XR400 Smoking????

Yup :), my XR is starting to blow smoke. It is not a lot smoke but I would like to fix the problem. I am looking for help on what to do. Do I need a full topend job? Valves? Values guides,? Rings? Rings and piston? How should I attack this issue?

Thanks for the input. After further investigation, it seem that while at idle with a quick snap of the throttle, you will notice a small puff of smoke. While under power, it doesn’t much. The smoke is really apparent while decelerating, down hill, with no throttle.

Any help on how to fix this XR will be appreciated. Web links? Anything. Thanks.

Any help would be appreciated


I dont know what year you bike is, but depending on how much use the bike has seen it might be worth it. If your gonna have it apart, its not going to cost much if you do all the work yourself. you'll probably need about $100 worth of parts if you are going to replace it all.

There are a lot of things it could be, but chances are that the reason for the smoking are the valve seals, or the valve guides. If you are going to have it apart, you can have the valves and seats resurfaced.

I know when I had my engine apart my cylinder on my 98 XR400 looked good, but I was burning alittle oil.

Does it smoke all the time, under decell, during accellleration only, or just at idle when you start it up, then it goes away. If it smokes only at first, then goes away, it's the valve guide seals. be more specific, and we can better help you. We all like diagnostic side-jobs.

Sounds like seals. Does your bike sit for long periods of time also, like in the winter months? It's a good idea to turn it over once in a while to keep things worked in.

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