Kohler 440 twin cylinder 2 stroke

[tanker]

what can all you masters of the 2 stroke smoke tell me about the kohler 440 twin cylinder 2 stroker. It is actually 436cc's it was in an argo and it was FAST. about 35-45 mph < this is what is going into the wedge.

[Don]

It's a good choice for a powerplant, Tanker. There's good and bad points, but I think in this case the good outweighs the bad. They have chrome cylinder liners, so they wear like, well, chrome, but when they finally do wear out the recomended fix is jug replacement. They're a five-port engine and you'll get really good performance for the size and weight. They were really popular in snowmobiles and ATVs, so parts are still pretty easy to come by when you need them.

Take Care
Don

[tanker]

thanks don, do you know what kind of hp these put out?

[jpswift1]

Im not exactly sure but Id imagine that it is somewhere between 35-40 HP. Don, I was reading on my Wiesco Piston box that it said not to install these pistons and rings in chrome plated cylinders. I never thought that there were many engines that had them, but now I know.........you learn something new every day!

[Don]

The single carb model was 37 HP and I think the twin carb was rated 44.

Don

[tanker]

37 horsepower, that should move the wedge right along with the proper gearing.


about a 20:1 gas/oil mix?

[hydromike]

about a 20:1 gas/oil mix?

With today's oils, go for 40 to 45:1. If you want less smoke, go for a semi or fully synthetic oil. I use Golden Spectro (available at many motorcycle/snowmobile retailers) and it's virtually smokeless once the exhaust temp gets up there. It makes you worry at first, because as we've all learned, two strokes are supposed to smoke like crazy, right? Check out the vids of the D/stock and the 503. Not really a blue haze following me around, which I like...

Smokin's bad for you. My girls don't smoke.

~m

[scramblerjohn]

attex

i have a kawasaki 440 daul card.i just want to know what lubes the bottom bearings.i see a sight glass,on one side,but the glass looks like plastic and you cant see through it so i dont want to start without knowing about the oil..thanks guys

[hydromike]

Two stroke diatribe...

John,

The oil that you mix with the gas is the only lubricant that a two stroke sees. The 440 Kawi might be oil-injected, but you don't have to use the oil injection system if you pre-mix the oil with the gas. I've not seen a "sight glass" on one before. I'd be interested in seeing a picture of what it is, and what purpose it would serve.

In a two stroke, the gas and oil actually enter the crank case as the piston ascends (because there's lower pressure in the case than atmospheric pressure outside the engine), where the oil that's mixed in with the gasoline lubes the main bearings, the connecting rod bearings, the wrist pin bearings and the cylinder walls. It also doubles as a cooling agent. That's why when you run a two stroke "too lean", you're not getting enough oil to the engine, and it can overheat, even if the cooling fan (on fan cooled engines) is running fine. That's why it's really important to have good, tight crank seals. If you don't, the partial vacuum inside the crankcase will suck air past the crank seals on the PTO and magneto. Since there's no gasoline out there (hopefully) the engine sucks just air with no cooling and lubricating agent. It may still run, but the engine isn't getting the right amount of gasoline either, so it'll start hard and run very poorly. Here's an animated GIF of the whole setup in motion on an air-cooled single cylinder with a tuned pipe. Sit and watch it for a while, and you'll understand everything. Also check out the mild "supercharging" effect of the tuned pipe as the intake charge and exhaust charge run up into one another, forcing as much of the fuel into the combustion chamber as possible.

Welcome to the "power band" my friends...



That was supposed to be animated <OK, I guess it is now(?)>. Apparently it's not working right.... A dual carb 440 Kawi has a lot of fun potential. Many were even CDI ignition, and are popular with the ultralight aircraft crowd.

~mike

[scramblerjohn]

kawasaki

thanks guys alot, it helps that some can awnser,the 440 was oil injected but the guy i got it from said just mix oil and cas together,i think it has the oil pump still on it,im want to tern the 208tt into a racer it should be fast,does the 7000 tranny with reverse slow it down or not realy,thanks again guys

[Don]

As much as I'd like to make the trade, if your machine's going to be for competition, you may want to keep your 6000, John. It's a little lighter, but the big difference is in reliability and strength. The more moving parts you have, the more likely you are to have a failure, especially when the power is being directly transferred through those extra parts.

If it's a racer, you won't need to go backwards anyway.

[hydromike]

Sorry the animation doesn't work correctly on the image. Checkout the home page of AttexATVs.com for the correct working version.

I seriously doubt the 7000 will slow you down vs. the 6000 transmission. I don't think that there's any reduction in the forward or reverse planetary setups. It should be a 1:1 ratio. The weight difference isn't that much in the grand scheme of things. The 6000 and 7000 series both have a 1" shaft, so I doubt one is really much stronger than the other, either. <I was writing this as Don was submitting his message, even though it looks like I'm just being argumentative... I agree that fewer parts are better, and he doesn't need to go backwards...>

A TT is a decent start for a racer. Just keep in mind that the frame may be somewhat fragile compared to later versions. Attex beefed up their frames considerably with the advent of race bred machines like the ST/400/R. Lots of cross-braces, gussets, etc.

To get an idea of what you'd be looking at, check out jpswift1's pictures of his racer. There are some pretty tight clearances in the narrower first generation bodies. It may be a challenge to fit a Kawabunga twin in there, but it can be done.

~m

[gotmuddy]

the animation works for me

[scramblerjohn]

attex tranny

don i still want the reverse tranny,i dont think that going to slow me down a holelot,where i ride i do need reverse,theres alot of woods,i still want to transfer the tranny to the scrambler,there trannys suck,i want to put the tranny in like joes garage,thanks for all the info

[Roger S]

I saw that animation at the attex site, and although I've been a mechanic for a long time, didn't fully understand what an expansion chamber did. Until the last year, refreshing my memory on 4 stroke performance theories. Valve timing, intake and exhaust.. of course it's during valve overlap on a 4 stroke where good things can happen. Low pressure at the exhaust valve and high at the intake. The intake flow can be moving at 70 mph and have several psi, filling the cylinder even though the piston has started moving upward. The exhaust port can have several negative psi helping exacuate the old charge and bringing in the new.

Maybe I shouldn't post in this 2 stroke thread but some will find it interesting.. here's what I read yesterday.

***
Lets take a moment to consider where it all started and where we are now. We took a 5 hp. lawnmower motor that was designed to turn a maximum of 3,600 rpm then bored, stroked, welded, ground, filed, polished, fitted, crammed, invented and generally violated the entire book on common sense and ended up with a remanufactured 10,000 rpm BOMB and all of this was done in the name of fun. Well, of course it is.

We just finished testing an engine with a .174 overbore and 3.000" stroker crank and at 9,000 rpm this is what was happening inside that engine:

1. The valves were opening and closing 150 times per second.
2. The crankshaft rod journal was traveling 79.8 mph in a 3" diameter circle.
3. The piston & rod moved, stopped then changed direction 18,000 times per minute (300 times per second).

Think about this:
The piston is at top dead center (TDC) in a momentary stop position, we've already had combustion, the piston travels down the cylinder 1.3671" reaching a top speed of 84.3 mph, while the crankshaft has rotated 75° and all of this has only taken 1/720th of a second to happen.

Another way to look at it:
The piston and rod start and stop 300 times per second reaching 84.3 mph between each cycle.
***