Firmstrong 4 Stroke Predator 79cc Monster 80 Motorized Bike Bicycle

It's been a while since I have done a 4 stroke! So, here is the 79cc monster 80 Predator 4 stroke on a Firmstrong cruiser. Pretty straightforward build with a 1.85” rear hub. Governor has been bypassed as well. Thanks for watching! Be sure to like and subscribe.

[@flamexbeatsbeatsbyflame8844]

Finally a nexus internal hub! So it CAN be done. I was worried the higher rpms for longer periods of time would cause the internals to degrade rapidly. I want to do one with a jackshaft, tired of my two strokes. Too loud and too much maintenance. Subbed

[@ericmcginnis9413]

Please upgrade the rear chain tentioner !

[@eastcoastlithics]

Im envying your bike because I have a 49cc 4 stroke haha

[@marcs4091]

Always been curious what's the top speed on one of those how does it compare to the 49cc?

[@bradleychardenet9453]

I got mine up to 40 mph with no governor , 18ft/lbs valve springs and a comet tav2 cvt

[@st.paulmn9159]

Bradley Chardenet Is the comet the one I see on the 212s? Doesn’t that rob a ton of power?

[@zoologicalmilitia2241]

@@bradleychardenet9453 How fast with the governor on? How about hill climbing?

[@bradleychardenet9453]

@@zoologicalmilitia2241 I got rid of it because I kept getting issues with it. I was tired of dumping money into it. But mostly downhill. I now have a mini bike that I built a 20hp Honda gx200 on it

[@nuada1067]

​@@st.paulmn9159 if you replace the default 2000rpm red spring that comes with the cvt with a 1000rpm green spring it doesnt rob much power

[@kennyh5083]

Totally AWESOME Dude!

[@johnbogacz3797]

I like your build. Those caliper brakes must make for an exciting stop or not...

[@SouthernCustomCC]

Yeah, the front has caliper/side pull brakes, but the back has a double reinforced Nexxus coaster brake. Nothing beats hydraulic disk brakes though!!! Lol

[@johnbogacz3797]

@@SouthernCustomCC I'm assembling one of those new aluminum built-in gas tank frames just got myself some $50 hydraulic brakes for the bike unfortunately with these brakes the brake lines are a little bit short for that frame so be aware of that if you should buy . But it's very easy to change these lines and also inexpensive KZbin as a couple of videos highly recommended. Good luck with future builds and enjoy yourself.

[@joeriost.v4959]

Probably won't see this but if you do I need help with a rear sprocket because I'm basically I'm doing the same build

[@FoochieA]

Where did you get the picture of the skull it looks like the one piece Jolly Roger

[@heavystarch100]

Will NEVER find the kit in stock!

[@codelicious6590]

Is this an actual kit they sell for bicycle conversion? If so, does it come with the wide crankset?

[@esesoke]

If you do a 212cc swap you will need wider cranks but if you keep it with this engine its normal bicycle pedals

[@cynthiaroesner1719]

Very quiet soinds like my mini bike 😂

[@jamesbondo13]

How to find this kind of jackshaft???

[@ciliciaann3504]

😎👍

[@titolopez5154]

NICE...

[@slimey831]

Just bought a bike with this motor but i doesnt have a muffler willa regular 2 stroke exhaust work

[@vertigo6982]

Ive been watching custom motor bicycle videos and today was the first time I heard two different videos mention a "3 hole cnc sprocket". Now is this something that is the norm to get? Is it something one has to get, or is that like a performance upgrade part?

[@brodyhays3599]

How tall was the engine with the tank and pipe off, I was gonna swap one of these into an electric quad but the space I have is only 7in high

[@zoologicalmilitia2241]

How in the hell did you get that predator on? I'm looking right now of a 79cc Predator and to get the sprockets to match up 90% of the motor sticks out over the right side!

[@nostalgiaholic4874]

Yep u need the torque converter

[@MrCbell57]

hi. Nice. If you have the motors already. Where do you get a 79cc bike kit that you can build a bike with? I have a 79cc but it needs a clutch for 5/8 shaft. Looking for a torque converter application that fits my motor. But not having any luck. Guess I should have bought a kit. Now I need the kit, without motor, and no one sells one. wow.

[@uncledonnytv7152]

Since that engine is on a slight bend, how much oil would you put in it?

[@thejdmguru621]

Sounds like a Ducati dry clutch

[@RustyShakleford1]

Why not a CVT?

[@Lk4ahro]

Where can i get the monster 80 pkg? mentioned i listened several times n couldnt get the name. Does it come with the gearbox?

[@SouthernCustomCC]

Thanks for watching. This was a gasbike.net engine kit. Best of luck!

[@bobbythompson4268]

Just got my firmstrong urban man, 1 speed, 26” bike in the mail today, I also ordered 2 sprockets so I don’t mess with the rag joint. I’ve been watching a ton of videos and the replacement rear sprockets seem the way to go for sure. So I got the 1.8 adapter, and I got a 36 and a 44 tooth sprocket, neither of which fit my chain. Am I doing something wrong? Is the chain with the kit a 415? Should I get a new chain, new sprocket? Any hell would be greatly appreciated. Thanks in advance. Bike looks awesome! I’m using a 2 stroke, I just realized yours is a 4.

[@zoologicalmilitia2241]

You probably need to buy a new chain and cut it, either 415-420-440 or 40 D for the big chains you need buy a chain breaker from Harbor Freight you can cut big chains but the push pin is too big for the 415 stock need the Walmart breaker.

