the builder had to rebuild after every race. 2 hrs. max on the engine, new piston, ring, wristpin, wristpin bearing, c-clips, crank bearings and gaskets. I would change the clutch pucks every race also.
Is it worth it?
- Thread starter BlackIceBicycleWerks
- Start date
Well that's for race conditions. On my bike I rarely go wot and if I do it's less than 10seconds. I imagine that would help alot with longevity.
then why modify the China, just leave it stock.
the honda 120cc ran great, the only part that is not stock is the billet flywheel. It has the stock cam, carb. the governor is pulled.
the honda 120cc ran great, the only part that is not stock is the billet flywheel. It has the stock cam, carb. the governor is pulled.
Well stock half throttle is 10mph where as the modified half throttle would hbe closer to 20 25. You see what im saying? I wont be going 40mph all the time.
The KTM/Morini motors are a quantum leap in quality compared to the ht's. You will NEVER get a ht running as hard as the quality motor will run, and if you DO even get close, it will mean constant rebuilding.
The better the engine you start with, the better your results can be.
I love the stock ht's and have tens of thousands of miles on my Pig, but if I were ever to want any kind of personal toy build, it would be KTM clone powered with a Tomar clutch and a custom torque pipe. The smooth operation, clean carburation and throttle response and the reliability of the ktm clone will be well worth the custom building required. You can spend just as much making a chinagirl fast and never get close to the same reliability.
The better the engine you start with, the better your results can be.
I love the stock ht's and have tens of thousands of miles on my Pig, but if I were ever to want any kind of personal toy build, it would be KTM clone powered with a Tomar clutch and a custom torque pipe. The smooth operation, clean carburation and throttle response and the reliability of the ktm clone will be well worth the custom building required. You can spend just as much making a chinagirl fast and never get close to the same reliability.
Ya i see what your saying and thats more of the kind of answer i was looking for. with the HTs it seems no matter what I do its still whip cream on **** lol but they are great just for cheap and easy to work with. But what about those predator 98cc 4 stroke? I would like to see those side by side. I imagine the 4 stroke would have more torque but the morini more top end?
99cc HF not made anymore. that's why I keep telling you about the 120cc Honda, there is aftermarket parts for them. If you want power at the top RPM's you can pay for it. they can produce over 12HP.
Morini gets most of the power after 8000 rpms to get it to 10-11 HP you have to have it full throttle, you stated you really only give half throttle so I feel the Morini is the wrong choice for you.
The Ktm clone I feel is the wrong choice also, actually any 2 stroke would be the wrong choice due to the fact that they like to be ridden on the edge to get their power, which is more than half throttle.
Morini gets most of the power after 8000 rpms to get it to 10-11 HP you have to have it full throttle, you stated you really only give half throttle so I feel the Morini is the wrong choice for you.
The Ktm clone I feel is the wrong choice also, actually any 2 stroke would be the wrong choice due to the fact that they like to be ridden on the edge to get their power, which is more than half throttle.
Ah yes I never thought about that. The two strokes always needing to be wound up all the way. I used to have a 125 dirt bike and it was a different animal at full throttle. You guys are so helpful! 120cc seems like alot tho. How hard is it to fit into a bicycle. Do you know of any build threads?
yeah 125's need to be on the pipe for any power. The bike I built for my brother doesn't have pics? I will talk to him and find out what happened. culvercityclassics (Jeff) has some nice 4 stroke builds, he was the first to mount the engine verticle, and Scotto has nice builds also
http://motorbicycling.com/showthread.php?t=44022
http://motorbicycling.com/showthread.php?t=44847
http://motorbicycling.com/showthread.php?t=41247
http://motorbicycling.com/showthread.php?t=32789
http://motorbicycling.com/showthread.php?t=44022
http://motorbicycling.com/showthread.php?t=44847
http://motorbicycling.com/showthread.php?t=41247
http://motorbicycling.com/showthread.php?t=32789
Those builds look awesome but ALOT of custom work. The honda seems practical but just very big and I have no idea how I would make those mounts. Wouldt it just be easier to mount it normally? lol Apart from the clearance issues of course. I will have to look more into these builds they do peak my interest.
