Rebuilding a 250r bottome end

[Ryah]

How hard is it to rebuild a 250r bottome end. I got a quote from a local shop for $650.00 to rebuild the bottom end. $300.00 was labor. I'm pretty mechanically inclined, can it be done with normal tools, or will I need special tools to get the job done right. I'd like to save myself $300.00, but not at the risk of messing up my bottom end.

[staceyl200]

Hi !! Get a manual and just take your time ,I,m in the middle of the same thing at the moment with a 85R and its in a real mess ,I got a proper Honda 85/86 ATC250R manual and its a godsend .. You will need a flywheel puller but you can get them off ebay cheap.
Good luck dude !!!
Stacey

[MN250R]

I agree, i did mine on my 85R. I got a flywheel puller from ebay , Manual off ebay, and took my time. Main reason for my bottem end disassemble was the old cast piston fell in there when 2 of the skirts broke off. What i would do is make sure when *Edited* put it back together you can shift smoothly through the gears. What i did was once i had the bottem end together , i slipped on the front sprocket, slid the shifter on, get it in neutral and make sure the sprocket spins freely. Then go through the gears. Oh and this is the time when extra parts left over are not a good thing :rolleyes:
good luck!:TrikesOwn

[atc86r]

its easy with the manual . Puller was $13 off shelf at local shop. Do it yourself and if you have problems a shop will put it back together. don't pry on cases and covers with screwdrivers. You'll be glad you did it and found out how easy it was and the money you saved.

[Dammit!]

I'm getting ready to do this also (if the parts I bought ever show up :rolleyes: ). I was figuring I could at least do most of it. Might need a little help with getting the main bearings pressed in and out but that should be it I would think.

[Louis Mielke]

It surprises me how many people here haven't had a bottom end apart. I think one of the best engines to start with is a CR80. After that any honda 2 stroke is easy. I took me three tries with an 80 before I had it right but every bottom end since has been cake. Just don't attempt to rebuild a crank in your garage. Let someone with the proper tools do it. Everything else, clutch, trans, crank bearings, counter blancer, no problem.

Oh and the best home garage tool ever is a large toaster oven. I mean it!
And a torque wrench isn't abad investment either. Most people say just tighten a bolt till its tight, not cool.

Also, remember some bolts/nuts should have thread locker used on them, don;t use red loctite, blue is more than suffient.

EDIT: Course now I'm sure to have started some kinda debate. lol

[Louis Mielke]

I'm getting ready to do this also (if the parts I bought ever show up :rolleyes: ). I was figuring I could at least do most of it. Might need a little help with getting the main bearings pressed in and out but that should be it I would think.


Don;t press them in! Heat your cases in a toaster oven (take the seals out obviously), and put your bearings in the freezer in a plastic bag. Then use pot mits to put the cooled bearings in the heated cases. They'll all but drop in I garrentee!

[Dammit!]

Don;t press them in! Heat your cases in a toaster oven (take the seals out obviously), and put your bearings in the freezer in a plastic bag. Then use pot mits to put the cooled bearings in the heated cases. They'll all but drop in I garrentee!

I'd have to buy a toaster oven. My local shop usually does little things like that for me for free. ;)

Good tip though. If I have an extra oven in my garage for powdercoating by then I'll give it a shot. Curious why a toaster oven instead of a regular oven. Any reason for that?

[Louis Mielke]

Perfect size for engine cases and heats up faster. Less area to heat. Well, I say toaster oven, but it depends on what toaster oven. I have a rather large toaster oven, You could put a small turkey in it. Best thing is it sits on the counter, no stooping that kinda thing. Right from the oven to the work bench.

Nothing says lov'n like horse power from the oven!

[200x Basket]

here is a step by step pictorial that i made.

http://www.3wheeler.org/vb/showthread.php?t=6218

[Louis Mielke]

Excelent write up. we should make something like this for the main page and inlcude the top end.

[RideRed250R]

LOL thats how trinity installs bearings lol... pc oven... just for larger engines.. but its the same principle ... also make sure your oven is evenly heated.. let it warm up before you put it in... also with the bearings the freezer works but ussaully they will go in with a warm case and a SLIGHT tap of a rubber mallet, i just always was concerend with HOT and cold touching sorta like a clay pot on a stove and put some water in it... thats my opinion
adam

[Yamahauler]

Some one make a write up for a tri-z with how to put the tranny together. Haha, I think I'd be able to figure it out, but a guide would be nice.
I bought my tri-z with the motor disasembled, and the tranny out.

[Yamahauler]

Another thing....Do you have to split cases to change crank seals on a tri-z?

[bluevetteguy]

A write-up link for a Z would be great. I'm doing a 6 speed swap on my 85. Got any links to some info that might help me out. I tore apart the 4 speed on my 76 T/A but this little tri-z tranny really intimidates(sp?) me.