Harbor Freight Predator 79cc 4 stroke shift kit build (reference)

[KCvale]

HOT DOG!! You guys just woke me up!!

Hi amigo, say hi to Jim for me ;-}

You guys would do well with a complete HF79 bolt on shift kit I think.
Long shaft transfer case perhaps?

 

[gary55]

OK Pablo you got me off the couch, well not really. We certainly could make this happen. I just question what the popularity of a HF 79cc or 212cc motor is. I mean yes they are inexpensive but by the time you rig them up, they are not inexpensive anymore. Besides they all look a little unkept, and I'm trying to be nice here. It is one thing to make something that works with your own hands. That certainly is a feat that should be applauded. But to create something that anyone can purchase and install that looks sick right out of the box, now that is a bit more difficult.

Let me as this. Is a centrifugal clutch what everyone wants? What if one created a manual clutch, belt drive that was really narrow so you don't have to pedal bow legged. Is that something that would interest people? Oh and it could fit just about every 4 stroke. Oh and have different ratios available. Is that appealing to anyone?

Their are no doubts in my mind that a manual clutch belt drive trans. with these features and with bearings at the clutch to shaft connection would be the most sought after in the four stroke community. If you made them to fit both a taper shaft as well as a 5/8" straight shaft and get somewhere close to cent. clutch pricing better get a good patent cause the market will be yours. I know for a fact I will buy one, and if it worked well I would be buying many more. For me I would want a long shaft option for a jack shaft shifter.

 

[Deleted member 25783]

You guys had a look at this manual clutch?
http://3dmotorsport.net/
Pat Dolan has been testing one, I did an inquiry. The engine at this time has to have a 3/4" shaft and minimum engine is a GC160. Pat is testing it on his Sportsman 200, as in Predator 212cc. With the right horse power centrifugal clutches, while cheap are just a builder option.

 

[Cozmik Mezzenger]

Ahh, I remember that build, it ended up with an HF 79cc so it's listed wrong on my page, but I bought that bike to put this 86/88cc engine in:

You are welcome.

 

[Cozmik Mezzenger]

OK Pablo you got me off the couch, well not really. We certainly could make this happen. I just question what the popularity of a HF 79cc or 212cc motor is. I mean yes they are inexpensive but by the time you rig them up, they are not inexpensive anymore. Besides they all look a little unkept, and I'm trying to be nice here. It is one thing to make something that works with your own hands. That certainly is a feat that should be applauded. But to create something that anyone can purchase and install that looks sick right out of the box, now that is a bit more difficult.

Let me as this. Is a centrifugal clutch what everyone wants? What if one created a manual clutch, belt drive that was really narrow so you don't have to pedal bow legged. Is that something that would interest people? Oh and it could fit just about every 4 stroke. Oh and have different ratios available. Is that appealing to anyone?

It is a good thing people don't all want the same things. The HF engine is very popular with me. And they are no more expensive than a two stroke with everything in the store on it just to break 30mph. Also, I keep my bike just fine, thank you. Oh, you meant "unkempt", as in untidy, messy, scruffy, straggly, disordered, disheveled, disarranged, rumpled, windblown, ungroomed, bedraggled, in a mess, mussed, messed up. Hmmm. I think I kind of like that! Just call me scruffy when I zoom past.

Or maybe I just misunderstood what you were saying altogether.

 

[bakaneko]

dayam, this thread has gotten quite long for just an interesting video. just to take a step back, this is just a reference for anyone looking to get started on a HF Predator shift kit build. im not planning on building this yet. also the gasbike kit just hit $200 (shipping incl). the kit has evolved quite a bit since it was first introduced: includes throttle linkage and custom air intake/carb now. i mean it is less than the HuaSheng kits now...

and, i know gasbike gets a bad rep, but ive had a good experience with them thus far one kit, many accessories, and one instance where they changed the centripetal clutch for me because I ordered the wrong one...

