More Flat-Slide Carburetors – September 1995

Dear Ralph:

With the never ending emphasis on increased performance, why are we still seeing mostly round-slide carbs (Mikuni VM) on the new sleds? Especially since the flat slide TM and TMX carbs can provide an improvement in throttle response, tunability, and power. The flat-slide technology was developed over ten years ago and applied to motocross bikes, so why have the snowmobile manufacturers been so slow to respond ?

Dean Pepperdine
Tipp City, OH

Yamaha does have quite a few flat slides on their machines. For the most part it is a matter of cost – the round slides are cheaper. The majority of “touring” snowmobilers may not even notice the difference, or even care. For them, the extra cost would not be justified.

But for the “other” riders (like you) it seems odd that the new “Super 600’s” don’t come with them. On these machines they could make of a few hp difference on the top end, and you would get much better throttle response. The throttle range where most of the riding is done is where the most noticeable improvement would be. Don’t forget that fuel economy is better too.

The advantages of flat slides are undeniable – but it all comes back to cost. A 38mm round slide runs about $125, where the flat slide runs about $175. On a three cylinder machine, that’s $150-$200 more. Multiply that by a several thousand sleds and the manufacturers save hundreds of thousands of dollars. The question is whether the majority of the buyers (of a certain model) would be willing to pay the difference.