12 raptor 350 wont run

my friend has a 2012 raptor 350 and he was riden in field and it just bogged down and died and wouldnt start after that. my first thought was the carb. i tore it down got a rebuild kit and rebuilt it. sucker still wont run. Its getting a nice bright blue spark but it still dont seam like its getting gas the plug seams to be dry. the carb is getting gas and the float is adjusted to the correct hidth. I'm kinda stumped right now any new ideas would be helpful.

Did you try a NEW spark plug? That would have been my first before tearing into the carb.

Compression? Ignition timing?

guess i shoulda added that into it too lol new spark plug, compression is spot on, i dont have a leak down tester so i cant test that but the timing is correct to. The only thing i can think of is a tight exhaust valve which really doesnt make sense to me because it has low hrs.  tomarrow ima yank carb outta the boots and see if its spraying fuel at all. Gunna try to isolate the problem.

guess i shoulda added that into it too lol new spark plug, compression is spot on, i dont have a leak down tester so i cant test that but the timing is correct to. The only thing i can think of is a tight exhaust valve which really doesnt make sense to me because it has low hrs. tomarrow ima yank carb outta the boots and see if its spraying fuel at all. Gunna try to isolate the problem.

Did you try to put fuel directly into the cylinder thru the spark plug hole and then try to start it?

Did you try to put fuel directly into the cylinder thru the spark plug hole and then try to start it?

i tried a small squeeze of start fluid in both the intake hole and the spark plug hole and nothing happened. i figuired sense it had a cv carburator the atomization of fuel had to be exstremely fine and mabie thats why the starting fluid didnt work.

i tried a small squeeze of start fluid in both the intake hole and the spark plug hole and nothing happened. i figuired sense it had a cv carburator the atomization of fuel had to be exstremely fine and mabie thats why the starting fluid didnt work.

Probably.

Try checking the valve clearances while you are working on it next too.

will do :]

piston.jpgpiston2.jpgpiston3.jpgvalves.jpgvalves1.jpg

 

So just a little update, i decided to just go ahead and yank engine from frame. I went to check the valves and when i was putten it on tdcc, i noticed when i opened the cam chain cover that there was a sandy oil mixture in there so i pretty much new at that point that checking the clearances wouldnt matter. I pulled everything apart and im going to have to do a top and bottom end rebuild, connecting rod bearings are way way out of spec. piston is obv shot. Luckly ill get away with a slight bore on the cyclinder and be able to reuse that. But the valves, vale springs, valve guides and the rocker arms are all gunna have to be replaced. Im not sure on the crankshafts condition because i havent split the case yet. But i guess what happened was he had put a brand new k&n airfilter in it and the bracket broke during a race and he finished it without realizing it had broke. Which is pretty self explanitory by looking at the intake side of the piston and seeing that nice sand blasted finish haha. Also the intake valve got stuck open almost a 1/8th of and inch and the exhaust valve is exstremly tight. I think another huge factor that played into this was he was runining to much of a lean condition also. He never rejetted the quad for his aftermarket pipes or the airfilter he was running in it. Needless to say after all of this i dont think he will be runing a k&n airfilter anymore. :p

Oh yeah. That'll do it! I always stick to the stock air boxes, for this reason. Good luck on the rebuild and post more pictures!

wow, been awhile since ive posted.. anyways yep thatll do it. k&n's are notorious for sucking in dirt. All i ride is Uni.

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