79cc Huffy

Skitch

Skitch

New Member
I have finished
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Nice set up Skitch!
Home brew jack shaft and 3D clutch which you bushed or did you make new clutch hub?
But the tie rod between seat stays and engine mount has me stumped. Also where did you terminate the breather tube.
I've got a 3D in the box in my shop waiting.
Tom
 
You can by a reducer with a extra tall keyway 3/4 to 5/8, look good because are to long and more costly. I think the rod is for adjustment of chain, engine up or down a bit. I also have 3D in a box yet..............Curt
 
The rod is to adjust the primary chain. There is a bushing / adapter for the clutch.
 

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Have you run it much? My first breather route was a dump similar to yours. Lubed up the rear tire good, making braking pretty exciting and generally making a mess. A catch can worked better, as did using 15-40 oil.
Thanks for the additional photos and info. Yours is a very well thought out build.
Tom
 
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Tom from Rubicon said:
Have you run it much? My first breather route was a dump similar to yours. Lubed up the rear tire good, making braking pretty exciting and generally making a mess. A catch can worked better, as did using 15-40 oil.
Thanks for the additional photos and info. Yours is a very well thought build.
Tom
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Thank you, Tom
So far only 5 or 6 miles. I have not noticed any oil coming out. To be honest, I am not recalling how I determined how much to put in.
 
I just went out to my machine shop/Tool Room and checked. My last fill was 1/2 a quart. On my last oil change I caught the used oil in a 1qt pyrex measuring cup to what was left after to initial catch can dumps. I have another engine on the bench that I plan decking the head 0.050" as I am told it is the single best mod. made on a Pred. 79
There was a recent thread that a forum member posted a photo of his 79cc with a sight glass installed left side.
Tom
 
Tom from Rubicon said:
I just went out to my machine shop/Tool Room and checked. My last fill was 1/2 a quart. On my last oil change I caught the used oil in a 1qt pyrex measuring cup to what was left after to initial catch can dumps. I have another engine on the bench that I plan decking the head 0.050" as I am told it is the single best mod. made on a Pred. 79
There was a recent thread that a forum member posted a photo of his 79cc with a sight glass installed left side.
Tom
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Good info, Thank You
 
As the pictures show, this bike doesn’t have a recoil starter. It starts by pedaling and dropping the clutch. My decision to go this way was aesthetic. I didn’t want the recoil starter and I did want an exposed flywheel. I think it gives it a more authentic look.
Now that it is built, it works but, I find there is a lot of clutch slipping to take off, and the bike does not want to run less than 15-20. It could pull more gear but minimum speed would be higher. A tuned centrifugal clutch would be just the thing. Just wanted to share my thoughts for the benefit of anyone else making the same design decision.
 
curtisfox said:
Sounds like you need lower gear ratio, what is the teeth count on your setup? And where did you get the jack shaft setup? Really like your bike..........Curt
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Curt, Lynne is still selling copycat SF wide pedal crank sets. A guy with a lathe and a straight knurl tool. It's a no brainer.
As you know, I replaced reduction drive sprockets with steel. The 7075-T6 hub and ball bearing assy. .
The boy holds his cards close to his vest, but I reckon his day job is Gunsmith. Done my fair share without schooling.
My favorite was converting a 1868 Vetterli from rim fire to centerfire and the producing cartridges for it. What made it all possible was still available 7MM Lebel brass.
Tom
 
Skitch said:
I purposely slip the clutch to get going. The dilemma is it could pull a higher gear for more top speed but, it would be more awkward during take off and low speed maneuvering.
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Slipping manual clutches is what you have to do. These little 79cc 3hp engines don't have any low end torque. When 3D clutches, used with the engines they were designed for. Are a dump the clutch and hang on.
Have you given any thought to running a 56T wheel sprocket? You don't have to go very fast on a Huffy to have a thrilling ride.
My Huffy-Davidson has the Bikeberry 49cc Huasheng kit to a 31T drive sprocket. Goes fine on the flat and struggles on long up grades.
Pat Dolan 212cc burn out Sportsman Flyer water burn out with manual clutch - YouTube
Tom
 
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