[@simsim7070]

Where did you get the motor mount for that red bike do you have a part number and the place we love it

[@SouthernCustomCC]

Thanks for watching. It came with the predator kit on gasbike.net back in the day. I am sure they still sell just the mount. Best of luck

[@Makermook]

I couldn't make out what kind of muffler that is. I just bought a 79cc Predator to go in a boat I'm building and I want it to be as quiet as possible. What brand muffler is that?

[@zoologicalmilitia2241]

That was a stock 2-stroke exhaust about $12.00, but what's wrong with a stock predator exhaust. Did you get your boat going?

[@FlockofSmeagles]

How fast does it get when you take the governor off?

[@senorboardhead]

That is sharp ! How do you use the Nexus 3 speed with that set up ?

[@SouthernCustomCC]

senorboardhead : The Nexus shifter is used just as it would normally be used when biking. It has no effect on the motor or speed of the bike. Yet, because the hub is larger @ 1.85”, you will need to set up your spricket accordingly to that size. Thanks for watching.

[@senorboardhead]

Southern Custom CC OK, so the three speed Nexus is only used when pedaling the bike ? The hub just freewheels when the motor is driving ?

[@SouthernCustomCC]

senorboardhead: Yes, sir. If you want to use the normal gears a bike has with the motor to have actual ’gears’, then you would install a jack shaft. Without one, the gears are just normal bile gears when pedaling. Enjoy!

[@senorboardhead]

Southern Custom CC Hey thanks ! Makes perfect sense. Smart of you to start with a bike that you could probably pedal a ways if you had to - even with a dead engine on board. Thanks again.

[@firehawk3860]

Can anyone answer me a question about what to do with the tube coming out of the OHV assembly? Do you just plug it up or put little air filter on it?

[@nostalgiaholic4874]

Yes

[@matthew27lamb31]

How much I am thinking of building one but don't want clutch i might use tiller engagement and Jack shaft how do u keep the rear adapter from slipping

[@SouthernCustomCC]

If you build yourself, your looking at about $250-$315 for motor set up, then $200 for bike, $35 for adaptor. The CNC adapter is a very user friendly, safe setup that easily installed with m10 allan bolts. Worth the money and the adapter assures an accurate, aligned sprocket. Just bypass the governor when setting up to get most power from the engine. Happy building and thanks for watching!

[@kreanardrobinson7311]

Can they be rode all day

[@st.paulmn9159]

No vertical mount?

[@natanaelgomes1736]

Top

[@bobbythompson4268]

Firm strong urban man? What size is the back wheel hub? 1.5” by any chance?

[@bobbythompson4268]

Damn, just heard you say 1.85. I already ordered a 1.5, not knowing.

[@SouthernCustomCC]

Sorry, man. Your going to love this ride though! Happy building.

[@bobbythompson4268]

@@SouthernCustomCC cool thanks! I ordered a new one... listed as 1.8, I figured that’s the one? Ha I hope so. I figure I’ll use the other one eventually, I want to get into this. Also, in doing so, I went from having just a 44 tooth, to also having a 36 now. I’ve heard about the pros and cons of both. I’d like to maybe do some long distance rides, so less teeth the better.

[@bobbythompson4268]

@@SouthernCustomCC Thanks again man. This bike just looks awesome and durable. Has a cool look with the whitewall tires, and the classic beach cruiser look. Seems like there are several options of directions to go with this one.

[@christiancampbell3523]

Did you have to use pedal extension?

[@SouthernCustomCC]

Christian Campbell: yes, I had to install the 3 piece wide pedal crank.

[@person-ce8cr]

What is the top speed

[@SouthernCustomCC]

I didn't max it yet. I was still breaking it in, but hit 30 and there was still a lot more the engine could have given.

[@person-ce8cr]

@@SouthernCustomCC so you didnt remove governor and got 30

[@SouthernCustomCC]

person : No, the governor has been bypassed. You can do it yourself on the cheap; otherwise gasbike.net sells the bypass kit for like $8. That will allow you the full potential of the engine.

[@alexayala3405]

@@SouthernCustomCC if i remove the governor, would it make the engine less reliable. I am not planning to use it for racing. i plan on using it for transportation. would i be better off getting the 49cc 4 stroke rather than a governed 79cc

[@SouthernCustomCC]

Alex Ayala : Removing the governor will not effect it's reliability in my experience. All it does is remove a restriction on engine potential. Gas bike.net sells a governor removal kit if you don't want to make a set up yourself. It's up to you... There is definitely power differences...i personally like the 79cc but they are not accepted as much legally as the 49cc in most places. Either way, be safe and have fun!

[@christianarcos4333]

Where did you get the motor mount

[@Benjicmm]

You can get them at gasbike.com

[@ryansanders864]

what kind of frame did you use looking for a frame to use that's like that what kinda of brand that bike is?

[@SouthernCustomCC]

This is a Firmstrong. Good bikes to build on are Firmstrong and Micargi. Hope this info helps! Happy building.

[@ryansanders864]

@@SouthernCustomCC also i put mine together and gas is pouring out of the carb any tips how to fix this issue?

[@deaththekid3318]

How do you get your chain to run smoothly? Mine rubs unless the rear tire is tightened unevenly

[@SouthernCustomCC]

death the kid : The easiest way to avoid this is to use a CNC rear sprocket adapter and push it close to all the way out so that the inner ring of the CNC in near flush to the inside of the hub wall. The second easiest is to set up the rubber gromets so that the fatter/wider rubber gromet is used in between the sprocket and spokes while the thinner rubber gromet is used on the inside of the job and set up. The next option you have is to order a smaller width rear tire and replace the one your have, but that would be close to as much money as the CNC sprocket. What ever you do... Don't buy and use a thinner chain...theu are weak and snap much more easily. Hope this helps! Thanks for watching.