Zr 440 Clutching [Archive] - Snowmobile World : Your #1 Snowmobile Forum

: Zr 440 Clutching


wls012001
02-02-2005, 08:09 PM
This may be long, lets start with what I have in it now, front 47.3 grams, orange/white spring, secondary, I have a 55/53, with green spring in the 4th hole. with this I'm running about 8650, which I found out today from a dyno, this is out of my peak HP range, which is 8100, alot lower. I'm going to put the green spring in the middle position, should reduce r's about 100, how is the best way to get my motor down to 8100, seems like I'm running alot of weight now, the book says stock weight is 46 gr's. But then again the book say's to run it at 84-8600 r's. any idea's throw them at me.This sled is used for sprint racing and 20-30 lap mini enduro's. The local a/c guy said to get out and test with this set-up, then adjust the front weight. Thanks

sled 1997 zr440

1fastcat800
02-07-2005, 05:26 PM
Sounds like you tach is off (ever been calibrated?). These motors make the best HP at 84-8500 RPM. You need more weight in your arms. Every gram will lower RPM about 150-200 as moving the secondary spring one hole changes the RPM about 150-200. I would try 48.5 gram weights and adjust the secondary to get it perfect.

wls012001
02-08-2005, 05:53 PM
Originally posted by 1fastcat800@Feb 7 2005, 05:48 PM
Sounds like you tach is off (ever been calibrated?).* These motors make the best HP at 84-8500 RPM.* You need more weight in your arms.* Every gram will lower RPM about 150-200 as moving the secondary spring one hole changes the RPM about 150-200.* I would try 48.5 gram weights and adjust the secondary to get it perfect.
399315


when I had it at the dyno, my tach would say like 8800, but dyno was about 8600, so I'm about 200 to high.
At 8086 Im at 91.36, 8111=90.93, 8131=90.36, 8167=89.54hp, so after 8100. I'm going down. we have 4 races left this year, so I figured I would clutch to this, then this summer, I will fine tune it on the dyno, timing/fuel etc. Thanks