two stroke cranks/rods

[Project300EX]

I just replaced the crank bearings and seals in my project motor. When I broke the motor down I noticed the rod is a lot different than the other motors I've worked on. It doesn't have a rod cap, it's just solid. I was told that the crank is pressed together. Would this have to be sent to a machine shop to have the rod bearing replaced? Also how can I tell if the bearing actually needs replaced? Thanks.

[400exrider707]

Originally posted by Project300EX
I just replaced the crank bearings and seals in my project motor. When I broke the motor down I noticed the rod is a lot different than the other motors I've worked on. It doesn't have a rod cap, it's just solid. I was told that the crank is pressed together. Would this have to be sent to a machine shop to have the rod bearing replaced? Also how can I tell if the bearing actually needs replaced? Thanks.

Yep you would have to have the crank pressed apart. If you grab the connecting rod there should be no vertical movement to it or play, and then there should be a little side to side, but you will need to refer to the manual for specs on that.

[mgraff400ex]

most shops the do a lot of engine work should have the jigs for pressing apart a 3 piece crank. The way i look at it is if you have it apart might as well replace them cause you're already there. it would suck to get it back together and it go out in 3 hours. Besides if you're rebuilding because of lets say a lean condition that scored a cylinder all the metal that came off the cylinder had to go somewhere and chances are it went through that bearing at some point.

[400exrider707]

Originally posted by mgraff400ex
most shops the do a lot of engine work should have the jigs for pressing apart a 3 piece crank. The way i look at it is if you have it apart might as well replace them cause you're already there. it would suck to get it back together and it go out in 3 hours. Besides if you're rebuilding because of lets say a lean condition that scored a cylinder all the metal that came off the cylinder had to go somewhere and chances are it went through that bearing at some point.

aren't they sealed bearings?

[CDCHONDAS]

Not totally sure what engine your working on but in general they are needle bearings on the lower rod end. so you have a rod, pin, bearing and 2 webs which can all be taken apart and rebuilt. I wouldnt try it at home unless you know what your doing.

[Project300EX]

I'm pretty mechanically inclined. I just heard the crank has to be pressed apart. It's an '88 Suzuki RM250.

[matt250r21]

You need a press for 2 stroke cranks, plus a fixture to hold the 2 halfs or a way to rebalance the crank after you press it back together.

[Project300EX]

Do any of the site sponsors do this kind of work?

[Aceman]

www.crankworks.com

I've heard their name a few times.

[Which 450?]

costs around 100 bucks in labor to have a crank rebuilt