Necro's 4 speed 125cc Lifan Build Thread

Discussion in 'DIY Home Built Motorized Bicycle (non kit)' started by TheNecromancer13, Sep 15, 2016.

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  1. TheNecromancer13

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    So I decided to go ahead with the 125cc lifan build. Engine and a few other parts arrived today, holy crap the engine is massive! Micargi puma arrives tomorrow. Then I can start figuring out how to mount the engine. Going to gear it for a top speed of just over 60 mph at 9500 rpm in 4th gear, which means about 13:1. First gear will be about 35:1, that should be interesting (wheelie time lol). I am going to make it purple and either black or silver depending on parts availability. Also going to cut out a giant skull with horns and make it into a fairing, with the headlights through the eyes. I made some little prototype skulls today, thinking one of them will house the turn signals, again through the eyes. This is really going to be more of a small cc motorcycle, should be a fun build.
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  2. Springfieldscooter

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    #2 Springfieldscooter, Sep 15, 2016
    Last edited: Sep 15, 2016
  3. TheNecromancer13

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    Got the frame this morning, upon opening the box it was apparent that the bike had been assembled by monkeys, so I took everything apart and redid it.

    Test rode it up and down my street, the turn radius is going to take some getting used to... the whole thing just feels weird to a guy who's used to a mountain bike frame. I'm sure it will pass.

    Now I'm going to take it to the bike shop and order some parts, then I'll repaint everything purple and silver and I can get down to building.

    Also I made a post of this on the motorized bicycle subreddit, and everyone thinks I am going to kill myself lol. They are not quite as open minded about larger engines as we are...
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    #3 TheNecromancer13, Sep 16, 2016
    Last edited: Sep 16, 2016
  4. mogollonmonster

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    Signing on for this one!

    Monkeys? You're too generous, my eleven year nephew was near to swearing when he helped with my unboxing. He was confident he could have done far better. So am I. Check out Lynn's website ( custommotoredbikes.com ) she's got some handlebars I think will fit the look you're going for. Look made for a chopper build. I think you'll know em when you see em.

    Any ideas on that back fender? I know Motakity and others have had issues with them breaking at the mounting tabs and other things. Personally I don't like the center brace at all, the way it comes, and have left my fenders off until I decide on (read: figure out) a solution. Bending and drilling 1×1/8 inch strap into new braces and tabs is the best I've come up with so far.

    60 on a Micargi stretch? Sounds doable. My Mustang rides pretty good near 40, and as a bicycle, it rides smoother and more stable than any other bicycle I've ever ridden. Its part of why I built mine. Admittedly, turn radius and clearance issues take a little getting used to, but it's worth it. Just remember to keep the inside pedal high, no level with the ground nonsense, you keep the inside foot UP, or you will scrub that pedal, and it could hurt you bad buddy. I'm more worried about that than the motor size or speed.
     
    #4 mogollonmonster, Sep 17, 2016
    Last edited: Sep 17, 2016
  5. TheNecromancer13

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    Custommotoredbikes is a great website, I get a lot of stuff there. My soultion for the fenders is to leave them off for now, especially considering that the front one doesn't even fit between the springer fork. About keeping the inside pedal high, I had plenty of practice with that after I built a bike a while ago that needed pieces of metal screwed onto the pedals to extend them so my feet could reach them around the engine, I crashed on the first test ride because the pedal hit the ground around a curve. Now raising the inside pedal is second nature.
     
  6. TheNecromancer13

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    Was talking to my neighbor this evening about my new project, I mentioned I needed to find an exhaust pipe, and he's like "I've got an exhaust pipe for you! In fact, I have two of them you can have!" So he disappears into his garage and comes out with a pair of stainless steel high performance motorcycle pipes and gives them to me for free, along with a book on the history of motorcycles. So yea, one of these is going to be my exhaust pipe: [​IMG]
     
  7. TheNecromancer13

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    I've got the engine sort of mounted and a jackshaft constructed, now I've got to figure out how to fit an exhaust and reroute the chain that goes to the pedals. It looks like I will have to have several stages of chain in order for everything to line up. I might redo the mounting brackets if I can find someone who owns a pipe bender.

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  8. Tony01

    Tony01 Member

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    Why use a jackshaft? I know that output sprocket is sticking way out on the motor, but from memory the shaft was something like 17mm right? I say take that shaft out, and have a shop turn it down to 5/8" or so and mill a key way in so that you can do away with the jackshaft. Or if it is 16mm ya can turn on the engine and file it down the five thou to 5/8" and put a regular sprocket on there.. Maybe with some kind of weld on sprocket adapter and a 12t output sprocket.

    This build is gonna be sick!
     
  9. TheNecromancer13

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    Mostly using a jackshaft so I can run the chain on the right side of the bike, I plan to use a freewheel to link the pedals with the motor so that they turn the same chain. Also cause if I did it with no jackshaft the chain would hit the frame.
     
