Just for fun: whats the biggest motor fitted to a bike?

greaser_monkey_87 said:
Well just about the only small 2 stroker I know of that puts out more hp than a 212 is a ktm/morini. Hard to say which one would win. I don't know how much torque those ktms put out, but I do know they produce about 9 hp stock.
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A 212cc will spank a Morini anyday. I ran around on the S6S (?? it's been awhile) that was rated at 9.4 hp. Not impressed. The 212cc engines run nice but are more than a typical bicycle chassis can handle. I am currently building a 212cc stroker that should net about 236cc and about 25 hp. Should be a fun bike.
 
sportscarpat said:
A 212cc will spank a Morini anyday. I ran around on the S6S (?? it's been awhile) that was rated at 9.4 hp. Not impressed. The 212cc engines run nice but are more than a typical bicycle chassis can handle. I am currently building a 212cc stroker that should net about 236cc and about 25 hp. Should be a fun bike.
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Fully agreed... I like 2 strokers and I run a built up China Girl engine, but there's no substitute for the torque a 212 can put out, and the engines I was refering to were the KTM and Morini type that make good top end power but they only make about 2 ft/lb torque... Yes, they are strong when in their powerband, but a big 4 stroke with less horsepower will win just about every time because of the wide powerband and fat torque curve. Now a 200cc 2 stroke with 40 horsepower will beat a 212cc Pred, but not a 50cc 2 stroke with 9 horsepower...
 
I have evil plans for a 125cc yamaha kart motor! !!

Lol 65mph bike in the works well the 300lb kart the motor came from went 65mph
 
But if your asking whats the boggest motor i would use then its the honda cr250 two stroke the air cooled 1986 version from an atc 250r
 
Honda OHC Dirt Bike Engine

I dream of using an XR200 or XR250 dirt bike engine on a bicycle. You think that a predator 212 is powerful?

A 1980's OHC XR200 will rev to 9000+ rpm and will produce 19hp in its stock configuration with 200cc of displacement, according to the manual! O.o Probably closer to 13hp in reality tho. It also includes a real motorcycle transmission.

The XR80 engine I'm using on my board track build produces around 5hp stock. I hope that EFI, free-flowing intake and exhaust get me to 7hp. All on 80cc. :D I should be able to break 10,000 rpm.

I can't wait to get this build done and post a video.
 
Re: Honda OHC Dirt Bike Engine

Techbiker said:
I dream of using an XR200 or XR250 dirt bike engine on a bicycle. You think that a predator 212 is powerful?

A 1980's OHC XR200 will rev to 9000+ rpm and will produce 19hp in its stock configuration with 200cc of displacement, according to the manual! O.o Probably closer to 13hp in reality tho. It also includes a real motorcycle transmission.

The XR80 engine I'm using on my board track build produces around 5hp stock. I hope that EFI, free-flowing intake and exhaust get me to 7hp. All on 80cc. :D I should be able to break 10,000 rpm.

I can't wait to get this build done and post a video.
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We should be able to hit about 20hp from 80cc. A well tuned 80cc scooter I saw a while back cranked juuuuust over 30hp, and was a 3-speed, so... yeah it was fast. I'm not sure at what RPM though, I think it was 12000?
 
Re: Honda OHC Dirt Bike Engine

mew905 said:
We should be able to hit about 20hp from 80cc. A well tuned 80cc scooter I saw a while back cranked juuuuust over 30hp, and was a 3-speed, so... yeah it was fast. I'm not sure at what RPM though, I think it was 12000?
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The only gotcha here is that these Hondas are very tall (due to their ohc design). My XR80 motor is 15.5" tall. The XR100 is 16" tall. Note that their height is actually less than the length of horizontal ATV/ pit bike engines. These horizontal engines are typically 17"+ long, precluding them from easy use in most frames.

Both xr's have 5-speed transmissions though. The xr100's gears are spaced farther apart with 5th being around .92:1.

20hp is going to be expensive to hit on the XR80. If there was a small enough turbo, 20hp-30hp might be easier though. ;)

P.S. A while ago, a company offered a 95cc hop-up kit for the XR80. The main issue with go-fast parts is that the XR80 bike is physically so small that few adults modify them. It's usually cheaper just to get your kid a bigger bike. An upshot is that the XR80 engines tend to be cheap and plentiful. I found a nice runner for around $300 with wound stator!
 
