Rebuilding a bottom end

[ats666]

Hi, Im rebuilding the engine on a 1979 yz250 for the first time well the bottom end that is.
The lower conrod bearing let go after 6 hours of riding during 30C temps as I was pulling into the driveway.


I have a fresh cyl, piston kit, head and gaskets, crank bearings.

There are no new crank kits aval (not shocking).

Engine is out of the bike but that`s all i`ve had time for.

2 Questions:

Does anyone know which flywheel puller I need?

Is the conrod ever salvagable or is it always toast?

I have a funny feeling I will have to goto E B A Y for a used crank and then rebuild it.

Thanks

 

[Bonehead]

You should be able to get a kit from hot rods. Rod, bearings and pin

 

[whenfoxforks-ruled]

79 should be the threaded rotor extractor, they make a bunch of odd sizes though. Refurbed rods, I do not know about that, measure and inspect. No rods for my old RM's, I would sure measure and inspect before fleabay! Best of luck. Mine does not have thrust washers, but there are much smaller washers between the bearing and crank. Pop the crank apart and see how the rod looks!

 

[jsantapau]

the flywheel puller for my 94 wr/yz 250 fits my 79 yz 400 dont know if that means anything to you but as for the rod take it apart and do some measuring..... I am pretty darn sure you can find a rod that fits.......might have to go to a different top bearing, might need to space up the jug . I know that the 465/490 connecting rod is the same length and uses the same bearings as the 79 400 but is a lot heavier and bigger around the bottom end bearing to the point you need to clearance the case a little to make it fit

 

[Ol'89r]

Like jsantapau said, Take it apart and measue the rod. Then, go to www.lasleeve.com and look at their chart. They offer rods, shims and big end bearings by size and you may even be able to find a rod and crankpin set complete.