1982 YZ250 project

[BMFR6]

So, over the past weekend I picked up Claytons 1982 YZ250 and it needs a little work. I'm guessing that I may have a few questions throughout the process and figure its better I just maintain one thread rather than start 100 new threads; after all, we love start to finish project threads right? I'll put up the first round of pictures tonight so you can see what I am working with, but in general all the work needed is engine work. The frame is solid, wheels, tires, cooling system and swing arm are all good; seems a majority of the bearings and seals have been replaced recently and the only issue with the chassis is leaking fork seals, easy fix.

Regarding the engine, a quick synopsis, the bike was submerged and stalled, while under water, the "rider" (not Clayton, FYI) tried kicking it over and filled the case with water. Did I get that right Clayton? In its current state, the head is partially removed, the head has been unbolted, the piston is about 50% to the top of its stroke and seized in the cylinder. The crank is rusted in place in the case. The pictures will paint a better picture , but if you can imagine the case, the connecting rod sticking up, and the head toggling back and fourth on the connecting rod. Good times.

I've been going step by step using the manual and just picking my way through when time allows; I should have the engine out this weekend. My plan is to pull the engine and split the cases . At that point I figure I will have the crank and head debacle separated. I'm going to make an attempt to get the piston out, toss the crank, connecting rod and piston in the trash and determine if the head is salvageable.

First question regarding the cases, is it feasible to think I might be able to sand/bead blast them to try and save them? I don't "think" there is enough rust in the case that sandblasting would throw the tolerances out of whack but I've never split a case before so I really don't know what to expect. I'm thinking the only concern would be making sure the crank bearings will be secure. Any other thoughts I may be missing?

Second question, what is the crazy possibility any of you guys know someone that would have a decent 82 YZ250 engine they would let go real cheap? Doing this as cheaply as possible is the goal and i would "like" to be riding this summer.

Again, I'll start posting pics tonight.

[McBiggity]

Well, I am as clueless as you are about it. But if you want an extra set of hands to pull the motor this weekend, just let me know. I'll even bring my own beer.

[BMFR6]

Well here is the invite...

Live viewing is available at predetermined times, the show is 18+ due to language and the potential for large amounts of blood. If you are a new comer, you need to know I am a bleeder and could routinely go through a full box of band-aids when I work on anything that has wheels. If you know how to stitch wounds, you will not be allowed to work on any aspect of the project as your sewing services most likely will be required at some point. BYOB, however food may be served from time to time as weather for grilling permits. Pets are allowed but fair warning, my cat may challenge your pet or yourself to a steel cage match if you mock his summer time hair cut. My cat will most likely embarrass you and/or your pet. He looks like a lion for a reason and I have not seen any hyenas around my house since he started getting his hair cut as such. Beer gets you in the door, more beer keeps you there, even more beer gets you preferential seating (except for Bruce who mocked my chair on blocks, you get to stand).

[SSearchVT]

The cases should be aluminum - so rust shouldn't be a concern.

To free the piston from the cylinder and make dis-assembly worlds easier - take the head off, and spray a good dose of penetrating oil onto the top of the piston (make a nice deep puddle) then put some plastic wrap over the top of the cylinder (prevents evaporation, etc). Let this sit for a few days - the piston should be able to come out of the cylinder - you might need to tap on it with a piece of wood, but it should come out.

[BMFR6]

duh, i didn't even think of the cases being aluminum.

good tip on the oil, thanks.

[TheIglu]

You got it right. Case filled with water and sat.

The head is good, I wouldn't worry about it. Find a decent crank/top end or swap out the motor and you got yourself a running tank of a bike!

[BMFR6]

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[BMFR6]

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[butcher bergs]

PB Blaster or Marvel Mystery oil will prolly help the jug/ piston separation go a bit quicker.

[breakdirt916]

ain't she a beauty!

personally, I would take my time, take pictures of every step, and slowly piece together the parts (for cheap) on ebay

chances are with an oldie (but goodie) like that, you won't fall into any bidding wars with anyone to win it

cylinder!

http://cgi.ebay.com/ebaymotors/1982-...Q5fAccessories

cylinder head!

http://cgi.ebay.com/ebaymotors/1982-...Q5fAccessories

4th over piston and rings! (new)

http://cgi.ebay.com/ebaymotors/YAMAH...Q5fAccessories

base gaskets!

http://cgi.ebay.com/ebaymotors/NEW-Y...Q5fAccessories

[BMFR6]

yeah, fortunately there seems to be a decent amount of stuff on ebay.

