Another SP500/F7 clutch gearing question - video clip - HCS Snowmobile Forums

Sno Pro Chassis Pre-2012 This is a brand-specific forum. Posts on this forum are assumed to be questions aimed at similar model owners, and are not looking for comments of a sarcastic or "bashing" nature. Please be aware that if you violate this policy you are in danger of losing your posting privileges on this website.The calling out or posting of another members personal information IE phone number or address is prohibited.

Reply
 
LinkBack Thread Tools
Old 12-04-2019, 03:07 PM   #1 (permalink)
Advanced Member
 
Join Date: Jan 2007
Posts: 82
Current Sled(s): 12 SP500, 07 Xfire 6, 05 F6 SP, 84 Indy Trail
Previous Sled(s): 02 MXZX 800, 97 MXZ670, 91 Mach1, 71 Ski Whiz 400sst
Location: Marcellus, NY
Favorite Riding Area: Central NY, Tugg Hill
Age: 40
Riding Since: 1977
Default Another SP500/F7 clutch gearing question - video clip

I completed the F7/SP500 swap last fall and had a blast with it on the trail last year. I left clutching alone - running the the stock F7 primary, SP500 secondary with the gold/black spring, and stock SP500 gearing. Attached is a screen shot of WOT on a long enough straight. RPM's would hit just over 8100rpm and seem to hit a rev limiter and bounce down to 7800 then climb back up to just over 8000. I would like to dial this better in for this year - what I should do?


Thanks to the HCS sp500 community for putting together all the how-to's on this project. Because of all the information here the hardest part was locating the parts. Any questions please let me know.
Attached Thumbnails
Click image for larger version

Name:	Screen Shot 2019-12-04 at 1.52.52 PM.png
Views:	41
Size:	837.9 KB
ID:	2065228  
cact34r is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 12-04-2019, 07:40 PM   #2 (permalink)
Super Advanced Member
 
Join Date: Jan 2003
Posts: 19,662
Current Sled(s): r and a hacked togeather Snopro
Previous Sled(s): Xf700, F7sp, F5, ZLs,Zrs, Ext, Jags, el tigre
Location: Minnesota
Favorite Riding Area: Back home In the Yoop
Age: 29
Riding Since: 1988
Default

Put the stock secondary spring back in it. That black gold will be too soft. It is border line to soft for a 500
Greg B. is offline   Reply With Quote
Old 12-04-2019, 07:52 PM   #3 (permalink)
Super Advanced Member
 
Crnr2Crnr's Avatar
 
Join Date: Mar 2017
Posts: 4,790
Current Sled(s): Green one's with Suzuki engines
Previous Sled(s): Green, Blue & Yellow
Location: 715
Favorite Riding Area: Wouldn't you like to know?
Riding Since: 70's
Default

Quote:
Originally Posted by Greg B. View Post
Put the stock secondary spring back in it. That black gold will be too soft. It is border line to soft for a 500
think I'm also going to put my stock spring back in the 500, at least it was a cheap n easy experiment.
__________________
the greatest post in HCS history

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Crnr2Crnr is offline   Reply With Quote
 
Old 12-04-2019, 11:38 PM   #4 (permalink)
Advanced Member
 
Join Date: Jan 2007
Posts: 82
Current Sled(s): 12 SP500, 07 Xfire 6, 05 F6 SP, 84 Indy Trail
Previous Sled(s): 02 MXZX 800, 97 MXZ670, 91 Mach1, 71 Ski Whiz 400sst
Location: Marcellus, NY
Favorite Riding Area: Central NY, Tugg Hill
Age: 40
Riding Since: 1977
Default

Thanks for the replies - I'm trying to understand more about this. The stock secondary spring is slightly stiffer than the black/blue, which I installed to try to bring the peak RPM's down a little when it was a 500 to keep it nearer to peak HP. Won't increasing the secondary spring rate 1)make the back shift quicker and 2) resist allowing the secondary to completely shift out? If putting the black/gold spring in to lowered peak rpm, wouldn't a stiffer secondary one raise peak RPM? Looking at the video and that still, I had the sense that I was approaching the limit of the stock gearing; with the stock track and less than ideal traction on that road would it be possible that I was spinning the track at max calculated MPH for that gear combination? I thought I read Greg wrote 105mph for stock gearing.



Based on the 700's peak HP at around 7600 wouldn't loading the motor more with a taller gear ratio be the direction to go? I've been thinking about this all summer but am going in circles.

Last edited by cact34r; 12-04-2019 at 11:40 PM.
cact34r is offline   Reply With Quote
Old 12-05-2019, 04:46 PM   #5 (permalink)
Super Advanced Member
 
Join Date: Jan 2003
Posts: 19,662
Current Sled(s): r and a hacked togeather Snopro
Previous Sled(s): Xf700, F7sp, F5, ZLs,Zrs, Ext, Jags, el tigre
Location: Minnesota
Favorite Riding Area: Back home In the Yoop
Age: 29
Riding Since: 1988
Default

Quote:
Originally Posted by cact34r View Post
Thanks for the replies - I'm trying to understand more about this. The stock secondary spring is slightly stiffer than the black/blue, which I installed to try to bring the peak RPM's down a little when it was a 500 to keep it nearer to peak HP. Won't increasing the secondary spring rate 1)make the back shift quicker and 2) resist allowing the secondary to completely shift out? If putting the black/gold spring in to lowered peak rpm, wouldn't a stiffer secondary one raise peak RPM? Looking at the video and that still, I had the sense that I was approaching the limit of the stock gearing; with the stock track and less than ideal traction on that road would it be possible that I was spinning the track at max calculated MPH for that gear combination? I thought I read Greg wrote 105mph for stock gearing.



