Motorbike to go kart

karthead · Trackday Trickster Joined: 01 Apr 2012 Karma :

Hi everyone, just thought i'm share my latest project with you all.
As the title says, i'm using a motorbike (well, basically the engine) to create a go kart. I got the motor from a wreckers, which was mounted onto the frame and had all the wiring, and sprockets+chain. The motor is from a Kawasaki KE125 (not sure what year, i didnt get enough from the wreckers to determine what year). A bit about the engine- It is a 2-stroke, rotary valve high revving motor that puts out about 14HP, and the bike was made to go 140km/h.

What i've done so far: 2 rebuilds. Replaced gaskets in the first rebuild and got a couple new parts. Disconnected oil pump to run on premix. New piston kit. Wired it all up, connected the fuel line to a weedwhacker fuel tank, mounted it back onto the frame and after about 10 minutes of kicking and kicking she started!
Then came the second rebuild to make sure everything is beautiful for the go kart. Replaced the engine cover gasket, put new screws in. Contemplating whether or not to replace crank seals (i've looked everywhere and i cant find the right one). Put it all together. Today i bought a new pod filter. Going to get new exhaust. Then i'll start it up so i can tune the carby due to new filter fitted.

Hopefully once the engine is done, i'll be able to pick up (and possibly do up) a go kart frame for free or cheaply. Getting all the individual parts for it and putting it together will be a bit expensive and difficult for me (i'm 15). Then i'll mount the engine on, put sprockets on, and she will hopefully be ready. I'm hoping to get 100km/h or a bit under out if her (it's not like i'm going to reach those speeds tho!).

Anyway, feel free to give me advice, cause i'll need it, and it's good getting a heads up about certain things.
Let me know what you think! Mr. Green

karthead · Trackday Trickster Joined: 01 Apr 2012 Karma :

oh and i'm reconnecting the oil pump...

The Shaggy D.A. · Super Spammer Joined: 12 Sep 2008 Karma :

karthead · Trackday Trickster Joined: 01 Apr 2012 Karma :

P. · Red Rocket Joined: 14 Feb 2008 Karma :

Gonna be gash.

karthead · Trackday Trickster Joined: 01 Apr 2012 Karma :

Here are a few images of what i've done...

P. · Red Rocket Joined: 14 Feb 2008 Karma :

No turbo, 125cc, not even a turbine.

This is lacking somewhat

Pol Anorl · Banned Joined: 13 Apr 2010 Karma :

karthead · Trackday Trickster Joined: 01 Apr 2012 Karma :

P. · Red Rocket Joined: 14 Feb 2008 Karma :

CHR15 has beaten you to it.

karthead · Trackday Trickster Joined: 01 Apr 2012 Karma :

P. · Red Rocket Joined: 14 Feb 2008 Karma :

He's done turbo, doing super charger and also doing jet engine go kart.

You are doing safety pin engine rebuilds.

I can see how this project will end.

Pete. · Super Spammer Joined: 22 Aug 2006 Karma :

I put one of those into a go-kart chassis. Actually I think it was a KH100 but very similar.

I left the engine in the frame and cut the bottom out of the frame so the engine was sitting in a 'cradle' so to speak. A piece of angle iron welded across the back made the rear cross-member of the cradle. I bolted that to the rear chassis rail of the go-kart with two mini gearbox extension rubbers to act as rubber hinges/shock mounts. Then I welded another bar across the front and put long bolts thorough that into the frame and used a stack of washers to set the chain tension.

I cut the rear brake lever and mount off the bike and welded the mount to the go-kart alongside the seat. The lever was used for a gearchange and I used a Cortina bonnet stay for a connecting rod. I hammered the left grip off the bike onto the lever for comfort.

I fixed the oil tank behind the driver's head on the back of the roll bar and that was the fuel tank.

I robbed the throttle pedal and cable out of a Skoda Rapid and fixed them to the kart (it only had 2 pedals originally). The Skoda's rear engine meant it had a very long throttle cable.

Finally I cut the silencer off the bike, capped it off and made a hole in the side, so the exhaust was across the back of the kart like a beetle exhaust and I welded a bit of Mini exhaust to it to link to the bike's downpipe. This made it very quiet.

You will find, like I did, that the bike's sprockets make the gearing miles too low because of the small wheels. You'll need to find a large front sprocket and a small rear one. You'll also find that the engine gets very hot as it's behind the driver's seat.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good Very Happy

Shaane · World Chat Champion Joined: 28 Jul 2007 Karma :

Scrap the 14BHP 125 engine and buy a 150BHP R1 engine Very Happy

You will enjoy more. <3
____________________
EMRA Roadstock #92 - Paperwork Permitted.
Previous: 1992 DT125R
Current: ~ 2005 ZX6R C1H

P. · Red Rocket Joined: 14 Feb 2008 Karma :

Shaane · World Chat Champion Joined: 28 Jul 2007 Karma :

That sounds lovely Paddy Razz

Would love t have a play in something mental like that Smile

____________________
EMRA Roadstock #92 - Paperwork Permitted.
Previous: 1992 DT125R
Current: ~ 2005 ZX6R C1H

karthead · Trackday Trickster Joined: 01 Apr 2012 Karma :

Sounds great pete, will also give me a bit of an idea as to what to do. Their great little engines. Do you still have the kart? How fast did it go? Maybe you would like to post a video... I have considered that kart wheels have much smaller circumference so i've worked the gear ratio to go 100km/h with 11inch diameter wheels. I think, from memory, it was about 1:35.

Paddy: i would like to move on from that stupid idea, hahahaa. haven't i told you i found the circlip? Wink

Shaane: I will most definitely do one of those when i'm older and more experienced Mr. Green

still, when i finish this one it will be crazy! Check this out- https://www.youtube.com/watch?v=mIZXQdmE298
Ill do a design like this, with the 150BHP engine that you're suggesting Very Happy

stevo as b4 · World Chat Champion Joined: 17 Jul 2003 Karma :

karting performance expectations have come on a long way since i helped build one in my teens. I found a free Suffolk punch 98cc mower engine, and it even had an auto clutch fitted as std! Thumbs Up

I thought that was worth having at the time, and the Kart was still fun until we sold it on for a profit. I should have poured petrol all over it and set it on fire though, because i didn't have a handy spare R1 engine laying around to bolt straight in! Rolling Eyes

Sako · World Chat Champion Joined: 19 Feb 2012 Karma :

this coud be quite a good project if done properly - good luck! Thumbs Up

Sako · World Chat Champion Joined: 19 Feb 2012 Karma :

this coud be quite a good project if done properly - good luck! Thumbs Up

DrDonnyBrago · World Chat Champion Joined: 03 Jan 2010 Karma :

P. · Red Rocket Joined: 14 Feb 2008 Karma :

I'm gonna make a road legal kart from a bandit engine.

Possible?

karthead · Trackday Trickster Joined: 01 Apr 2012 Karma :

karthead · Trackday Trickster Joined: 01 Apr 2012 Karma :

_Iain_ · Banned Joined: 01 Feb 2012 Karma :

Yes they can, availible online.

Registered as a quadricycle, the main issue is the requirement for the differential. Karts solid rear axel makes it a bit of a headache...then road rubber, headlamp heights etc. also a 125 from memory...
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Please be aware that the above post may be full of complete nonsense.
Riding: '07 KTM Duke II, Baotian BT49QT-20 Driving: '88 Volvo 340