sxviper_mn
New member
I have a 2002 viper, I need to change the rivets in the me weights back to stock after going out west last year. Where dose the heavier rivet go in the inside or outer hole? I’ve heard both.
vmaxjohn
New member
Might be best to despribe how your motor was running for rpms. What was it on take off and at close to top speed?
sxviper_mn
New member
Over revved at take off and at speed, about 8700 to 8800 at speed, when it was set up at Yellowstone Yamaha it was at 8400 to 8500 it was all most dead on, but from the factory it always seemed to over rev.
If you ride below 2000' and your over-reving, try 4.5 grams in both holes. If it's a 100 or so rpms low, you can always fine tune it higher with 1 or 2 shims behind the primary spring. Any more than that and you'll need to go with less weight. If it still over-revs with 9 grams of rivits, then you may want to try a w/w/w or a blue/w/blue primary spring. Both springs have the same preload as the y/w/y (same engagement) but with softer rates.
Y/W/Y preload 45kg rate 2.50kg
w/w/w preload 45 kg rate 2.25kg
b/w/b preload 45kg rate 2.00kg
Y/W/Y preload 45kg rate 2.50kg
w/w/w preload 45 kg rate 2.25kg
b/w/b preload 45kg rate 2.00kg
vmaxjohn
New member
Mtviper, you know your stuff. Shims don't effect shift out rpm though, just engagement. Those tips are right on though!
sxviper_mn
New member
Thanks! Mtviper I appreciate the info...I will give it a try :P
The shims do have a slight effect on shift speed as well. Think of it this way. If you add 2 mm worth of shims, the spring will be compressed 2mm more through out the entire sheave travel. Granted the effect of the shims is reduced as the spring is compressed tighter, but its still there. Which is why they are mainly used for engagement purposes.
I use them for fine tuning when the rpms are within 100 rpm of my target rpm. 1mm dosn't seem to make alot difference, I will usually use 2mm. Three shims (3mm) are the max you can use with most stock Yamaha springs without coil bind at full shift. If it takes more than 2 shims to get where I want, I'll pull more weight out or try a stiffer spring
I will also use them if primary spring is sagged a bit, and I want to milk the spring out for a few more miles! While I wait for a new spring to get here.
I use them for fine tuning when the rpms are within 100 rpm of my target rpm. 1mm dosn't seem to make alot difference, I will usually use 2mm. Three shims (3mm) are the max you can use with most stock Yamaha springs without coil bind at full shift. If it takes more than 2 shims to get where I want, I'll pull more weight out or try a stiffer spring
I will also use them if primary spring is sagged a bit, and I want to milk the spring out for a few more miles! While I wait for a new spring to get here.