Calling all 4 stroke frame mounters



As I finish up my 2 stroke jackshaft kits, I am ready to move on to designing one for the 4 stroke. For those of you who have, or have seen, multiple 4 stroke kits and mounting plates, how similar are the engine mounting holes between the Honda, Huasheng, Titan, etc? My initial thought is to use the engine mounting holes to mount the bearing plates for the jackshaft but I need to know that they are all the same or at least close. I have one kit that a friend let me borrow. Would like to know how similar it is to the rest.


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i have honda 50 cc and grubee stage 2.0 kit

i think other engines were designed according to honda engine.

i think honda engine is original and all others are imitations of it.

so i think they could be almost identical.

the engine bottom has 4 holes that uses Metric bolts i don't remember the

exact size of the bolts but i think i was something like M6.00 or something.

i don't know exact dimension for holes position

i would like to have jackshaft kit for my bike so i can use different gears:)

by the way the gearbox that is on your picture isn't same as mine.
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They are all just to be M6 but engine thread just to be 1.0 pitch (that's make them harder to unscrew by vibration - normal bolts have it 1.25.
That's not easy to find them - take them hardened or at last stainless steel A2 grade (A4 is to weak).
I have the Honda and Grubee Skyhawk II as well. I believe that the 4 holes around the PTO that mount the gearbox are in the same position on the Honda and clones. I know the Grubee gearbox fits both the Honda and clones the same.

My question would be whether a plate between the gearbox and engine would cause problems in the gearbox with the length of the PTO.
I wouldn't think that an 8th inch or so would cause any problems. But, rather than slipping something in between the gearbox and motor, what about outside the gearbox, where the washer would go?
I am not talking about the gearbox to motor mounting but the motor to motor mount. Are the mounting holes the same? Will the different in-frame motor mounts work with the different 4 stroke motors?
be aware that crankset you are going to need has to be "wide" in order to clear the engine's width. when i bought my engine kit i came with wide crankset.
Good to know, what exactly do you mean by wide? What is the distance from the center of your frame to the inside of the crank?