BMW F650 crankshaft

[stingray18]

First posting.

Had a knocking in engine only at 4,000rpm, not below and not above.
pulled down engine, to find play in big end.

Acording to BMW and all parts diagrams, the whole crankshaft comes as one piece - no parts are available just to replace the big end bearing.

Is there anyone out there that has tried pressing the crank apart so as to replce the bearing.

I'm sure it can be done, but would like information before attempting it.

Any input would be grateful.

[pete376403]

ask the question here http://www.advrider.com/forums/forumdisplay.php?f=15

Somebody must have done it before

[Howie]

You could also try having a hunt around the threads on this site http://f650.com/phpbb3/index.php

I found this article about Rod bearing faliures fairly quickly, but there is bound to be more info out there http://faq.f650.com/FAQs/EngineNewFAQ.htm#Rod Bearings Failure

[sidecar bob]

I understand that the motor is a Rotax, have you tried to search for Rotax bits without going through BMW?

[stingray18]

Yer tried all avenues with the rotax motor.

Aprilia and BRP use same motor, only they use straight cut roller bearings on the mains and needle rollers on big end.

Engine definately been aopart before!!!

[pete376403]

Hmmm, what sort of rollers do BMW use?

Also - speedway engines (500 singles) use a pressed together roller bearing crankshaft. There are a few guys around who do a fair bit of this sort of work, if you can find the parts it should not be too difficult to et the crank assembled and aligned.

[MIXONE]

Try B&G Automotives on 3rd Ave I think.The owner rides a beema and has rebuilt lots of bike motors in the past including several for me.

[stingray18]

Ureka!!!

Managed to get it apart.

Main bearing run without oil - seized on crankpin - turning inside conrod.

Managed to find bearing from UK although found the mains are exactly the same size, more expensive though for mains.

Will have to get conrod sleeved to fit bearing, but crankpin OK witth a polish.

[tamarillo]

bad luck.. what sort of miles has she done? any obvious reason.

[stingray18]

According to the tacho 150,000.

[clint640]

According to the tacho 150,000.

Jeez, just run in really <_<

Interested to know how you get on with the crank rebuild, I want to give my KTM a big refresh when she hits the 100K km mark, have ordered all the bits & am happy doing most of the work myself but pressing the new bits onto the crank is best left to experts I think, so I need to know who the experts are.

Cheers
Clint