Trail and stock classes do not allow engine modifications. Keep in mind that your sled needs to remain stock, so don¹t remove any air delivery components such as air box dividers or filters. Not all jetting charts are right on the mark, so make a few test runs to verify good performance. Follow the sled manufacturer¹s jetting chart that compensates for altitude and temperature. To achieve good performance on race day, the fuel delivery needs to be adjusted by installing smaller (leaner) jets in the carburetors. Some circuits supply fuel, so check with race officials. State that it contains 10 percent ethanol, but it might actually have more, which could result in disqualification. Spark plug insulators should be light brown and the center electrode should have s fine white ring around the perimeter. Stock classes will usually run 87 octane fuel in a stock engine and most rules state that up to 10 percent ethanol is acceptable. Most rules require the length of the studs cannot be more than one-half inch above the tallest lug. Use as few studs as possible to reduce weight of the track but provide enough traction to eliminate slip. However, a chisel stud requires more power to pull it out of the dirt.Ī 50/50 ratio of chisel studs and ice picks works well on racetracks with a clay starting line. For example, chisel point studs work very well for starts due to the big face of the stud that can grab more dirt for traction than a pointed trail stud. The best studs and stud configuration will vary by racetrack conditions. Your race sled¹s track will need the right traction products, too. Once the correct length of the center shock and front torque arm is achieved, make sure the spring is stiff to prevent compression and hold the skis off the ground during the run. When this is set, the sled will pivot on the center shock and spring. Adjust the length of the front limiter straps and spring to tune the weight transfer. The rear suspension can be lowered with a limiter strap and a shortened rear shock. Using straps to tie down the front end is cheap and easy, but it reduces suspension effectiveness. Expect to pay a shop about $100 to install a set of spacers. Shock spacers are the best way to lower a sled, but the shocks will have to be disassembled. The front can be lowered by installing soft springs, short shocks or by compressing the shocks with chains or straps. ![]() The sled should be set as low as possible. The correct transfer is set by lowering the front end and the back half of the rear suspension. If this happens, it means the sled will transfer weight correctly, but stop the transfer with the skis hovering above the ground. At that point, the lift should require more effort. The front of the sled should lift fairly easy until the skis are up to 2 inches off the ground. To check weight transfer, the driver should sit in ready position while a helper lifts on the front bumper. Too much transfer would raise the front too far and not allow enough of the track to touch the ground for traction. If the skis touch the ground, the drag will slow the sled. An ideal setup allows the sled to transfer weight quickly at take off with the skis 1 to 2 inches off the ground and hold them there until the end of the run. Weight transfer is perhaps the most important part of setup for a grass drag sled because it helps the sled hook up and accelerate. Sled manufacturers¹ race shops and performance shops have access to ISR rule books, or contact the race circuit for class-specific regulations. ![]() Most circuits follow rules set by International Snowmobile Racing (ISR). It¹s up to you make sure your sled is safe and legal for competition. ![]() Many of these set-up tips apply to impromptu, laketop drag races, too. ![]() Your trail sled¹s carburetors need to be re-jetted, the clutches need to be tuned and the suspensions must be set-up to get the most traction on dirt. Older sleds with a good setup can still be competitive in grass dragging.Ĭhances are you or someone you know owns a late-model sled like a Firecat, EDGE, REV or SRX just like the ones professional drivers raced a few years ago. Even though grass drag racing is pretty straightforward, it’s necessary to make sure you and the sled are prepared. There are many races across the Snowbelt every fall and most have classes suited specially for beginners and their stock sleds. Perhaps the simplest form of snowmobile racing to get involved with is grass drags.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |