first time 250r overhaul, please help!

[two85atc250r's]

Well, my engine is toast. I blew the skirt off of the piston on one side and locked it down. I found the biggest pieces inside the exhaust and when I pulled the jug off I noticed that there were lots of shavings down inside the crankcase. It is not totally locked it will move a little and I am wondering if it is just the shavings in there that are binding it up. The cylinder looks really good with no blemishes at all on the inside. I'm pretty sure I can save it without having to have it machined. My questions are this: Is there a chance that I can just bust it open and clean it out and just get by with a new piston? How do I figure out what size piston I have? Would those pieces that got down inside the crankcase have shredded the inside? I have done top ends but I have never split the case on a 250r and am wondering if I would be getting in over my head. I want to try and fix it myself if at all possible. Would really appreciate if someone who has done it might be able to walk me through it a little to get me started. I have got two of these engines so extra parts is not a problem. Thanks for any advice you guys might be able to give me on where I need to go from here, just hope to get my baby running again before summer!

open the cases take everything out the clutch side an take the stater an fly off (do you know how to split the case open?)

most likly you can get away with cleaning it out but it may have broke somthing but mostlikly not if you need any help pm me i had the same problem about a year ago

[TheNewn]

If you don't already have one (you should before attempting this) buy a clymer manual...

[86 Quad R]

Originally posted by TheNewn
If you don't already have one (you should before attempting this) buy a clymer manual...

better yet. get a honda service manual. as mentioned, you'll need to split the cases and clean things up really good. while your in there inspect all the bearings as well as the tranny parts, clutch basket, shift forks and the areas around the tins that cover the crank.

if the engine isnt standard bore there should be an oversize number on the top of the piston i/e .25, .50 ect ect this indicates what oversize the bore is over stock. i/e a standard bore is 66mm. so if there is a .025 on the piston it neans that it is a 66.25mm or a 1/4 mm or .010" over bore.

[two85atc250r's]

I pulled the motor out last night and am headed up to my local honda shop to get the flywheel pulled off. Also pulled the covers off both sides and everything looks good. Guts of the tranny all look good but haven't started taking anything out. I don't know specifically how to split the case but I know I am capable of doing it. Will I need a special case splitter or just a generic one? Are there any other special tools I will need to complete the project? Once again, thanks for the help. I do have the OEM service maual, is that just as good as a clymer?

[86 Quad R]

if there is a local cycle parts supply you should be able to find the flywheel puller there and save the shop time at the dealer.....

a trick that i ise to split the cases is to use a rubber mallet and a plastic puddy wedge to aid in the seperation of the cases. DO NOT USE anything metalic.

during the process i suggest that you follow the proceedure as laid out in the service manual and yes its a better manual than clymer.

[two85atc250r's]

I can't find any numbers on the piston but there is a lot of carbon on there so they could be underneath. I am pretty sure it is not standard bore. The guy that I bought it off of thought it had been bored. Is there any other way to find out? Can I have the cylinder measured or something?

[86 Quad R]

take some brake cleaner and a wire brush (brass-you'll use it later in other areas) and clean the top. if its a pro-X or OEM it'll have the over size on there. if its a weisco or other it'll have a part number with the oversize as part of the number.

if your REALLY serious about wanting to learn how to work on these machines and are mechanically inclined to do so i'll suggest that you get a set of gap gages metric/standard calipers from a local harbor freight or likewise. :cool:

[two85atc250r's]

On a second note, I picked up a second bike that the guy said only need rings, but when I pulled the flywheel cover off tranny oil poured out. What would cause this?

[86 Quad R]

pay closer attention to it.......... more than likely its pre-mix oil and smells of gas or fuel. chances are that the crank seal is bad.

[two85atc250r's]

Would that oil being in there ruin the stator or the spark generator? It doesn't seem like premix, it seems like gear oil to me. No fuel smell.

[86 Quad R]

in that case your seal at the counter balancer holder is leaking.

[kit bazile]

hey if you need any parts are any help just pm me the luck i have with them i tare one down seems like everyweek ant the right 86 quad r :D

[two85atc250r's]

Thanks alot for all the help. I am still stuck at the flywheel. I can't find anyone that has the puller to get it off. Can you just pull it off with a regular claw puller? As soon as I can get it off I am going to dive into this thing, wish me luck. I will post any questions, I am sure there will be plenty. Thanks again guys for the support.

