DS250 Clutch Hop-Up evaluation
#1
05-23-2009, 09:38 AM
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DS250 Clutch Hop-Up evaluation
Just wanted to pass along the results of my personal evaluation of some clutch performance improvements to fellow DS250 owners who might also be looking to get more performance out of their Can-Am DS250.
The following data represents my comparison on a 500 ft drag strip with timing lights between the stock factory clutch calibration, a DIY lightened CVT roller mod, and a performance tuned CVT clutch kit from Full Power Performance (FPP) that incorporates custom springs and roller weights.
After some discussions with other forum members and some R&D, I came up with a simple D.I.Y. mod involving lightening of the CVT clutch roller weights. This mod alone has proven to increase the hill climbing ability of the DS250 greatly over stock.
There isn't a significant improvement in the drag times, but then again with a 17 HP 4-stroke quad you're not ever gonna see a huge 3 second gain, etc...
The lightened rollers pulled more consistent than stock thru shiftout without adversely or negatively affecting top speed. Definite difference is that the engine rev's higher and doesn't knock and rattle under load, as is so noticeably does being lugged stock... now pulling 6600-6700 RPM, up from 5200 RPM stock.
The FPP clutch kit was even better and picked up 1/4 second in 60 ft and over 1/2 second in 500 ft, which I know doesn't sound like much but is pretty significant for a 17HP 450+lb machine. For those who understand ET's, you know this shows that it's accelerating & pulling harder from a dead stop, as indicated by the faster 60 ft times, and therefore at the end with wide open speeds is equal to a quad length, or two, difference thru the gates...
The FPP kit engagement of the centrifugal clutch was raised closer to peak torque than the stock calibration and provides noticeably stronger take-off.
Shift out occurs at a higher RPM closer to at peak HP, as well.
Even with the taller big meat grabbing 22" rear mud lug tires, it will power-brake in the hard packed drive way and actually spin down the test track.
The huge benefits of both the lightened roller mod and the FPP clutch kit come off the track and with enhanced hill climbing ability.
We ran this 250 up a short and steep side hill to the test track from a dead stop at the bottom. In stock form it lugged down to a complete stop right in the middle and stalled the centrifugal clutch (slipped) at 3400 RPM. With the lightened rollers, the 250 actually spun the wheels up the hill at over 4500 RPM (1100 RPM closer to peak torque) and the FPP clutch kit was even quicker at this with it's significantly higher engagement RPM. Both improvements are definitely snappier and more responsive compared to stock, more fun in the trails and hills, or in the sand, and easier to wheelie or power slide. The optional 14 tooth front sprocket from FPP (to gear down some) improved things even more!
Note: This comparison was done on my wifes 2008 DS250 with stock gearing, larger 22" rear tires (taller final gear ratio), stock exhaust and spark arrestor installed, stock airbox & lid with Uni Filter, stock carburetor jetting #105, AICV active, 180 lb rider, temp 72 deg F, 1549 ft elevation.
Hope this information is useful to someone...
Click on Chart to enlarge to see.
The following data represents my comparison on a 500 ft drag strip with timing lights between the stock factory clutch calibration, a DIY lightened CVT roller mod, and a performance tuned CVT clutch kit from Full Power Performance (FPP) that incorporates custom springs and roller weights.
After some discussions with other forum members and some R&D, I came up with a simple D.I.Y. mod involving lightening of the CVT clutch roller weights. This mod alone has proven to increase the hill climbing ability of the DS250 greatly over stock.
There isn't a significant improvement in the drag times, but then again with a 17 HP 4-stroke quad you're not ever gonna see a huge 3 second gain, etc...
The lightened rollers pulled more consistent than stock thru shiftout without adversely or negatively affecting top speed. Definite difference is that the engine rev's higher and doesn't knock and rattle under load, as is so noticeably does being lugged stock... now pulling 6600-6700 RPM, up from 5200 RPM stock.
The FPP clutch kit was even better and picked up 1/4 second in 60 ft and over 1/2 second in 500 ft, which I know doesn't sound like much but is pretty significant for a 17HP 450+lb machine. For those who understand ET's, you know this shows that it's accelerating & pulling harder from a dead stop, as indicated by the faster 60 ft times, and therefore at the end with wide open speeds is equal to a quad length, or two, difference thru the gates...
The FPP kit engagement of the centrifugal clutch was raised closer to peak torque than the stock calibration and provides noticeably stronger take-off.
Shift out occurs at a higher RPM closer to at peak HP, as well.
Even with the taller big meat grabbing 22" rear mud lug tires, it will power-brake in the hard packed drive way and actually spin down the test track.
The huge benefits of both the lightened roller mod and the FPP clutch kit come off the track and with enhanced hill climbing ability.
