Anything I should do while its apart?

[250RWANTER]

He 85ATC250R, I DID read your last post, but you said it was caused by running to lean...I was just curiuos if there were any specific reasons as to why it would run lean.
I obviously got lied to about why it didnt run, but how was I to know? Unless I pulled the bike apart right there.
Oh well, I'm stuck now.

I will just do whatever is necessary on the bore, I dont wanna worry about i heating up to much.

Now as far as crank seals....or air leak...how do I go about checking for those?

I'd like to have the state of mind that everything is up to par when I do get it back together.

Thanks for all of the advice!

[Lots_Of_Nothing]

well, thats just one of the things to look for when buying a used bike, atleast now you learned, next time, before paying, if it doesnt run, tear the cylinder off and take a look, crank seals, just see if there is oil in the crank area, i would go ahead and replace them anyways just to update it and be on the safe side,, for air leaks its kind of hard to check without it running, but when it gets running, what i do is go around all the areas where it could be leaking and spray a bit of wd-40 (i check gasket places, and carb boots) you can tell if it is leaking because it will suck it in. when a gasket has a leak it will usually make a noise, like when you first start it if theres anything major you should be able to hear some air getting sqeezed through an opening.

it ran lean because the guy who owned it didnt put his glasses on to see how many oz. of oil to mix into the number of gallons.

[250RWANTER]

Hey thanks, I appreciate the help!
So I guess I need to order up crank seals too huh?
Are they a pain to replace? Sounds like it.
Anything else you can think of that I should update/replace?

[hondatrikesrule22]

It really sucks replacings crank seals cause you have to take your entire motor apart. While you replace the seals, replace your bearings also.

[samster143]

I don't see how ANYONE can tell how much to bore a cylinder with out using precision instruments to accurately determine the actual bore and how much it is out-of-round. They get kinda egg shaped in the middle and that has to be bored away. also all the grooves the piston mad have to be bored away. Just send it to someone who does this work and they mwill be able to tell you the straight deal. That looks to have siezed and might take .040 to clean it up. my.02

[TimSr]

I don't see how ANYONE can tell how much to bore a cylinder with out using precision instruments to accurately determine the actual bore and how much it is out-of-round. They get kinda egg shaped in the middle and that has to be bored away. also all the grooves the piston mad have to be bored away. Just send it to someone who does this work and they mwill be able to tell you the straight deal. That looks to have siezed and might take .040 to clean it up. my.02

Couldnt say it better. Its not likely that youll get away with not boring it after a meltdown, and the "how much" question should be left to the person doing the measuring and boring. I highly recommend www.wiseco.com , and get it back with a new bore, piston kit for which it was bored, and also request wrist bearings which wiseco also handles. Check rod bearings while your in there. Boring is not a performance modification, and you dont bore based on "how much power you want". Also, you should replace the head gasket when you open the top end.

When you get it back, monitor your spark plug a lot, and make sure your coolant is flowing properly. The piston shown is melted. Either the guy is a bald faced liar, or somebody in the household took it for a ride he didnt know about. It died while being run hard, under lean conditions. This is most commonly caused by improper carburetion, or cooling system failure. (the hotter the more, the more lean it runs) A leaking crank seal on the flywheel side is a possibility, but not as common. Any of these usually have to be combined with running it hard. Ive got a couple of matching pistons here. One was caused by carburetion, and one was a failed coolant pump.

[250RWANTER]

So basically, I guess I am taking the motor apart? Greeeeaaaaatttt. That should be fun. Does the Clymer book cover all of this? I have everything off. Wiseco is in the same town I live in....well, one of there shipping centers is and I can get everything from there if I need too.

Crank seals sound fun. So I should just replace them now? No way of knowing if they are good or bad without it running huh?

I'd hate to get it back together and find they are bad.
Any special tools needed to get to them/replace them?

Thanks guys

[250RWANTER]

oh and coolant flowing properly.....this is an aircooled model...no coolant...correct? Or am I misunderstanding you?

Plug should be a tannish color...right? 20:1 mix should be correct right? Thats what it says on the tank.

Thanks!

[Lots_Of_Nothing]

you dont need any special tools to replace crank seals, although you may need a flywheel puller to get the flywheel off, and maybe a clutch holder to hold the clutch basket while you losen the nut (or just use impact), theres no coolant, he must of misunderstood you, 20:1 would be correct for back in the 80's but nowadays oils are alot better so you dont need to mix so rich, most people with air cooled R's run 32:1, a tannish color on the plug is good.

[Lots_Of_Nothing]

also, since you allready have the engine apart, if i were you, i would go all out and replace everything, all the seals in the base, all the gaskets, and the crank bearings, if your going this far with it, you might as well go 100%

[hondatrikesrule22]

So basically, I guess I am taking the motor apart? Greeeeaaaaatttt. That should be fun. Does the Clymer book cover all of this? I have everything off. Wiseco is in the same town I live in....well, one of there shipping centers is and I can get everything from there if I need too.

Crank seals sound fun. So I should just replace them now? No way of knowing if they are good or bad without it running huh?

I'd hate to get it back together and find they are bad.
Any special tools needed to get to them/replace them?

Thanks guys

No special tools, just alot of cussing to get your transmission back together.

Yes you have an aircooled, no coolant.

You should be mixing at 32:1. Alot of people run 50:1 also. Back then, you had to mix your fuel exrta rich cause the oil back then sucked. Now, you have sythetic oils that you can run 50:1 without problems. Some dude on here runs his 250r at 100:1 !

[250RWANTER]

Hey I appreciate the help man.
Guess this isnt turning out to be such a good deal after all

What kind of $$ am I looking at to replace all of this stuff?

So do they sell a COMPLETE gasket kit for these motors? I dont even know where the crank seals are, but if I see an exploded view of it all, I am sure i can do it. I'll also need all of the torque specs which I am hoping the book
will cover also.

Will the clymer book cover all of this?

Cylinder doesnt look grooved really....just some piston material stuck to it. My luck, the head will be cracked or something :Evil

Thanks man!

[hondatrikesrule22]

The manual should cover it all.

You should replace everything, but I would just rebuild the top end. Escpecially if you are new to this stuff. I know crank bearings cost around $20 a piece and there are 2 of them. Then there are various other bearings and seals. I am guessing around $400 for the rebuild. Good luck!

I am always looking for new bikes, so drop me a line if you wanna sell her!

[Lots_Of_Nothing]

complete gasket set - around $35
complete oil seal set- around $30
crank bearings - around $40
wrist pin bearing - around $7
wiseco piston -around $100
bore- depends where you have it done $??
flywheel puller - around $15

its real simple, just take your time and make sure you pay real close attention to everything your doing, it also helps to take pictures along the way so you always have something for a reference to see how everything was before you took it apart.


oh and, just so you know, crank seals come in a complete oil seal kit

[250RWANTER]

So around $300 for it all...SOB.
Is there on online place that you guys like to use to get this stuff? Good service and good prices? (not sure if thats possible to have both )

So now I am torn between just the top end or the whole shebang.
Basically about $100 difference I guess.

Piece of mind is worth more than that.

Seems like a fairly straight forward and 'easy' job for the mechanically inclined. I am sure I could do it with some help from you guys if need be

I like the picture idea!

Oh and the 'complete gasket set' does that include top and bottom end? Which would defeat the need to purchase a top end kit with the piston.

Thanks!