Jump to content
Sign in to follow this  

Trail Bike Project

Recommended Posts

For tight trails the 1 st thing to do is get your suspension sag numbers set properly (if not done already) and put on some quality tires for the terrain you ride and gear it to suit the terrain / trails you ride. Don't go to low on gearing unless your in 1st gear a LOT already on really slow stuff or you will spend to much time shifting up and down everywhere else. The XR motor is strongest down low so so my opinion is to run a little tall gearing, as much as you can get away with. For tight single track on a XR400, I would not go any lower than 15/47 - 15/48. I like stock gearing for single track here in MI. Makes 3rd gear an "all day" gear. Put it there and forget it unless you stop or hit the road.

 

I cant tell if that's a 250 or 400 but XR's have a lot of engine braking when chopping the throttle so turn your idle up just a little to reduce that. It keeps the bike more balanced front to back on and off the gas for the twisty turns.

 

For the XR, it's mainly set up of what you have. That will get you a long ways in overall performance. Exhaust will be a minimal gain in power but combined with good jetting can get you improved response and low end. I run the stock pipe so no opinion on exhaust brand.

Share this post


Link to post
Share on other sites

If you're after more power: a new slip-on exhaust can (for minimal gains) costs about the same as a 426cc piston kit with machining cost (no resleeving necessary), I think that's your best torque per dollar investment. The XR engine is so easy to work on.

 

Mikuni pumper carb is also nice, but nowhere as much difference as the 426cc vs stock engine.

Share this post


Link to post
Share on other sites

Mikuni pumper carb is also nice, but nowhere as much difference as the 426cc vs stock engine.

General consensus seems to be that these 2 mods are about equal in difference making. FWIW

Share this post


Link to post
Share on other sites

the pumper carb is an afternoon bolt on project.  the 426 kit is not.  If you sell the bike, you can put the stock carb back on and get at least 50% of the cost of the pumper back on ebay.  In stock form, the engine is bulletproof.  It may also be after the 426 kit but there will be some who are leary of buying a used bike like that.

  • Like 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×