Can't decide on what to do now..

[Vikingimike01]

Hey guys! I currently own a 66cc 2 stroke bike, with a jackshaft kit, a DIY welded sport scooter exhaust, CDH reeds, and CNC head.

I am having a lot of problems with the frame, and the engine, mainly the bicycle part of the whole thing. Because it's not a cruiser, not anything like that, it's a women's hardtail mountain bike. I have to DIY everything on it, and it's a lot of work. For example now that i am done with the build (Of course its not running after not finding the piston i need, ordering 2 smaller ones, getting a guy to fix my cylinder by taking off the same amount of material so the piston is at the top of the cylinder..) and had to put the exhaust on the other side because of the shift kit, so rewelding the whole thing, and now the pedals are not long enough so i can't actually pedal because i hit my leg on the exhaust, and the fuel tank is on a piece of wood screwed to the frame... it's a mess basically. Now, since it hasnt really ran, i have 2 options, wich I need you guys's help on:

• Try to keep this thing, get it to run with spare parts and stuff, DIY the rest of the problems any way i can to get it to run, and then if it breaks it breaks and i can sell the remaining parts

OR

• Before using it, since most of the parts havent even been used, i can sell it part by part, as new, and get a different engine.

After having done any of that, I have 2 options again:

• Getting a Lifan AX100, wich is a 2 stroke 98cc engine, that makes about 6.25kw or 8.3 horsepowers, with a 4 speed shifter (1 reverse 3 forward gears)

OR

• Getting a Lifan 125cc, wich is a 4 stroke 119cc engine, that makes about 5.8kw or 7.7 horsepowers, with a 4 speed shifter (1 reverse 3 forward gears again)

If i get the new engines, I am also gonna use an other frame, wich is more like a moped frame, it's one of those bicycles that have the small 18" wheels, and have 1 thick tube as the frame, and can be folded, but I'm going to weld it so you can't fold it. And then weld some motor mounts and basically have a more moped looking bike. I have a picture, but its not that good at all, about how that frame looks. (the blue frame bike)

And, with my amazing artistic abilities, i drew up this, on how I imagine it! (of course forgout about the fuel tank, but it'd go on the gray metal that symbolizes the welded iron pipe

 

[inspectorcritic]

I'd just get a factory kit and a run of the mill typical bicycle if you half to weld there's something wrong.

 

[Frogslayer]

Interesting. In sure that 18 inch bike would work but probably not be fun at 40mph

 

[Vikingimike01]

Lol, could be true, haha! May need to think again about the frame! I'm looking for something with way less maintenance, that's why I don't know if i should go with the lifan 125cc 4 stroke, or the AX100 2 stroke.. I am thinking the 4 stroke may be better? Basically I wanna put it on and not have to worry about it doing weird stuff. May even end up converting my current bike but that aint fun at 40 mph either (Used to hit 39 with stock 44t sprocket) because theres not even a front spring. Maybe I'll go with a fat tire bike?? I do have a frame and am buying a new frame for my ebike, sooo... Yeah. What do you guys think?

 

[Vikingimike01]

I have decided on getting the 4 stroke.

Now I need a little help with gearing. I found this on an other forum: 1st gear is 2.833:1, 4th gear is 0.958:1

What size sprocket would I need, for a normal speed? Let's say 50mph max speed in 4th gear, at about 8000RPM. What would it do if I put on a 42t sprocket from my old motorized bike? In first, and in last? Or does anyone know how to calculate it? I have a 28" wheel (26 but im gonna put it on a fat tire bike and the tire is about 2" thick )

 

[CrazyDan]

What is the output sprocket on the 4 stroke engine? If it's a 9 tooth you'll need a 100 tooth rear sprocket on a 27" tire (my 2.5" hookworms measure 27" inflated) to max out at 60.4 mph@8000 rpm in 4th gear, 1st gear would be 20.4 mph@8000 rpm. You might need a jackshaft to get more reduction so you don't need to find such a large rear sprocket.
Your 42 tooth sprocket would give you 143.7 mph in 4th gear (if it could ever pull it) and 35.9 mph in 1st gear.

 

[Vikingimike01]

It has a 14t output sprocket

I defenetly need a bigger sprocket then or somehow a jackshaft or something

 

[Vikingimike01]

remember this is not a 1 speed it has different reduction lol.

i was watching videos of these motorized bikes, people have a size 41 sprocket. What if i use the jackshaft kit for my current motorized bike? Not sure of the sprockets, but i think it has a 10 or 11 tooth sprocket and a 18.

 

[Vikingimike01]

Guys, what do you think about me making my own frame? An actual frame, not a bicycle.. From steel.. I can weld more or less now. I'm going to use scrap bicycle parts as the handlebars and wheels and stuff like that but the actual frame will be made by me. It's going to have a 26" fat tire front wheel wich is 4" thick, and a 15" back wheel wich is either 4" or 3" thick. No suspension because I'm not that advanced into making my own stuff, only front suspension.