sled exhaust

[brandon]

Hi guys I just bought a 91 617 rotax sled engine and I need to know where I get dimensions for the exhaust to make a new one and I was thinking a twin exhaust. Also I was looking for advice on a secondary clutch and belt. Thanks for any help

[K-fab]

Secondary clutch - don't use the Arctic Cat three tower setup if your car weighs much more than 850 lbs or so. *While a great clutch, on a heavier buggy, they'll brake off eventually - it mainly comes from whoops and landing while on the throttle. *The clutch gets banged open really hard and the towers suffer.

[hero_saku39]

Originally Posted by K-fab\";p=\&quot

Secondary clutch - don't use the Arctic Cat three tower setup if your car weighs much more than 850 lbs or so. *While a great clutch, on a heavier buggy, they'll [s]brake[/s] break off eventually - it mainly comes from whoops and landing while on the throttle. *The clutch gets banged open really hard and the towers suffer.

[smilie=blowkiss.gif]

[Akpilot]

Brandon,
K-fab is right about the Arctic Cat clutch, it is a great clutch for a snowmobile but on a buggie they slam open when the rear wheels leave the ground. *The Team secondary is a enclosed helix design and wont slam open. *Stay away from the ER numbers as that is a designation for electronic reverse. *As far as the belt goes Pick a belt that works with your primary - stock - and get the secondary team clutch that works with your primary. *Then once you have the clutches and belt you can set the center to center distance so you have the correct deflection. *

On the exhaust, I first purchased a twin exhaust kit from Crank Shop for my setup. *They are made for a snowmobile but (mine) are in 4 pieces. *I then cut and twisted each piece to fit my chassie keeping the total length as close to what they gave me. *I have since went with a single, I measured the circumferance of the stock pipe at every inch, then cut that pipe taking out what I needed and replacing it in the configruation that fit my chassie. *Time consuming to say the least, but if you stay close then it's worth it. *Opsled might have a stock pipe you can purchase to get a measurement / cut and reconfigure for your particular application if you go the single route.

Wayne

[K-fab]

[quote=hero_saku39\";p=\"52707]

Originally Posted by "K-fab\";p=\"52700":28x8lbfl

Secondary clutch - don't use the Arctic Cat three tower setup if your car weighs much more than 850 lbs or so. *While a great clutch, on a heavier buggy, they'll [s]brake[/s] break off eventually - it mainly comes from whoops and landing while on the throttle. *The clutch gets banged open really hard and the towers suffer.

[smilie=blowkiss.gif][/quote:28x8lbfl]Nice catch! * * * Duh on my part. *I boo-boo'd. *

[brandon]

This engine is for a small buggy I'm going to build 650-750lbs would be my guess .The primary clutch is stock I seen some team clutch for this sled on ebay I think .I would think that it being 617cc other motor similar in size would have the same size exhaust. Do you guys know If they made twin pipes stock or if its aftermarket. I didn't want to buy the pipe if I didn't have to is there a performance sled forum where I could ask for dimensions .Thanks greatly apprenticed

[opsled]

Your 617cc Rotax (type 643) is a RAVE valve engine so pipes from other engines that don't have RAVE valves probably won't work very well. I have the Dynotech dyno sheet in my hands for your engine and with the stock single pipe it made 106.4hp at 7500rpms with 74.5ftlbs of torque. At 7750 it was down to 102.3hp and at 8000 it dropped quickly to 68.7. With twin pipes they will make 120+hp and carry through to 9000 or so. Rave valves engines will produce great torque over a wider rpm range than engines without but they are finicky on pipes. Since your exhaust port timing changes with the RAVE, building the right pipe is a little more complicated than engines without variable exhaust timing. Making your own will be tricky buisiness. With the stock single pipe these engines pull VERY!! hard from 5500 to 7500rpms. I'm not sure how much hp you need but the stock single pipe will probably be more than enough. I would have to look again at the numbers but if I remember right with the twins they were making more hp but the rpm range they were making it in was much smaller so clutching would be much more critical than with a single and you could have bogging issues in certian conditions if you can't keep the rpms up.

I have the identical engine listed here in the for sale section with all the clutches, drive and pipe. I also listed just the engine without the clutches, drive and pipe on ebay last night. If the engine sells without those components they will be available if you need them.

* That is a very strong pulling engine you have there with very good hp. With the right pipe it should really fly in a wheeled buggy in the 650 to 750 lb range. The sled it came out of weighed about 525 dry and would easily go 100+mph. It takes a lot more power to spin a track than wheels so you should be happy with they way it performs.

* * * * * *opsled

[nutz4sand]

Something else to consider if you are building your own and not off plans OR can modify plans and CAN (sometimes!) save you two "issues" is to set the sled motor sideways if the pipes will clear the suspension that way (saves redoing pipes. You can offset the motor and counteract weight with battery and such) and then run the power to a small import car diff (Saves buying/making a rear carrier and helps to gear down more.) This is not everyones answer but just a path you might at least think about if it could be incorporated. You can use both sled clutches (excepting the rule posted above on AR-cats clutch of course!) and a sleds reverse gearcase. Connect the lower shaft with a chain to the car diff and have reverse. This eliminates $$$ rear carriers and usually means the pipes retain factory integrity. Bill

[brandon]

Thanks for the information guys. Opsled I would be interested in the tach , temp gauges ,and the exhaust pipe .I have the 2 in 1 exhaust y I doubt the facotry pipes is going to work but I need the measurement to make a new one I sure I can match the shape and length of the stock one I have a powerhammer and a lot of sheet metal working tools.Thanks

[opsled]

The tach and gauges are listed with the engine on ebay so unless the winner doesn't want them they won't be available. The pipe and clutches are not listed with the engine but the buyer may need it so for his application so I need to keep them until that auction is over.

*To duplicate the pipe you will probably need to cut it open to see how far inside the stinger goes. They don't just start at the end of the pipe but extend inside sometimes 12" or more. It is also critical to RPM and performance. I will let you know how things go.

* * Good Luck, Phil (opsled)