https://www.gasbike.net/collections...ucts/79cc-monster-80-bike-engine-kit-4-stroke

 

[gary55]

dayam, this thread has gotten quite long for just an interesting video. just to take a step back, this is just a reference for anyone looking to get started on a HF Predator shift kit build. im not planning on building this yet. also the gasbike kit just hit $200 (shipping incl). the kit has evolved quite a bit since it was first introduced: includes throttle linkage and custom air intake/carb now. i mean it is less than the HuaSheng kits now...

and, i know gasbike gets a bad rep, but ive had a good experience with them thus far one kit, many accessories, and one instance where they changed the centripetal clutch for me because I ordered the wrong one...

https://www.gasbike.net/collections...ucts/79cc-monster-80-bike-engine-kit-4-stroke

I still use them on occasion as well. It is not the rep. of the company that is in question, but the rep. of the trans. that comes with the engine kit that I would consider if you are contemplating the 7g. I guess it's ok if you don't mind pulling the clutch off to re- lube the bushing once in a while.

 

[MarcusMitchell]

I've been working on a 79cc shifter for about three months now, and the main problem im having is chain strength. I'm using an SBP 4S jackshaft kit, and have had ZERO problems with it, other than the fact that it needs to be drilled for the mounting pattern on the bottom of the engine.

I've bypassed my governor, put a 20lb (overkill, i know.) battery to power the lights (two led headlights and a dual tail light with blinkers and brake light), and 16" hangers for a more upright riding position. I will soon be getting my head milled .026" for a 10:1 CR, from the stock 8.5:1. I'm still looking for suitable valve springs, and i might have a machine shop fabricate a new balanced crankshaft and a higher lift camshaft. I will not be doing any carb work to maintain my 80mpg, and will not be doing any valve port work except for some polishing.

I also heard that these upgrades could increase the HP to 6.5, from the stock 3. If this is true, then my 65lb (soon to be 50lbs) will be able to hit 75 easy, because i will be able to utilize all of my gears to the max. I currently have it going 40mph peak, with a slight tailwind, with just the bypassed governor.

anyone know where i could find springs though?

 

[CrazyDan]

I've been working on a 79cc shifter for about three months now, and the main problem im having is chain strength. I'm using an SBP 4S jackshaft kit, and have had ZERO problems with it, other than the fact that it needs to be drilled for the mounting pattern on the bottom of the engine.

I've bypassed my governor, put a 20lb (overkill, i know.) battery to power the lights (two led headlights and a dual tail light with blinkers and brake light), and 16" hangers for a more upright riding position. I will soon be getting my head milled .026" for a 10:1 CR, from the stock 8.5:1. I'm still looking for suitable valve springs, and i might have a machine shop fabricate a new balanced crankshaft and a higher lift camshaft. I will not be doing any carb work to maintain my 80mpg, and will not be doing any valve port work except for some polishing.

I also heard that these upgrades could increase the HP to 6.5, from the stock 3. If this is true, then my 65lb (soon to be 50lbs) will be able to hit 75 easy, because i will be able to utilize all of my gears to the max. I currently have it going 40mph peak, with a slight tailwind, with just the bypassed governor.

anyone know where i could find springs though?

I highly advise messing with your jets after changing anything from stock. The main jet may not be sufficient for the additional rpms. Are you running the stock box exhaust and air filter or aftermarket? If you make it breathe easier it might run too lean.

 

[KCvale]

I also heard that these upgrades could increase the HP to 6.5, from the stock 3. If this is true, then my 65lb (soon to be 50lbs) will be able to hit 75 easy, because i will be able to utilize all of my gears to the max. I currently have it going 40mph peak, with a slight tailwind, with just the bypassed governor.

What are you using for brakes?
I have built a lot of fast shifters and I recommend front and rear disc brakes.

That little 5 speed IGH 49cc could never push the bike to 70, but she'd play with 50 all day and the brakes were needed.

It's not how fast it can go, it's how fast it can stop.