Mini Baja buggy snowmobile engine swap!

[Kartorbust]

That's kind of what I thought, but I'd rather ask someone who has more exposure than what I've had.

 

[Snaker]

Should be a perfect engine/chassis matchup. I've had the 488 Fuji and found them to be my favorite twin fan. I disagree about the oil type. I different brands in them without problems. I stuck with Polaris Blue on the Fuji liquid and 550 fans engine's but no worries on the 488.

I agree with the Fuji oil injection, high reliability, the biggest issue was getting air in the feed line and not bleeding.

Kaptain Krunch, your photo's show the CVT driven mounted backwards to the drive. Whats up with that? I know the buggy world seems ok with that to a point, but I don't think you will get away with that on the larger diameter pulley's.

 

[Kaptain Krunch]

Kaptain Krunch, your photo's show the CVT driven mounted backwards to the drive. Whats up with that? I know the buggy world seems ok with that to a point, but I don't think you will get away with that on the larger diameter pulley's.

By backwards, i assume you mean in front of the engine rather than behind? The driven is certainly rotating in the correct direction.

As far as why - well thats how it was setup when i got it, and it really fits best in its current configuration.

I dont see how the clutch would know if its in front of, or behind the engine. That being said, i've done a few sled engine swaps (2 golf carts, one go cart, and lots of snowmobile chassis - engine swaps), and each one had the driven mounted behind the engine.

Please educate me on the problems you see, i could very well be overlooking something simple! Thanks.

 

[anickode]

If you mean backwards by the spring mechanism on the secondary being opposite (turned inward) from the mechanism on the primary (outward), that's how it's SUPPOSED to be. On ALL symmetrical belt clutches. The "backwards" ones are the 40 series and 780s mounted on a backplate with the spring out.

 

[Snaker]

I was referring to the both pulley's having the fixed sheave on the same side of the belt in the photo's. If that is a P90 it would be a symmetrical system and should have the fixed sheaves on opposite sides.

Oh oh, I pulled a boner. That does have the fixed sheave on opposite sides. I guess I got confused by doing some recent work on the GY6 style.

Appologies

 

[Kaptain Krunch]

I was referring to the both pulley's having the fixed sheave on the same side of the belt in the photo's. If that is a P90 it would be a symmetrical system and should have the fixed sheaves on opposite sides. As far as the spring wind I couldn't see it, but it does have a specific wind direction also.

I doubt your going to find a reverse wound spring for a Polaris driven. Also the P90 wouldn't have the dual ramps for Torque Sensing like you see on the go cart stuff.

The clutches are in their stock configuration as you would find on the atv or snowmobile they came on.

Moveable sheaves are on opposite sides. The spring is wound in the correct direction.

 

[Kartorbust]

Its amazing to find out these in there competition stock form will go upwards of 30-40mph with a stock Briggs model 20 back then, even with that firewall. So what kind of ratios does that gearbox even have? Information seems to be lacking on in web unsurprisingly.

 

[Kaptain Krunch]

Its amazing to find out these in there competition stock form will go upwards of 30-40mph with a stock Briggs model 20 back then, even with that firewall. So what kind of ratios does that gearbox even have? Information seems to be lacking on in web unsurprisingly.

So i actually hadnt even looked into the ratios honestly, glad you asked!

The transmission is a 1341146, found in then polaris xplorer 300 4x4.

Anyways gearing internally is
3.29:1 F
5.13 R
6.64 L
The final drive ratio is 1.83:1
This gives me approx 6:1 in high range 12.15 in Low

The p-90 clutch starting ratio is 3.83 ending in a .76:1 overdrive.

In high, if i set my clutch to grab at 2500rpm, i'll be doing 8mph on takeoff in high range, with a top speed of 110mph at 7k rpm (approx when this engine starts to fall flat, could probably push it to 7500).

Might be a little steep....im not really looking to go 110mph, but im going to try it as is. I dont have much room for a bigger rear or smaller front sprocket. Low range you could basically cut those numbers in half.

 

[Dingocat]

I guess I missed most of this. Deffinitly going to be keeping my eye out for one of the Sae Baja cars.

 

[Denny]

So what’s the end of the story? Did it ever get running and driving?