WR/YZ 250F | Forum profile

Just a update I am waiting on carb and clutch parts right now. That is why this thread has not had any posting. It will be about a week and a half.

You won't notice the difference between 13.5:1 and 14:1 compression. Many people (myself included) only use one compression ring on the stock 13.5:1 piston.

Remove all Advertisements I seriously don't understand all this Jetting stuff. Pilot jets, leak jets, something a few clicks from the top...what does it all mean? My 07 YZ runs fine, would I bother touching any of that stuff? What jetting does my bike run as standard?

Roger that...09yz250f sorry...Its cold as hell out, so im going to take the carb off 2moro and mess with the needle clip position...Thanks again guys..

Quote: Originally Posted by bil2303 Are you replacing the stock headlight also ? Good call, to be legal you generally need to have a high/low beam and the fact that the WR hearlight is not considered DOT legal doesn't help much either. But from the sounds of it, you were able to get it street legal without a inspection....is that correct? if that is the fact, then no need to replace the headlight other than t is a pile and doesn't...

Got to the bottom run of chain. Push up on the bottom run until its tight with your left hand. The idea is to take all the slack out of the chain. Take your right and and pull the chain out away from the rear sprocket. If you can pull it out 1/4 of a tooth, its worn. If you can pull it out over 1/2 a tooth, replace it now. Some guys will replace one at 1/4 tooth. Others don't replace one until teeth start breaking off the rear sprocket....

Quote: Originally Posted by Charlie755 You dont just replace the rod. You will need to order a whole crank assembly. You'll have to split the cases but you shouldnt need to use a press to get the crank out but you will need one to get the bearings out unless you are talented enough to knock the bearings out with a socket without damaging the hole the bearing goes into. For the crank I have a big plastic hammer and one or two good wacks...

Sounds to me like you got the cam timing wrong.

Obviously a race bike, and presumably kept in good condition. Ride it. See if the bars fit and anything else that may be too personalized for the previous owner that would cost you $$$ to fix. Go in with a good offer.

I'm more intrested in the bennies of the 1 or 2 ring piston. GYTR just happens to make it in a 14:1 setup. I doubt bumping the compression .5 is going to make that big of a difference, but it's not going to hurt. I'm going to put a new top end in regardless, I'm just trying to decide who to go with. I like JE, I used there 14:1 in my TRX450R and have been pleased with it. 30+ hours and running strong. Just trying to expand...