[Qracer]

Don't use a jaw style puller, it will wreck the flywheel. Get the right puller, I have seen them on E-bay for around $10. That is a lot cheaper than a new flywheel.

[86 Quad R]

as mentioned. DONT use the claw puller. you need the mo-pro type and should be able to get it at any local cycle retailer.


http://www.motionpro.com/images/items/08-0026.jpg

[two85atc250r's]

The only reason I was thinking of using the claw puller was because the flywheel is going in the trash. It had gotten wet in there and it is totally rusted over and corroded. I have another one to put back on it when it goes together. So if I am gonna toss it will it be ok to just use the claw puller? It won't hurt anything else will it? Thanks again guys.

[86 Quad R]

it sure can............... if by chance one of the claws puts less pressure than the others, it can cause things to pull to one side. resulting in a bent crank. not to mention "safety" reasons. i've heard of instances where the flywheel and puller shot across the shop lol

just how rusty is the fly wheel?

[two85atc250r's]

Ok then, I am convinced. I will just wait until I find the right puller. I just didn't want to have to wait for it to come in the mail, because no one here in town has the right one. The flywheel is almost totally covered in rust and is solid brown in color. I can bust the rust of with a steel brush but it is really pitted underneath. Can you save a flywheel that is that bad? Thanks.

[86 Quad R]

Originally posted by two85atc250r's
Ok then, I am convinced. I will just wait until I find the right puller. I just didn't want to have to wait for it to come in the mail, because no one here in town has the right one. The flywheel is almost totally covered in rust and is solid brown in color. I can bust the rust of with a steel brush but it is really pitted underneath. Can you save a flywheel that is that bad? Thanks.

yup. i've seen some purdy ruff looking flywheels that still functioned like it was sposed to. make sure that the surfaces of the stator and pic-up coil are nice en shiney.

[C-LEIGH RACING]

If that flywheels rusted that bad, could be the threads where the puller goes into the flywheel are messed up & the puller like your suppost to use wont work, just thinking though.
I've seen a few like that & the jaw pullers only way left to get it off.

How ever bad it is rusted, if those puller threads arent messed up & you get it off without messing it up, just have it bead blasted with media like walnut shell or glass beads.

Funny thing about rust, & something a lot of people dont know, some of the longest lasting cylinders to ever be used is one thats just sat out & allowed to rust over real heavy in the sleeve & then a good bore & fit put in them.
Sounds crazy, but real is real.
Neil

Originally posted by C-LEIGH RACING
If that flywheels rusted that bad, could be the threads where the puller goes into the flywheel are messed up & the puller like your suppost to use wont work, just thinking though.
I've seen a few like that & the jaw pullers only way left to get it off.

How ever bad it is rusted, if those puller threads arent messed up & you get it off without messing it up, just have it bead blasted with media like walnut shell or glass beads.

Funny thing about rust, & something a lot of people dont know, some of the longest lasting cylinders to ever be used is one thats just sat out & allowed to rust over real heavy in the sleeve & then a good bore & fit put in them.
Sounds crazy, but real is real.
Neil


ha i think i got a rusted cylinder laying around its not bad rust but it is a lil

[86 Quad R]

that totally slipped my mind.:rolleyes:

neil is currect two85atc250r's about the rust in the threads where the puller tool goes in. what i have done in the past is to use one of those 15.00 hand held blasters (with fine aluminum oxide media) to hit those threads with great results. :cool:

[bushwesl]

Originally posted by 86 Quad R
one of those 15.00 hand held blasters (with fine aluminum oxide media)

And where would one find one of those $15 hand held blasters? Got a link? :)

[86 Quad R]

either THIS (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92857) one or one of these A (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=93221) B (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=95793) C (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=45998)

the first is the one i've got :cool:

[two85atc250r's]

The threads are very rusted. I tried to clean them with a brass and steel brush but with little results. I don't even know if I could get the puller to thread in there as bad as they are. I will post some pictures of the flywheel and my two project bikes. I'll get it off eventually, then the real fun begins.

[two85atc250r's]

I found this puller on ebay, 10 bucks. Does it look like the right one?

