HELP!!! REBUILD 85' CR250 PROJECT 2ND CHANCE

[SCOOTER77]

O.K. i got this bike in a trade and the guy said all it needed was a top end, well i got the cylinder off and theres freakin metal frag everywhere. i'm thinking i need a new cylinder, crank, piston/ring set, split cases clean thouroughly for metal frag reassemble and enjoy the old dog. sound about right? any help would be great btw i found a great deal on a crank out of a 83' will that work in my 85'? hope the pics work thanks in advance for any help.

---------- Post added at 08:35 PM ---------- Previous post was at 08:29 PM ----------

here's some pics of the bike to enjoy, i know "why not just get a nicer bike instead of piecing together an old dog" well i dont exactly have alot of extra money right now and i really want the satisfaction of being able to say i brought this thing back from the dead.

[wamxp1mp]

That could be metal from one of the bearings or piston, no the crank from an '83 won't work that motor was left sided kick/water pump an right side chain.

The motor that would be similar is the 84 and 85 models are the years they had the ATAC power setup which was a valve that opened a volume chamber it's that thing in front of the cylinder. The 86 CR 250 was honda's first year of the HPP powervavle setup so the motor is different but still try n compare parts numbers first. The 85 model does not have a hard plated cylinder wall so it can be bored out to the next size over.

Becareful with those old magnesium center cases over tighten a bolt and they will crack and cannot be welded! Unless you want to see an awesome fire.

Things to check are the right side case cover n raditors for clogging n dirt etc the magnesium cases flake under the water pump area. The only known fixes are the more common JB weld or the trying to find a cover that is still usable good luck part is discontinued.

Make sure the ATAC chamber is clean and operates smoothly they like to gum up and the teeth of the actuation arms like to shear off.

Also replace the lock washer under the rear drum they love to freeze and can make wheel bearing changes a nightmare.

Those are probably the only real problem areas of the bike if it was treated right they was pretty reliable.

[OLDMXRACER 393]

Welcome to ATM. Looks like you have a real good starting point to build on. I'm no help on your engine though. I'm a southern Illinois guy myself. Where you at?

[SCOOTER77]

thanks for the help guys, well i just bought a head, jug, piston, atac chamber, clutch lever and clutch cable for 185 bucks shipped to my door. the jug has been resleeved but needs a hone, i'm gonna send it out to be machined to next available size and matched with piston. then i need a crank and some other random stuff and i can start workin on this old horse. oh btw old mx.. northern il here, waterman to be exact, i have an indoor mx track less than a mile from my house. i dont race but i spent alot of time on a banshee when i was younger and ever since i traded it in on a street bike i've wanted to get back in the dirt, hopefully i can pull this rebuild off.

[OLDMXRACER 393]

Ah...Waterman. Midwest VMX has had a race there last 2 years and they say it's a hoot. I assume they will be there again coming January. Lots of good mechanics hang around here that will help with questions.

[dklassen]

If I remember correctly the 85 was a one year wonder. The frame, seat and fenders looked like the 86 but the engine was a one off. The 84 had reliability problems that weren't common for a Honda (before or after). Lots of top end failures on the 84. The 85 did not have the problems as the 84. I'm not sure how many parts interchange but I suggest that you only buy parts made for the 85. I wish you the best of luck on your project. Keep us posted on the progress.