i have a 2001 honda 400ex thats all stock. i rolled it over in a river and got water all through the motor. me and some friends took it apart and rebuilt it but we just cant get it to run like it used to. there is no power at all. it got beat by a 200s 3 wheeler in a drag. anyone got some advice?

 

Something didn't go back right. I'd run a compression test. You said rebuilt. What exactly did you do? New rings? You should of changed the oil 4 or 5 times after the water damage even if you did rebuild otherwise that water sit in the bottom of the case potentially causing damage to the new parts.

 

yeah we put new rings filters and valves but never touched the bottom end and we did change the oil about 5 times. ill run a compression test on it tomorrow
thanks

 

Yeah, your compression might not be there from the rings or the valve seats.

Or you could have failed to get the timing right at the timing chain.

Carb issues can also be a possibility.


Describe how it runs a little more in detail.

 

well it seems to run good but there is just no power at all. and it bogs down everytime i shift. and after i get to 3rd gear it dont go any faster 4th and 5th just suck. we did take the carb apart and cleaned it. and we were messing with timing but im pretty sure that its right now. i didnt get a chance to test the compression today but i will do it first thing tomorrow and post what its at. thanks

 

OK... and it's no better after getting the timing for sure right?

Compression numbers would be good.


If that's not it, since you had the carb apart, if you took the slide and needle out, you may now have your carb out of sync... the slide and butterfly need to be in time with each other and the shot from the accelerator pump.

I have instructions already posted somewhere on that... "IF" they are needed after ruling out other things.

Also, it is possible your screws may be backing out in there... the ones that hold the slide to the link arm that lifts it up. Mine did that once and came all the way loose. It bogged like crazy of course.