We ran this 250 up a short and steep side hill to the test track from a dead stop at the bottom. In stock form it lugged down to a complete stop right in the middle and stalled the centrifugal clutch (slipped) at 3400 RPM. With the lightened rollers, the 250 actually spun the wheels up the hill at over 4500 RPM (1100 RPM closer to peak torque) and the FPP clutch kit was even quicker at this with it's significantly higher engagement RPM. Both improvements are definitely snappier and more responsive compared to stock, more fun in the trails and hills, or in the sand, and easier to wheelie or power slide. The optional 14 tooth front sprocket from FPP (to gear down some) improved things even more!
Note: This comparison was done on my wifes 2008 DS250 with stock gearing, larger 22" rear tires (taller final gear ratio), stock exhaust and spark arrestor installed, stock airbox & lid with Uni Filter, stock carburetor jetting #105, AICV active, 180 lb rider, temp 72 deg F, 1549 ft elevation.
Hope this information is useful to someone...
Click on Chart to enlarge to see.
#2
05-24-2009, 10:28 AM
Join Date: Feb 2000
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Front Sprocket comparison
Here is a 300 foot comparison of the FPP clutch kit with the stock 15 tooth front sprocket against the FPP 14 tooth sprocket that is offered as an option.
Note: We dropped back from 500ft to 300ft because we weren't seeing that much increase in MPH beyond the 300ft mark in the previous testing, indicating the clutches are pretty much shifted out and the acceleration is flat-lining after that with the engine just revving out. This explains why other brand 250's with manual tranny's out run the DS250 in 500 ft, the DS runs out of gear ratio well before that but surely can give them a run for their money in a 300 ft burst, though.
Due to noticeably increased wheel spin, the 14 tooth front sprocket with this FPP clutch combination only picked up 0.03 seconds in 60 ft and barely 0.005 in 300 ft on the lights. It would be quicker with better traction, via playing with tire pressure, shock pre-load, etc, but we stayed consistent throughout testing with the same track conditions we first started with.
What this data demonstrates is that it doesn't lose any ET (elapsed time) by gearing it down a tad ( as we had feared ) but actually gets to this 300 ft finish line quicker, even with more wheel spin...
Although it might give up 2 or 3 MPH when tapped "all-out" down a fire road, etc, the 14 tooth front sprocket is definitely snappier and more fun so I'll be keeping that sprocket on for the wife for our type of trail riding.
Note: We dropped back from 500ft to 300ft because we weren't seeing that much increase in MPH beyond the 300ft mark in the previous testing, indicating the clutches are pretty much shifted out and the acceleration is flat-lining after that with the engine just revving out. This explains why other brand 250's with manual tranny's out run the DS250 in 500 ft, the DS runs out of gear ratio well before that but surely can give them a run for their money in a 300 ft burst, though.
Due to noticeably increased wheel spin, the 14 tooth front sprocket with this FPP clutch combination only picked up 0.03 seconds in 60 ft and barely 0.005 in 300 ft on the lights. It would be quicker with better traction, via playing with tire pressure, shock pre-load, etc, but we stayed consistent throughout testing with the same track conditions we first started with.
What this data demonstrates is that it doesn't lose any ET (elapsed time) by gearing it down a tad ( as we had feared ) but actually gets to this 300 ft finish line quicker, even with more wheel spin...
Although it might give up 2 or 3 MPH when tapped "all-out" down a fire road, etc, the 14 tooth front sprocket is definitely snappier and more fun so I'll be keeping that sprocket on for the wife for our type of trail riding.
#4
05-25-2009, 08:41 PM
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#5
05-30-2009, 03:41 PM
#6
06-01-2009, 01:54 PM
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Clutch Roller weight
Here is a diagram to show what you'll be looking at to do that lightened weight mod. Shows what you'll see after pulling the left side cover off the engine to expose the clutches...
You'll need some type of a jewelry scale, postage scale, etc that reads in 10ths of grams in order to weigh the rollers and see which version you have.
The most common is the 18Gram roller weight, but there have been some 24 gram versions which obviously will require a different grind weight than the 18.
If you do have the common 18 gram rollers, then lighten each by 5 grams to make them all 13 grams each to work in conjunction with stock springs in the rear driven clutch. It's really not that complicated if you take your time.
I got my complete clutch kit from Full Power Performance, their kit already comes with special rollers to match their new rear clutch springs so you wouldn't have to worry about modifying your stock rollers. This will require taking apart your rear driven clutch to install those springs, or if you don't have the needed tools you can always send them your rear driven clutch and they will disassemble and install the springs for you...
You'll need some type of a jewelry scale, postage scale, etc that reads in 10ths of grams in order to weigh the rollers and see which version you have.
The most common is the 18Gram roller weight, but there have been some 24 gram versions which obviously will require a different grind weight than the 18.
If you do have the common 18 gram rollers, then lighten each by 5 grams to make them all 13 grams each to work in conjunction with stock springs in the rear driven clutch. It's really not that complicated if you take your time.
