79cc Monster 80 Bike Engine Kit - Complete 4-Stroke Kit

darkcobra94

New Member
Nov 23, 2011
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louisianal
Any thoughts on the new 4 stroke kit offered by Gasbike.net?

http://www.gasbike.net/products/79cc-monster-80-bike-engine-kit-4-stroke

I have been waiting to get another 4 stroke, after my 4G crapped out and I got tired of belt issues, I just want something reliable yet cheap for my leisure.

What would I have to do additionally to get this kit running? Can I use the stock muffler? Stock gas tank or buy one to mount above?

I have had great luck and put many many many miles on my china girl, but I want something a bit more quiet :)

Thanks for any replies!
 
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nsanecopilot

New Member
Sep 28, 2014
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orlando
Im with you as im ready to move on from the 2 strokes. This looks like a good kit to me. Im leaning on getting one. But just want to hear some practicle knowledge first
 

curtisfox

Well-Known Member
Dec 29, 2008
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minesota
Looks good to me, there are a lot of guys running the 79 predator, non kits. A kit would sure make it simple......................Curt
 

Tony01

Well-Known Member
Nov 28, 2012
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sf bay area
Nothin "monster" about that motor, it's one that doesn't have any performance parts out for it and really doesn't make much power. Get the 212 instead. Though it does seem like a big step you can always just run the stock carb and put a muffler on it. You can always upgrade it later too, no shortage of parts for it.
 
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I bought one from king motor bike. Negatives are : No throttle linkage for throttle cable. pineapple sprocket adapter instead of hub adapter,cheap way out. Gas tank and muffler wouldn't fit in Micargi Huntington frame. Master link was missing from primary chain and primary chain was to short to boot. Motor mount didn't fit without some rigging. Positives are motor ran great. I bought this kit to replace a piece of C__P GT80 kit I bought from gasbike. When I finally got it running correctly(turned out to be a reed valve set up to tight) it vibrated so bad I pulled it off the bike. Crankshaft had 3/8 inch side to side play and that's probably causing the bad vibrations.
 
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More on King Motor Bike 79cc predator build. Crank shaft did not fully penetrate the clutch bore so when the crank shaft clutch retaining bolt was tightened it locked the clutch bell against the transmission thrust washer and mounting plate. Simple fix was I found a bolt that was the same outside diameter as the clutch bore and milled it with a file to .3" thick,installed the clutch and placed the homemade spacer in the clutch bore then installed the crank shaft clutch thrust washer and retaining bolt. This effectively lengthened the crank shaft to the correct d1minsion. Now it has about .01" play. Also, the engine mounting holes were drilled slightly off and I had to slightly file the CNC mounting plate to make it fit. I know it was the mounting holes in the engine because I have 3 other mounting plates that fit other 79cc engines and the all would not correctly fit this engine.
 
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nsanecopilot

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Sep 28, 2014
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orlando
My dax 2stroke stroke just failed so i need to order a kit. I wonder if my rt carb would work on the 79cc. Its 4 stroke time for me. I would love to see any pics of your build, and your mods. Be safe out there
 

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
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RT and NT carb swaps are a GREAT mod for 79cc four strokes. The stock carbs are prone to clogging and idle issues.
Slide carbs are designed for throttled engines, something most 4 strokes lack, so you get better throttle response and MUCH easier cleaning/upkeep/replacement.
 
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nsanecopilot

New Member
Sep 28, 2014
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orlando
I cant find any aftermarket intakes for the 79cc . So im going to hold off on this kit now . I am definantly going 4 stroke on next bike. I basically need a replacement motor for now anyways. Do post some pics of your build.
 

Derwood21

New Member
Jul 8, 2016
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Rocklin, Ca
I bought my 79cc from Harbor Frieght but I'm using the Gasbike motor mount and Jackshaft. Agk makes an aftermarket intake for a 19mm slide card they also sell, they have other parts for these motors too. I did the intake and slide carb, picked up a header off ebay I baffled and this things scoots pretty darn good.
I had started with a 66cc 2 stoke and after having numerous issues with keeping it going I got fed up and did the 4 stroke swap and never looked back. There may not be that much towards aftermarket parts for these motors yet but I feel they are getting more and more popular so I'd bet we'll see more upgrades in the near future for them.
Tried to attach a pic of my build, we'll see if it shows haha
 

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Amarion1

Member
Sep 15, 2012
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Bellingham WA
I cant find any aftermarket intakes for the 79cc . So im going to hold off on this kit now . I am definantly going 4 stroke on next bike. I basically need a replacement motor for now anyways. Do post some pics of your build.
For the intake you can use the exhaust flange from your 2 stroke kit, you just have to file out the holes a little wider. I cut it off with about an inch of pipe to work with. And if your 2 stroke intake is steel then you cut the flange off and use the bent tubing from it and shove it in at the angle you want for your 2 stroke carburetor then weld it solid or have it welded. For your exhaust you can cut the stock flange off and put your own tubing on it. I used bike handle bar and the 2 stroke muffler with some pipe still attached. And also use your 2 stroke gas tank

Here's my photo bucket album of the 79 predator I built for a guy I work with. It's his daily driver and I think he's got 30ish hours on it and it's running strong. I did pull the governor out for more rpms than stock too. If you have any questions feel free to message me. I'm happy to help

There's good pictures of my intake I described in there too


View Album, http://smg.photobucket.com/user/Furcat/library/Daves bike
 

Amarion1

Member
Sep 15, 2012
99
2
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33
Bellingham WA
I think I used the same gearing as that kit comes with except I used a 56 tooth sprocket from boy goes fast on ebay for the rear wheel. 23$ and free shipping if I remember correctly. That 44 it comes with will have terrible acceleration. He cruises between 30 and 35 nicely with that setup
 

mobike91

Member
Sep 14, 2010
111
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lebanon, oregon
For the intake you can use the exhaust flange from your 2 stroke kit, you just have to file out the holes a little wider. I cut it off with about an inch of pipe to work with. And if your 2 stroke intake is steel then you cut the flange off and use the bent tubing from it and shove it in at the angle you want for your 2 stroke carburetor then weld it solid or have it welded. For your exhaust you can cut the stock flange off and put your own tubing on it. I used bike handle bar and the 2 stroke muffler with some pipe still attached. And also use your 2 stroke gas tank

Here's my photo bucket album of the 79 predator I built for a guy I work with. It's his daily driver and I think he's got 30ish hours on it and it's running strong. I did pull the governor out for more rpms than stock too. If you have any questions feel free to message me. I'm happy to help

There's good pictures of my intake I described in there too


View Album, http://smg.photobucket.com/user/Furcat/library/Daves bike
Let's wake this thread back up. So I ordered one of these kits while at work tonight. You were sayin that you can take the governor out of the engine? Where is it located?
 

Amarion1

Member
Sep 15, 2012
99
2
8
33
Bellingham WA
Let's wake this thread back up. So I ordered one of these kits while at work tonight. You were sayin that you can take the governor out of the engine? Where is it located?
I used this

http://www.affordablegokarts.com/79cc-harbor-freight-govenor-removal.php

Make sure you pay attention and get all the metal out. I stuck a magnet in the area of removal for some reason i don't remember and there was a small washer hiding in some grease where a took it apart

Be careful though if you're using just the parts the kit comes with. I don't know how removing the governor conflicts with the stock throttle parts
 
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