Help me pick a bike motor

Discussion in 'General Questions' started by Tifford, Apr 25, 2008.

  1. Tifford

    Tifford New Member

    Hey guys,

    I know a lot of you guys & gals have been there and done that so I'd like some advice.

    I have a diamondback Edgewood for a bike.

    I noticed that a lot of guys have 25cc engines above the rear tire. Can I go up to 50cc? The reason why I ask is that the roads in SC are narrow and I want to be able to keep up with city traffic but still get around 100 mpg.

    What would you guys suggest for me if I want to be able to go 45 to 50 miles per hour? Would I still be in the 100 mpg range?

    I'm 6 foot and weigh 230 pounds.


  2. ocscully

    ocscully Member

    First your speed expectations are a bit beyond the capabilities of the average motorized bicycle and any of the kits/systems currently available. If you feel that you really need to reach those kind of speeds you would be better off looking at a scooter like the Honda Ruckus. There is a new 50cc 4-stroke rack mount kit available from thats Dax that claims it can run at 35mph all day and has a max speed approaching 40mph. Only time will tell if these speeds are accurate. And there are members here that are trying the NuVinchi CVT Rear hub that may be successfully reaching speeds above 40 mph. As to your 100mpg requirement that should't be a problem. The 50cc Honda or its various clones seem to be getting around 120-130 mpg the smaller 35cc Subaru/Robin 4-stroke approachs 200 mpg. But once again the speeds from these various engine kits is in the 25mph to 35 mph range.

  3. sparky

    sparky Active Member

    Yea, if you're that serious about the speed and feel like spending some money... get a rack-mounted 50cc 4-stroke like a honda, a super solid, full suspension bike (wouldn't go with the walmart brand this time), & the NuVinci hub.

    Only other thing I can think of is the engine kerf has, the GP460 2-stroke I believe. "Headache loud" is how he described it & that is true. He said he hit 50, tho. You'll have to check out his posts about his muffler that helps a bit & his gearing & such...

    I wouldn't take the cheap way out on this tho. NuVinci would be it for your situation. And might be mine, too... quicker than I thought since cops can still consider my motored bike a motored vehicle or motorcycle. Laws here are too vague, so I may upgrade quicker than expected as my current bike isn't worth registering, insuring, etc.

    Maybe you need a motor scooter?
  4. Tifford

    Tifford New Member

    Looks like I'll have to find a Honda 50cc engine. I called the DMV here in SC and they said that I had to keep it under 50cc.

    Looks like I'm going to have to find the right gearing to make it go 40mph.

    Too bad..I had a small 4 hp pressure washer engine that was going to be perfect.

    Looks like either a new Honda engine or a look at chain saws.

    Thanks for the thoughtful replies. I will check back on Monday. Cheers!

  5. Tifford

    Tifford New Member

    Almost forgot...thanks for the nuvinci heads up.
  6. kerf

    kerf Guest

    Forget the bicycle and get a motorcycle. First off, these engines and drive units are not designed for sustained 40 mph speeds. Secondly, bicycles are not designed for sustained 40 mph speeds, the bearings, tires, wheels and brakes would take a beating. Speaking of a beating, meeting the asphalt at 40, after a catastrophic failure, won't help you much either.
  7. autobo7

    autobo7 Member

    yeah kerf has it dead on....
    If you need to keep up with city trafic, you want enough power so they wont be passing you every five seconds. If you had the gearing to make 40 or 50 your acceleration from 0 to 20 would be terrible. Ignoring those problems, if you could push a bicycle to that kind of speed with good acceleration, they dont have the supention so that you can hit a bump in the road at 45 and live to tell about it, braking is also a big issue, i think a little 50cc or 150cc scooter might work a bit better for your needs
  8. sparky

    sparky Active Member

  9. Tifford

    Tifford New Member

    A turbo that I think could fit on a 50cc engine. It is the KKK KP31 turbo off of the smart car.

    Granted a bike isn't the best thing for suspension but I think it can handle it.

    I know that there are 50cc scooters sold out there with a turbo for around a grand.
  10. sparky

    sparky Active Member

    You're crazy, man... you're crazy!!

    That bike you're wanting to put this on isn't even full suspension. That is a minimum... which means you pretty much have to make it rack mounted... you're using it daily at high speeds & up hills, so you need a 4-stroke.

