Raven 250 will not start
 

On my son's bike the oil spinner came loose and wore a hole in the side of the crankcase. I cleaned it out the best I could and replaced the spinner and crankcase cover. Tried to start it and the motor turns just fine but will not start. It has spark but just in case I pulled the coil off my bike and tried it on his and still nothing. Removed the spark plug again and checked for spark again and it has spark. Put my finger in spark plug hole and checked for compression and it has compression. Before I replaced the spark plug I sprayed in some starting fluid and still nothing, not even a back fire. Not willing to start throwing money at the problem without some advice as to where I should be looking. Any help with this will be greatly appreciated.

I hope I don't sound stupid, but what's an oil spinner?

Do a compression check.

It's that thing that shares the space in the right side crankcase with the clutch basket.

Did a compression test and it was zero. Replaced cylinder and piston and it started and ran like new.

Centrifugal oil filtration. It's what the CG engine uses for removing fine particulate from the oil. Many other small Honda 4 strokes use them too, including the 125cc in the current Grom and other bikes.

Glad you found it. The metal from the spinner and cover must have chewed up the rings and cylinder. Thankfully these engines are cheap to rebuild. Good proof that an actual Guage test is better than the old finger method.

The only mistake I made was ordering a standard rebuild. I should have ordered a big bore kit for my bike and put my old stuff on his bike.

To me a big bore is not worth the money,a few more cc's won't make it run any better than stock.

Depends on the kit. The Motocult kit is worth every penny, but it's properly machined and setup to make more power. The stage 3 kit makes over 20hp to the rear tire with an exhaust and a PZ30 carburetor. A typical Hawk makes maybe 13-14hp at the rear wheel stock with a properly jetted carburetor.

I basically have that exact kit on my bike, I just got the cam first before he ever offered them and ordered the cylinder, piston, and head.

It's no joke.

Thanks Dan ,thats good to know. Might give it a try,was thinking of buying a new bike any how. Maybe this is all i need.