help with motorcycles

[novass]

I dont know much about bikes. I have ridden them and tinkered on a couple, but its not a subject I am very knowledgable in. Reason I ask is cause I found an old go-kart frame and I wanna put a bike engine on. I dont want it to be insanely fast, but kinda fast and cheap and reliable (im not too picky eh? LOL). I was thinking a 125-250 2-stroke would be adequate, but I dont know which manufacturer to go with, etc.

any help or suggestions you have is appreciated!

[666fast]

I don't know which manufacturer is the best, but I'd bet they are close to the same. They were all designed to take abuse.
I think the hardest part would be the clutch and shifting machanism. It wouldn't be hard to make the cluth a pedal like a car, but I would fabricate some linkages to use a regular stick (like a cars) to shift.
I've seen one built that had handle bars just like a bike, but the steering was really twitchy. It had too tight of a steering rack. Turn the bars an inch and it turned 90 degrees. It was way too fast, you could easily flip it over.

Mounting the engine should be damn easy. Especially if you know someone who can weld. If you don't care about the engine vibrations, just make some solid engine mounts and weld them to the frame and bolt the engine down.

Do you have just the frame itself, or is it everything minus the engine?

[novass]

its an old go kart my brother and i bought a while ago. it has a crappy briggs and stratton on it, only 3hp, i found it in our parents garage when they conned me into cleaning it. I can weld, and both my roomates are mechanics for Subarus, so they can help. Basically i just wanted to know what the "Ford" of bikes was LOL but i think your right, they were all designed to be abused.

just somethin to tinker with. can never have too many toys!

[sportVeloce]

My advice is that you stay away from a 2 stroke 125 or 250. Race bikes which are generally the bikes (upto about 2000) that have 2 strokes are your KX, CR, YZ and RM. These bikes are heavy on maintenance (piston should be replaced every 8hours - official manufacturers recommendation). They chew chains and sprokets etc and thats just minimal stuff. (btw I raced bikes for a few years).

I would recommend that you go for a good old 4 stroke 250. It will have heaps of torque for a kart and be as reliable as hell.

4 stroke bikes are the Diesel equivilent to cars.... My pick would be a Honda XR 250 motor. I wouldnt piss on one to ride, but it would make a good kart engine. I had a race car (mini-sprint car) that had a GSXR 1100 motor, twin Webers, huge set of extractors and side-pipe and ran on Methanol. NOW thats one hell of a KART :twisted: Pulled real hard, damn dangerous and only breaks on one side! Now you know why they need the front and top Wing.

Anyway, XR 250 or some honda 4 stroke and you will be laughing all the way to the bank! Reliable, go hard, oil-injected and wont need a rebuild after 8hours!

[sportVeloce]

Oh yeah as for clutch and shifting machanism its a sinch:

Gear boxes on bikes are like a sequential in cars. Back and forward... no H-pad. All you need is a bit of pipe and couple of universal joints - you can literally weld it up in an hour. I can send you diagrams and pics of my race cars if you need it. As for the clutch just attach it like a normal bike clutch. So its on the gear stick. Then you dont need to build custom mounts and assembly.

Hope that helps!

[novass]

thanks a lot sportVeloce!!! the mini-sprint car you mentioned sounds like a lot of fun to drive! i would kill myself with that LOL

could you send me those diagrams? what do you think the price range and availability of the XR250 is?

i can use all the help you can offer. you know what they say, measure twice, cut once. thanks for the help

[666fast]

A quick search told me that the XR250 bike is $1700. My guess is the engine alone would be in the $1000 range.


the clutch and shifter should be very easy to make. For the clutch, just run the cable to a pedal. You will probably have to get a longer cable though. Super easy. the only hard part (which shouldn't be that hard) is setting the right amount of travel on the pedal. obviously you don't want it too short. You could push the pedal and rip the cable from the motor/tranny thingy. Getting it just right is nothing more than trial and error, but it should not be hard. It's the same deal with the throttle.

