350x Motor

[hondaex420]

I am in the process of rebuilding a 350x motor and putting it in my 300ex frame...what is the biggest bore i can put in it that will last me a long time??

[jbwoodie]

I have seen them over 500cc. So you can just about do whatever your wallet will allow. That was the motor they were putting in 250r frames before the 400ex was realeased.

[dork]

you can do lots of overbores, but when you go past an 86mm piston you need to resleeve and bore the cases for it. 86mm on stock stroke is 393cc. after that there are 425,432, and 452 cc. i have a 452 kit in mine, thats a 92mm piston. so far so good, going on 2 years. run good oil, change it often, and stay under 11:1 and it will last a long time. one thing to check is your rod's side clearance when the top end is off. if its over .025" you need to rebuild it. remember these motors are 20 years old and many are on original bottom ends. if they have alot of miles and run with dirty oil they will wear out the thrust washers. i've seen quite a few 350x's with broken rods due to worn thrust washers.

[fastleo]

i just got done with my 350x 300ex conversion and it has the power but the ride sucs i even put on +1+2 a arms and a +2 swing arm and a wide axle it was fun at first but it beat me up. im already going to put it in a 250r frame. get a hold of me some time if you need help... andy

[Caseys 300ex]

Originally posted by fastleo
i just got done with my 350x 300ex conversion and it has the power but the ride sucs i even put on +1+2 a arms and a +2 swing arm and a wide axle it was fun at first but it beat me up. im already going to put it in a 250r frame. get a hold of me some time if you need help... andy

Did you put aftermarket shocks on there or just your stockers.

[fastleo]

i put my buddys 400ex front shocks on it and i used the stovk 350x for the rear