My friend has an 05 660 Grizzly and he was wanting to boost his transmission performance. I tried this question on the Yamaha forum but have had no response. I have seen where EPI makes a secondary spring for it, are there any other suggestions about springs or clutch kits?? Thanks[img]i/expressions/face-icon-small-smile.gif[/img]

 

epi makes a full kit plus you can send the sheave to get machined by hauck.nice reviews on that