xs650 Horse Power

[Punkskalar]

Now, let's get back to the thread. I'm interested in these nice little home grown how to's on free horsepower. I've got a 72 motor that leaks around the base a bit. When I tear it down I'll probably go through the head and lap valves, mild port/ clean. But I also have a later crankshaft and rods chilling in a box ...somewhere. Can you mix the early pistons to a later rod? What else can we do to run these a bit harder?

That 72 will have a decent set of pistons and longer rods, stick with those. You can't swap the pistons onto different rods as the early pistons are 22MM in the wrist pin, while later pistons are 20MM. That early head is a nicer casting than the later ones too, so a good cleanup of the ports and some polishing will really help it out.

IF you keep the stock bore, you can delete the base gasket and use a thinner copper head gasket for a full point or so in compression bump Go ahead and keep that 72 camshaft as well, its my preferred camshaft for building engines with. IF you delete the base gasket and install a thinner head gasket, you'll have to redegree the cam by pressing the gear off and getting it to open at the right timing again. Not too hard, but a little time consuming.

Overall, you can make that 72 a screamer, and YES, you can rephase the early engines if you soo choose.

[Punkskalar]

Rollo is good people, he had my back when someone was ripping off my parts No stresses there....

[650Beezer]

Early high compression pistons, using a 256 set of rods and pistons... Longer rod, same bore, shorter piston height = longer dwell at TDC and BTDC... Deck the head and delete the base gasket - just make sure the valves are gonna clear the pistons. That should get you in the 11:1 range or so. That and some good head work and free flowing exhaust with a good set of carbs will get you there [/QUOTE]

Can you build such a motor? and if so, how much $ ?

[Punkskalar]

Can you build such a motor? and if so, how much $ ?

If you have a 256 Donor engine (74 and down) in good shape, then take a look here: http://hughshandbuilt.blogspot.com/p...-services.html

I don't want to distract from this thread, I think there is some cool information being shared here for the budget minded builder

[ROLLO]

Punkskalar always have your back your hell of a guy . There was nothing on anyones product but everyone has problems with everything . But a rebuild motor is a rebuild motor out of 30 year old parts . I tell whats cool when your runnin your 60,000.00 and the dude who built it leaves a rag in the pan . everyone has bad days .

[cros36]

If you have a 256 Donor engine (74 and down) in good shape, then take a look here: http://hughshandbuilt.blogspot.com/p...-services.html

I don't want to distract from this thread, I think there is some cool information being shared here for the budget minded builder

hugh, with all due respect i just wanted to throw it out there that my 74 is a 447. i think that some 74's are 256 and some are 447, not for certain. just dont want confusion on the subject.

[Punkskalar]

hugh, with all due respect i just wanted to throw it out there that my 74 is a 447. i think that some 74's are 256 and some are 447, not for certain. just dont want confusion on the subject.

yeah, there are a few oddball mismatches mid year in 74.

[got556]

I'd just like to apologize coming off like an ass earlier lol.

I was in a bad mood and I think the heat is getting to me. So again I'm sorry for the dick move back on the other reply.

[killkill]

IF you keep the stock bore, you can delete the base gasket and use a thinner copper head gasket for a full point or so in compression bump Go ahead and keep that 72 camshaft as well, its my preferred camshaft for building engines with. IF you delete the base gasket and install a thinner head gasket, you'll have to redegree the cam by pressing the gear off and getting it to open at the right timing again. Not too hard, but a little time consuming.

does this go for any xs650 motor? having a tough time figuring it out in my brain, but having a problem doing that...i guess you're gaining more length in the cam chain which would make the cam be running behind where it should be? all year cams press off? would like to make a little more compression out of a (mostly) stock motor.