making a 2002 yz426f trail friendly

2 replies to this topic
  • SSnova72

Posted October 09, 2013 - 09:47 PM


Hi all, I am very new to the dirtbike scene and picked up a well running 2002 yz426f. It has tons of power for me but seems to just bounce me around on logging roads, and overheats in the tight technical single track. What recommendations do you have to make the bike more trail friendly? I will never race on a track, and I will likely wind up doing 90% of my rides through rocky hardpack roads or tight single track. The KTM boys seemed to really soak up the bumps a lot different than me.

I was thinking about putting lighter springs and oil in the forks, a heavier flywheel and a bigger sprocket in the rear. I am around 200 lbs, and a beginner rider, what sort of spring rate should I be looking for? Also it seems that my back tire never wants to stay underneath me. Its always sliding out one way or the other, is this because of rear suspension adjustments that are required? Also, my front fork seal was weeping a bit when I got it, so who knows how much oil I am missing...

That was long winded but I appreciate any help or insight from you guys! Thanks!

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  • Hoosier-Daddy

Posted October 12, 2013 - 02:15 PM


Dont know your budget or mechanical abilities but get that suspension set up for you. If you dont plan on sending to someone to set up for your weight, ability, and terrain has a spring rate calculator. Valves and springs work together and I leave valving to the suspension companies. Set your sag too- you can search that topic.

Engine ice coolant will greatly reduce overheating. 9oz gytr flywheel weight will help low speed stalling and traction. I went bigger back sprocket for tight trails. 13/51 helped. Trying 13/52 next because I still rarely hit 5th gear. The heavy flywheel and bigger back sprocket will reduce need for so much clutching which is also contributing to heat buildup.

With the above done that bike will be totally different in the woods. Much more fun and easier to ride. Many people rave about the rekluse clutch too.

Friend had 426 that was a beast to start until he put hotcams with auto decompression. He said he should have put them in long before he did.

  • Smoke2323

Posted October 13, 2013 - 06:28 PM


I got a good deal on a YZ426 as well. When I got it, it was all MX and I only ride desert and wooded trails. When I got it I serviced and adjusted the suspension. I'm 205lbs. You do not need to revalve anything. Replace your fork fluid and set the level. You will need a special tool for this. Make small adjustments to your comression and rebound till it feels better. Slide the dust seal down and gain access to the oil seal. Using a very thin feeler gauge or film negative(is what I use), slide it between the fork leg and the seal all the way around and remove any small dust and debris. Google it, lots of videos. Set your rear/race sag. Again google more videos. My bike has only over heated once, in the AZ desert on a very difficult single track trail climb. As long as your moving you should not be over heating. I always shut the bike off, when I'm waiting up for people. Speaking of which, I install a auto decompression cam(Hot Cams) and adjusted the valve to insure one time, kick starts. I got a hot start cable from a Honda CRF450 w/90deg bend(eBay) at the carb end and removed the yzf hot start plunger, connected the cable from there to the unused decompression lever. Worth every penny and time spent doing. A kick stand is a must. Pro Moto Billet is the best but expense. I love mine. Hand guards are nice. They protect your hands and your expensive hand controls, from falls. I recently installed a 13t front sprocket, I wasn't that blown way by the gain in lower speed climbing ability. Which this bike does lack, a little. As far as keeping your rear wheel underneath you, you will get use to it and may need to change your style of riding. A good rear tire and proper tire pressure goes a long way15psi. It has taken me about a year to get the bike set up just perfect for me. It really doesn't need anything else. I have thought about a rekluse clutch to help From staling on really difficult climbs but it going to be hard to drop 3-4 hundred on a kit and I get better every time I ride. So may be will never need one.

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