[SKELLEY521]

😁😁😁👍

 

[Budro2]

I’m following too. Always interested in clutch tuning, just don’t have an x model and don’t plan on doing clutch tuning in my Rmax.
Rock on Skelly information always has value!

 

[SKELLEY521]

Just some quick comparison pics of all 3 springs side by side.
I put all 3 spring at the same starting point against the scale so you can see the springs coil progression.

Also a view from above. I used a sharpie to show where the spring stops.
I didn't get measurements of the Yellow spring, but with a straightedge, it appears the yellow is about the same height as OEM, but the green spring is much shorter.
Now I'm curious so I'll get measurements again.

pics...
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[SKELLEY521]

I got lengths just so I had a reference and out of curiosity.
Apparently spring load at 3" & 2.2" is what matters for operation performance.
OEM lower limit is 4.360" so that's almost 1/2" (.480")
I don't know the Limits of the EPI springs, but either way, springs are a inexpensive item.
$21 for OEM and $26 for EPI

Lengths

OEM 4.843"
Green 4.804"
Yellow 4.870"

I have almost 3k miles on OEM and it's still at new tolerances.
I guess we shall see how the EPI springs fair as I have a reference to come back to.

Gotta have a pic, so here's OEM tolerance..
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[SKELLEY521]

Added lengths to my pic so I have info in one pic.
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[SKELLEY521]

BMP Tech Tuesday - Secondary Clutch Springs

 

[SKELLEY521]

Adding this info here.
I had a 6x6 sheet of Teflon and made a 1/16" slippery washer.
As you can see in the pic, there's not much space and I was concerned with getting a good seal on that O-ring to the Spring Cup.

Maybe a 1/32" washer will work or a film type washer, but I don't know how well a film washer would hold up.
Next time.

Anyhow, Pic....
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[SKELLEY521]

Bottom of Cup has a bevel inside.
I measured from the bottom of the O-ring wear to the bevel edge and get 3/32" of usable space.
A 1/32" washer may work successfully, but I wouldn't feel comfortable going any thicker.
The wear thickness pattern is harder to see in the pic than it is in person.
.

 

[SKELLEY521]

I posted this in the Alternative Lube thread, so going to follow up here too.
Ordered 1/32" 6x6 sheet of Teflon and made a washer for testing.
Chemical-Resistant Slippery PTFE Sheets
Pics..
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[SKELLEY521]

Well I got to test the Green spring.
I'm still running 18g weights so I can tell the difference from the OEM spring.
I only put about 15 miles on it.
A mix of fast switchback trails, slow mud crawling trails with 1 high speed run on blacktop and hard pack.

I don't have enough time on it to nail down all aspects yet, but one thing I noticed:
~ It's a subtle increase vs OEM. More subtle than I expected.
Now I'm even more intrigued to try the Yellow....lol

 

[SKELLEY521]

The rule of thumb for our machines with stock spring and 28" tires are:
18g for better performance & 20g for better cruising.

I tested 18g and 20g weights on the OEM spring.
The difference is subtle and I could live with either honestly, but either choices are better than stock 22g IMHO.

Now through in the green spring and that changes.
Even though the Green spring increased rates are subtle, it starts to draw the line more for me.
I still like the 18g w/ the green spring as I spend most of my time 35mph and below, but the short time I spent at higher speeds (45+) it was obvious the 20g would be a better choice.

 

[ldjbuff]

Very good information being shared in these posts. Thanks a lot.

We dyno every off road vehical we own and you have taken some of the guess work out for me. Once mine is broken in, i plan to get the PV3 from weller and still up in the air on clutch kit brand. Might go weller as well.

 

[SKELLEY521]

Very good information being shared in these posts. Thanks a lot.

We dyno every off road vehical we own and you have taken some of the guess work out for me. Once mine is broken in, i plan to get the PV3 from weller and still up in the air on clutch kit brand. Might go weller as well.

One thing to research before getting a tune is which exhaust you plan to run.
IIRC the stock exhaust was better for bottom end and the aftermarket exhaust really helped the top end a lot.
Hopefully someone with more knowledge of the exhaust get help get you the facts.

I love my Weller Racing ECU Flash and it's one of my top mods.
A aftermarket Sheave will help with more top and bottom end as it gives maximum belt travel.
I just installed the Hunterworks sheave and I'm putting it through it's paces.
Now I'm tuning with springs and weights to match my riding style/conditions.

Changing to 18g HV roller weights was one of my other favorite mods.
Beside the ECU Flash, it's one of the most noticeable changes you can make IMHO

 

[ldjbuff]

One thing to research before getting a tune is which exhaust you plan to run.
IIRC the stock exhaust was better for bottom end and the aftermarket exhaust really helped the top end a lot.
Hopefully someone with more knowledge of the exhaust get help get you the facts.

I love my Weller Racing ECU Flash and it's one of my top mods.
A aftermarket Sheave will help with more top and bottom end as it gives maximum belt travel.
I just installed the Hunterworks sheave and I'm putting it through it's paces.
Now I'm tuning with springs and weights to match my riding style/conditions.

Changing to 18g HV roller weights was one of my other favorite mods.
Beside the ECU Flash, it's one of the most noticeable changes you can make IMHO

Yeah I assume I will always run the OEM exhaust. All my ATV's have drag pipes, so its nice to have a quiet system.

I mean we are so bad on our atv's that we test fuel. Some oxygenated fuels gain 4 hp at the peak of the power band. But that is $20+ a gallon fuel.

One comment I hear a lot on these sxs's is that they lose their stock pep with bigger tires. Do you feel you lost that feeling?Or do your mods make up for the additional weight.

 

[SKELLEY521]

I think the 22g weights the cars come with are to heavy. They give you that jerky throttle. Belt pinch force is to soon. The motors not even making any RPMs hardly.
If I bought one today, the first thing I would do is change weights, if I never done anything else would be to drop 20g in with stock tires.

Larger tires hurt performance for sure, but that's mainly because of the weight.
I've had 2 different sets of 28" tires.
Switching to 18g moved the shift phase higher. It slightly delays that initial jerkiness of 22g and once you start rolling, you're running slightly more RPMs which counter the weight.
One set of 28 tires/wheels weighed 48 lbs each. The 18g weights were just enough to keep me good, but when I switched to 28" tires/wheels that weighed 50 lbs each I needed to do something.

That's where the Aftermarket Sheaves come in to play. Lower belt travel gives you better take off and faster speeds on the upper end.