Defender jerky at low speeds
- Thread starter Dragoon
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On my 2018 Jerky is an understatement. When going about 5 mph and slightly downhill it acts more like a mechanical bull than an expensive UTV. It's been doing this since it was new. I took it back to the dealer for them to fix and they said it was normal. I don't really believe that. I tried cleaning the clutch out with compressed air to remove any dust that may be causing it to stick but that didn't fix it. It's funny I don't really notice it when I'm my deer lease because I'm always going faster but at my house putting around the yard I really notice it. My current thoughts are I need to change the belt. Maybe it was made wrong and is acting like a flat spot got burned on it or maybe I did burn a flat spot on it but I can't recall when that could have happened or it could have happened at the dealer before I bought it, it had 10 hrs on it so it's possible. If the belt doesn't fix it there are some after market springs that lower the engagement rpms of the clutch that could work but it seems when this happens I have enough rpms going that the clutch should be staying engaged. I'm also thinking maybe the vehicle speed sensor could be causing it since it's so rhythmic. If anyone comes up with a solution to this I'd sure like to know.
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It seems to be a pretty typical issue with the Can-Am vehicles. It almost seems to me like the weights are off in the clutch because it can't decide when to engage/disengage. The electronic throttle doesn't help either because it's so sensitive that I think it causes more sharp engagement/disengagement of the clutch when it's already fighting the weights.
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I just put the old belt back on and I'll keep the new one until i need to change it. I'm no clutch expert, but I have a feeling I'm going to be by the time I get this resolved. One of the things I noticed was the belt looked a little loose before i removed it. I was thinking it should be a somewhat tight so when the primary clutch engages it hits the same location on the belt. I can't find any spec on deflection so maybe it's not an issue or maybe my secondary isn't holding the belt at the right location. I also noticed a polished location on the primary that seems larger and better defined than the clutches I've seen in pictures. Anybody know if this is normal?(See Photo). I'm thinking the looseness of the belt is letting it flop around and cause this. I guess I need to buy the tools to remove the clutches and see if anything is out of ordinary. Another thing I noticed was that the new belt i put on and drove maybe a 1\4 mile had the cord wore down noticeably more in about 3 spots on each side but they weren't directly across from each other which makes me think there is something not functioning right with this clutch.
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wow, that's interesting. I'm really surprised that this issue has gone unnoticed and unfixed by Can-am. I don't drive less then 10mph that often, but when I do it would be nice to have a smooth ride.
Thanks for digging into this issue and keeping us updated Mark!
Thanks for digging into this issue and keeping us updated Mark!
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If I remember correctly, the belt was always loose on the primary side of my RZRs. It was the secondary that gets squeezed tight all the time. There is a break-in period on new belts so that they wear in evenly. I'm almost to 40 hours on my Defender Max and the jerkiness has gotten much better. I'm thinking the belt is finally breaking in. Also, I noticed the jerkiness initially is tied to the machine being cold. It's like the v-twin is extra lumpy when the engine is cold and that combined with the electronic throttle seems to make the clutch real twitchy. Once everything warms up my Defender runs a lot smoother.
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I have the same jerky response to throttle input on my 2019 Lonestar. It seems that this is normal as I saw that mentioned in several ranger and defender comparison videos. Do agree the low speed roll should be a lot smoother though.
Yeah, I may just have to get over this issue and move on. I just went out last weekend and put about 60 miles on it and didn't notice it at all. It seems i only notice it at home. It may be as Dragoon suggested that it is just cold because at home I drive it in real short periods. I'm still going to take the clutches apart and see what's up in there though.
Andystoy19
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I have a new 2019 Defender XT Cab HD10, which jumps a bit on initial engagement at low throttle position (less than 10 miles, 16km on it so far). I came off of several outlander XTs the latest was a 1000 and they react in a similar fashion.
The CVT system on the primary clutch is controlled by a spring and flyweights that create centrifugal force. The initial engagement is about 1800 RPM so as the RPM increases the flyweights on the clutch arms overcome the spring resistance and allow the primary to close on the belt, grabbing the belt and initiating movement. These vehicles are heavy, mine is close to 2000 lbs. The outlander was 800 lbs.
If you are at a throttle position that is close to engagement the clutch closes and pulls down the engine RPM causing the spring to release the clutch and the next instant the RPM increases and the clutch closes again causing the vehicle to jump, jerk, lurch forward and so on. Solution try to stay above engagement RPM to reduce or eliminate this condition.
In the skidoo mountain sled world the CVT is similar but calibrated for much higher HP and less torque because the two stroke engine (850 cc and 165 HP at 7800 RPM), clutch engagement is about 3800 RPM. I do realize that the turbo sxs are similar HP, much more torque and much heavier than sleds.
In the skidoo world the first thing I do with a new machine is remove the belt and wash it with soap and water to remove any particles, powder etc. rinse and dry. I use a Scotchbrite pad to scuff the sides of the belt slightly and do the same to both surfaces of the primary and secondary clutch which sometimes have over spray from the factory of corrosion inhibitor. Wipe the sheave areas with a clean shop cloth and some guys use a bit of brake clean. Reinstall the belt and check deflection, the belt stretches (wears on the sides) a bit in the first 100m (160 km) and requires adjustment on the secondary clutch to remain in the correct spot on the primary for proper low speed engagement. The secondary contains a cam that can be adjusted to open or close the secondary to maintain proper belt deflection. As the belt wears it becomes skinnier, longer resulting in the belt engaging higher on the primary resulting in accelerated wear because this changes the effective gear ratio at engagement. Belt life is much shorter on these sleds than the expected life on sxs etc.