I got my complete clutch kit from Full Power Performance, their kit already comes with special rollers to match their new rear clutch springs so you wouldn't have to worry about modifying your stock rollers. This will require taking apart your rear driven clutch to install those springs, or if you don't have the needed tools you can always send them your rear driven clutch and they will disassemble and install the springs for you...
Last edited by mbarryracing; 06-01-2009 at 02:02 PM. Reason: correction of spelling
#7
06-03-2009, 11:30 AM
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Here are some vid's with the clutch kit.
YouTube - Can Am DS250 Clutch Kit by Full Power Performance - improved takeoff
YouTube - Can Am DS 250 Clutch Kit by Full Power Performance - brake torque demo
YouTube - Can Am DS250 Clutch Kit by Full Power Performance - high RPM acceleration
YouTube - Can Am DS250 Clutch Kit by Full Power Performance - higher RPM acceleration Demo
YouTube - Can Am DS250 Clutch Kit by Full Power Performance - incline acceleration demo1
YouTube - CanAm DS250 Clutch Kit by Full Power Performance - incline acceleration demo 2
YouTube - Can Am DS250 Clutch Kit by Full Power Performance - improved takeoff
YouTube - Can Am DS 250 Clutch Kit by Full Power Performance - brake torque demo
YouTube - Can Am DS250 Clutch Kit by Full Power Performance - high RPM acceleration
YouTube - Can Am DS250 Clutch Kit by Full Power Performance - higher RPM acceleration Demo
YouTube - Can Am DS250 Clutch Kit by Full Power Performance - incline acceleration demo1
YouTube - CanAm DS250 Clutch Kit by Full Power Performance - incline acceleration demo 2
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#8
06-03-2009, 11:33 AM
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Here are some video examples of a stock machine clutch calibration stalling on hills and needing a helping hand to get moving again. The clutch is slipping because the engine is not making enough torque at that low RPM to keep it locked up. The result is stalled forward movement becoming a dangerous situation.
As any snowball effect, the clutch slips and gets hotter and causes it to slip even more...
http://www.youtube.com/watch?v=Ue5wl...eature=related
Notice the rear tires are NOT spinning, and he has the throttle pinned... it's just grunting going no where.
http://www.youtube.com/watch?v=u1Zxp...eature=related
Another with the engine lugging way down under load, barely getting it done... not very exciting or responsive.
YouTube - MOV01662
This same scenario is what was happening to my Wife on steep hills in PA, leading to my clutch research. Her 250 eventually stopped forward movement all together and then what? Reason for the busted up / stitched rear fender... Lucky the only thing she hurt was her bravery.
http://www.youtube.com/watch?v=jtl1t...eature=related
Listen to the low lugged RPM of the stock clutching during the donuts in these vids. Very subtle and not very exciting and not making much power. Almost sounds like it's gonna stall out if it grabs hard enough... The rear wheels actually stop spinning at one point in the 2nd vid.
DS250 in snow - YouTube - Truveo Video Search
DS250 doing donuts in snow - YouTube - Truveo Video Search
As any snowball effect, the clutch slips and gets hotter and causes it to slip even more...
http://www.youtube.com/watch?v=Ue5wl...eature=related
Notice the rear tires are NOT spinning, and he has the throttle pinned... it's just grunting going no where.
http://www.youtube.com/watch?v=u1Zxp...eature=related
Another with the engine lugging way down under load, barely getting it done... not very exciting or responsive.
YouTube - MOV01662
This same scenario is what was happening to my Wife on steep hills in PA, leading to my clutch research. Her 250 eventually stopped forward movement all together and then what? Reason for the busted up / stitched rear fender... Lucky the only thing she hurt was her bravery.
http://www.youtube.com/watch?v=jtl1t...eature=related
Listen to the low lugged RPM of the stock clutching during the donuts in these vids. Very subtle and not very exciting and not making much power. Almost sounds like it's gonna stall out if it grabs hard enough... The rear wheels actually stop spinning at one point in the 2nd vid.
DS250 in snow - YouTube - Truveo Video Search
DS250 doing donuts in snow - YouTube - Truveo Video Search
#9
06-04-2009, 02:55 PM
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Sorry about those bad links that didn't work above. Here are the corrections since I couldn't edit that posting...
http://www.youtube.com/watch?v=Ue5wl...eature=related
http://www.youtube.com/watch?v=u1Zxp...eature=related
http://www.youtube.com/watch?v=jtl1t...eature=related
http://www.youtube.com/watch?v=Ue5wl...eature=related
http://www.youtube.com/watch?v=u1Zxp...eature=related
http://www.youtube.com/watch?v=jtl1t...eature=related
#10
06-27-2009, 09:42 PM
ds 250 clutch mod.
mberry, do you have a contact for full power performance? I'm convinced my wife's machine could use this same mod. The machine is just missing the edge it could and should have. I have been researching other items for her ds 250 like wheel spacers for the front wheels, 14 tooth sprocket, a 2" rear tire size increase, are there any other recomendations you could suggest to make the 250 even better?
Thank You.
Thank You.