what are some explanations as to why my 99 wr400 doesnt start, ive just finished replacing shaft, seals, bearings ,gaskets, coolant and oil and now it wont start and if it does start it start with throttle on backfires a bit then when i let go of the throttle it dies. p.s  before water pump rebuild it started first kick everytime hot or cold. i had bike upright when i did it

cam timing is off

i didnt go anywhere near it, ran absolutly perfect then after water pump no start

Fouled plug??

i can cant check it atm because i dont have the tools with me. how would it have fouled because before i did the water pump it started and ran perfectly?

Pretty hard to give you any advice when you don't give us any details.

Obviously, the waterpump change has nothing to do with your problem.

Most likely, you have skipped a tooth trying to start a bike that has problems from  (fill in the blank here), OR, you have a simple maintenance issues in the carb or wiring. 


...and if you don't have tools, how did you change the water pump?

first of all i dont have the tools to get down into the sparkplug i have other tools for the water pump, im mentioning the waterpump because my bike ran perfect until i rebuilt the pump. i have not had any other mechanical issues since ive had the bike (1 year now) 
if it is the pilot jet how can i check if it is without pulling the carbi appart if there is one

okay after a long time of trying i managed to get my plug out it doesnt look that bad condition it could be carbon fouled but im not sure either its not or it just a crazy coincidence that it happened at the same time

I think you might want to invest in a service manual, and read the maintenance schedule. 

Replace the plug, rotate the carb and remove the plug to remove the pilot jet. Replace the jet, do not clean it.

Check wiring harness at the battery and behind the number plate for loose connections


If you plug is black, you need to start looking at why. It should be light tan in color, more or less.

diid you lay the bike on its side to do the pump if so gas can run out into your intake and flood the engine and foul the plug. I had a 250 that it happened to me on.

Thanks everyone, plug was fouled due to running rich got new plug and adjusted it and runs like a dream. And I already have a manual

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