Phatmoto 79cc bike

Discussion in '4 Stroke Bicycle Engines & Kits' started by Tigger, Oct 21, 2019.

  1. Tigger

    Tigger New Member

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    Bought this bike and after a little struggle it is up and running. Still need to make some mods happen and tweak a few things, but I think I'm going to like it.

     
  2. motorhedfred

    motorhedfred Member

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    So tell us what mods you've done. You had to have done something to get it up to 40 mph (I assume you meant miles per hour, but you just said "40" in the video). 40 kph is about 25 mph which would be more in line with how fast they go stock.

    Also, coming up on 3 weeks since you've posted, how do you like it so far?
     
  3. indian22

    indian22 Well-Known Member

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    40 mph would be quite impressive from that stock engine setup.

    Rick C.
     
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  4. motorhedfred

    motorhedfred Member

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    Anyone can be confused once in a while. Benefit of the doubt...
     
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  5. Tigger

    Tigger New Member

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    Maybe my precision of language wasn't quite on point but not confused. I did mean 40 mph. Can't find the screenshot of my top speed of 42 mph for some reason. Cruises comfortably around 33-34 though. The rear sprocket change from stock 50 tooth to 44 tooth probably accounts greatly for that. The road tires help decrease rolling resistance as well. Have installed a different carb as well, but I'm going to be replacing that with a better version soon.

    Overall, I enjoy the bike just gotta keep up with the loosening bolts as they turn up. I ride it about 5-6 miles every day on average and I'm just now on tank 2 of fuel. So Id say that it's doing quite well on the fuel economy. Screenshot_20191112-010535.png
     
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  6. motorhedfred

    motorhedfred Member

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    I think they put the huge sprockets on these to keep the top speed down. There's no reason that engine shouldn't be capable of pushing that bicycle to twice the stock speed with proper gearing.

    Ride on and stay safe.
     
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  7. indian22

    indian22 Well-Known Member

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    Tigger I'm impressed with the speed out'a the box, but with 44tooth and I'd guess you a rather light fellow somewhere south of 200 lbs. as well. This inexpensive kit bike just rose higher in my opinion and with the Felt style frame it looks expensive as well.

    Enjoy!

    Rick C.
     
  8. motorhedfred

    motorhedfred Member

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    I wonder if you could replace the jackshaft with a longer one and rig a dual cent clutch 2-speed setup like some of the early '70s mini bikes had... I also think a long tube header pipe would give that Lifan more grunt to pull smaller sprockets. $$cha-ching$$
     
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  9. Taffy13

    Taffy13 Member

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    When I was looking at that jackshaft tube I was wondering about turning it into a shifter aswell.. also a long tube exhaust would do great things for the low end of that motor I would assume.
    Also how stable is it at 40? Does it shimmy or shake any???
     
  10. waynesdata

    waynesdata Active Member

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    I had no idea a 79cc predator was that weak. A 66cc 2 stroke will do 26 up hill same frame. Starting to think 3hp stock rating is exaggerated.
     
  11. Taffy13

    Taffy13 Member

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    Those are the 79cc lifan engines And 40mph isn't to damn bad.
     
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  12. waynesdata

    waynesdata Active Member

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    40 kph or 40 mph? 40mph is about what I expect for 3hp on that frame and wheel set.
     
  13. Taffy13

    Taffy13 Member

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    Hey did say 40 miles per hour. And those are actually only rated at 2.5hp but from what I hear they make more with exhaust and good tune
     
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  14. waynesdata

    waynesdata Active Member

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  15. indian22

    indian22 Well-Known Member

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    You might be right on the longer pipe on the small 4 cycle.

    Vender description for Lifan engines are kinda' hit & miss on power. I've a Lifan LF152 F, even model # varies buy vendor, that is the 98.8 cc (no kidding) engine. Why not 100 cc or at least round it up or down? Anyway power is 2.5, 3 or 3.5 hp depending on the listing. I put a CVT on it and bench tested for a few hours, but left it as is. I may use it one day for something. No complaints just don't have a bike in mind for it yet. This one is pretty quiet and smooth running bolted to the bench.

    79cc, almost 80, power rating is I'd think subject to questioning. Especially in light of a really good 40 mph through a CVT...which uses a bit of the power in transmission. Over all I'd think the bike an outstanding value for the $600. price tag. Long term riding will determine ultimately the actual value. It's a good looking setup which doesn't hurt either.

    Rick C.
     
  16. Taffy13

    Taffy13 Member

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    Yea with those engines I think it's all about the tune you put on them that really determines the overall horsepower I think the different brands detune or tune there engines for safety / emissions reasons.

    But yea, I would really like to know how it holds up in the long run if your using it as daily transportation.
     
  17. indian22

    indian22 Well-Known Member

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    If this is an accurate replica of a Felt frame & assembled properly I'd see no reason for this bike not to track well. I know guys that run modified 15 hp 212cc Predators on actual Felt frames and they cruise 55 to 60 no problems.

    Rick C.
     
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  18. kelly dean

    kelly dean Active Member

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    I've been following along here and i dont think im ready to throw in an extra 2 strokes on the deal yet. I have done a sneeze over 55 with a 2 stroke on a walmart bicycle and thats just thrilling, scary lol. And i'll throw in with a grain of salt i think those phatmoto's are certainly one of the best looking 4 strokers i've seen....kelly
     
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  19. indian22

    indian22 Well-Known Member

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    I like them both Kelly 2 or 4 stroke..now throw in electric which has a lot of real attributes as well. Why select one when you can build and ride all three? If you like one better than the others no need trashing another persons preference either. Ride what you like and build what you will; that goes good for me and should for others as well.

    Rick C.
     
  20. kelly dean

    kelly dean Active Member

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    never thrash anybodys effort i've built 5 bikes and mostly just bolt it together but even that with this chinese stuff can be a challenge at times. I know what goes into it, one of the great things is there are a lot of options and differant ways to get motorized. after my first 2 ebay motors i wasnt ready to quit but i realized that i had better give this stuff some research and learn whats really going on. I've certainly thought about 4 strokes when i see numbers like 212cc thats like wow. Always handy at twistin a wrench and doing some things acquired skills from work history.I didnt know the first thing about these engines let alone a differance in a 2 or a 4 stroke. Self studied 2 strokes learned the cycle of how they actually work learned port timing ive studied porting all these aspects of a 2 stroke and i dont feel like i know much. So many things id like to do and learn still. I'm basically on a chinese 2 stroke budget and everything else gets more pricy after that I wish i had equipment to fab i follow what all you guys that are really building things what your doing here and i greatly admire it. I admire anybody who buy a kit and try to make it work. For now i'll build 2 strokes so far its the only thing i know anything of and if i spread it out its within my means.....kelly
     
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