question

[Cathal]

i bought a yamaha yz 250, 2001 with the crankshaft gone, the big end bearing went and the bottom of the con rod snapped, the cylinder and everything else is ok, but inside the casings where the crank spins there is a small bit of damage, the con rod snapped off and is after scraping the casings and took a chunk out. its not that deep and it will not cause the casings to leak,

I am wondering, if the bike will still run ok when i put it back together

Thanks
Cathal

[Big Maico 393]

Originally Posted by Cathal

i bought a yamaha yz 250, 2001 with the crankshaft gone, the big end bearing went and the bottom of the con rod snapped, the cylinder and everything else is ok, but inside the casings where the crank spins there is a small bit of damage, the con rod snapped off and is after scraping the casings and took a chunk out. its not that deep and it will not cause the casings to leak,

I am wondering, if the bike will still run ok when i put it back together

Thanks
Cathal

First off welcome to !

Yes it will run if it doesn't leak, but how big is the missing chunk? if it's not any deeper then a MM I would worry about it. if deeper you might want to get it welded up to keep if from totally blowing out under pressure.

[Cathal]

Thanks

yes its deeper than a mm about 3/4mm and about 20mm long, but its not on the bottom of the casings its on the side closer to the top, and it wont be able to blow out under pressure because the casings are alot thicker there.
So should be ok yeah?

Eidt: BTw would it be ok to wash the casings and the bearings in a diesel bath?

[MXtras]

Originally Posted by Cathal

would it be ok to wash the casings and the bearings in a diesel bath?

Not if you are going to have them welded. Non petroleum based solvents should be used if the cases will be welded - solvents like brake cleaner.

I assume you have all of the bearings and seals out of the cases?

Scott

[Cathal]

had a serious problem, order parts from america, i live in ireland, and turns out its a 97 bike not 00 so i had to change the parts quick before he sent them, luckely he did'nt send them, but.... there is no aftermarket crank for 1997 so i had to order a con rod so the origional can be rebuilt. one problem i have is: you know the plastic bit on the crank, that is damaged and i need to get a new one so if anyone has any ideas where i could get one it would be great

Thanks

edit: But it would be ok to wash in diesel bath if i was not going to weld the cases?

[MXtras]

Yes. Pretty much any solvent would be fine as long as it's not acidic. Some solvents will destroy your seals, but all of the seals should be replaced during a case split anyway.

As far as the crankshaft - have you priced an OEM replacement? The factory cranks will have NO misalignment, while rebuilt crankshafts will, guaranteed, have some misalignment. The misalignment will cause vibrations and will destroy your bottom end bearing much sooner than normal. I have never had what I consider success with rebuilt crankshafts.

Scott

[Cathal]

yes i;ve found a site which sells them and i dont know what the story with the price is, there is one for €173 and another for €427 the one for 173 says crankshaft and the one for 427 says crankshaft assy

so i dont know what the difference between the two is? maybe one is build the the other has to be pressed together??

here is site
[Only registered and activated users can see links. ]

ok found it its gona cost €508 for a new oem crank big steep ah

[Cathal]

i'm going to get the crank rebuilt i think,hav'nt got much of a choice, the plastic slugs on the crank are damaged from the con rod smashing and need to be replaced so i am wondering does anyone know where i could get these?

[xtchahos]

hey i live in ireland myself and ride a 96yz250 i find ebay.co.uk is a very handy place for parts u could get a complete engine for the price of that crank regards paul