1970 Polaris 400. Buildin my go kart..NEED HELP

[BLACKEDOUTX19]

Ok model is:
I Know it is a Polaris 398cc Motor,(might be a 1970 Polaris Charger motor) might be bored out to 440 but dont know. Thats what the guy said.its a EC40P.
the engine is a two cylinder two stroke with a cooling fan built into the flywheel. It is rated 27 hp at 6,500 RPM (maybe more?). It has 2 Mikuni VM30 carburetors on it. is the oil mixed with the gasoline at a specified ratio of 20:1?? That's 1 US quart of 2 cycle sled oil mixed to five US gallons of regular gasoline right??. Spark plug is NGK B7ES gapped at .020"?



Anyone got any info to help me with parts? I think i need a new ignition coil as there is great compression just no spark.
And what gearing should i run to get a lot of low pull, but still hit like 60?
It is going to be an offroad kart, as i have like 12-14" tires on the back that are like 8" inches wide.

Whatcha guys think? Anyone worked on one of these?
And i have a pretty good sturdy frame, will post more pics?

 

[crazycart]

I am going to assume this does not have a CDI pack because of the age. I would check the points before you go spending money on a coil (unless the coil is physically broken) Replace the points and condenser and adjust to specs.

 

[Kenny_McCormic]

20:1 is indeed 1 quart for 5 gallons.

 

[BLACKEDOUTX19]

Replace what points???

 

[anderkart]

I cant find any free online manual for your model. You should probably post a thread here:http://vintagesleds.com/bs/index.php?board=3.0

 

[BLACKEDOUTX19]

Thanks anderkart!
Ive lookin for a site like that!

And do you need shcioks on your go kart, for it to be true off road?

 

[BAMBY]

get this show back on the road!!! it should be sick

 

[Rickracer]

That thing would make a LOT more power with a pair of expansion chambers on it instead of that two into one exhaust manifold,

 

[Kaptain Krunch]

That thing would make a LOT more power with a pair of expansion chambers on it instead of that two into one exhaust manifold,

Good luck finding the right expansion chamber for that engine. Im sure it had one stock, and that MAY be obtainable though ebay or at a sled scrap yard, but finding twin pipes for it would be near impossible (if they were ever even offered)

 

[BLACKEDOUTX19]

rickracer...
1. I gotta get it running first
2. Probably replace some parts for reliability
3. thenn maybe some perf parts...

But throw some url's at me if you got any
I might go down and throw some plugs into it tomorrow, will it turn over for a bit with like no gas in it??

Thanks

 

[BLACKEDOUTX19]

And can someone draw up how the engine would turn the axle?

 

[Degerovita]

The motor will not run without gasoline. Here is a pic I found on the forums using a snowmobile on a kart.

 

[Kaptain Krunch]

That not a sled engine, same general drive train as one though.

 

[Degerovita]

Sorry, was doing a google search and it popped up. but like you said, same concept.

 

[BLACKEDOUTX19]

oh gee thanks dude. Im gettin new spark plugs and fuel lines this weekend.

 

[anderkart]

Did you ever diagnose/fix your no spark issue? What was the problem?

 

[BLACKEDOUTX19]

not yettt, im just gunna get some new fuel lines and spark plugs and try and fire it up. Then if that doesnt work, points and condensers, and if that doesnt workkkk haha

 

[anderkart]

I was reading some snowmobile engines had 2 wires that ran to a tether type kill switch. The kill switch normally completed the circuit between those 2 wires but when the kill switch was activated it cut this connection to kill the spark... I dont know if your engine is setup that way or not but I just thought I'd pass the info I'd learned on.

Did you ever post a thread on that Vintage Snowmobile forum?

 

[Kaptain Krunch]

I was reading some snowmobile engines had 2 wires that ran to a tether type kill switch. The kill switch normally completed the circuit between those 2 wires but when the kill switch was activated it opened the circuit to stop all spark... I dont know if your engine is setup that way or not but I just thought I'd pass the info I'd learned on.

Did you ever post a thread on that Vintage Snowmobile forum?

Most every engine with points works that way, because it needs the electricity from the stator to power the coil.

 

[anderkart]

Most every engine with points works that way, because it needs the electricity from the stator to power the coil.

I understand that but I've also seen quite a few one wire kill switches used on older motorcycles. These would achieve spark without any outside wire connections being made just like a Briggs or clone motor.

I dont know anything about Snowmobile engines, do you think BLACKEDOUTX19's engine here definitely needs these 2 wires identified and connected together together to achieve spark?