Topic: CB400F pistons in a CB350F

[jsedacca]

Hey guys,
     I'm currently in the midst of my cb350f engine build. I have stock CB400F pistons (51mm) that I plan to use. From what I gathered, this is the maximum size to bore out the cb350f jugs. My main question is, is there anything that needs to be done to the combustion chamber area of the cb350f head? I'm assuming I'll need to use a CB400f base gasket but what about the head gasket? Any help/insight would be greatly appreciated. Thanks

                                                     Jared

[fmctm1sw]

Hey guys,
     I'm currently in the midst of my cb350f engine build. I have stock CB400F pistons (51mm) that I plan to use. From what I gathered, this is the maximum size to bore out the cb350f jugs. My main question is, is there anything that needs to be done to the combustion chamber area of the cb350f head? I'm assuming I'll need to use a CB400f base gasket but what about the head gasket? Any help/insight would be greatly appreciated. Thanks

                                                     Jared

Something tells me the valves were different.  Other than that, not sure...

[ttr400]

Yes you can fit the std 400F pistons (51mm) to the 350F. This will leave you with a wall thickness of 2.0mm on the sleeves, this is borderline but I have done it. The last one I did I sleeved it with new sleeves to allow an over bore if required later.

You can use the CB350F base gasket, but you will have to fit a custom copper head gasket. Combustion chambers OK as they are. The 350F valves are smaller than the 400F. you could fit std 400F valves if you are going to do a head job.

350F Valves:
Inlet: 26.0mm
Exhaust: 22.0mm

CB400F Valves:
Inlet: 26.5mm
Exhaust:23.0mm

Kevin

[jsedacca]

That was the answer I was looking/hoping for. Thank you

[jacksonc]

I've got a 400 and it isn't like super powerful or anything I'd get some jugs from a 400 and put in the 460 kits, then you'd have a really big 350