We have released two kits, one with the 4" silencer and the other with a 7" silencer. We also offer all the individual parts that make up the kit for those DIY customers. You can learn more about the kits and parts by clicking here. A note about the adapter plate: While the existing oem engine plate allows for front-to-back adjustment, this adapter plate allows for side-to-side adjustment so aligning your clutch sprocket to the rear sprocket is very easy. Positions the engine just in front of where the hood closes for clearance. Stay tuned for more swap parts soon.

Important News (Please read our important news articles for up-to-date information.)

Snowmobile Setup Instructions - I seem to answer the same questions all the time, so I quickly put together an initial set of instructions on how to set up Kitty Cats, Polaris 120s and Arctic Cat 120s. I will take more time to refine the directions and I'll try to add photos and videos as I have time. I hope this helps everyone get a quicker start to racing.

Yamaha Engine Performance Upgrade Kit - We now offer a performance upgrade kit for the Arctic Cat 120s with the Yamaha engine. The kit includes an upgraded performance camshaft, valve springs, gaskets, offset flywheel key, and carb jetting. This will allow your Arctic Cat with Yamaha engine to compete with all the other 120cc brands that are on the race track and backyard. (ISR LEGAL)

Installing Valve Spring and Setting Valve Lash - Please click here to open the instructions.

Rev-limiters - Do valve springs still make any difference?
- We are extremely disappointed in the ISR decision to implement rev-limiters. We've dealt with model difference performance since 2001 and there are other unexplored ways to resolve this issue more economically than to force every stock sled owner to spend $50 for a rev-limiter on every sled. There was also ZERO testing done on this before the 2014/15 season when these devices had to be implemented and they were not initially available for everyone until well after the season started. Our suggestion to ISR was to leave all classes the way they've been for 14+ years and just add a "rev-limiter" class for those racers who don't want to take the time to make their sleds competitive. Those wanting to race in that class could run in both classses because the rev-limiter has an on-off switch. Then the proper testing could have been accomplished without jamming this poorly planned rule change down everyone's throat. As far as valve springs go, THE VALVE SPRINGS WILL BE EVEN MORE CRITICAL. Just like the sprinter class and past chain drive classes, this will become a race to the first corner. Whoever gets to the first corner will almost always win the race. That's where the valve springs come into play. With our special ISR LEGAL valve springs, they get your engine from idle to max RPM quicker than any other valve spring on the market, thus getting you to the first corner first. Click here if you unfortunately need to purchase a rev-limiter for Arctic Cat or Polaris.

First Time Race Dad Article

(Please note: We have a tremendous volume of inventory turn-over and there may be times that we sell out of a product before your order is placed. We are constantly restocking our shelves, but there is always a chance that we may have sold the last item and waiting for more to be delivered to us.)

Winning Championships Since 1980

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Thank you for visiting our website and welcome to Olson Brother's Dist, Inc. (OBUPS.COM) online store. We are committed to providing the highest quality parts with leading edge innovations in high performance racing. Whether it's oval ice racing, ice drags, grass drags, or sno-cross; Olson Brothers is here to provide you with outstanding performance and service. (Read more)

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NOTICE TO OUR VALUED CUSTOMERS (Jan 2026)

Jonn (Olson Brothers)

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(Please note: We have a tremendous volume of inventory turn-over and there may be times that we sell out of a product before your order is placed. We are constantly restocking our shelves, but there is always a chance that we may have sold the last item and waiting for more to be delivered to us.)

Send mail to the WEBMASTER with questions or comments about this web site. Copyright © 2003-2026 Olson Brothers Dist, Inc.

Send mail to the WEBMASTER with questions or comments about this web site.
Copyright © 2003-2026 Olson Brothers Dist, Inc.