Author Topic: Found a 1985 ATC 250r motor need some advice (Read 3025 times)

madman636 · « **on:** July 15, 2014, 10:49:34 AM »

I have a 1986 TRX250r rolling chassis project. I found a 1985 ATC250r motor that is complete but has been sitting for many years. Any advice on using this as the foundation to my motor?

Hawaiiysr · « **Reply #1 on:** July 15, 2014, 12:07:29 PM »

Check compression. Pull the head. Check the bore. Change the clutch fibers, and h20 pump seals and bearing. Change the trans fluid and install a new plug. Kick her over and have some fun!

That's wishful thinking. An 85 is a good motor to start with. If you want to play it save rebuild it. A manual is worth its weight in gold. And all the fellas here are more then willing to answer any questions you may have along the way. Welcome to the site:)

kb250r · « **Reply #2 on:** July 15, 2014, 01:28:01 PM »

X2 as hawaii suggested....run over the check list new fluids,ext check for leaks and giver hell!!!

madman636 · « **Reply #3 on:** August 13, 2014, 11:03:59 AM »

I have the top end pulled apart. Need to bore it and put a new piston in it. I am thinking about going with the 68.50mm. Any recomendations on who to send the cylinder to for bore and a port job?

Thanks,
Mike

KASEY · « **Reply #4 on:** August 13, 2014, 09:42:07 PM »

what is the bore at now? because boring past a couple of sizes is really not advisable,,

Tbone07 · « **Reply #5 on:** August 13, 2014, 09:58:32 PM »

You'll have to see what bore the cylinder is at right now to tell if there's more room available for another overbore.

Stock bore is 66mm

Looks like these guys gave you a pretty good head start and i'd recommend checking the same things. If you don't want to do a complete tear-down and inspection, there will only be so much you can tell from the outside