it and see if that eliminates it.  I went with the T&M Designs chain slider and that solved my issue.  They are a much beefier design.

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