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Defender jerky at low speeds


Dragoon

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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.

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My 2019 lonestar is the same way. Everything I've read is that it's normal. I don't like it, but I'm just dealing with it. I either speed up or slow down. Mine tends to "surge" from about 5 mph to 8 mph.

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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.

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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

Edited by Andystoy19
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Let's get to the point!! Can am has an issue at low speeds and it should be fixed, I'm tired of spending up to nearly $30,000 on rigs and with known issues as the can am defender crew I bought last year , as I'm about to drive off sales rep says theres a spring upgrade for low speed surging ??? Why not tell me before I paid for it.

I had 4 polaris crews before this and reason I went to can-am was polaris drives get worn out around 3000 miles and then say that's normal ?? So I get a can-am and it's been good other than the surging at low speeds.

Please tell me how to fix this if there is a fix ??? Maybe China rigs dont have these issues. Pretty sad the top sellers cant build a decent rig when you are paying big bucks for there product.

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I think its just the way the design of the belt and how it engages the clutch all come together. The machine is engineered to have high torque. It makes it hard to load and unload it on a trailer with wheel chock tie down system (the ones you drive over and strap the tires to the deck of your trailer). 

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As I stated in my two previous posts some jump at clutch engagement is to be expected add to this callibration of the itc (intelligent throttle control) which has a slight delay built-in (no cable to throttle body connection) and some machines will be more jumpy than others. Unless you buy a machine with a torque converter or manual transmission not much will change even when going to other manufacturers with the same type of Cvt system. 

Using work mode slows down the throttle response so the machine is less jumpy on rough ground at low speed. I use work mode and low range for loading and unloading off the trailer and find this works for me since I don't stop when climbing the ramps. I have learned how to control the ITC and barely notice the jerkiness even with 30" tires.

Another poster mentioned that the dealer said there was a different primary spring? I haven't seen the specs on the new spring but if is softer it will engage the clutch at a lower RPM which might work better for a stock machine on a farm or acreage where a stiffer spring would increase the RPM at engagement which might work better for a machine witha heavy load and or larger tires.😉

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On 2/5/2019 at 8:18 PM, Dragoon said:

Bummer! It's probably going to be real grabby until it breaks in a bit.

When you took the belt off did the secondary clutch move freely and smooth. Because the rollers in the secondary tend to brake. I know this cause I have a 17 hd10 xt max mine got real jumpy. Pulled the secondary apart found that both rollers were half gone.

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we had the same issuewith the 2021 we got today until we fastened drivers seat belt.  Jerkiness seamed to go away.  Math have something to do with the governor that kicks in if drivers seatbelt is unhooked.  Maybe worth a try.  I think on my older 2018 defender I jumped around the governor feature.  No jerking 

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Try a speed limiter bypass plug.  They cost about $6 on eBay.  Jumps around the need to have drivers seatbelt fastened

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Jus got a 2021 defender… the gas pedal hesitates so bad …. And this thing is so extremely bumpy riding around !!!!  Turned the shocks up today and it is worse!!! Anyone adjust their shocks and if you got good results what setting did you set them at ?

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9 hours ago, Can Am girl said:

Jus got a 2021 defender… the gas pedal hesitates so bad …. And this thing is so extremely bumpy riding around !!!!  Turned the shocks up today and it is worse!!! Anyone adjust their shocks and if you got good results what setting did you set them at ?

The lowest settings on the shocks should be the softest ride. Turning them up will just make them more stiff.

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Does adjusting the shocks give you a higher or lower clearance or is this just for ride comfort?

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As you increase the tension on the cam on the shock it increases ride height about an inch from the lowest to the highest setting and also stiffens the ride slightly as you compress the spring. Its easier to adjust the cam if you jack up the machine and let the shock extend. Try the different settings to see what works for you.🙂

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