New Member…Help! 2002 Yamaha Warrior 350

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MeowKat94

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New to the community here, just purchased a 2002 Yamaha warrior 350 and started a rebuild to get this baby up and running!

Have run into a few issues with startup and hoping someone has had some of the same issues or give some suggestions!

Engine has good compression. Have good spark. Fuel is getting to the engine just fine. Will not start no matter WHAT. Engine cranks over, and you can feel compression from the exhaust. Even tried pop starting, which started up for about 5 seconds then nothing.

All electronics are new including battery, entire wiring harness, magneto/stator coil, starter, relays, CDI, solenoid relay, rectifier.
Bottom top end/piston is brand new and has been rebuilt. New carburetor. Valves are brand new and timed to spec. New starter and starter clutch. When we took the engine apart the cam seemed fine. No metal shavings or sludge that we can see. Have flushed the oil twice now.

Any suggestions?
 
Based on what you are saying if it tried to run when you bump started or if it tries to run on starting fluid I'd lean towards a carberator adjustment more than anything else. Even new ones don't always work properly right out of the box. I'm not sure if while you were in there you did the little rubber manifold between the carb and the head but if that isn't new check it for cracks and leaks, or make sure you tightened everything there up right. If there is an issue there it's like trying to drink soda through a straw with a hole in it, the motor won't get the fuel out of the carb
 
Thank you for your response!
I have also tried starting fluid, it still did not start at all even when spraying directly into the intake and covering the intake loosely (no airbox/filter installed at that time). I will try some carb adjustments when I have some time. Note: also after attempting to start multiple times, ended up flooding the engine and fuel starting coming out of the bottom of the reserve. The manifold between the carb is brand new and there are no rips in the boot. No other exhaust leaks from what I can tell either.
 
Are you sure you're getting good spark? Are you getting it at the right time? Does it start on starting fluid?
Have double checked spark, and spark is very good and a nice light blue/white. Have noticed lots of air/compression coming through the spark plug housing on the motor while checking spark. Not sure if that is 100% normal as it seems high, it was not that high prior to replacing changing the piston. Not 100% sure about spark timing though, I don't have the equipment to check that type of timing... I have checked the stator/magneto with a multimeter and the ohms are well within specs according to the manual. I have had to change the spark plug twice already though, as after a few start attempts, the spark plug is fouling black with soot.
 
Based on what you are saying if it tried to run when you bump started or if it tries to run on starting fluid I'd lean towards a carberator adjustment more than anything else. Even new ones don't always work properly right out of the box. I'm not sure if while you were in there you did the little rubber manifold between the carb and the head but if that isn't new check it for cracks and leaks, or make sure you tightened everything there up right. If there is an issue there it's like trying to drink soda through a straw with a hole in it, the motor won't get the fuel out of the carb
Not sure if you saw this, I forgot to hit the "reply' button. Whoops!

Thank you for your response!
I have also tried starting fluid, it still did not start at all even when spraying directly into the intake and covering the intake loosely (no airbox/filter installed at that time). I will try some carb adjustments when I have some time. Note: also after attempting to start multiple times, ended up flooding the engine and fuel starting coming out of the bottom of the reserve. The manifold between the carb is brand new and there are no rips in the boot. No other exhaust leaks from what I can tell either.
 
Sounds like the timing might be off. Double check your timing marks. Does it spit back through the intake.
 
Not sure if you saw this, I forgot to hit the "reply' button. Whoops!

Thank you for your response!
I have also tried starting fluid, it still did not start at all even when spraying directly into the intake and covering the intake loosely (no airbox/filter installed at that time). I will try some carb adjustments when I have some time. Note: also after attempting to start multiple times, ended up flooding the engine and fuel starting coming out of the bottom of the reserve. The manifold between the carb is brand new and there are no rips in the boot. No other exhaust leaks from what I can tell either.
I would double check your timing and make sure all your grounds have good contact , maybe take your time go thru the electrical system , also what harness did you buy cause some of those ebay amazon harnesses are pinned wrong I just rebuilt the whole motor and all new electrical and as soon as I hot start it fired right up , also what jets sizes you running in the carb and is your air fuel screw set at 2.5 turns out ?
 

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