Yeah I agree, Jeff and Scotto do great work, the amount of customizing depends on the frame that you are going to use. The engine mount can be made with billet bar clamps, like the ones used for dune buggies, and a mini bike engine mounting plate
Yeah i guess thats not too bad. I just need to find a big solid steel frame to fit that big of an engine into. The part I was most concerned about was what gear box could I use for that and does anyone sell super wide cranks or would I need to make some? Same thing with the gear box. It seems like it would be very hard to make a gear box from scratch for the engine.
Scotto used a Felt cruiser, whats cool is has horizontal rear dropouts which are great for tightening the chain with tensioners. check out Bikeberry for the wide 3 piece cranks and affordablegokarts (AGK) for the jackshaft assembly, he has step by step tutorials for governor removal, hop ups and engine/ motorized bicycle builds.
Ya I was just looking into the build and pricing it out and such and working on dimensions to get a rough idea of what the build will entail. I was thinking perhaps of just mounting a 125cc 4 speed lifan. It would be easy to mount about as wide as the 120cc honda with a gear box. The lifan has the enclosed components so I do like that and the fact that it has a chain drive. I cannot find the chain size for the lifan drive sproket tho. I dont suppose you would know that? The lifan seems to be a decent engine and I would get the best of both worlds. The torque for hills and out of turns and the gears to still cruise at 35 to 40mph. They only bad thing I can see with the lifan is that it is heavier than the GX120 and I would have to work on an exhaust for it. Am I over looking any other unforseen problems?
Maybe something smaller than a 125 lifan it seems more than what I need. perhaps a 70cc 4 speed?
I don't know anything about Lifan engines.
In California motorized bicycles with internal gears are not legal to ride on the streets. anyways then it would be a motorcycle?
Harbor freight makes a 79cc 4 stroke $100. AGK has aftermarket parts for them and they have used them for their builds. You would most likely have to fabricate a custom exhaust for any engine used, part of the fun.
In California motorized bicycles with internal gears are not legal to ride on the streets. anyways then it would be a motorcycle?
Harbor freight makes a 79cc 4 stroke $100. AGK has aftermarket parts for them and they have used them for their builds. You would most likely have to fabricate a custom exhaust for any engine used, part of the fun.
Ya I know I was just trying to get a general idea of what this build would take. And yes they are illegal here too but I would only really need it in one gear on the street and just use the gears for the off road trails. Wouldnt it still be super wide with the jack shaft and such. I take it the HF buids are more popular than a lifan build because I could only find one build with a lifan. I have read that the lifan engines are a slightly vettdf quality than the HFs. I just like the idea of the simple enclosed gear box. One crash off road I think would destroy the jackshaft
Here is what I did for my exhaust. I had an old header from a china kit exhaust, and I cut that off leaving about 2 to 3 inches of pipe. Dremeled out the bolt hole pattern to match the engine's. Got a flex pipe exhaust from ezm, and hose clamped it to the head pipe. Instead of using the pipe clamp that came with the flex pipe, I used hose clamps to secure it to the frame. that should work for just about any engine. For the pedal clearance, I went to Lowe's and got a propylene (NOT propane, propylene, says MAP/PRO on the cylinder and its yellow, came with a nozzle for $50. Me and my buddy put it in a vise and heated it red hot, used a seatpost to slide over the arms, bend them out in one spot and back in at another. Took about 10, maybe 15 minutes to do both arms and was a piece of cake. Let it cool at room temperature and you're golden. It will work for either a one piece crank or a 3 piece.
Racing is the proving grounds for R&D. Scotto, Jeff, myself and many others have used the jackshaft system without fail on the track.
I’ll measure the width to get you an exact measurement but I don’t think it is wider than 5”. It doesn’t hang out past the cranks. Jackshafts are pretty durable, the shaft is 5/8” solid steel.
I’ll measure the width to get you an exact measurement but I don’t think it is wider than 5”. It doesn’t hang out past the cranks. Jackshafts are pretty durable, the shaft is 5/8” solid steel.
Ok sounds good and thanks for the idea of bending them out! and it seems like it would be alot because the 4 stroke is so wide plus the shaft and everything.
