Vmax 500 Clutching

stein700sx

stein700sx

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Feb 12, 2005
Messages
1,999
Location
Southern Manitoba Canada
Looking for some advice on what to do with clutches on my 2001 500. I just installed reverse. With that reverse kit I changed the gearing one tooth up on the top gear. Went out for a short ride and this is what I noticed:

Engagement is around or just over 4100
top rpm was around 8200 Both of these numbers seem a little high?
Could not get the shift out because conditions around here do not allow for long pulls. Did mange to find a dirt road that had just less than a 1/4 mile of snow cover. Saw just over 90mph on the dream-on-meter. Before the gear change the top mph was 85. Should I be changing sprins in the primary? I think engagement should be around 3800rpm and top out at 7800rpm
Thots?

Stock primary and secondary and the belt has about 300 miles on it. The rest of the sled is stock as well but the track. Its a 1" ice ripper
 
just add some tip weight to it. engagement looks fine. it is over reving on top as peak is 7800rpm for the twins. new primary springs are cheap and it probably should have one while you are at it. i would try it with a new spring 1st before adding weight to the tips. might want to clean and scuff up the primary clutch faces while you are at it if it has not been done in awhile.
 
Try adding the tip weight 1st like Maim said. If that does not bring the higher end shift rpm down enough try a multi angle helix like in the setups below

I found these similar setups in the tech pages a few years ago. I used the top one. It works great. I kept jetting stock. It seems kind of rich but with todays gas it's better to be safe.

500 XT and 500XTC tuning (Very Similar Sleds to Yours)

- 45/39 Helix, 8-ab weights and stock springs (WPW-Primary&Red Secondary. 0.8g rivet in the tip and might have to change slightly to hold 77rpm.

- 47/41 helix, 8-ab weights with a 0.8 gram rivet in tip & pivot empty. Gear down 1 tooth & drop mains 1/2 a size.



For what it's worth I think you would be better off putting your 21/39 Stock gearing back in if you can get your shift rpm down through clutching changes. I have 21/39 gearing in our old xtc500 with over 8000 non-rebuilt stock miles on the clock and still managed to see 102 mph on the dream meter in great conditions. It also went 87.2 mph in a local 1000' radar run which was about 97 or 98 on the speedo. Here is a formula to calculate gearing.


9(number of driver teeth) x 2.52("track pitch) x 60(Minutes in an Hour)=1360.8

1360.8/63360(inches in a mile) = 0.02148

0.02148 x 7800(Shift RPM) = 167.5

167.5 x 21/39(your stock gearing) = 90.2 real mph or 101 mph at an estimated 12% speedo error by my obsevations

167.5 x 22/39(current up one tooth gearing) = 94.5 real mph and 105.8 mph on the dream meter if you could find some downhill ice.

This all assumes a 1 to 1 full shift no overdrive.


Hope this helps
 
depnds on the motor for the gearing.

my 01 sx500r with the 21/39 gearing would only do 80 mph on gps fully cluched, with a 1-1/4 ripsaw for traction and cbperformance aluminum front end (drops 20 lb). with stock clutching, it only hit 80.1 mph on gps with factory clutching. with vmaxjhon's clutching i hit 80.68 mph in the exact same conditions. fuel milage was also 8mpg on a good day.

same sled track and clutching but re-geared to 22/39. hit 95 mph on gps and was getting 10-11 mpg.

we where running 1 mile on hardpacked snow on a lake and the last run the sled only had 3000 miles on it.
 
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