XS2 engine idea thread.


Gold Coast, Queensland
Alright I started this thread as a way to keep all my ideas in an accessible place as well as allowing others to input their suggestions.

My working platform is a 72 Xs650 engine of unknown internals.
All I know about this engine is it was a spare for a speedway sidecar, it had an oil cooler between the heads oil feed line and it is known as a "306" to Xs gurus.

From what I understand I have the sort after "hot" 256 cam shaft. With the longer 256 rods.
I had planned to fit a 750 kit to this motor, but most are made for the 447 engine.
This left me looking at getting 447 rods fitted to the 256 crank and the crank and cam rephased to 277 by Hugh from HHB.

I have also found that the sump filter and stock charging system are major issues with these engine, so I had planned to fit a PMA kit and the sump filter mod on offer from Heiden tuning.

Just a few ideas so far. Feel free to pitch in.


Staff member
I'd think Hugh or someone would be able to find a 447 motor to trade for yours. Someone out there wants a 256 for their XS1 restoration. Rephasing and boring an early engine might be more hassle than its worth.

My charging system has been fine. PMA is good for battery elimination but beyond that a decent condition rotor will last.


Gold Coast, Queensland
I had been thinking of that as well time. The bloke I bought the engine off would not sell me the two 447 engine he had as he said they were beyond repair.

The problem with a motor trade is that because I live in Australia no one wants to pay the shipping. I have posted a trade in the swapping area just in case there is interest. I also posted a trade over in the XS650 forums.


'73 CB350, '78 XS650 Cafe Killer
Heres a photo of my '78 XS650.. goodluck on your build man.. Ill be tuned in.. holler if you need anything!


FWIW, I really don't believe there's anything wrong with the stock XS650 charging system with one caveat. The original rotor will fail in very short order. It is because of the technology used for wiring insulation at the time these bikes were built. Heat and vibration do them in quickly now that they're old. A good rewound unit should last as long as you do. Have it rewound and check the brushes once in a while. You're golden!

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