CB360 Engine upgrades

Hello DTT, I've been wanting to make some improvements with performance, besides weight and better air flow. Now that I have a job and now can afford more than just making it look nice, I would like to upgrade my engine. I was wondering if a 2mm or 3mm bore kit would be a smart idea if I just did that and ported the head. I have read most of Sonreirs threads about his big bore 378cc, and would like todo something similiar but not as intense as his or PJs. If I have to do cam modification I would like it to be were I can do it ( without a mill, machine, or CNC) or send it to someone, just not buy an expensive racing cam. I would get a racing cam if there was one for 100-200 bucks, but doubt it severely, but who knows. So I guess I am maining asking, is if i could just do a 2mm, 3mm bore kit and port the head and get HC pistons and be good, without cam work, and valve work. Once again I wouldn't mind doing cam or valve work if it didnt costs out the wazoo. I am looking to upgrade my engine for basically $300-$600, I think I saw somewhere were Sonreir said his modifications were up to 2 grand, dont quote me on that, just really thats what sparked my question if engine modifications can be done to a cb360 and improve performance pretty decent on a budget. Thanks DTT members let me know if you are confused with anything I said.

overbore it to 378, run a mild racing cam that will still work with stock pistons, make sure it's hardfaced, get your rocker arms hardfaced as well, match port the intake port to the carb boot, and the boot to the carb, copper head gasket, build it carefully and patiently

rockcitycafe said:

overbore it to 378, run a mild racing cam that will still work with stock pistons, make sure it's hardfaced, get your rocker arms hardfaced as well, match port the intake port to the carb boot, and the boot to the carb, copper head gasket, build it carefully and patiently

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Sweeeet, I think I will do this, this winter or later on, when I want to do something, since a project is never done. I might just start on it, roughly how much do you think that would cost? Thanks RCC

3mm bore needs new liners and block bored.
If you doing new liners, go to 74mm ;D

crazypj said:

3mm bore needs new liners and block bored.
If you doing new liners, go to 74mm ;D

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haha, I guess I will do 2mm then, just a quick question, dont want to suck you in and waste your time. But I saw your build and did you modifiy the stock cam? And is the extra 22cc worth the work? I saw that you said it made quite a difference and your cool videos. Thanks

22cc makes a big difference.
I didn't modify cam to change timing, drilled it for oil feed.
I did modify cam sprocket mounting holes but you can do that with a chain saw file (if you don't machine block or head you don't need to re-time cam)
If you do skim head 0.020" to bump compression, you can re-fit cam without slotting holes, gives more top end rpm capability but you lose some bottom end.
Expect at least 34bhp to the wheel with proper carb mods with cam retarded (not slotted)

crazypj said:

22cc makes a big difference.
I didn't modify cam to change timing, drilled it for oil feed.
I did modify cam sprocket mounting holes but you can do that with a chain saw file (if you don't machine block or head you don't need to re-time cam)
If you do skim head 0.020" to bump compression, you can re-fit cam without slotting holes, gives more top end rpm capability but you lose some bottom end.
Expect at least 34bhp to the wheel with proper carb mods with cam retarded (not slotted)

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So basically all I need to do is bore out the cylinders and drilling my cam for oil, and do a little modification to the cam and I am good? I would like to get new pistons, but if thats not nessaciary I guess I wont do it. And I may be mistaking but I thought the cb360 stock had 34bhp, but I see you said at least. Thanks again

34bhp at the crank isn't the same as 34bhp at the wheel
They make about 27~28bhp at the wheel stock (less when badly modified, timing a little off, carb sync 'out' remove silencers, air boxes, etc)

crazypj said:

34bhp at the crank isn't the same as 34bhp at the wheel
They make about 27~28bhp at the wheel stock (less when badly modified, timing a little off, carb sync 'out' remove silencers, air boxes, etc)

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Ohh right, I am almost 98% that I am doing this, this winter. Thanks again, and thats a pretty good improvement, just it seems the problem is getting everything to work together. I will try my best.

Has anyone on here used or know about the Megacycle cam for the cb360? And also was wondering if anyone knows if the wiseco 68mm high compression pistons are already set up to except a bigger cam?