What engine to put in my go kart.

[modelengineer]

In my opinion, don't buy an engine with the view "I'll make it better later", get an engine that will do what you want stock. It ends up (usually) being cheaper. For that engine you would need custom machined performance parts ($$$$$$$).

What's you aversion to sled and bike motors? Get one and you won't be sorry, and it will do everything you want + more.

 

[CMsoccer21]

well, i dont want a bike motor cause i dont want to have it be manual. id be willing to put a snowmobile engine in there, actually i kinda WANT to put a sled engine in there, but the problem is the hassle in finding one. im finding it difficult to come across snowmobile engines in the size and year (i dont want a motor from like the 1980's... i want a relatively new one) that i want. so basically i was looking at that engine because its fairly big, im not worried about the money in improving it, and its convenient.

 

[Jerryburger]

Hmm..... 2 cents!....

Even the most cruddy pedestrian low-tech sled motor will scoot you down the street in style. I would seriously open your requirements to include early to mid 70's air-cooled engines. They're self-contained (no radiator or plumbing), usually fan-cooled (so you don't have to worry about air-flow), and since most gearheads tend to pass them up, pretty cheap!

I have a 290cc single-carb twin (24hp) mounted on a gokart, and this is by NO MEANS a fast motor, even by 1971 standards, but it really gets your attention when you pin the throttle (see below). I have MUCH fine-tuning to get it performing as it's supposed to (throttle opens up only a little over half-way; drive belt to long, causing "bog" off the line) and it's pretty scary anyway. If you have access to these things, I'd exploit it for your project.

Since you want it for off-road one of the single-cylinder motors has a lot of "grunt" but when a twin hits it's powerband (if you gear it right), should give you quite a shove, too.

 

[CMsoccer21]

yeah your probably right. so where would i go about trying to find one of these engines. ive tryed to google them, look on ebay, craigs list, and so far to no avail

 

[Jerryburger]

Try your local-area Craig'sList first. Ebay is good; just watch the shipping prices. I was just on there and and to fight from hitting the "BID" button on a couple!....
Not getting the carb shouldn't end the deal- they're fairly generic, and most of them use either Tillotson HD (big) or HR (mid-sized) carbs, which you can pick up for about $25 on ebay. Getting the clutch is pretty important- some engines use weird clutches that are hard or expensive to locate. Getting the exhaust manifold is pretty important also, for the same reason. My favorite motors are the Polaris TX 340,400,440 motors (doesn't matter which- they're all screamers). You get dual mikuni carbs on a bullet-proof Fuji motor that makes its power at 7500 rpm (wow!).
Here are a couple of mouth-watering examples .....
http://cgi.ebay.com/ebaymotors/Skidoo-Rotax-Snowmobile-Engine-Motor-477_W0QQcmdZViewItemQQ_trkparmsZ72Q3a1209Q7c39Q3a1Q7c66Q3a2Q7c65Q3a12Q7c240Q3a1318QQ_trksidZp3286Q2ec0Q2em14QQhashZitem360101502985QQitemZ360101502985
This one is a screaming deal....... Do you know how to snipe? Wait until the last 2 minutes or so and throw abid on it. (Or get AuctionSniper and swoop in the last 7 seconds). If you bid early, sometimes people will "shill" the price up and try to get you to pay your maximum bid. That's why you wait...... I'D jump this if I needed another motor!
http://cgi.ebay.com/ebaymotors/CCW-KYORITSU-NOKI-KEC-340-SNOWMOBILE-MOTOR-ENGINE_W0QQcmdZViewItemQQ_trkparmsZ72Q3a1419Q7c39Q3a1Q7c66Q3a2Q7c65Q3a12Q7c240Q3a1318QQ_trksidZp3286Q2ec0Q2em14QQhashZitem260305409242QQitemZ260305409242

Holy stinking cow! Look at this one! It's a new version of the one above. WOW!
http://cgi.ebay.com/1971-Mercury-ROCKET-LIGHTNING-Snowmobile-Motor-UNUSED_W0QQitemZ370104345078QQcmdZViewItem?hash=item370104345078&_trkparms=72%3A1209|39%3A1|66%3A2|65%3A12|240%3A1318&_trksid=p3286.c0.m14
Now... go get it!

