Inline twin 132cc 2 stroke

Will'smotobikes19

Well-Known Member
Joined
Apr 9, 2018
Messages
1,658
Hey guys I had another idea in the area of frankenstein engines, take 2 regular 66cc jugs and make a new crankcase and crank from a homemade mold based on the regular crankcase only wider and meant for 2 cylinders, therefore having a 132cc monster! or even use the 48cc cylinders that would be 96cc but probably double the power or more of a regular 48cc engine. I know, I know it would require engineering but you could take inspiration from the snowmobile engines they make that are multiple cylinder 2 strokes.
 


FurryOnTheInside

Well-Known Member
Joined
Sep 23, 2013
Messages
3,994
Oh yeah just simply cast a new crankcase and make a new crank. :rolleyes:
Sorry, sarcasm isn't helpful but that doesn't sound at all practical! Also it would be very wwiiddee and both pistons must reach TDC at the same time which is not smooth and makes starting twice as hard.

So maybe make it a tandem instead of a twin, using not much more than the existing parts. The rear of the front engine's ring gear can mesh with the front of the rear engine's output gear?
That allows the pistons/cranks to be 180° offset which would be much smoother, and easy to start.
Also, making custom exhaust and intake routing is surely easier than trying to cast a case and construct a crank.
It would require a roomy frame, of course, but at least it would clear the pedals.
 

Will'smotobikes19

Well-Known Member
Joined
Apr 9, 2018
Messages
1,658
Can you find a picture of a tandem twin? for the pedals you could use the wide pedal crank that mb rebel sells I think its for the 212s the homemade engine shouldn't be wider than a 212 if it was the inline. I think it would be quite amazing to cast the crankcase I even made a crappy little ground forge in my backyard, of course I have no idea how to make a mold for it maybe make one out of wood or something the crank would probably be even harder to make. I don't have a lathe or anything but I did take a machining course.
 

FurryOnTheInside

Well-Known Member
Joined
Sep 23, 2013
Messages
3,994
Can you find a picture of a tandem twin?
Is that what it's called, tandem twin? There's a photo of a member's trandem triple in your previous thread.
I'm not certain that the big ring gear will be able to reach the output gear of the rear engine. I have only one engine on the coffee table in front of me and I haven't measured it. It looks pretty close though. o_O
Personally, I think the best thing about these little 66c engines is that they are narrow so they fit between your legs and between the pedals on a bicycle (and that they are cheap, of course).
 

Will'smotobikes19

Well-Known Member
Joined
Apr 9, 2018
Messages
1,658
I might just go for a regular 2 stroke racing engine. my 79cc predator bike isn't working out I think the shaft has a slight bend from running it without a clutch or anything from 2 years ago when I bought it. Also the cheap chinese clutch has alot of play in it and something catches when I try to start it and it doesn't stay running. I think I'm going to use either a modifed gx120, a racing 2 stroke or a homemade engine instead. The pred can go in the 30mph range but the slight bend inand the shaft and the governor slow it down.
 
Top