With the shifting, it's another no brainer. If you don't mind the cost you could get a jockey shifter (also known as a suicide shifter) that is made for a motorcycle and just make the linkages a little longer. It would probably be cheaper just to make it all yourself though.

[JN396]

Hey man; dunno about modding karts w/ bike engines; but a guy in one of the forums I hang out is selling his:

http://www.bayarearidersforum.com/forums/showthread.php?s=&threadid=36727

All I can say is that shiznet is expensive! Watching that 600cc gixxerkart on rf always makes me as giddy as a schoolgirl! Goodluck with the project and take some pix of your progress!

[novass]

thanks for all the feedback! ill post some pics, but its gonna be a while. i have a tendency to start a lot of projects at once. the only thing puttin this project on the shelf at the moment is the engine. i dont want to spend a whole lot on this, its just gonna be for fun, not to race. but i do want it to be fast! LOL

oddly enough the reason i started thinkin about building this go-kart was when i remembered when i was younger and my parents bought my brother and i a go-kart. we would take it to a big flat parking lot and usually get in trouble pretty quick, but it was so much fun runnin from security in their golf carts. the kart back then only had a 3hp Briggs&Stratton, but i was also a lot smaller so it was faster then their shit. i want to have a fast one now so i can relieve the glory days, do donuts around those bastards.

[sportVeloce]

Hi Novass... nice to meet you!
I will contact you with the info you need on the clutch and gear shift setup. As for the XR 250, you wouldnt go buying a complete bike from Ebay. You would go to your local Wrecker and get a complete motor with good compression for a couple of hundred bucks. All you need is an old 80's to early 90s motor. Nothing flash, the good old heat-proofed black barrell and metal cased gearbox (gota love the good old days)... plenty of torque for a kart!

Here is a pic of my kart (1100 cc, twin 43s, headers, methanol, ported and a couple of mods...btw i sold it about 12mths ago). The pics are crap due to my scanner disagreeing with XP and my Sony handycam not taking perfect pics of photos... i will scan them properly when i get this thing working.... anyway.. heres one...

http://www.geocities.com/sportvelocesv/DSC00172.JPG

[oic0]

For something cheaper and more reliable use a sport quad engine. Nearly any will have enough power and be reliable enough.
Blaster 200: 2 stroke, light, air cooled, kick start, no reverse ~16hp
Warrior 350: kinda heavy but bullet proof, has reverse ~20 rwhp,
400ex: same kind of bullet proof but lighter and no reverse ~25hp
Z400 (new so hard to find engine): liquid cooled, reverse, ~30hp
Raptor 660R: (dont get an 01): liquid cooled, reverse, ~34hp
Banshee 350: 2 stroke Kick start liquid cooled Twin, no reverse, stock ~39hp, moddable to 100+
-RD350 RD250 RD400, Kick start old street bike engine the banshee is based on, light, aircooled and around 39 hp also (close to 50 or more with pipes).

[novass]

thanks for the info, ive been lookin into quads too. ive been meaning to take a trip to the bike yard, i just started school again for the summer, which im not too happy about, but this is gonna delay the whole project a little. i found a guy sellin a bike im gonna go try and look at this weekend. i dont know much about it, a friends sister that lives about 45 min away told me there is a guy sellin one down the street and it runs, but thats all she knew, worth a shot, i guess

[Geert]

If you want to see what a kart can do with a GSXR 1100 engine (Suzuki), then you really have to see the movie that can be downloaded from the Nurburgring website. Crazy! :twisted: Guess the bill for the tires must be huge... :wink:

http://foto.renn.tv/web/videos/gixxerkart_video.wmv

[nthfinity]

i used to be the build and prep guy at a motorcycle/atv/etc. place.... and as far as reliablity, i highly recomend yamaha motors. but none, save rotax, are that disimiler. ive not seen any bike/quad transmisions converted to a stick before, but it would make sence if it were up/down like an arcade game. an older 2 stroke motor from a yz 250 would cirtainly kick your ass...
good luck!