What sprockets for an '02 426?

I just picked up an '02 426 with very little use. It is practically brand new, but the previous owner put on a 47-tooth rear sprocket. I am having trouble stalling out on the trails. I plan to trail ride only, and I want to improve it's stalling tendencies. After searching on this site, I think I would like to switch to a 13-tooth front and a 52-tooth rear. The chain looks brand new currently. Do I need to change the chain when I do the sprockets? Also, what brand should I buy? Is the TT store the best place to buy from? If I still have a problem with stalling after this mod, I will look into adding flywheel weight. I did a search on this topic, but didn't find anything that tells exactly how to do this mod or where to get the weights. Any additional info on this would be great.


IMO 13/52 is way to much. You need to make small changes until you find a set up that works for you. On my 426 I was running 14/52 or 14/53 depending on the trails. Good Luck.

I have an 01 which is basically the same machine. Stock gearing is 14/49. You can do a search on this forum and get all kinds of information about gearing. I'm an MX'er that has also done some trail riding. I went to a 50 tooth rear and love it. If I was strictly a trail rider I would add teeth to the rear, but would try it one tooth at a time til I found what I liked.

Most people will tell you to change the chain and sprockets at the same time. For my money, the best deal going is from MotoSport. They advertise in all the mags and have a web site: http://www.motosport.com/ Also, shipping is free if you spend $100 bucks. I buy almost all my stuff from them.

If you're not a hard core racer, get the basic steel sprocket package and chain from motosport. It is a little heavier, but will last a lot longer than the expensive light weight aluminum stuff from Renthal and others. And, there is no substitute for good chain maintenance. Good Luck.

I run the stock gearing on my 426. The best deal on chains and sprockets is the Primary Drive brand from Rocky Mountain MC. When I bought mine I got, a steel front and rear sprocket and a O-ring chain, plus a can of chain lube for $54. I bought 2 sets. :D

As for your stalling issue, do a search on Rekluse Auto Clutches. :applause:

I would agree with Primary Drive from http://www.rockymountainatv.com/ since you can get a really good deal on the complete sets.

As for your sprocket size...I would imagine that you would be happy with a 14/52 set-up but you may want to try stock first and see how you like it. That may be all you need. I run stock on my 426 that I use mostly as a trail machine, but I like being able to really open it up as well. Stock is a pretty good balance for myself.

I also have an 02 YZ426F. I'm not sure how the trails are in Texas, but while riding singletrack and rocky technical stuff here in Cali I run a 13/50 set up. 13/50 and 13/51 seems to be very popular on tight technical trails. For chains I would recommend a Regina ORN o-ring chain. They seem to hold up better than DID. For sprockets I like Sidewinder Ti-Moly or Ironman if your on a budget. You get what you pay for when it comes to chains and sprockets. Also I would make sure to install new sprocket bolts and nuts on the rear. The TT store has excellent prices and service. :applause:

I second the TT store, you just can't beat 110%!! The service is also like none I have ever experienced. I also feel that it is the least I can do to try and support this great site where so much knowledge is shared at the expense of TT. We should all do what we can to support it, lest it be taken away!! Just my 2c.


If you're trail riding only, I'd suggest you install a Rekluse and I'll be you won't need to change the gearing. I had lowered the gearing from stock on my 02 (I added two teeth in the rear) prior to installing my Rekluse and while the change helped a bit with tight trials, it was a drop in the bucket compared to the change the Rekluse made. I definately would not have changed the gearing on my bike if I had done the Rekluse first. There's stuff I used to have trouble stalling on that I now take in 2nd gear and at times I wish I had a bit more in the fifth gear. If you're riding trails on a 426, get the Rekluse, I promise you'll be pleased and amazed.

I run 14/50 and find it great for trails.

I also have a 15 tooth front that i can use with the same length chain.

With 14/50 you are on the limiter at approx 125km/h. The bike is reving pretty hard if you want to cruise at 100km/h but it hooks up great!

Mine is an 01 426, I dropped the front sprocket to 13 tooth, then to 12 tooth, stock rear. Front sprockets are about 25 ea vs 65 for the rear. Final drive ratio, stock is 3.5:1 at 12 tooth it is 4.08:1. I ride tight technical trails in Nevada, lost top speed, but having the deep hole helps on the tight step stuff where I tend to bust my ass. A rekluse is probably the next step plus going back to the 13 tooth.


Gear it how you like, but one of the best things you can do to prevent stalling (other than a rekluse or flywheel weight) is put in an autodecompressor cam...

I have 13/51 gearing but wish my first was a little deeper and fifth a little faster but the only way to get that is WR gears which I don't have the money for.

I have 13/51 gearing but wish my first was a little deeper and fifth a little faster but the only way to get that is WR gears which I don't have the money for.

You ride in 1st gear?

You ride in 1st gear?

almost half the time. Actually yesterday was the first time I hit a good throttle in 4th and I still haven't hit near full throttle in 5th. For trail riding gearing down is a must. The only problem is when you hit a big open part and open it up it feels like the gears are really close together but still it is not as bad as my friends ktm 125 thats way geared down and is a super close ratio 6 speed you can't even tell the speed difference when shifting. The ultimate set up is wr wide ratio gears that is geared down. My dad's bike is a wr426 with 13/51 gearing an his first gear is much lower than mine and his 5th is much faster so the wr gears are the ultimate trail tranny but they are usually very expensive

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