I have the black spring now, but I got a catalog in the mail from EPI and they list a RED secondary spring part # KSS4 for the 650. I was just wondering if anyone had tried it?

Is it good for very large heavy tires and rims like 28" or what?

In order to avoid confusion: I am not talking about the usual red (primary) spring that a lot of people on the board are using.

 

Did you find out what the engagement pressure was as opposed to the black one for the secondary?

 

Send them an email asking the values of both springs, so we can compare what a red secondary would offer over the first. I know I'd be interested.

Just ordered the EPI Red Primary yesterday, hopefully it'll be here this week for me to try out.

 

here's what the catalog says:

2.5" load 1.25" load

Black 52.2kg/115lbs. 99.9kg/220lbs.
Red 107.6kg/237lbs. 148kg/326lbs.

 

What they are telling you is that the Red spring has almost 1/3 more pretention than the black. Pre-tension equates to side pressure on the belt. The idea is that the more side pressure you have on the belt, the more HP gets eaten up with belt drag and the less efficient the transmission is. what you want to do is get to the minumum side pressure that you can and not have your belt wear or slip for the amount of power you have.

Not enought belt pressure and the clutch will backshift too fast and put you in too low of a ratio coming out of turns, too much and it won't backshift fast enough and you'll loose RPM's climbing hills.

I hope this helps![img]i/expressions/face-icon-small-smile.gif[/img]