I know I should have posted this sooner, but I finally have my motor out and I need to know what could be wrong with it. It's been about 3 months since I stopped running it and started tearing it down. Last time I ran it when I'd rev it up there was a humming sound coming out of the motor like something may be loose. Could it also be the crank bearings? The piston was pretty much junk too. Also, does anybody know what to do about a pitted head?

 

The pitted head! if it hasnt been milled before, mill it, remachine the squish band, and polish it.

 

First, get a manual for it! Second, I eard the same sound coming from my 250R, so I rebuilt the top end. I found out after I got it all back together that my lower rod bearing was bad. If you have the cylinder off, move the rod side to side, if there alot of play, thats your culprit. Find what the maximum amount of play is and use a feeler gauge to measure it, chances are thats whats worng. I don't think it could be the crank bearings because the seals would be bad and it wouldn't run, or it owuldn't run right anyway. I may be wrong on the last part though.

 

that last reply is not accurate.when checking rod bearings always pull up and down on the rod to see if there is play in the bearing amount of play requires replacement.
and polisjing your head will do nothing other then make it look pretty .if you have pits in the head then just use a small dremel and remove the high spots and make sure there are no points sticking up where it could create a hot spot and and worse create detination.

 

Don't use a dremel, what I did was use fine sand paper, 220 grit I think, and put the whole piece of paper on something level, then moved my head around on it in a circular motion to create a smoooth surface. Mine wasn't that bad, but it takes awhile if you want it smooth. After i was done I put the head on the cylinder without the gasket and checked for spots that weren't even. I used a dremel to polish it, I didn't know if it would do anything, but I decided to do it anyway. killer, how is the way I check for play worng, thats what more than one person have told me, and it was in the manual, according to reputable people from this forum.

 

I already have a manual for it and there is a lot of play in the rod so that means it's coming off.