with 25 inch mudlites am i going to loose any top end speed by installing the black spring

 

I believe the black spring will lower your RPM a little. RPM = speed. HP = how many RPMs you can make and sustain. Its all about RPM. With the weight of the 25" mudlites and slightly lower RPM you will loose top end speed and some acceleration. Not so much that a Grizzly will spank you or anything. I don't have a black spring, yet. I'm still undecided if I should get one or not.

 

Hi, I lost about 4kms (2mph)on my top end after i installed the black spring, but the new cdi will make up for that plus the black spring is good for belt life.

 

I gained 1mph after the install. 'course I jetted at the same time. Maybe I'd have gained more w/o, but I don't know.