
KnappAttack
24X ISR World Drag Racing Champion
- Joined
- Feb 19, 2004
- Messages
- 4,846
- Reaction score
- 6,101
- Points
- 1,733
- Location
- Welch MN
- Country
- USA
- Snowmobile
- 2023 Sidewinder LTX-LE
2017 Sidewinder LTX-LE
A public service announcement brought to you by Clutchmaster, who we haven seen here in a while, which really bums me out... He is a wealth of information!
Clutchmaster just purchased my Pro-4 secondary to replace his STM secondary that cracked. He sent me pics of cracks in the webbing on the STM.
It sounds as though that this is a reoccurring theme with the STM secondary. He mentioned STM claims the Yamaha "triple harmonics" are to blame. Clutchmaster said his STM secondary has only 3500 miles on it and has never blown a belt with it installed. He thinks the heat cycling, thin sheaves and thin webbing are to blame, for the cracking, not harmonics. He has run on the 270 tune 90% of the time for those 3500 miles.
He has the Pro-4 in his hands and has measured the webbing to be thicker on the Pro-4 along with the sheave thickness to be thicker, not to mention the Pro-4 has more webbing in it than the STM does too.
He googled the cracks on STM & there's also cracking reports on the 1100 Cat twins and Ski-Doo triples as well, so this appears to be a more common theme than just the Yamaha triple engines. Keep a close eye on them! Just because there billet, doesn't mean they won't crack.
Clutchmaster just purchased my Pro-4 secondary to replace his STM secondary that cracked. He sent me pics of cracks in the webbing on the STM.
It sounds as though that this is a reoccurring theme with the STM secondary. He mentioned STM claims the Yamaha "triple harmonics" are to blame. Clutchmaster said his STM secondary has only 3500 miles on it and has never blown a belt with it installed. He thinks the heat cycling, thin sheaves and thin webbing are to blame, for the cracking, not harmonics. He has run on the 270 tune 90% of the time for those 3500 miles.
He has the Pro-4 in his hands and has measured the webbing to be thicker on the Pro-4 along with the sheave thickness to be thicker, not to mention the Pro-4 has more webbing in it than the STM does too.
He googled the cracks on STM & there's also cracking reports on the 1100 Cat twins and Ski-Doo triples as well, so this appears to be a more common theme than just the Yamaha triple engines. Keep a close eye on them! Just because there billet, doesn't mean they won't crack.