I always wonder and it really is on my todo list but ya seldom see GY6 engines used. They have a CVT mounting capability, give great HP to weight ratio, e and kick start and an internal generator. It is a mass produced (read cheap) and amazing little power plant for a bicycle. https://www.google.com/search?q=GY6...:en-US:official&client=firefox-a&channel=fflb

Can get em in some crazy big CCs but even at 50cc will turn the back wheel really fast. LOL, I am old. I just want the rear wheel to turn. Slowly and with great dependability. (@40MPH)
 
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Dan said:
I always wonder and it really is on my todo list but ya seldom see GY6 engines used. They have a CVT mounting capability, give great HP to weight ratio, e and kick start and an internal generator. It is a mass produced (read cheap) and amazing little power plant for a bicycle. https://www.google.com/search?q=GY6...:en-US:official&client=firefox-a&channel=fflb

Can get em in some crazy big CCs but even at 50cc will turn the back wheel really fast. LOL, I am old. I just want the rear wheel to turn. Slowly and with great dependability. (@40MPH)
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I agree about the dependability of the GY6 engines, I have a 2008 Rocketa 150cc scooter that I've done a few minor mods to, about 62 mph all day long at around 7000 rpm on the flat not bucking a strong head wind, fairly torquey little engines witha good flowing exhaust Uni filter and a little upjetting on the stock carb, chunk the cvt rollers and replace with some 12-14 gram sliders to get cvt operating better..... fun little ride and would be the berries set up right on a streched cruiser build.


Yee Haw........!

Map
.wee.
 
Or, you could just buy a motorcycle with motorcycle wheels, bearings, spokes, frame, brakes and you could keep up with traffic with no problems.

I'm just an old guy who doesn't see the attraction to overpowering a vehicle designed for 20mph, tops.

Oh, wait a minute. My avatar car was originally sold with a flathead four banger and could maybe reach 60 mph in a pinch. So, what did I do? Dropped in a 383 CID stroker engine making over 350hp.

Okay, now I get it......nevermind. :)

Tom
 
Greg58 said:
Tom what do you need all that power for? Isn't the speed limit 70 mph.
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Reminds me of an old Bill Cosby routine about him buying a Shelby Cobra.
He said he needed a car that would do 200mph to get to work. :)

But to answer your question, Greg, it's so I can get up to 70mph, real quick. :)

Tom
 
Ya beat me to it Tom... LOL

Its not about top speed for me either with the old hot rods, its about 0-when I get ready to let off as quickly as possible..

Years ago I built a 406 cid Small block Chevy for a 1971 Chevy pick up I had, all balanced, 11.2 compression, comp cams 532 lift 294 duration solid lift cam, nicely worked 64cc heads, old Wieand 7546 single plane high rise with 780CFM Holley... B&M Hole shot converter..... blah blah blah.... engine saw 8500 RPMs many time and would set you back in the seat hard if you could manage to get it hooked up on the street... Oh yeah point A to point B was a thrill, I loved the times when the kids would pull up beside me at a red light in there Camaro, Mustang, Firebird or rice burner.... and when the light would turn green they hammered it and then realized I was right beside them until I hammered mine and showed them my tail lights.... oh yeah I broke a few u-joints wore out a lot of tires and got around 6-7 MPG but oh was it fun.....!

OK sorry, got off on a rabbit trail there....!

Map
 
I recall the Dodge Tomahawk from some years back..that was basically a Viper engine in a motorcycle:
http://en.wikipedia.org/wiki/Dodge_Tomahawk

Technically it wasn't street legal. Might not have even been technically a motorcycle, considering it had 4 tires!

Boss Hoss has done some crazy builds as well. From 2000-2008 they had one called "Stud Hoss" that used a 502ci big block Chev engine.
http://en.wikipedia.org/wiki/Boss_hoss

Largest production motorcycle tho, has to be the Gunbus 410:
http://theawesomer.com/photos/2013/10/gunbus_410_the_worlds_biggest_motorcycle_1.jpg

410ci (6728cc) V-twin
~350HP, ~525 ft/lbs torque
1433lbs

No matter what, there's always someone more suicidal than the next man.
 
We built a recumbent once with a 212cc. We were only running a front brake. It was a front wheel drive lowracer. The acceleration would suck you to the seat! 0 to 60 came right before your life flashed before your eyes. We raced cars all the time, it was fun watching peoples jaws hit the asphalt. lol it had 20in tires and a custom made 60tooth sprocket on it.
 
empire steve said:
We built a recumbent once with a 212cc. We were only running a front brake. It was a front wheel drive lowracer. The acceleration would suck you to the seat! 0 to 60 came right before your life flashed before your eyes. We raced cars all the time, it was fun watching peoples jaws hit the asphalt. lol it had 20in tires and a custom made 60tooth sprocket on it.
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wow ... if you happen to have some pics of that bike I'm sure most of us would like to see it... I know I would, but if not I'll just imagine what I think it may have looked like..LOL!

Map
 
Bike is still in the shed. Its been stripped sort of but ill get those pics today for you. Its not one of my show bikes so its not pretty and has been reworked a bunch of times. How it held up that long is beyond me. lol Back in her day she was unmatched in her acceleration and top speed. A very scary bike indeed! xct2
 
empire steve said:
Bike is still in the shed. Its been stripped sort of but ill get those pics today for you. Its not one of my show bikes so its not pretty and has been reworked a bunch of times. How it held up that long is beyond me. lol Back in her day she was unmatched in her acceleration and top speed. A very scary bike indeed! xct2
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Thanks looking forward to seeing the pics, dont worry about how it looks.... around these parts we dang near give trophies for good ole Red Neck engineering, thats what built this country and made it the great nation it once was before all the idiots took over....LOL!

Map
.flg.
 
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