Fixing 03 650 Crank issues

Hi all,
Just suffered my first crank failure on my O3 650.
I know Husaberg have tried to adress the issue in 04 by destroking them from 650 back to 628 ( although my manuals show the 650 and 628 both with an 82 mm stroke ?? dont think so)
And in 06 they have upped crankpin dia from 32 to 35mm.

Repairing my 650 with the 03 crank is not an option. No point repairing a known weak point without trying to improve it.

The question is, do the later 650s share the same case height which would allow an 06 crank to be purchased and fitted ?
Do the SEM and Kokusan share the same taper angles/ lengths for flywheel mounting ? Ie can I fit my SEM onto the 06 crank, and then when it invariably fails do a Kokusan conversion?

What are my other options for reliable repair? Other than one one of JBS kits (I dont need a 750)

Or do I just push it in the corner of the shed, throw a tarp over it and make out it never existed ? :lol:

BTW, Desert useage- long periods of upper end RPM

I know this has been a big issue with the 650s, surely someone has come up with a fix other than frequent replacement ?

Anyone ?

JoeUSA said:

Is a 82mm stroke JBS crank & rod kit available?

It seems like this would be a good product! '


Regards,

Joe

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I dont believe JBS does any cranks other than his 750 strokers, however I too believe he would enjoy reasonable sales of 650/628/550 35mm pin/balancer less cranks if he were to offer them.

Luckily, I have a good friend within a CNC machining business,so if it becomes absolutely essential, having a crankshaft fabricated is not an issue. But at this stage, I'm weighing up all my options :wink:

nsman said:

Hi Ausberg,
When trying to repair/update a 03 450 prototype engine that had suffered a crank failure,it was found that the keyway position is different between SEM and Kokusan cranks.Also the crank pins between 03 and 04 models have different oilway hole positions, so a 04 crank pin will not line up in a 03 crank web.

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Thanks for the information nsman. If the seperation angle is enough, having the crank machined for the different SEM keyway location would not be an issue- as long as the tapers/lengths were the same.

In regard to the crankpin, the plan is to get right away from the 32mm pin i believe all pre 06s use, so I dont plan on trying to reuse my webs-
either a complete 06 628 crank will be purchased if it is compatabile with my cases, or a one of made as per previous posts. But that is a last resort option.