Crank bearing pins

[700vflash]

I had to get a different crank for a rebuild and noticed that 1 of the 4 bearing pins that lock the bearings in place is noticably shorter. I thought the one might of been damaged but now I have 2 stock cranks and they are the same, it is the bearing on the right side. It just seems odd that all have decent pins and 1 just has like a dimple. Is this correct or should all 4 pins be the same? Thanks.

[AKheathen]

I had to get a different crank for a rebuild and noticed that 1 of the 4 bearing pins that lock the bearings in place is noticably shorter. I thought the one might of been damaged but now I have 2 stock cranks and they are the same, it is the bearing on the right side. It just seems odd that all have decent pins and 1 just has like a dimple. Is this correct or should all 4 pins be the same? Thanks.

that is correct, the pto bearing is usually nippled, not pinned

[700vflash]

Thank you, I was a little concerned about that, although I figured that was normal since both cranks were the same.

[crazycanuck]

that is correct, the pto bearing is usually nippled, not pinned

I just noticed my new hotrods 4 mil crank doesnt have any bearing dowel pins.....

do they only come on OEM cranks??

[AKheathen]

I just noticed my new hotrods 4 mil crank doesnt have any bearing dowel pins.....

do they only come on OEM cranks??

hot rods just use o-rings instead of pins

[dajogejr]

Oh boy....

I had one of those dowel pins come loose, get sucked up in the combustion chamber and it smashed the shit out of my dome and piston.

 

So, I'm removing ALL of the dowel pins and using a bearing loctite to keep the races from spinning in the cases.

 

Crankworks and hotrods/wiseco use an Oring.

 

I no longer trust those dowel pins.

 

[AKheathen]

ouch, looks like it snagged on a couple ports........did the cylinders fare good? need re-plating?

[700vflash]

looks like confetti, that sucks! Is that a rare issue or does that happen often with these crank bearings?

[dajogejr]

Here's the whole story...and I'm very sorry to hijack your thread 700.

New Vitos crank this year. It is a solid piece, came within .003 right out of the box and welded pretty good.

I'd drop it in, but my buddy does an even better job welding cranks and he pressed off the OEM bearing on the PTO side and I dropped on a TZ.

 

I sucked a crank seal mid year. Tore the motor down to replace them both and seal 'em up.

When I split the cases, the dowel pins were laying in the case cavities...out of the crank.

 

So...I took the pins, put them in a vice, smooshed them, and pressed them back in.

 

I thought nothing of it.

 

Sealed the motor up, went to the track and made one pass.

Got back to the pits and pulled a plug, noticed aluminum.

 

So...not knowing when I'd run the bike again, I purged it at very, very low RPM. It killed the motor.

 

I took it apart a few weeks ago, I think the cylinder is fine. Gonna hone them both (cylinder was freshly plated this year, only about 40 to 50 passes made this year)

 

Piston and dome are obviously trashed.

 

I think the crank is going to be ok since I was only purging when all this happened. If I was making a pass...it'd be another story.

[700vflash]

Hell man, no need to be sorry! Sounds like a good lesson learned right there.