With all the tuned Sidewinders (belt blowers) coming into the shop, we needed to do some intensive testing as these "belt blowers" need to be a thing of the past. Using a precision ground bar and depth mic, I started to really get down to the nitty-gritty on this issue.
Belt blower #1 (2020 SW LTX studded track)
3 belts in 115miles. Nothing but heat from belt and clutches. Offset was 61.2mm with 1 shim. 300 TD tuned with Daltons.
After machining 3.5mm off of the back of the secondary, with 1mm shim and the circlip, the offset now was 58.7mm.
After numerous back to back runs, basically riding the sled like an a$$hole (owners own words), the belt showed a little "chipping" on the top cogs, one side only. But, no blown belts and this was 150-200 miles.
Took out the shim and butted up against the circlip, the dimension is 57.7mm and no issues. The owner is happy and has well over 500 miles on his belt as of last week.
Belt blower #2 (2017 SW RTX non-studded track)
3 blown belts on 1 ride, puppied the sled back to the trailer with an old Yamaha 8DN. Offset was 60.9mm. Precision EFI 280 tune and Thunder Products Clutching. Got a call saying he's dropping of the sled at my shop and wanted it just like Belt blower #1.
Machined 3mm off his secondary, offset is now 57.8mm and after a good weekend, no more belt issues.
Belt Blower #3 (2017 SW BTX with 153" 2.5 track)
Usually not a belt blower, but could blow a belt on command when full throttle. Offset was 59.9mm...no shim and against circlip.
TD tuned, with all the tunes including race tunes.
Machined 3mm off of the secondary and with a thin shim, the dimension is 57.8mm with 1 shim. No issues so far.
Belt blower #4 (2019 SW tuned with RCMP?)
Blew belts on command. Clutches always hot and not happy with clutching setup. Installed Thunder Products Clutching Big-V setup and did some offset checking, he is now "catwalking" his sled down fields he could never do before.
3 more sleds in the works at the shop.... 2 of them with Hurricane bundles running 300 horse and 1 Precision EFI 280 that were set between 57.5-58.0mm. Will be updating this thread when we have more info.
P.S. there are so many more out there that we have told to run this offset and know of a few that have been able to hold it wide open for long periods of time without blowing belts.
Post here is it is working for you