Snowmobile Engines for your Kart Section

[Jerryburger]

Hi guys-
I got my snowmobile motor finally- banged up because the guy didn't crate it, and UPS did their usual. (Broken clutch pulley, bent fan grill, sparkplugs busted off.) I dumped oil down the carb (tillotsen HD86a), sparkplug holes and exhaust header, then spun the motor by my drill and a socket. Everything seems ok. I'm going to start cleaning the gunk off of it tomorrow.
I warned you that I was going to start picking your brains for info when I got my snowmobile motor. If anyone is familiar with the Sachs SA2-290 motor, plz feel free to jump in. My first question will be regarding the wiring that comes out of the fan housing: 4 wires- 5 jacks on the engine. I'll post a better picture soon. So far as I can tell the Sachs SA2 motors (290, 340, 440cc) are almost the same, with respect to the basics. I'm going to try and do a little research tonight.

 

[847]

i've never heard of that .. sounds crazy..

 

[ironman]

o yea another project ride lets aim for the high 50's mph or even higher

 

[Jerryburger]

Once again, I am Here To Annoy.......
Here are the pix.... notice how it's banged up compared to the E-bay pix above. (Not too happy, but unless its possessed by the "Christine Thing", there's not much I can do!)

Pic 1 Compared to a B/S 3hp...

...and the last is the wiring, labeled 2, 31, 51.

 

[ironman]

sweet looks like late night in the garage

 

[redcali]

well one thing you want to do is, work out what accessories the snowmobile had.

did it have headlights, blinkers, brake lights etc. did it have a dash.
some of the wires May be. for the brake lights (on/off) or gear position lights.

im guessing it has an alternator. on my bike engine that is a 3 wire bundle (red/yel/blue)

 

[crazycart]

I can tell you they are somewhat doggy engines( compared to new sled engines) Especially with a 1 carb into 2 cyl.Those carbs are usually junk if they haven been used in a while,probly needs a rebuild kit.The points can also be a pita.I personally wouldnt run that clutch with a broken sheave,just for safety.Check the fan belt for cracks,and maybe even the housing for stuff like mouse nests(ive found some in sled engines before lol)Im not to sure about the wiring on that,maybe find a manual?They will push a cart around damn good though

 

[Jerryburger]

THX for ALL the input! Last night I did a bit of Googling and noticed that the basics are pretty similar between all the manufacturers. A lot of the parts seem to be common, along with the basic designs. On one of the motors, it had a simular wiring set up- the yellow were for charging/power, and the black wires are part of the ignition for each coil. I'm going to have to buy a cheapie V/O meter and do a little sleuthing.

 

[ironman]

hey jerry how is that motor coming along there

 

[Jerryburger]

Well- I got it to fire and run okay (video). Until I have something to put it on, I just stuffed the intake and exhaust and put it away for safe-keeping. Right now, I have to take care of "Older Yellower", and then I think I'm going to butcher the good parts off my "Ugly Kart" laying on its side in another picture and use them as the basis for the snowmobile engine project. None of my other frames can handle it. Hopefully you're motors are coming together?

 

[ironman]

not really got it to run for a second when you pour gas in the carb. but its hard to get the right air flow on the intake and man does it where out the arm pulling on it to start it up.starts on the first pull but just trying to keep it running is a different story.

 

[I like karts]

Oh man I took the briggs off my kart last night, it is so small!

Im going to have to lengthen and widen the back for the jet ski engine

 

[Jerryburger]

Hi All!
This is a brief update for the 2 cycle snowmobile fans....

I found this spec sheet on Ebay, scanned and shrunk it....
It has a few useful bits of data, such as the PTO shaft dimensions, hp/rpm, etc. This is for anyone else messing with an old Sachs motor.

 

[Jerryburger]

ONE STEP CLOSER......
I just won a new (to me) clutch for the motor... the idea of the one with the broken pulley spinning at 7200 rpm kinda scared me. There's going to be enough horrible things going on in the engine room as it is, without the clutch coming apart.

 

[Jerryburger]

ANOTHER BRIEF UPDATE and a Thank You for all the help everyone has given me on this project.....
WHEN WE LAST LEFT IT, the Sachs motor ran sorta, and pee'd fuel on me as it ran. (See video, where I'm moving quickly to plug it!) Since then, the Wonder Of The Internet has blessed me with a lot of useful info. Some diaphram "pumper" carbs have a fuel return line to (I'm guessing) maintain a steady supply of fuel to the carb. The elbow that was squirting gas on me is the return. COOL! Thanks Russ for your help on that!
Meanwhile, I've ordered 2 sparkplugs, a diaphram kit for the carb (just in case) and a new air intake screen/filter. I can't wait to see how well this thing runs with proper plugs, carb settings (low 3/4, high 1 1/4), and some good honda oil.
In the meantime, a new clutch is on it's way, I just received my new ATC axle (awesome for live axle karts!) and soon, I'm going to start purchasing the metal for the project. This is exciting, because this is the closest I've come to a "Ground-Up" project so far.

...and one more question (of many, I'm sure!)...
I plan on using a flex-pipe to a small automobile muffler for the exhaust and I know that's not a proper expansion chamber but, as long as I adjust the jets for correct mixture and the plugs read ok, it shouldn't harm the motor (just alter/lower its potential performance).....right?
I was considering Assburgering an expansion chamber by using an old fire-extinguisher body, but there are a horrific amount of variables involved in tuning these things. The stock muffler is out of the question- none to be found.

 

[Russ2251]

Don't know if you've seen this. Long, but interesting read...
How Two-Stroke Expansion Chambers Work, and Why You Should Care

 

[Jerryburger]

Thx, Russ! So you know what I'm up against. I'm going to keep my eye pealed for any images of the stock muffler for the motor and try to copy its dimensions as closely as possible. So far, the only occurrence of this motor is in Allouette Snowmobiles 1971-1973 and the occasional slow-moving 6-wheeler atv. I could copy from a similar type motor (Generic 300cc -ish twin) and see where that takes me...

 

[Russ2251]

Switching from stock muffler to small megaphone gave me a surprising boost in power and speed.
If I had to guess... maybe 1 hp (or better) gain?
With increase in compression ratio...maybe 2 hp total?
Wish I still had access to dyno to verify.

 

[crazycart]

What clutch will you be using? There may have not been a expansion pipe made for this engine stock (MAYBE aftermarket, possibly AAEN) Most of the sleds back in the day did not have the technology of expansion champers and just used the regular pipe and muffler.And if they didnt use that they had the megaphones( usually racers) I would try to find a pipe from that era around the same CC. I have seen the flex pipe and car muffler done before, but it requires alot tuning/jetting if you want it running perfect. I found this site, 1974 Alouette Super Brute 295, 340, and 440. They had expansion pipes. Looks to be the same engine as yours. Hope that helps good luck with your project its gunna be sweet!

- Also, If you switch that old carb out to a 32-38mm roundslide mikuni, you will notice an AMAZING power boost. The mikuni is an alot higher quality carb, you will get better response, and power throughout the rpms. I can guarantee it.

 

[Kenny_McCormic]

Ya know what, every time I look at that thing it looks a little more like the rust seized Chaparral in the garage. Even the mod #s on the chart look familiar. I need to make a single seat snowmobile cart that will run 100+ mph, I know where there is an engine out of a suzuski nomad 400 (im assuming its 400cc or close to it)with reed intake that should work well.