what's the difference in operation with these 2 helix's

[bluemonster1]

On my SXR 600 I now have a 51/43 helix.In the primary I have 8dn-20's with 2.7 inner amd 3.6 outer holes ,15.6 rollers and y-g-y primary spring. Secondary spring is Green wrapped at 80. I get the 8200 at launch and rpm's climb to 8400-8500,so that is all good. Sled is geared down 1 tooth on top and has the 1.25 ripsaw.
My question is ..how is that 51/43 helix working for me compared to a stock 47 helix? Sled is perky and runs good on hard packed snow..my mph today was about 84 mph..not to happy with that.Anyways once I hit the really deep snow,sled struggles ..like I have it pinned and then I can feel that the motor is having a hard time keeping the rpm's up,starts to drag the rpm's down,can hear the motor slowing down and she is having a hard time pulling thru 3 feet of powder.It sounds weird like maybe I am slipping somewhere.Isn't the clutch supposed to shift to a LOWER gear so to speak and rpm's still stay at 8400.It is not backshifting properly then or what? Is it the 43 angle doing this and maybe going back to a straight 47 helix would be better for the powder snow.Should I go back to 14.5 rollers also? It just doesn't feel or sound right in the deep stuff.Could someone explain to me what is going on between 43 and 47 .Is 43 dragging me down or what?

 

[mopar1rules]

stock helix is 47*. its 47 deg thru the whole shift. you now have a 51/43 helix, which starts out at a 51* angle and then transitions to a 43 deg angle somewhere on the ramps, or its progressive, in which it is always slowly changing from the 51 to 43 deg at the end of shift. i think the start angle of your helix may be too much....reason for 8200 out of the hole. the 51 start angle, might also be whats hurting your backshift....i doubt it, cause 51 isn't the steepest and you have a green secondary spring @ 80deg. the larger rollers you put in the primary, are providing you with less shift force, which is probably what allowed you to only hit 84mph. just try a helix swap for now, leaving all else the same, and see what ya get. maybe turk can chime in. its always easier for me to diagnose clutching problems, when i'm there in person on the sled....lol.

 

[boondoctor]

Monster, maybe you are a tad rich, and the motor is slightly struggling to accelerate, just thinking out loud, as lots of powder sucks up horsepower. I like 90 degrees for off trail use myself also.

 

[bluemonster1]

mopar......I think it is supposed to be normal around 8200 rpm at launch and then slowly climb to 8500.I think I will try the 47 helix again only and see if anything changes. I may then decide to install the 14.5 rollers to get more shift force.The belt may be slipping in the primary,there is a dark line on the sheaves which is almost to the top.This may prove the idea of belt slipping at that point.By the way all my clutches are totally rebuilt,all new springs and belt is in good condition. Doing the helix switch will be quick and it will or will not tell me something.Second thing after testing ,I would install 14.5 rollers which will have brand new bushings installed in them also.Thanks for the input,anyone else want to chime in.

 

[bluemonster1]

boon doctor..tell me about it.I was busting drifts along the service road, and I all of a sudden got thrown down into the big weeds and bull rushes.I said to myself..oh no..it is like 3-4 feet deep in that stuff.I almost didn't make it out,man didn't sound good when I pinned it thru it also.Was loosing power and rpm's and I was afraid to keep it pinned,let off a bit and got on it again,over and over and almost lost the sled in there.

 

[bluemonster1]

I know that the more you wrap your secondary(more twist) your rpm's climb .90 might be good if you are steady in deep power,thought 80 would be safe for on and off the powder.