I have a 86' 250r and i am thinking about buying a bore kit for it. It brobably wont be a 330, but it will probably be a 310. is it worth buying and would i need any other mods to make it run the way it is meant to be run? i already have an esr pipe, 36mm carb, and its been ported and polished. I also wanted to know if anyone has any problems with a kit. thanx


86' 250R
87' 250X

Ride Red!!!!!!!!!

 

I just recently installed the 310 kit on my 85 250R and love it. I am running the stock pipe w/FMF silencer, 36mm carb, RAM valve, and reed spacer. Here is my advice, if your lower end is in good shape and doesn't need the crank rebuilt then get the 310 kit if money is an object. If you must rebuild the crank, and you should if there is ANY slack at all, then get one of the bigger kits (330, 350). I rebuilt my crank then got the 310 kit and it cost the same if I had bought the bigger kits because they split and rebuild the crank on the bigger ones.

 

I have a 330 kit in my R and love it, the only problem is that all that HP strains alot of the other parts so expect to go through trannys and crankshafts. I currently MX race and hit the track twice a week I inspect my motor very often and it seems that I wear out the crank and 2nd thru 4th gear about once a year so make sure to take that into consideration

 

also when installing a 330 kit you have to machine the cases to allow clearance for the larger sleeve to fit.