[BMFR6]

well, just going to attach some pictures for now, will add some comments tomorrow. in the end, i found some good news and some bad news. overall i think i am coming under my expected expenditures and fortunately there is a machine shop right down the street.
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[BMFR6]

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[butcher bergs]

Eeewwww! That crank pic made me cringe a little.

I'm curious what the bad news is...

[BMFR6]

Eeewwww! That crank pic made me cringe a little.

I'm curious what the bad news is...

lol. that crank looks better than i thought it would! couple minutes with some wd-40 and things are actually moving in the case now. still need to spli it before i can really find out the damage though.

[KB]

I'd pb blast the shit out it then fill it with oil slap the head back on it and fire the thing up. It's only a little rust.

If the crank goes nothing lost nothing gained. If it goes buy another motor. Or another cheap basket gas with a good motor and have a parts bike.

KB

[BMFR6]

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updated comments tomorrow.

[BMFR6]

eh, had a last couple minutes worth of ambition. so we are down to a frame.

[gregp]

Wow. That bike brings back bad memories for me. I had an '82 YZ 125. One of the biggest problems I had was with the seals in the steering head. IIRC, the coolant flows through the steering head somehow to get into/out of the radiator. If the seals are not *perfect*, your stem bearings will only last a week.
I also had the motor/transmission apart 5 times in one day because the Clymers manual had several errors. The bike would shift 1-2-4-3-5-6! I finally threw the manual in the trash and swaped the gear sets around to get it right.
I was very happy to get rid of that one...
Personally, I always wanted a cherry '78-'79 YZ250.....
Good luck with your project! I once saved a Can-Am 250 that had a crank in very similar condition. It was easy, but it wasn't cheap!

[BMFR6]

So over the weekend I pulled the engine out, waiting on a flywheel to arrive then I can split the case and see what the total damage is. Gave the rolling chassis a decent once over cleaning to remove some of the heavy grease and grime. I think I'm going to wire brush it down, use a degreaser and then just rattle can a fresh coat on. Not worried about the looks, but there is some bare metal here and there that I uncovered by cleaning it. Like to just get some paint on it to prevent rust in those spots, could care less about the typical wear spots. Took the swing arm off, have to do some heavy greasing on all the pivot points that don't have zerks on them. When I took the rear shock out, took the bike off the stand and it didn't even squat. Not sure if there is anything I can really do on the rear shock, probably just clean it and throw it back in. Wheel bearings and brake shoes are good, just as Clayton said they were. Head bearings and seals should be good, I'd like to take the triples out prior to throwing a coat of paint on, but not sure I want to disturb these seals. Forks are out, need to do the seals and oil and they will be good to go. Provided there are no major problems in the case, I should send out my parts order this week. Drop the head off at the machine shop and then I'll be ready to go. Provided everything goes according to plan, I may be reassembling next week.

[BMFR6]

Wow. That bike brings back bad memories for me. I had an '82 YZ 125. One of the biggest problems I had was with the seals in the steering head. IIRC, the coolant flows through the steering head somehow to get into/out of the radiator. If the seals are not *perfect*, your stem bearings will only last a week.
I also had the motor/transmission apart 5 times in one day because the Clymers manual had several errors. The bike would shift 1-2-4-3-5-6! I finally threw the manual in the trash and swaped the gear sets around to get it right.
I was very happy to get rid of that one...
Personally, I always wanted a cherry '78-'79 YZ250.....
Good luck with your project! I once saved a Can-Am 250 that had a crank in very similar condition. It was easy, but it wasn't cheap!

yeah, the coolant/seals issue has me a little concerned but such is life. I hope the manual has been corrected, haven't dug into a tranny before so it will be a learning experience.

[BMFR6]

flywheel puller showed up today so i was able to split the case. after doing that, i wished i could have just put the cases back together, pretended not to see what i saw and forgot about it.
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[BMFR6]

the picture of the crank doesn't really show the layer of rust and crap on it. it has to be over 1/8th thick. but, i'm not going to admit defeat yet. once i get things a bit cleaned up, we'll see where we are at.
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[SSearchVT]

Clean it up - then pull the seals out of the case, and then put the case halves in the oven on a cookie sheet (with a layer of tin foil) with the bearings facing down. Turn the oven to 400 or 450 - the bearings should just about fall out by them selves. To put the new ones in - put the bearings in the freezer for a few hours, and the cases in the oven again to about an hour. Pay attention to the direction of the clutch case seal (and spacer). If you put them in backwards it'll rev and smoke like crazy.