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Gear spun on camshaft

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Hey guys, I have a 05 crf250r. Has anyone ever seen, or maybe heard of the cam chain gear getting "spun" on the camshaft? 

Im wondering because these cams/gears are a press fit. And the bottom end on my old engine locked up and grenaded. After building a totally fresh engine from top to bottom, I'm having a no start issue. Back fired 3 times from exhaust.

 

Cam lobes are facing rear and slightly up.

Cam gear marks are level with head, right crank mark lines up with case. Second mark on stator is almost perfect with the line on the left casing. 

Carburetor was torn apart and cleaned. I did remove the TPS but Im pretty sure I have it exactly where it was before. There was a ring of dirt around the screw when it came out. That's how I know.

I think my jetting is pretty close to where it needs to be. The bike should atleast start.

I'm running a #42 pilot, #165 main, NCVS needle, 3rd clip position, fuel screw 1.5 turns out

Engine - hotrods crank & bearings, cylinder works 269cc big bore kit, head re-worked ---> valve seats cut, new oem intake valves, springs, keepers ect. Exhaust valves ground.                       Stock exhaust

Intake valves measure .005 and exhaust valves measured .003 which is a little tight, but according to the manual, still falls within spec. 

When I got head back, I sprayed brake clean into ports and the valves didn't leak one bit after sitting several minutes. 

Compression test was 49psi. Seems a bit low as manual says 57psi at stock bore/piston. I feel like it's a little low for a big bore kit. But it's a brand new cylinder/piston ect so it's not technically broke in yet. Rings were installed correctly, and ring end gap is pre set by cylinder works. 

 

Sorry for the long post, but this bike is driving me nuts. 

Does anyone have any type of idea??

 

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Yes it's actually quite common for engines that have failed / seized to spin the cam sprocket and alter timing.

People re-use the cam when rebuilding the engine as it looks fine but

like you the cam's actual timing is off despite all the timing dots properly aligned, creating a no-start condition.

Edited by mlatour

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Thank you for the response. I couldn't find much on this issue. I only found one post where someone had this exact problem. 

Any suggestions on a new cam? 

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theres a hole in the cam gear that should, line of sight, line up with the hole in the cam lobe.

 

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Replaced camshaft, and bearings, and got a wiseco shim kit.                         (even though I paid extra to have the head shimmed when I had the head work done)

Put it all back together and she fired right up. 

Thanks guys 

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