[two85atc250r's]

I found this one at my local harbor freight for 11 bucks. I think I'll go pick it up this afternoon. Thanks for the tip.

[two85atc250r's]

Here's the flywheel

[two85atc250r's]

And here's my two projects. If all goes well hope to have them both going for summer.

[two85atc250r's]

.

[kit bazile]

thats it

[C-LEIGH RACING]

Looking at that pic, dont look that bad.
You could probably spray some lube in there & screw the puller in untill it stops, then back it back out some & then screw it back in. Do that a few times & soon or later it will go all the way in.
Once you've done it a few times, pull the puller completely out & wash the threads out with some more spray lube to get all the broken loose rust out.
Neil

[two85atc250r's]

you think I could re-use that flywheel if I clean it up?

[86 Quad R]

i've seen em in worse shape that worked fine.

[two85atc250r's]

Thanks again guys. I've ordered the puller so I am just waiting for it to get here. Once I get the flywheel off I will keep you guys posted on the breakdown process. Everyone here has been a big help, I don't think I would have tried this for the first time by myself without advice. I really appreciate it.

[two85atc250r's]

Anyone have a 66mm piston they want to get rid of? I would like to go bigger but my budget does not allow it. Maybe next time, for now I'm staying stock.

[86 Quad R]

before you just go en stick a piston in there you should measure the bore for wear and tapper. if it exceeds the exceptable limit then you may very well need to bore.

[two85atc250r's]

Thanks. I will have to take it and get it measured, I don't have a dial caliper. But I will get it done before I install a new piston to make sure it is within limits. Sorry for my ignorance, and thanks for all your patience. lol.

[86 Quad R]

you got a harbor freight near you?

[two85atc250r's]

Yeah I do, just right down the road. Do they carry the calipers I would need? I've got a regular inside/outside set but nothing that would get down in the jug.

[86 Quad R]

you can use These (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=5649) or These (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=94447) in conjunction with what you already have. :cool:

[two85atc250r's]

Man, thanks so much for all your advice. I will go and pick some up this afternoon. One thing I don't have a problem spending money on is tools. I'll post my measurements once I get them done so maybe you can tell me what you think.

[two85atc250r's]

How much might I be looking at to have my cylinder bored? I got it really clean and looked down in there with a light and found a couple really shallow scratches. Does it need to be totally perfect? Would I have to resleeve it or just have it bored? Once again, sorry if I have some dumb questions, I just want to do this right.

[86 Quad R]

prices can range from 30.00 to 60.00 but its important to use someone that does cycle cylinders frequently as the port openings on a two stroke need to be smoothed out(chamfered) and the exhaust bridge releived(recessed)

in many cases if the system hasnt been contaminated by dirt(scared cylinder) and the bore wear and taper are within tolorences a light honing to clean the sleeve up will surfice but i personally preferr a fresh bore.

the only time a sleeve needs to be replaced is if its on its last bore or has been damaged severely by a grenade.

[two85atc250r's]

Any suggestions on someone I can send it to to have it bored? I doubt there is anyone here in town who I would trust to do it. If I am going to go ahead and have it bored what size would you suggest I go with? Will I need to change anything else like exhaust or carb if I have it bored? Thanks again, maybe all my dumb questions will help someone else. lol

[86 Quad R]

check around at some of the local machine shops or cycle repair services. if ya need to, go visit with them. ask the important questions. if they do bore cycles. ask f they relieve bridges and chamfer.

[TheNewn]

You shouldn't need to change your carb/exhaust when you have it over bored to the next size. Perhaps jetting, but not by much i would think.

Unless you feel like going bigger, i'd only bore it to the next available size. Obviously you only have so many bores available on a sleeve, and if you skip a few sizes thats only that much less you have for cheap rebuilds in the future. If you understand what im saying.

I'm not sure what the next size would be on an overbore, if you're still on the stock size of 66mm, you could go to 66.25, or 66.5 i guess. Check with your shop.

[two85atc250r's]

Alright thanks guys. I will go and visit some of my local shops and see if I can find someone to do it. I have only got about 6 or 7 hundred to spend, I just hope I can get this motor fixed right for that. We'll see I guess when I get inside it. If there are any other must do's on a total rebuild please let me know. I don't want to miss anything.

[two85atc250r's]

Do I need to do anything to my head while I am at it?