Xr400 Timing

[clarkie_1990]

G'day guys, i have an xr400 that i think im having problems with the timing, the bike will run but not when it is underload, it will bog down and miss. this only happened after the bike was run to about 120 km/h. is this the timing, any advise would be greatly appreciated.

Thanks corey

 

[elcamino12sec]

I would first go through the carburator and give everything a good cleaning. Pay special attention to the main and pilot jet to see if they have any blockage. I would not assume timing right away as your problem, timing does not usually change by itself so drasticly the bike runs very poor. If you pull your case cover you should be able to check the marks on the stator to see if the timing is within spec. I have never worked on an xr400 but there should be an arrow that lines up with a few dots or some kind of mark on the left side of the bike.

 

[XR250rdr]

120km/h is less than 75mph. Thats no big deal for an XR4. Unless the bike has a ton of miles on it I really doubt the timing chain jumped a tooth. Check the carburetor first.

 

[Trailryder42]

What kind of exhaust is on it? Stock or an aftermarket? Something blocking the exhaust will give your symptoms. Check the simple things first.