XT225 FAQ - Fuel System


Why is my wife's XT so hard to start sometimes?

My wife has an XT225 and it is a really nice bike for her. The problem is if it sits for more than a couple of weeks, it is really difficult to start.


This is a common complaint about the little XT and it is because it is way too lean from the factory to start easy when it is very cold. The easiest things to do to fix this are:

  1. What is called the Z1 muffler modification. This comes from the XT225.com forum and you can click here to see the images and detailed instructions on that web site. This opens up the exhaust a bit making it breathe (exhale) easier.
  2. Remove the brass plug covering the mixture screw so you can adjust it as necessary (about three turns out from bottom). Click here to see a very good tutorial with pictures on the XT225.com forum.
  3. Remove the snorkel from the airbox so it can breathe (inhale) a bit easier on the intake side.

With these mods completed you will need to do a little jetting. Check out our pre-packaged jet kit. The good news is that when you are all done you should still see about 80 mpg and the bike will start easier and run better everywhere!


Jetting questions for my wife's TTR125

I have been tinkering with my wife’s 2006 TTR125 and have installed the BBR air filter, pipe and your jet kit. The problem is when I read the manual it says that there is a fuel screw on the bottom of the carburetor. Yet when I look, there is the hole but no screw. There is a little brass plug or something up there.

Also the manual says that the needle should have 3 positions and ours just has the one. Since the weather has been getting cooler her bike is getting harder to start and has a big bog right off of idle. We mostly ride trails so the bog is a big nuisance. Her jetting as of now is 110 main, 17.5 pilot, factory needle, & no adjustment on the fuel screw. Any thoughts or ideas would be greatly appreciated.


You need to remove the brass plug to get to the mixture screw. To do this, drill a small hole (be careful not to drill too deep or you could damage the head of the mixture screw!) through the plug, then screw a small sheet metal screw into the hole. Grab the screw with a pair of pliers to pull the plug out of the hole.

You can also use a small thin washer to shim up the needle since yours doesn't have any adjustment grooves.

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