I have a friend with a Griz660 and every time we race, I beat him off the line and he stays right there just behind me the rest of the way. I told him that EPI had a kit that might help him. I got my friend on the phone and we called EPI today. He wanted to order the $179 clutch kit for his Griz. We talked to a tech at EPI and he said the kit would really help the Griz but that there was nothing that could be done to the Griz660 to make it beat a 650 out of the hole! I was grinning from ear to ear!!! I love my 650!

 

A friend of mine got the EPI kit for his 660, he said it gave him more tire turning power at lower speeds, but takes away from his higher speed performance. He did not feel that his 660 was turning his 27" tires very well. Now it is better.

I still think my 650 cranks my 28" tires nicely. But, a lot of people are getting EPI kits for their 650. They probably ride much more seriously in the mud than I.