Interesting side note the Gates CF belt is the same for my sled as well as the defender? That would indicate that the center to center distance is similar but the primary clutch and calibration is different.
I haven't received my shop manual yet but should have it by the end of the week, so I will read up on recommended belt deflection etc. and update if there is some interesting information.
In the operator's guide page 101 and 102 they recommend inspecting the belt, cleaning the sheaves and inspecting the levers and rollers on the drive pulley (primary clutch) after 100 hrs.but there is very limited info on what to look for (page 123) and page 95?
Yes I do read the complete operators guide on any new toy before using it. I will remove the CVT cover and perform the belt and sheave cleaning, check the belt deflection and adjust if necessary and possible?
I suspect that Canam do not dwell on belt maintenance on the Defender because they market it as maintenance free for the first year. They are usually operated at lower speeds resulting in lower belt temperatures but machines that are turbo'd and are rock crawlers or swamp buggies with large tires will exhibit higher belt failures. FYI.
The CVT system on the primary clutch is controlled by a spring and flyweights that create centrifugal force. The initial engagement is about 1800 RPM so as the RPM increases the flyweights on the clutch arms overcome the spring resistance and allow the primary to close on the belt, grabbing the belt and initiating movement. These vehicles are heavy, mine is close to 2000 lbs. The outlander was 800 lbs.
If you are at a throttle position that is close to engagement the clutch closes and pulls down the engine RPM causing the spring to release the clutch and the next instant the RPM increases and the clutch closes again causing the vehicle to jump, jerk, lurch forward and so on. Solution try to stay above engagement RPM to reduce or eliminate this condition.
In the skidoo mountain sled world the CVT is similar but calibrated for much higher HP and less torque because the two stroke engine (850 cc and 165 HP at 7800 RPM), clutch engagement is about 3800 RPM. I do realize that the turbo sxs are similar HP, much more torque and much heavier than sleds.
In the skidoo world the first thing I do with a new machine is remove the belt and wash it with soap and water to remove any particles, powder etc. rinse and dry. I use a Scotchbrite pad to scuff the sides of the belt slightly and do the same to both surfaces of the primary and secondary clutch which sometimes have over spray from the factory of corrosion inhibitor. Wipe the sheave areas with a clean shop cloth and some guys use a bit of brake clean. Reinstall the belt and check deflection, the belt stretches (wears on the sides) a bit in the first 100m (160 km) and requires adjustment on the secondary clutch to remain in the correct spot on the primary for proper low speed engagement. The secondary contains a cam that can be adjusted to open or close the secondary to maintain proper belt deflection. As the belt wears it becomes skinnier, longer resulting in the belt engaging higher on the primary resulting in accelerated wear because this changes the effective gear ratio at engagement. Belt life is much shorter on these sleds than the expected life on sxs etc.
Interesting side note the Gates CF belt is the same for my sled as well as the defender? That would indicate that the center to center distance is similar but the primary clutch and calibration is different.
I haven't received my shop manual yet but should have it by the end of the week, so I will read up on recommended belt deflection etc. and update if there is some interesting information.
In the operator's guide page 101 and 102 they recommend inspecting the belt, cleaning the sheaves and inspecting the levers and rollers on the drive pulley (primary clutch) after 100 hrs.but there is very limited info on what to look for (page 123) and page 95?
Yes I do read the complete operators guide on any new toy before using it. I will remove the CVT cover and perform the belt and sheave cleaning, check the belt deflection and adjust if necessary and possible?
I suspect that Canam do not dwell on belt maintenance on the Defender because they market it as maintenance free for the first year. They are usually operated at lower speeds resulting in lower belt temperatures but machines that are turbo'd and are rock crawlers or swamp buggies with large tires will exhibit higher belt failures. FYI.
Andystoy19
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Just received my 2016 Shop Manual Defender series HD8 and HD10 and 2018 Shop Manual Supplement for the Defender Series. There is no mention of checking or adjusting the belt for deflection but does say on Page 17 of the Shop Manual that the belt should be replaced when it measures less than 1.445" (36.7mm) across the area of the first cord. Note this measurement is not at the top of the belt but lower down where you see the first cord exposed.
My belt for reference, the secondary sheave metal surface is just below the bottom of the top cogs. The belt deflection appears correct for a new belt. This is a tad higher than the initial recommendation was for the mountain sleds. I do not see the same mechanism for belt adjustment as the secondary has on the mountain sleds. For now I will accept that there is no belt deflection adjustment mechanism unless someone else knows of one or I find it on line??? FYI
My belt for reference, the secondary sheave metal surface is just below the bottom of the top cogs. The belt deflection appears correct for a new belt. This is a tad higher than the initial recommendation was for the mountain sleds. I do not see the same mechanism for belt adjustment as the secondary has on the mountain sleds. For now I will accept that there is no belt deflection adjustment mechanism unless someone else knows of one or I find it on line??? FYI
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