It's not recommended to use synthetic oil in old sleds. Stay with the real oil. I still say run it 40:1 for best fuel consumption and performance.

It has some details, but it is really good for motor specs and snowmobile maintanence.

Go to your local sled dealer, and buy a book called Snowmobile Service Manual 11th Edition by Intertec Publishing. This book covers all sleds from 1962 to 1986. It covers Engine Specs, Lubrication, Factory Standards and cool pictures of Vintage Sleds. You can buy it here: http://shop.store.yahoo.com...

I would run it 40:1 with some really good oil, like Yamalube. The manual recomends 20:1, but this is too rich. This is why your plugs get fouled. When the books says 20:1, thats when there was leaded gas. The new oils are better, and today's gas has no lead. Your factory plugs should be BR9EV with a...

[img]http://www.vintagesnowmobiles.50megs.com/7_1C_2.jpg[/img]

[img]http://www.vintagesnowmobiles.50megs.com/Life_Gir_Sled_PP32.jpg[/img]

[img]http://www.vintagesnowmobiles.50megs.com/1973_EVINRUDE_BOBCAT_SS_440_6A_THUMB.jpg[/img]

It doesn't matter what you ride, it's how you use it!!!

[img]http://www.vintagesnowmobiles.50megs.com/8_PP314.jpg[/img]

From the Associated Press Wire Release: Arctic Cat has issued a warning to various riders of non-Arctic Cat snowmobiles. It seems that riders that follow Arctic Cat ZR 900 Snowmobiles are advised to wear chest Protection. Reports of large Ice and Rock chunks have been taking out riders as they fooli...

[img]http://www.arctic-cat.com/snowmobiles/lineups/images/2004/enlargements/S2004ZRJEPUSG.jpg[/img] 600 class: Pol- stock-13.644--86 MPH dealer prep-12.855--90 MPH Cat- stock-12.886--92.04MPH dealer12.515--94.40MPH Doo- stock-13.582--85.42MPH dealer-12.912--91 MPH Yam- stock-14.392--77 MPH dealer 14...

Bob at Image Enterprises builds some serious 3 cylinder motors for those sleds. Probably faster than a lot of newer sleds. He even sells fully restored sleds and parts. He has over sixty! [img]http://www.imageenterprises.com/gallery/pics/1.jpg[/img] Image Enterprises (Bob Owner) 2162 Vista View Dr. ...

1980 Polaris TX 440 F/A. The most reliable sled I ever owned.