 

[CMsoccer21]

Thanks a lot man! im really interested in that last one.... looks like its in great condition, and so far, the bids are fairly cheap. And as far as i know, well he says nothing about it, but it comes with everything i would need?

 

[CMsoccer21]

How do you guys mount these snowmobile engines?

 

[crazycart]

That last one, i wouldn't get, its for a rare sled, and would be hard to get parts for. Leave that for a actual snowmobile collector.

I have a Kawasaki 340 twin in my 3 wheeled Harley golf cart.The cart itself is well over 500 lbs and it will throw you back in your seat and get up to around 50 MPH

 

[CMsoccer21]

and what exactly would i need for it other than a muffler... i dont really plan on doing anything to it?

 

[modelengineer]

Yup, just add whatever is missing (exhaust, carb, spark, whatever, it might come with all this) and bolt it to the kart. There's a bit more to it but that's basically it. You don't need to modify it at all.

May need to clean/rebuild the carb if it's REALLY old.

 

[CMsoccer21]

well in the pictures, it looks like its just missing an exhaust and i probably need a clutch too. do torque converters work with sled engines cause i have one from an old sled. and it says the engine was never used so the carb prob isnt bad but ill check anyways if i end up getting this one.

 

[modelengineer]

I thought all sled engines had torque converters on them. With a torque converter you don't need a clutch.

 

[CMsoccer21]

ya i know i wouldnt need a clutch... but im just saying it doesnt look like there is any sort of clutch or torque converter on the engine, and i know that most sled engines use torque converters, so do you think any random one would work on this engine?

 

[Jerryburger]

Most of the old air-cooled motors have a 30 degree taper shaft, like the CCW motor in the ad. This is the easiest motor to get a primary clutch for.
If you look at the bottom of most of these motors, it's just 4 beefy bolts to secure it to a frame of your choice. You might have to make your own mount- but it's just cutting and drilling...
Most of the old snowmo motors use Tillotson Carbs which (most of them) have buikt in fuel pumps. (You can mount the tank at a convenient level!)

Exhaust? If you're lucky enough to get the old mounting flange along with your motor, you can fab a flex pipe and muffler onto that. Most used snowmo mufflers are kinda expensive, being that they have to fit under the hood of a sled. I'm using an old stock Harley muffler (cheap- because most riders yank them to put on aftermarket pipes) and it works good.
Check out Lowrider v 2.0 in the Photo Gallery Project Log section of this forum. I took lots of pictures and through many mistakes managed to get it working.

 

[CMsoccer21]

How much performace do you guys think I would get out of this engine, with alll of these mods in it. And dont say it will be too expensive, right now im planning and money isnt a factor.
Honda GX390 Engine:
No Governor
UNI Air Filter
32mm Mikuni Carb with tuned main and pilot jets.
ARC Billet Rod
Racing Cam .315 lift
ARC Racing Billet Flywheel
Ported and Milled Cylinder Head with increased compression
A straight Header
New Intake and Exhaust Valves
Lash Caps
Reinforced Rocker Arms
Chrome Moly Push Rods
An Indexed spark plug
32 Lb Valve Springs

 

[Kenny_McCormic]

I think it will put out quite a bit of power for a few hours, then the block will come apart.

 

[jr dragster T]

I think it will put out quite a bit of power for a few hours, then the block will come apart.

Block will be fine as long as you plan to run around 6300 RPM. Truely that's where the clones should stay. There are karters runnign 12 grand all the time on clone blocks but thats very risky.

 

[Kenny_McCormic]

He wants to run 32lb springs...

 

[CMsoccer21]

its not a clone, its the actual honda gx390. by clone you meant one of those chinese made motors that copy the hondas right?

 

[Kenny_McCormic]

Your still crazy wanting to take one past 8 for a fun app.