Engine for off roader

[ZombiPotent]

Hey all
I'm pretty new to the world of kart building. I have spent a decent few lunch breaks looking at engines / clutches etc.
I came across the following engine on TradingPost (Aussie site that works a bit like ebay), and was wondering if you guys could give me any feedback?
The engine is here:
http://www.crazysales.com.au/index.php?productID=1276#desc
It costs $425 AUD ($325 USD) including postage.
What are your thoughts?
I'm looking for info like how easy will it be to get other parts (esp clutch) / how suitable is it for my kart / what quality is it likely to be etc...

I'm basing my kart on the one we had when i was little:

• Off road
• Square frame
• Live axle rear wheel drive
• Single seater

Except with a lot more juice! (The one we used to have was a 50cc)
I'm pretty tall but skinny so I only need a light frame, I realise this probably means i have more than enough power, but i was to gear it for accelleration so I can powerslide it on gravel / dirt.

Thanks in advance for any info / reccomendations / feedback
MdV

 

[modelengineer]

Hey.

FINALLY, someone near me that is interested in off-road karting. I see you're doing eng. at UTS, I'm a first year eng. student at UNSW.
I'd advise buying a motorbike, stripping out the engine and brakes, and selling the other parts. I'm currently in the process of doing that, my GS-500 engine will end up costing nothing. Yes, $0 for a 50hp, 6 speed manual bike engine. I might even earn money on the parts if I had the time.

Anyway, those 13hp engines are very expensive for the performance, and CVT's are expensive, and clutches don't give great performance (but they're cheap).

Regards,
Andrew

 

[TravisD]

WOW peolpe from australia!! i thought i was alone, Im also building off/on road karts and other stuff, sucks i live in fart north queensland, and Modelengineer and ZombiPotent i would love to see ur work and pictures!!

and as i am hear do u think a suzuki ds 80cc two stroke would be acceptable for a small go kart maybe off road? im finding it hard to find some motor and that ones just sitting around so i thought why not use it if i can,

oh and thanks for that website above!!

 

[modelengineer]

I had a DS-80 when I was younger, awesome little bike. I think it would work alright in a kart, they're about 7.5hp and 5 speed. However, if it works as a bike then selling it and buying a different engine might be the best option.
The DS-80 would be really good for an on-road kart only though.

^ It's a bit more finished than that atm, not long to go now.

 

[ZombiPotent]

Motorbike heeey?..hmmmmmmmm

Thanks guys!
So you reckon a motorbike engine? How much am I looking at for an old (i assume) motorbike?
And how torque-y are they?
My knowledge of small engines is pretty limited, will there be a lot of know-how required to make the engine run well?
And how easy are they to install?
Cheers.

EDIT: I'm pretty sure we just posted at the same time haha.

 

[modelengineer]

The torque sort of depends on what sort of engine you get. A large capacity single cylinder will have more torque than a 4 cylinder of the same size, but the 4 cyl will rev higher and have more hp (this is just generalising). For an off-road kart you want torque which means big single cylinder or twins. I think a 250cc or more single cylinder 4-stroke would be best. For the size of kart which I posted earlier, it is recommended to use a 350cc to 650cc single cylinder. I went with a 500cc twin because it was cheap.

If you have some cash in hand then you can buy a written off motorbike for cheap, I know where to get them. Then you recoup all, or most, of your money by selling the spare parts. If you don't want to do that then the engine will be more expensive and, as you say, from an older bike.

The engine should run well straight out of the bike if you keep the stock exhaust pipe and stock air box, no tuning should be required.
They are pretty easy to install if you know how to weld (which I assume you do, since you need to weld the rest of the kart) and can use a drill press.

Hope this helps,
Andrew

O, and here's where you get the damaged bikes. You have to go to the auction and bid on them.

http://www.manheimfowles.com.au/fin...&model=&rm=view_results&state=New+South+Wales

http://www.pickles.com.au/damaged/l...=description&ed_search_type=AUCTION&x=50&y=14

The bikes classified as "repairable write off's" will be too expensive, you're looking for ones which say "statutory write off" - meaning they can never be registered again. You will only be bidding against wreckers, and they only bid up to about 1/2 the value of all the parts (inc. the engine), so it is pretty likely that if you *just* out bid them you can get all your money back, and even make some money.

*EDIT* I just looked at those auctions and it doesn't look like there are any suitable statutory write offs in this auction, but next month there might be.

 

[TravisD]

hey thanks for the help and links, your information is very clear and easy to understand, i hope to see more of that kart buggie above, it looks sweet!!!,

And how much do you think i can sell that ds80 of mine for? it still looks pretty good but might need some paint hear and there, right now the bike is apart and the motor was sitting in my room for the past week, i have seen peolpe selling theres for $1200 but is that the right price to go for? every thing works and is there

Thanks

 

[modelengineer]

I'm not really up to date with bike prices, but if you got it assembled and touched up the paint then yes, I think you could get $1,000-$1,200 for it, depending on the year and condition.

Then for $1200 you could get the most kickass motorbike engine from the auctions. My GS-500 cost $1035 and most of it I will get back, so you could spend like $2,000 or so, and you should get at least $800 back. Almost certainly more.
At the auction I went to, for $2,400 you could get an Aprilia 1000cc V-twin. That's about 120hp, fuel injected goodness. lol! And get most of that back in parts.

 

[TravisD]

man that would be soooo sweet!!, i think i might put it all back together redo the frame and front forks paint, new sprokets and chain, and sell it, and then get a nice motorbike engine,

Aprilia 1000cc V-twin!! man strap that to a homemade kart!! that should fly, but i think that would be to much trouble for a noob like me, i just started a few weeks ago with out any knowlege of anything of motors execpt fuel goes in there, but now i have taken apart several motor and know more about motors than my dad and all my friends all put together!!