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But it's just a band aid to fix the loss of power or issue.
Mach Z Low RPM fix? Change the ramps!?
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I installed hot rod spring 160/350 and adjustable ramps. 87.1g. Hits 7700 initially and builds to 8100. Haven't had a chance to run it against another test sled.
The topic of this thread is low rpm at wot
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Or maybe clutch calibration isnt on point. Not the first time when new model comes out. Not enough testing on different conditions/altitudes.
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2,226 Posts
That's interesting.
You have increased the weight 2g,ish from 85.5g,
I was expecting at most a 300 increase from 7700 with the stock arm's. From your results with stock arm's i should over rev.
What was your rpm prior to switching the spring and arm's.
Type of track
Studs
Belt
Mach or other.
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94 Posts
Sounds like you have too much weight on center and not enough on tip. What type of adjustable weights are those, any pics?
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I may end up moving one magnet from the middle to the tip but I want to try it against my brothers x 900r first. I orginally turned 7700. Ripsaw 1.25" track. 144 studs in the center. 571 belt. Mach.
Last year I had a 21 XRS 900 with Whalen speed green wheel kit so I have ZRP tail stander weights in it from that.
Last year I had a 21 XRS 900 with Whalen speed green wheel kit so I have ZRP tail stander weights in it from that.
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8 Posts
did your engagement lower with the 160 start?
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5,147 Posts
Just an FYI on different ramps. Had a great talk with Greg Goodwin about the development of his ramps. He said he found that a difference of as little as .005 in the curvature of the ramp would effect the shift by 100-150 rpm’s. That’s a pretty minute amount. A sheet of 20# copy paper is roughly .0035.
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80 Posts
Been 5 years since the SW came out, I'm sure they have been testing this for a few years to catch up on a King of the lake sled like all the advertisments! It will come.......
Has anyone contacted BRP or there Dealer on this issue . These machines are brand new
And slow . BRP should be at least giving some 600 decals ,Well the engineering department figures this out they have a problem.🐌🤕
In all my years of testing I have found weight profile to effect clutch performance and shift more that total weight.
One step at time here. I do have a list of items I will be ordering and doing. Spring cup will certainly be done when I work on primary spring swap to a Dalton. But I do want to test with Dalton ramps on their own first.
IMO without actually checking, I believe the offset must be good since after 15 to 20 2500ft+ runs back and forth my secondary is basically just barely warm, and the primary is just a tad warmer then secondary, and the belt itself is also barely warm. This is huge for me coming off the Winder where the belt and all sheaves would be so hot you could not hold them for any length of time. These 900r clutches are coolest ive seen after so many multiple HI SPEED passes. The wind veins BRP designed into these clutches are certainly doing their job.
Dan
Yes first thing i did was check the deflection, it was very loose however once tightened rpms remained.
I agree about multiple runs, IAT comes up fast and you can see the ECU pulling back. So Im aware of that happening.
The ramps helped me see the difference, and I simply do not like the flat spot in the mach ramps. The rest will come along.
And just to catch you up, the ADR test mule revs perfectly. And that sled has same loose belt deflection, and running same lake mulitple runs,that sled did not seem to drop ever below 7900.
Dan
Disagree....MUCH of this is the Mach ramps. Driving these two sleds back to back its instantly felt. I do not like the Mach ramps at all.
Now that being said, the top end RPMS are still lower on one sled then the other(with same ramps installed) but are much closer within 150rpms or so. That is a lot closer than 400+ rpms difference and may be attributed to the single ply track vs 2 ply. As a matter of fact, In my conversations last spring with rep at shows, all the test mule Machs had single ply tracks, could that be why the rpms are off? Did those test mules rev correctly due to having single ply LIGHTER tracks? Dont know but it certainly is plausible.
I'm actually a lot less concerned that their is a boost leak/issue now. Yesterday I was running my lake and seeing much better speeds even while under revving. And I think once I have this thing clutched with my setup it will be right where it should be.
IMO the Mach Z ramps are a total miss. Guys may disagree but you have likely not slapped another set of ramps in you Mach yet to compare the hard hit of the NON FLAT SPOT ramp. I will take a hard bottom pulling sled every time over the Launch control which is simply a gimmick that I really do not need.
Daltons arriving today with Chris's super fast shipping from his place in NE USA to me in Muskoka Ontario exactly 1 week. Thanks again Chris for getting them out to me.
Dan
I hear ya, and I was also thinking similar. But I now feel its more clutching and I can work through this. Its the poor guys who never clutched before that will be looking for a fix, and BRP really should come out with some sort of fix to get it closer. Unfortunately they cannot change ramps due to LC, so maybe a spring bulletin would get it closer in simple manner but IMO the ramps make the Mach feel lazy and sluggish out of hole and drive off compared to Adr, so much for flagship Mach feeling fastest.
Dan
After I tightened defection, where I like.....Loaded sled to truck, drove home and sled would not go into REV trying to unload. Had to move sled a tad to get it to kick in. But since that time its been good. So there is a point of too tight.
But I will say, the low section of cogs even with top of driven sheave is a crock, that is super loose overall and will have terrible drive-off.
Dan
Clickers simply change the angle of ramp. They are not adding/subtracting any actual weight like and adj ramps does with slugs. Does they work? YES, but IMO not ideal way to change rpms. I more like to add/remove pivot bolt weight(length of bolt) on a Clicker style ramp then changing the angle.
Dan
Great to know! I had no idea Goodwin was a sponsor and I wanted to be careful here as I seem to constantly get in trouble on DT for posting stuff by non sponsors!....
That being said, I have a long time relationship with Chris at C&T. He answers my email in minutes no matter what day or time of year. I have no doubt Goodwin has great service too but I tend to stick with the guys I have used for many yrs.
Dan
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