Based on the 700's peak HP at around 7600 wouldn't loading the motor more with a taller gear ratio be the direction to go? I've been thinking about this all summer but am going in circles.
You need more helix and a stiffer spring. Your are probably pulling the belt through the clutch bogging it down and it won’t back shift fast enough to recover. I/e the secondary is not keeping up with the primary.
Greg B. is offline   Reply With Quote
Old 12-05-2019, 08:00 PM   #6 (permalink)
Advanced Member
 
Join Date: Jan 2007
Posts: 82
Current Sled(s): 12 SP500, 07 Xfire 6, 05 F6 SP, 84 Indy Trail
Previous Sled(s): 02 MXZX 800, 97 MXZ670, 91 Mach1, 71 Ski Whiz 400sst
Location: Marcellus, NY
Favorite Riding Area: Central NY, Tugg Hill
Age: 40
Riding Since: 1977
Default

Thanks for that advice Greg - I think I'm going to try the SP600 cross country helix 44-42 and 180-280 secondary spring and see how it acts. I don't want to throw parts at it but not really sure how to find a kit for this application.
cact34r is offline   Reply With Quote
Old 12-06-2019, 01:40 AM   #7 (permalink)
Super Advanced Member
 
Join Date: Jan 2003
Posts: 19,662
Current Sled(s): r and a hacked togeather Snopro
Previous Sled(s): Xf700, F7sp, F5, ZLs,Zrs, Ext, Jags, el tigre
Location: Minnesota
Favorite Riding Area: Back home In the Yoop
Age: 29
Riding Since: 1988
Default

Quote:
Originally Posted by cact34r View Post
Thanks for that advice Greg - I think I'm going to try the SP600 cross country helix 44-42 and 180-280 secondary spring and see how it acts. I don't want to throw parts at it but not really sure how to find a kit for this application.
Speedwrex has a kit for it. It is similar to their mod sled clutching. They had me using that secondary spring. The helix was a 71/56 I think. The primary was a 150-200 with 64.3 full tipped weights in the 03 small pin clutch. My gearing was 20/46 with 10 tooth drivers which is stock 2011 sp500 drive train. It would go 107 on the speedo with a 1 inch track on a lake.
Greg B. is offline   Reply With Quote
Old 12-06-2019, 02:21 AM   #8 (permalink)
Super Advanced Member
 
mnstang's Avatar
 
Join Date: Aug 2007
Posts: 7,865
Current Sled(s): 8000 high country, SnoPro 500, zr900
Previous Sled(s): many cats
Location: Independence, MN
Favorite Riding Area: Northern MN
Age: 37
Default

It's bad practice to try to adjust your rpm with the secondary. Softening your secondary might give you a couple of mph's on the very top end but it's a less aggressive spring and will be a little lazier feel and just won't be as good in corner to corner. The stock spring works pretty good for me. Are you ok with giving up backshift and acceleration, for 2mph on top end. Who cares about that for this sled
mnstang is offline   Reply With Quote
Old 12-06-2019, 10:44 AM   #9 (permalink)
Advanced Member
 
Join Date: Jan 2007
Posts: 82
Current Sled(s): 12 SP500, 07 Xfire 6, 05 F6 SP, 84 Indy Trail
Previous Sled(s): 02 MXZX 800, 97 MXZ670, 91 Mach1, 71 Ski Whiz 400sst
Location: Marcellus, NY
Favorite Riding Area: Central NY, Tugg Hill
Age: 40
Riding Since: 1977
Default

Quote:
Originally Posted by Greg B. View Post
Speedwrex has a kit for it. It is similar to their mod sled clutching. They had me using that secondary spring. The helix was a 71/56 I think. The primary was a 150-200 with 64.3 full tipped weights in the 03 small pin clutch. My gearing was 20/46 with 10 tooth drivers which is stock 2011 sp500 drive train. It would go 107 on the speedo with a 1 inch track on a lake.
Thanks for that - that's great information. Did you consider this a good trail set up?
cact34r is offline   Reply With Quote
Old 12-06-2019, 10:55 AM   #10 (permalink)
Advanced Member
 
Join Date: Jan 2007
Posts: 82
Current Sled(s): 12 SP500, 07 Xfire 6, 05 F6 SP, 84 Indy Trail
Previous Sled(s): 02 MXZX 800, 97 MXZ670, 91 Mach1, 71 Ski Whiz 400sst
Location: Marcellus, NY
Favorite Riding Area: Central NY, Tugg Hill
Age: 40
Riding Since: 1977
Default

Quote:
Originally Posted by mnstang View Post
It's bad practice to try to adjust your rpm with the secondary. Softening your secondary might give you a couple of mph's on the very top end but it's a less aggressive spring and will be a little lazier feel and just won't be as good in corner to corner. The stock spring works pretty good for me. Are you ok with giving up backshift and acceleration, for 2mph on top end. Who cares about that for this sled
I agree - I'm not interested in top end speed at all; honestly just want a snappy trail setup that will deliver decent mpg. We ride 150-200 mile days and 10mpg is really helpful. I just knew that what I had wasn't right and want to get it dialed in.
cact34r is offline   Reply With Quote
Sponsored Links
Advertisement
 
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -4. The time now is 05:07 AM.



Powered by vBulletin® Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.