Safety of the 212cc motorbike kits?
 

How safe are those 212cc kits that you can mount on a bike? I a have been thinking about getting a cheapie mountain bike with rear suspension. Brace the hell out of it, then go put dirt bike parts on it.... (Triple tree, real breaks, rims, tires, etc, etc) I don't see me being able to get a hawk (or any bike) anytime soon. (As in the next year) So if anyone can state how well those things can hold up with time, or has anyone made one of these kits?

Sincerely,
John Doe

I have seen a lot of 80cc bicycle motors but never 212cc??? Do you have a link?


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The 212 is a honda clone. Ive made a 200cc motorized bike but I did the job from scratch. If you do a good job there safe. I would go with thick spokes and double wall rims. Keep a close eye on all the bolts and spoke tightness. I wouldn't use an aluminum frame. Ive been trying to buy a real motorcycle cus Iam tired of playing with these. Ive made 4.

May I ask why? Not really road worthy, or you looking for something more or what? I would think that would be as quick as a dual sport with a engine that big.... What typically fails first on these bikes? Have you seen any with a transmission? Could you get it registered as a motorbike or moped?

Here you go!

Sorry for late reply I didn't see your post

Pretty cool.

Thanks for the link.


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The 200cc has a CVT tyranny. I built a 97cc four stroke flat head side valve using a heavy duty derailleur with a cartridge that has an overdrive and a granny gear its 7 speeds. The main problem is that bicycles wheels are not speed rated. They tend to fall apart at the speeds I ride. I have custom made double wall wheels that are doing fine so far.(cost a bundle) Getting the electrics working is tricky you have to setup some way to power it all. And there is no buddy seat. It costs more to build one then it costs to buy a china bike if you can find a china bike to buy that is. At least you wont get ripped off multiple time trying to buy a motorcycle like I have been. Just know the cost can add up very fast. Getting it reged is super tricky but Ive heard of people doing it.:shrug:

Okay thanks for your reply I have to rethink that now:)

Ps you may have saved me a bunch of money!

The only reason to build one of these is for the fun of it. You dont really save any money. Ive got well over $2000 into my 200cc bike. Its fun but I would have been better off with a china bike.

Yeah I have also however thought about ditching the kit all together and picking my own parts, parts that I couldn't just put on a hawk....

Ya I dont do kits. I design all my bikes my self. If your thinking about fabing one of these start thinking about jack shafts and gear ratios.

Okay good to know what gear ratios do you use? Also how far do you think a 18 HP will go? I wouldn't think that it would be to far from the hawk with a engine like that I think that is also has a tranny.... Water cooled :P I don't know how hard it would be to add a radiator.... Or any of the other goods that would come with water cooling....

http://www.pccmotor.com/4st25zoohcwa.html

Years ago I build 5 of the 80cc (actually 66cc) engine kit bikes. They worked OK but I don't consider them safe. Bicycles are not made to go that fast. Three of my friends crashed, one seriously injured. Switched to reviving old Honda Cub type bikes, mostly Trail 90s, with new Lifan engines. Much safer.

Put that engine on a bike and you could do over 100 mph. I wouldn't recommend it. ( the speed not the engine ;)). The gear ratio is dependent what you want to do with it. I gear mine with 50 mph cruse speed and lots of low end. I would have to check it out to find the ratio I chose. I will look for the link for the gear ratio program I use. It works great. If you can weld or braze you will have no problem adding a radiator. Start with a strong frame and strong wheels and you will be fine.

What is the best frame to start with? I want something like a mountain bike frame (or a soft tail beach cruiser would be okay.) to start with what is a cost effective brand for this purpose or will someone just sell me a frame? Also about the speed, would a upgraded tires rims and bearings make it safer or is the light whight it's self the issue?

i know that people around here ride the smaller cc bikes and are always replacing rear rims because the drive sprocket runs off of the spokes that were never made to have torque on them ... if i were going to build one i would mount the engine over the rear tire and make/buy a unit that drives off of the rear tire, not the spokes

Yea my plan was to replace the rims with ones that are solid (more like a car rim.) I wonder how well a friction drive would work? Be easier but I wonder how handling would be affected? (Higher center of gravity....)

I use firmstrong frames. For the 212cc use the Chief frame it will give you plenty of room for the engine and a nice long wheel base making it more stable at speed.. I know people that have used this frame and the 212cc for racing. Got to over 100 mph with it. Of course for those speeds ya need speed rated wheels and tires. Yes upgraded wheels make it safer. Thick spokes and double wall rims. Some guys use moped wheels to get speed rated. You can not power a 212cc bike from the spokes. It will tear them clean out. You need to use a jack shaft. And you have to drive the rear wheel with a sprocket. If you dont know how its done let me know and Ill fill you in. (hint think disk brake hub)

Friction drive with a 212cc is not a good idea. It will make your tire bald very quick and when it gets wet it slips. You want to drive it with a jack shaft and a strong sprocket.

sprocket is not the problem, it is what the sprocket goes on

The sprocket goes on a disk brake hub. Use a sprocket instead of or with the disk. My setup uses a adapter I made to use with a disk and a one way sprocket so the pedals dont spin when your riding. One side of the hub you peddle with. The other drives the wheel.

I've ridden a few mainly the 66cc marketed as 80cc but a few bigger. Unless you do some serious stuff to them like Merlin has they are supper sketchy scary. The tires / rims and brakes seem to make the most difference but having a good suspension and drive train would be a big plus. I knew one nut who put one on a fixed gear. It did not last long.

Haha that sounds super "safe".... This will be a fun project....

Thanks I got it all figured out, or at least for tonight I do....

How hard do you think it would be to get rid of the pedals all together?

That is the easiest way to go. Here is a forum that deals with this stuff:
http://motorbicycling.com/index.php

Thanks man that seem like a cool site I will have to look into it more! With next pay check I will get my victim....:)

A lot of people are building bikes with the 212cc engine over there. There is thread of mine somewhere over there that shows my build. oldtimer54 is the nic on that site.

I am thinking I am going to stick with the 250, may have to scrounge for some stuff.... i.e. A transmission and some sort of engine:P JohnDoe on there as well.... I will look into your thread.

That would be kind of fun putting one of those bikes together. I would possibly try it if I wasn't on a steep hill with a highway to ride on to town.

In other words if I was in town I definitely would.