What's wrong with this picture, I am sitting here at work.. and you are out on the lake.. relaxing???
Yes. Almost every weekday evening (unless I have company over), I go out on the lake in my scooter and spend 1 to 2 hours answering emails, surfin the net and read the newspaper. I have no svc at the cabin, but 1/2 way out in the lake 4/5 bars.
Radical Rex Said...
In the moguls going slow under 20mph isn’t fun with the clutch engaging, disengaging. Jerky and Bit tiring
For sure. Any fix for it? Thanks
Can’t find the jerky 850 thread....
Surging off bottom end
what you are feeling is "engagement surge" or "jerk", where the clutch feels a sudden powerful upshift and when you let off the throttle, it immediately "lets go". Press throttle again, even very slowly, the clutch pushes on the belt, the handlebars feel like they "jerk" out of your hand. When you try to do a wrong-foot-forward on a sidehill, the handlebars feel like they are surging out of your hands and the vehicle speed ends up being too fast to control your one-foot-walking.
I know you have a trail sled, but what I explain is the same I've felt on the 850 and 600 G4 trail and BC trail sleds I got to run last few winters.
It does not matter to me if it was a 1986 Polaris Indy 400. Im going to set the belt deflection the same way based on the idea that Im looking for "tension" between the two pulleys. I dont care about belt height. I want sufficient "tension" between the two pulleys that balance between the belt not burning from the friction on the belt-to-shaft surface and clutch engaging on the belt. If the tension between the two pulleys are at an amount where the belt seems loose, then when the clutch engages on the belt, it can push the belt up in the sheaves, higher than its lowest ratio (1st gear) and feel "surging" or "jerking" of the belt.
My opinion, this "sensitivity" is purely clutch parts; namely the ramps and their inherent start angle. When i remove the 441 ramps from an 800etec and install my DJ ramps (415/441 blend) the sled will have the same result of the surging off the bottom end. Then I get rid of the sensitivity with my ramps by going from a 160/xxx primary spring to a 130/xxx primary spring.
Ive also made shims to test belt clearance, placing a plastic shim made out of windshield washer jug plastic or blue crazy carpet and put that shim on top of the primary clutch spring cover. This shim will be in between the spring cover and governor cup. That shim will push the sheave more closer to the drive belt. Hahaha....can't use "sun dried" crazy carpet because that plastic was hard and blew into pieces and jammed the clutch. No damage though, just have to hit the kill switch because the sled keeps on going when the throttle is off. HAHA...i was laffing.
I've taken a set of the 966, 965 and 990 ramps and ground a modified tip on them, this lowers the engagement speed a bit, but mostly, loads the bottom end more and completely eliminates that "sensitivity". I literally breath on the throttle and my sled starts to move like a tundra xtreme. I can make my own sled crawl at a 1/4 mph.
Radical Rex Spex...
I know the sheet there says 2900 but the one I got to drive was 32~3300 engagement speed.
At this point you can change the start force of the primary clutch spring. Lowering the start force from 120/xxx down to 100/300, and this should lower the engagement speed about at least 200 rpms. Some people want higher engagement speed than stock, with studded track, etc and can do that with a different ramp that will still be more silky smooth than the 968.
There is another way by using a less aggressive ramp on the start like one from an 850 expedition extreme (982 ramp) but I would have to look at the 982 side by side with the 968 to see what kind of curve it has.
I gotta get over to my office and get those ramps to compare.