96' CR125 SEIZED!!!

[AustinHeath89]

Ok, i bought the bike from a guy in my town who knew nothing about the bike, i know the original owner (who took the bike apart down to the frame and could not put it back together) he took the bike up to a friend of mines moto shop and said here you can have it. My friend (who has now moved, which is y im not asking him this) put the bike back together with aftermarket exhaust, piston, pretty much everything. He then sold it for 1000$ to the guy i bought it from. the guy rode the bike till the gas that was in it ran out. he went to put new gas in it (the day before i bought the bike), but is was NON-MIXED fuel!!! he kicked it over a bunch of times (he says) and it never started (DUHHH) so i bought the bike for 600$. Great deal for what is in the bike and the low hrs total between 3 owners. SO i got all the gas out of the tank/carb/engine and put new 40:1 gas in it. the bike ran great untill about 3 hrs of riding. the bike all the sudden seized around a corner while i was down shifting. I pushed the bike back and it then could be turned over but sounded funny like a bearing was blown. so i took the bike back down to the frame and it now in 100000 pieces in my living room. im getting the bike powder coated black and gold as we speak but i cant find out what is wrong with the bike...

What i have noticed...
1 piston ring and all top end looks PERFECT
2 botom end from what i can see with the cylinder off looks and feels fine no excessive play or anything.

but, when i put it all back together, and move the kickstarter the motor gives off a sound like a bearing is messed up, any ideas,

Should i fuel it up and try to start it?

Thank you for the help and i will post pics once the powder coating gets done!

UPDATE: The connecting rod has about a quarter the a half inch of play up and down.

[crdude]

Did you turn it over with the top end off? Im thinking it could be a shot crank bearing. and if it locked up and then free'd up with time it sound like you over heated it.

[AustinHeath89]

Check the update at the bottom of the thread.

Thank you for the help!!!

[crdude]

That sucks, time to rebuild the bottem end!

[AustinHeath89]

Time to get my hands dirty(er) and continue the tear down...

Took the bike up to the Moto Shop [Only registered and activated users can see links. ] in Pensacola, FL to help me with the tear down and guide me on the bottom end rebuild.

Here is a pic of my living room before i got the swing arm off to powder coat black, i was going to do the rims, but i didn't want to get them done and the first time i take the bike out the rim to flex and chip off the powder coating so i decided to go for the swing arm instead.



Other Reasons...

Rims = 100+ un-lacing and re-lacing
Swing Arm = an additional 20$ to my already 150$ powder coating bill

[dogger315]

The connecting rod has about a quarter the a half inch of play up and down.

I don't know how you plan to deal with the big end rod bearing, but I would
recommend replacing the crankshaft with either a Wiseco or Hot Rods crank
kit. You can get a brand new one on Ebay for under $160 with free shipping.

If you try to replace the bearing, you will need to have the crank blown apart,
install a new bearing and probably a rod then pressed back together. Their
are few shops I would trust to do that job right, and none are in P'cola.

When you factor the labor for crank rebuild plus a new rod and bearing, you
are bumping up against the cost of a new crank anyway.

At least you have a shop that is willing to work with you on the rebuild, I
would take advantage of it.

Don't feel too bad, a 16 year old tiddler that hasn't blown up already is a
ticking time bomb, at least you got that "check in the box" early.

Keep us posted.

dogger

[AustinHeath89]

As for having a shop that would work with me on the rebuild, i guess i had my hopes high, there a small shop so they dont get to good of deals from weisco.

i got a call this morning from the shop saying that i was going to need to replace my whole crank (which as explaned by dogger would be the best anyway) because the main bearings are shot, or so they say. the motor has just the cylinder off (how do they know the main bearings are shot?) there is noplay in the crankand it spins freely,i think they are trying to just get me to buy a new crank cuz its easier.

anyway they wanted 700!!! for the bottom end rebuild with a wiseco kit!!!

so im going to order my own wiseco kit off the internet and just get to work pulling the old crank out.

DOES ANYONE HAVE A STEP BY STEP TUTORIAL OF HOW TO DO A BOTTOM END REBUILD WITH PICTURES???

if not ill take pics as i go and make one

[dogger315]

DOES ANYONE HAVE A STEP BY STEP TUTORIAL OF HOW TO DO A BOTTOM END REBUILD WITH PICTURES?

I posted a series of articles detailing a CR250 engine build in the Honda two
stroke section. Might be of some help.

Before you consider doing it yourself, make sure you have a good service
manual and the necessary tools. Unfortunately, you can't go down to your
local Pep Boys and rent a case splitter or flywheel puller.

Unfortunately, I'm swamped right now with restoration projects or I would
do the bottom end rebuild for the cost of replacement parts - it should only
take a few hours. The good news, here's your opportunity to "jump in" and
learn by doing and save yourself a bundle now and in the future.

I will be glad to offer advice and assistance and answer questions along
the way. You can post them here or PM me.

Good luck with it.

dogger

[AustinHeath89]

OK GOOD NEWS i found a local guy with a jet ski shop and he let me use one of his bay's today to remove the engine and split the case. Got the motor out no prob, and started the dis assembly...

The tear down was the easy part (with the right tools that is) so i got the motor all to pieces, and now im scared, i have all the parts and didnt loose anything, but the trans is scaring me. there are so many little pieces and all, i hope it goes back together right...

now i think the only thing i need is a crank puller to put the new crank back in.

im ordering a OEM or HOT RODS kit this friday and also a new manual.

if there are any tips or suggestions on the re assembly please let me know!

Austin