  10. Tony01

    Tony01 Member

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    Hey I rolled through your town on the Amtrak. Had half an hour to see downtown and that's it.. Quite the industrial city. Got some big hills there.
     
  11. Agreen

    Agreen Member

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    I get that people are looking out for you, but if I can ride my dumpster find no-name frame (chopped, extended, re-welded) with a gx200 and only a rear coaster, then you will have no problem with yours.

    Looks good! Do Oregon laws allow an engine that size on a bicycle? (SC laws sure don't!)
     
  12. TheNecromancer13

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    Na, Oregon laws are actually super restrictive, 34cc and 20 mph, 30 mph if you get a license and registration (which is impossible for a motorized bicycle anyways, and whether a 34cc engine could even do 30 mph is questionable) but where I ride they're not really enforced unless you are breaking other traffic laws which actually matter or otherwise being a jackass. I'm thinking of trying to bull**** my way through the homemade motorcycle registration process just in case, although it's probably not necessary and might not be possible to actually get it registered.
     
  13. TheNecromancer13

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    Yesterday I started to figure out how to route the chains under the engine. It was a pain but I figured it out eventually. Not exactly pretty, but I'll redo it later once I know if it's going to work and make it look nicer. The bike is going to have 4 chains: 2 to link the pedals to the jackshaft, 1 to link the motor to the jackshaft, and then a final drive from the jackshaft to the rear freewheel. I also test fitted the exhaust pipe header. I'm probably going to throw on a cheap muffler temporarily just to get it running, and add the motorcycle muffler later. BTW harbor freight chain breakers are ****, you're better off using a hammer and center punch.
     
  14. Agreen

    Agreen Member

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    To reassemble a chain, use a pair of vice grips with a tiny nut that's a slightly larger diameter than the chain's pin. It allows the pin to drop in fully, and you can control the depth using the screw on the vice grip. I've had good luck taking chain apart with a hammer and punch on a vise. I always end up breaking chain breakers.
     
  15. MEASURE TWICE

    MEASURE TWICE Active Member

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    http://www.ebay.com/itm/391332018388?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT

    I got this on Ebay and am using it to break 35 Chain. It says 40 as well as other sizes but I never tried it on anything else. I don't have pedals anymore and it is legal off road only with OHV sticker.

    Putting chain back together I use master link.

    If you want to reassemble without master link, this tool does not do that, just so you know. Maybe someone knows how with this tool, but other types of tools specifically mention they do both, but not this one.

    I was happy it did not distort the chain and also took apart the chain like butter.
     
  16. TheNecromancer13

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    Today I figured out how to convert the little foot peg gear shift into a lever to shift with my hand. I also redid the mounting brackets so that the engine sits lower in the frame, and made a few minor changes to the jackshaft.
    Still to do: Add ball end to shift lever, add throttle, add gas tank (arrived in mail today), finalize jackshaft, add front and rear disc brakes, swap out wheels for mag wheels, add muffler, add headlights, add kill switch, test ride, take it all apart and paint/powder coat everything and put it all back together.
    So... progress!

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  17. Tony01

    Tony01 Member

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    What is that bike in the background?
     
  18. TheNecromancer13

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    Those are my dad's 1970s BMW and Triumph which I will someday fix.
     
  19. TheNecromancer13

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    Getting closer...

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    New wheels arrived this afternoon. Found them when I got home from work. 6 hours later and it's almost 11:00 at night and I've gotten the disc rotors mounted on both wheels, put the wheels on the bike, and got the front disc caliper mounted and adjusted, although it still doesn't have a cable yet. Still got to figure out how to mount the rear caliper, since the bike frame doesn't have a bracket for it. I'd figure it out tonight, but the neighbors would probably call the police if I was in my garage at 2 AM blasting Guns N Roses and using noisy machines. Not to mention that my parents would probably throw me out of the house. Anyways, custommotoredbicycles was very specific about how you can't mount a disc brake onto the rear wheel of the wheelset I ordered due to the bearing sticking out too far, but where there's a will there's a way, and it wasn't really that hard to figure out. Harder was getting the wheel to fit into my frame, I had to make my own spacers for it. Let's see here, what else... Still need to figure out which gas tank to use and where it will go. Might have to redo the shift lever. Ordered a 4 pack of the wrong size exhaust gasket, didn't find out till they got here. Ordered a different one. Redid all the mounting hardware and added 2 more mounting points. Still waiting on the CNC twist throttle to arrive. Accidentally cut my hand on a piece of metal and didn't notice till I saw blood on the floor. Filed down the piece of metal. I'll stop rambling now and go to bed.
     
  20. curtisfox

    curtisfox Well-Known Member

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    #20 curtisfox, Nov 22, 2016
    Last edited: Nov 22, 2016

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