The Lifan engine thread

Discussion in 'Battle Scooters' started by hugemoth, Feb 22, 2011.

  1. iatethepeach

    iatethepeach Been here awhile

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    Thanks, everybody. I will go with the 4-up. T-Bolt's Piranha 140 looks like the ticket. They sell a CDI upgrade that might make starting a little easier for my gf. She's no wimp but she will be a total novice. Maybe I'll also get a larger kickstart lever.

    Any thoughts on carb size? It looks like a 22mm comes with the motor. I'd like to use the stock CT90 airbox and muffler (or hack together an exhaust that looks similar to stock).
  2. Oscarjp

    Oscarjp n00b

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    go with vm26mm carb, when you buy the motor from tbolt i believe they give you a discount for the 26 and they keep the 22 that its included in the engine package deal.
  3. pnw

    pnw Long timer

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    If she is really going to ride how about the electric start version. It less than $60 more and comes with a complete wire harness, it looks like all you would need to add is a battery. Then non ES model would be lighter though and you could get away without a battery by using capacitors. The capacitors have been working well for my Lifan 120/125 in place of a battery.
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  4. iatethepeach

    iatethepeach Been here awhile

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    Thanks, fellas. This bike will be a kick-only manual, for sure. I'm very interested in reading about your capacitor setups!
  5. pnw

    pnw Long timer

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    I got the capacitor idea from reading posts from Hugemoth. My Lifan has a half wave stator, yours might be a better full wave. What I used on the charging circuit were 10 2200uf 50v capacitors instead of a battery, wired in parallel powered by a scooter 12v regulator/rectifier. The headlight (also LED) circuit is regulated but not rectified by the regulator. I wired 4 of the capacitors in parallel after a diode so the headlight current is now DC and smoothed by the capacitors which I stuck in the headlight bucket. By using all LEDs even the low output two coil stator provides enough power. Lighting is smooth other than some flickering at slow idle which smooths out just above idle rpm.
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  6. hugemoth

    hugemoth Big Brother is watching you!

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    My Lifan 140 came with a 26 mm carb which seems about right. Make sure the intake tube you use is 26 mm on both ends.
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  7. pnw

    pnw Long timer

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    For a rainy day project I'm thinking of doing a 141cc big bore kit on my Lifan 120cc (despite marketing as a 125) - 152fmi, only $150 on TBoltUSA. They indicate that the Lifan 27mm/23mm big valve head is required. Is there a way to tell what head my lifan has without pulling it off to check?
  8. hugemoth

    hugemoth Big Brother is watching you!

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    I could be wrong but I think the smaller valve heads use the big round screw in adjustment caps while the 27/23 mm valve heads have the type with 2.small.bolts. BTW there are big valve heads sold.on ebay that are advertised as Lifan brand but are not. May be just fine but they use different size ball bearings on the cam as well as other minor differences.
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  9. hugemoth

    hugemoth Big Brother is watching you!

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    What is the stroke on your 120cc? On the 140 the stroke is 59mm, bore 55.5mm.
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  10. pnw

    pnw Long timer

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    My valve cover cap screws were 8mm and the head indeed was a 27/23.

    The stroke on the 52.4mm bore 120cc is 55.5mm. So maybe the big bore cylinder has a ~59mm bore to equal 141cc? It will end up over square instead of under square.

    the big bore kit has 57mm piston

    [​IMG]
  11. hugemoth

    hugemoth Big Brother is watching you!

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    Let us know how it goes. Should cut some weight too with the aluminum cylinder.
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  12. pnw

    pnw Long timer

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    Will do. I should receive the kit by next week but it will take me a couple weeks to get to it. Next week I'm hoping to do the "old west scenic bikeway" in the John Day area - depends on the weather, not if rain is forecast or if it gets too cold there.
  13. pnw

    pnw Long timer

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    Received the big bore kit today.
    You're right about the weight, the sleeved aluminum cylinder weighs almost 4 pounds less than the stock cylinder. Seems OK quality but the stock parts are noticeably better. I would have already installed and be testing it out but there are differences with both the head and the base gaskets and I messaged TBolt about it, probably won't hear back until next week.
    The base gasket included in the kit has a smaller hole where a rubber O-ring type seal sits in a depression in the case so the base gasket doesn't clear the O ring and since the O-ring sits proud of the case it won't work with the thickness of both the gasket and the o-ring. The head gasket also has a smaller hole at an oil port so that o-ring seal doesn't fit there either.

    Here are pictures I sent to TBolt


    Stock head gasket on the left lower left hole is the one in question
    IMG_1476.JPG

    Here is the stock base gasket with the zip tie at the hole where the o-ring is, the supplied base gasket is on the motor but the hole at that location doesn't clear the o-ring
    IMG_1478.JPG

    Any ideas Q?


    EDIT: TBoltUSA messaged back that they don't use the rubber seals. I think that is excellent service to text back on a Friday night (them in Pennsylvania).
  14. pnw

    pnw Long timer

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    OK you asked so here it is. I finished the 141 big bore and used the same VM22 carb, same pit bike exhaust and it is running 16t front and 45t rear sprockets. It now does power wheelies opening the throttle while idling at a few mph and clutch fully engaged. Not slipping the clutch or pulling up on the bars or leaning back. There is a hesitation off of idle that went away when it warmed up. I need to break it in before searching for top speed but I will be switching to a 17t front sprocket. It has gotten really cold around here but I'm still hoping to do the "Old West Scenic Bikeway" on a bicycle late this week or early next week, camping along the way. After that maybe something on the CT unless it turns even colder.

    I'm still running the regular 87 octane gas that was in the tank, maybe it should run premium?

    I expected it to be harder to kick start with bigger displacement and a high compression piston and thinner head gasket but it doesn't seem noticeably harder to kick, starts on the first or second kick and no kick back that I had read about on the 140 Lifans.
  15. CrapKerouac

    CrapKerouac Been here awhile

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    Are these engines as reliable as the original Honda's?
  16. hugemoth

    hugemoth Big Brother is watching you!

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    Could be easier to kick for several reasons but that's a good thing. Will be interesting to hear how it goes once it's broken in. My 140 pings on 87 octane but does fine on 91 which may be due to the long stroke.


  17. hugemoth

    hugemoth Big Brother is watching you!

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    More reliable by far. Modern design and metallurgy. CDI, ball bearing cam, better flywheel/stator design, etc..
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  18. CrapKerouac

    CrapKerouac Been here awhile

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    Oh wow. Cool. A better inexpensive engine from China. Good to know.
  19. TheOtherBart

    TheOtherBart Long timer

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    My apology if this has already been answered, but is there a Lifan engine that would be a bolt-in replacement for an XL100? Bonus if it's at least a little bigger displacement.
  20. hugemoth

    hugemoth Big Brother is watching you!

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    A CG200 might fit. Somewhere online I've seen a diagram with measurements.
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