I just finished a 3 wheel motorized trike for my wife. It has a 3hp harbor freight 4 cycle. I have it geared with a 10 tooth sprocket from the auto clutch to a 24 tooth jack shaft input to a 8 tooth jack shaft output. That goes to a 56 tooth wheel sprocket. It has a top speed of about 20mph and cruises at about 15mph. I would not want to go any faster than 20mph on a three wheeled bike. What I like most is it pulls real good. My wife took it for a ride and really liked it which made me very happy. I just need to paint it and pretty it up some.
3 wheeled 4 cycle
- Thread starter Dulcijo
- Start date
dirtwarrior
New Member
was this a kit?
silverbear
The Boy Who Never Grew Up
Nice job! Simple and clean. A basket up front would give her some stowage. Is there any way to rig up a rear brake? I'm guessing it originally had a coaster brake. Good engine choice as it has plenty of grunt, starts easily and is a smooth runner. No wonder your wife likes it. Looks like fun...
SB
SB
Thanks for the comments. I have been thinking about a basket and trailer hitch. If you look closely at the picture I put a rim brake on the rear and it works pretty good. I never liked the coaster brake. I used some clutch levers for brake levers which lock. That comes in real handy as parking brakes so it doesn't roll off on a hill when you leave it unattended.
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silverbear
The Boy Who Never Grew Up
I see the rim brake now... good to have in case the front brake fails. Yes, a trailer hitch would be a good idea. I've also got a trike under construction and have figured on a kind of trailer for it so the dog can go, too. What I want to do is keep the trailer very light and use something I already have... a kiddie trailer which is meant to attach to the axle on the left side of a two wheel bike's rear wheel. Should be simple enough to make up a little bracket off the back end of the trike to accept the attachment hardware. Kiddie trailers are very light weight and have little drag. Mine is good for about a hundred pounds of cargo... a child or dog or bags of groceries.
SB
SB
I have got a trailer from the link below. It works real good and attaches with a small hitch on the rear wheel which is included with the trailer. I will have to do some fabrication to get it to work on the trike.
http://www.frugah.com/aosom-elite-ii-bike-cargo-luggage-trailer-w-removable-cover-black-red/
http://www.frugah.com/aosom-elite-ii-bike-cargo-luggage-trailer-w-removable-cover-black-red/
silverbear
The Boy Who Never Grew Up
That will work nicely and is a bit more substantial than mine, I think. The hitch is much like mine... quick and easy to attach and remove the trailer.
SB
SB
From reading some builders comments on gearing 4cycle engines I would like hear comments on my understanding of the difference in 2cycle gearing to 4cycle gearing. Most 2cycles with manual clutches have an average top rpm of around 6000 rpm. The 6000 is rated on the piston shaft rpm. The piston shaft to clutch shaft is internally geared with a 20 tooth to 82 tooth gear. That drops the clutch shaft rpm to around 1500 rpms. From the 1500 rpms is where you start gearing down.
The 79cc 4cycle has an actual governed rpm of 3600 rpm which at first seems half of the 2cycle 6000rpm but in actuality is around twice the 1500rpm that the 2cycle clutch shaft puts out. The clutch shaft on the 4cycle actually turns 3600 rpms(or more). The predator 4cycle has to be geared down about twice what the 2cycle is geared. If you go from a 10 tooth clutch sprocket to a 44 tooth wheel sprocket on the 2cycle kit you must go to a 10 tooth to nearly a 90 tooth wheel sprocket to get the same results on the 4cycle predator. 90 tooth is pretty impractical so a jack shaft with compounded gearing is necessary.
Any comments on this train of thought?
The 79cc 4cycle has an actual governed rpm of 3600 rpm which at first seems half of the 2cycle 6000rpm but in actuality is around twice the 1500rpm that the 2cycle clutch shaft puts out. The clutch shaft on the 4cycle actually turns 3600 rpms(or more). The predator 4cycle has to be geared down about twice what the 2cycle is geared. If you go from a 10 tooth clutch sprocket to a 44 tooth wheel sprocket on the 2cycle kit you must go to a 10 tooth to nearly a 90 tooth wheel sprocket to get the same results on the 4cycle predator. 90 tooth is pretty impractical so a jack shaft with compounded gearing is necessary.
Any comments on this train of thought?