    So, rack mounted 4-stroke with NuVinci on a different bike that you're still gonna need to add headlights, taillights, brake lights, turn signals, a horn, etc... or get a scooter that has all that stuff already. Going ~50mph will require you to register & insure any type of vehicle -- bicycle, scooter, truck, suv, whatever. Might as well go with a solid full suspension frame with transmission for $1500 give or take a few hundred.
  11. vrrcar

    vrrcar Guest

    I think that once you get out there and go 25 or 30 mph on a bike you will realize that this is fast enough. Most bikes are not made to go as fast as you want to. The brakes for one thing are not that great on most bikes. I have a gary fisher Joshua x1 with a 40 cc zane motori 2 stroke. It will reach 38 mph but scares the you know what out of me. Do not buy a scooter. You will have to buy insurance, reg. it and probably get a special endorcement for your drivers lic. One of the main reasons I have a motorized bike is to beat the hight cost of the pre listed things. Anyway a great engine is the Tanaka 35cc. I have one of those also but mainly use it for long distances because it is reliable as you can get and gets great mileage. Always starts on 3rd pull when cold and first pull when warmed up. You will get about 35mph on the flats. Iuse all my motors on the GEBE kits. For the bigger engines get a 14 tooth counter sprocket. For the 26cc size get the 11 tooth sprocket. I have all 4 of their sprocket and just takes a min. to change one out for different ridding conditions. My first kit was a GEBE kit with the Tanake 26cc pure fire engine. This a sweet engine and will do 30mph all day long with 12 tooth sprocket and it actually gives close to 200 mpg as advertised by the company. Get a good quality full suspension bike. Do not mess with the cheap Walmart junk bikes. Always wear a good quality helmet and use a rear view mirror attached to your glasses or helmet. Be extremely aware of your surrounding's when motoring down the road. Many people enjoy scaring you by coming to close as they pass. I have had them yell out the window at me and even throw things. Lots of stupid jerks out there so be aware of any vehs coming from behind. Motorizing a bicycle is dangerous. Hope this helps you and keep the shinny side up.
  12. kawasaki999

    kawasaki999 Member

    This could be what u r looking for, full suspension and a disk brake up front for good stoping power, target sells it for 250.00, and with the gp 460 it will do 50+ mph. The stock clutch springs suck on the 460 engage at 8,000 rpms so you will have to find 50% lighter springs, kerf is trying to find more springs.

    Attached Files:

    Last edited: Apr 27, 2008
  13. kerf

    kerf Guest

    I have a 460, please explain how you go 50!
  14. vrrcar

    vrrcar Guest

    do not do it!!!

    Anybody who goes 50 mph on a bicycle is suicidal. What is the point??? Do not do it!!! Skab city or morgue at worst.
    Last edited by a moderator: Apr 27, 2008
  15. dbigkahunna

    dbigkahunna Guest

    I understand where you are coming from.
    However, get your feet wet, then decide if you really want to keep up with traffic at 45 MPH on a bicycle.
    I am a little bigger than you are being 6-2 and 270. I have a DE scrubber with a 49cc two stroke and it can push me 40 MPH. BUt it wont do it like a motorcycle. I do not use my engine to get me started, I use the pedals. Once I get moving, I bring on the throttle still assisting with the pedals until I get up to a decent speed then I back off the pedals and let the engine take over.
    I have ridden large displacement motorcycles for years. These are different. When you figure out YOU are the transmission.
    Do a bunch of reading on the forum then get your feet wet. The first system you go with may not meet your requirements. If not you can sell it and try something else.
    But if you want this to be a motorcycle, you will be sorely disapointed. If you look at these things a being a fun way to get around and live in their limitations, you will open the door to one of the most absolutly fun ways to get around.
  16. kerf

    kerf Guest

    I'm running a 18.75/1 gear ratio and on a cool day, with no head wind, on level ground, my bike will hit 45 mph. To do it, she is turning 11,000 rpm, that's screaming and will kill the engine in pretty short order. I've geared to my current ratio from 21.43/1 to drop rpm at cruse. At 25 she's running 6050 rpm, a reasonable cruse but hills I once accelerated up now put a load on the bike.
    The point to all this is, even with 4 hp, the bike won't come close to cruising with 40 mph traffic. Maybe someone else knows how to do it but I'm just not interested in killing myself.
    Last edited by a moderator: Apr 27, 2008
  17. sparky

    sparky Active Member

    So... it was *you*?!? I thought it was kerf.

    What kinda mpg's do ya'll see with the 460?? Can't be that much better than a motorcycle, can it?
  18. kerf

    kerf Guest

    Who cares about mileage, the fuel for the 460's running over $6.50 a gallon, it's not a very economical engine. But it do go fast and it do go loud.
  19. wavygravy

    wavygravy Guest

    zipping around above 30 mph does not a good ambassador make for motoredbikes! besides its illeagal! & attracts bad vibes from cops & public! please follow the law & be good ambassador for the cause!
  20. kawasaki999

    kawasaki999 Member

    kerf, how do I go 50? I have had it to 52.2 mph and 13,000 rpms and that by a gps, I never had a chance to run the 460 with the stock muffler because it blew the exhaust at the seat, so I installed the x-can muffler which has 2 exhausts 2 to 3 mph increase to top end, and a nitro blast ingnition 20% gain in power. Its a gebe belt drive so 95% of the power is put to the rear wheel, gear reduction robs hp. I dont do this speed very often and dont recomend anyone trying it without a full suspension bike with GOOD! brakes. I cruise 25 to 30mph 99% of the time. Ps.let me know if you hear anything on the lighter springs.