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Q:I am looking on where to start on clutching and gearing for an MXZ 660 with a Crank Shop 670 improved stock package in a lightened MXZ S-chassis. It has 48mm carbs, Crank Shop motor and pipe and also has good traction. This sled is currently being used for asphalt and is pushing 155 hp at 8500 rpm. - MachZ975
A:In order to give accurate information on gearing other information is drastically needed. Peak engine rpm, hp, torque curve, and broadness of power are just some of the other variables. Dyna-Tek Racing experts said they used CF1 ramps in the primary with 310-460 spring with hollow pin with three sets. They used a 50-47 secondary clutch cam with beige spring at 22 lbs. and using 23-44 gearing for ice. There will never be anything better than testing so get your parts together and start making runs and trying new combinations. Good luck! - Experts
Q:What is the reason for using mag or TI clutch arms to stop some of the over-shift at low mph? Is it really for more belt grip at top end? One guy told me that they were made for race sleds that run a higher rpm. - MachZ975
A:Although it varies from sled to sled, the use of the light mag or TI arms lets you run more pin weight at the tip of the arm and does help with belt grab and rpm consistency. - Dyna-Tek Racing
Q:I thought I'd throw this one out to see if anyone has experienced this problem. I have a Yamaha 600 SRX mod sled that surges at high rpms. It has high rpm pipes and CDI with race porting and 38mm flat slide carbs. The engine pulls great to 9400 rpm then falls flat and picks back up after the rpm's have dropped. It is not a clutching problem as the problem occurs on the engine dyno as well. We have already eliminated the electronics as the problem as we have tried 3 different CDI's and 2 known-to-be-good stators and wiring harnesses. Fuel flow on the dyno looked good. Any thoughts? - Jabber
A:Sounds like a fuel delivery problem to me. Try a larger output fuel pump and a larger flow needle and seats. - Dyna-Tek Racing
Q:I was wondering what I need for putting a studder button on my 1997 P/S 800? Anyone know and then how to wire it? - MCB Racing
A:One of the most popular and universal systems is with the use of an aftermarket tachometer that has an external shift light wire and a Bosch style relay. You can use a momentary button on the handlebars or use the brake light switch. Another option is made by DYNATEK ignitions and is a stand alone unit. - Dyna-Tek Racing
Q:On asphalt I picked up 3-tenths and 2 mph with a button clutch vs. the stock roller. Will the button work better on grass? Does the helix angle change between the two clutches? - bigkid
A:A lot of the larger horsepower race sleds are going back to button clutches and are having good results. They seem to be more consistent in varying conditions and easier to dial in initially. Roller clutches generally use smaller helix angles than button style clutches. While the button style is the older technology, ultimately consistent performance is what you are after, but again, it will vary from sled to sled. - Experts