09 M8 clutching help

[phatty]

8500-9200 feet today in 4 feet of Utah Fluff.

HCR 153" 70g weights, stock secondary

pulled 7800 all day long. Sled was a rocket! Suspension is stiff as a board on the trail, but i did have it custom set to hold 240 lbs off an 80 foot cliff... hahaha cant wait to drop it tomorrow!!!

 

[black swan]

adjustable weights, which ones?

stock 75's at 10-11k only pulls 7600ish. Plenty of snow for testing here, and diffinitely need to drop weight. Maybe diff spring too. 09 SP 153

i'm thinkin 73's but what about adjustables?

 

[Coxy]

You're pullin 7600, at 10-11k feet, and your sled is setup with 75's stock??? Are you sure?
Im gonna borrow a spring to try as per the suggestions in here, and probably order up some cutler/dalton adj weights to fine tune... hopefully that gets er close.

 

[phatty]

yesterday rode at 10,000 feet all day with the 70g and could only pull 7650... snow was still at least 3 feet deep but setting up.

Have yet to put on the SLP single, but i am hoping i can stick with the 70s though i feel i might have to drop to the 65-75 adjustable weights...

 

[GlennRMK]

That seems weird

I am running around that RPM with on my 09 M8 162, stock with just a Jaws can. That was with 73 gr weights ans a 120/310 spring. Trying a 120/340 tomorrow. Will let you know how it goes.

I was running 68s in my 06 M7 with Speedwerx single, thing can and RKT head up to around 9000-9500 ft and pulled 8000 RPM no problem. This is with a 120/340 primary spring

 

[thekrust]

The first 100mi on my 09 M8 153 it ran awesome 7700rpm everywhere from 5000 to 7500ft was lovin it! Last ride it would only pull 7400??? Looked at my clutches today and found the the secondary clutch mostly destroyed! It looks like there was no bushing installed between the 2 sliding halves. It is just a sloppy mess of piled up aluminum now. Hopefully can get fixed before X-mas.

 

[PCDOC]

The first 100mi on my 09 M8 153 it ran awesome 7700rpm everywhere from 5000 to 7500ft was lovin it! Last ride it would only pull 7400??? Looked at my clutches today and found the the secondary clutch mostly destroyed! It looks like there was no bushing installed between the 2 sliding halves. It is just a sloppy mess of piled up aluminum now. Hopefully can get fixed before X-mas.

WOW must have been an OFF day at the cat factory when that baby was assembled. Somebody must have been hungover.

 

[thekrust]

It was possibly built on Tues. after along weekend!! I hope it was just the clutch assembly guy that was screwed up and not the whole build team.

 

[dunatyk]

Hopefully this gets figured out quick. I have an 09 m8 le and first ride out i was pretty mellow out it but when i went out Saturday in mine will only pull 7300 -7400 on deep powder climbs sometimes it even dropped to 7100. I am running stock with around 70 miles on the sled forgot to mention it has a HPS can. In the field behind my home it will only pull 7700 and that is at 4500 feet. I am going to pull the can and go back to stock and do some testing to see if the can is affecting my performance. I will post results of what i find. Maybe they just need to loosen up a little more???

 

[iluv2fly]

Man these things are all over the board RPM wise. Mine pulled 7850 on a trail at 8500ft with the stock 73's and a 140/310 primary spring. If I would have left the stock pipe on, I would have installed some 70's with the stiffer spring and called it good.

 

[Coxy]

keep trading info Dunatyk, sounds exactly what mine acts like as well. What altitude were you at up top?
I aquired a black/pink drive spring that is in theory 120/340 (slp spring?). Now if its true that for every 10# increase in finish rate you get you gain approx 100rpm, it is probably going to be a bit too much spring, but i suppose it all depends... The R's were hunting all over hells half acre, so between stabilizing and bring them up, it could be close.

 

[iluv2fly]

Coxy I would not believe the 10# is equal to 100rpm statement. I installed a 150/330 spring on mine and it did not increase upper rpm much at all but it did hold rpm much better. Instead of running 7700 down the trail and falling to 74-7500 in the deep snow the stiffer spring would run maybe 7850 down the trail and when you got off in deep snow it would hold that rpm really well. Give it a shot and report back to us on how it works. I have just never seen the 100rpm gain per 10# like I have heard people claim.

 

[Coxy]

Fair enough, yeah i just gathered that info up durin reading. Quite possibly might toss it on the truck and go for a short Christmas eve ride tomorrow, to the same spot we were playing the last time out, so it'll be a descent comparo for sure. That would be sweet if it worked good, then id have to pick up a case of beer for buddy that had the spring

 

[Coxy]

Glenn, any updated on your testing with this spring?

 

[GlennRMK]

SPRING seemed to work well.

The snow was very, very deep. Deepest I have ever ridden. Over the hood, face shots, almost getting stuck in the flats, and I managed to get stuck for about an hour and half, but only got stuck once

Powerclaw rocks!. Very impressed!

Sled spent a lot of time wide open today. Definitely broke her in pretty good today and she has about 75 miles on her.

I did get to climb some hills and I was carefully watching my tach and speedo. Seemed to be running right around 7700 +/- 50 RPM and track speed was around 42-43 MPH. Seemed to pulling hard and sounded very crisp. Running quality seems very good.

In the meadows the snow was piling on the hood and seemed to be struggling to breathe a little. Also have a noticeable exhaust side bog. Lay her to the right, RPM drops to 7400. Tilt her to the right and it went right back up 7600 RPM and climbed to 7700 RPM.

The hills and meadows were inbetween 9000 and 9500 ft.

That being said, I have a D&D torsional kit sitting here with a BDX 42/36 helix. I am going to try that next time.

ANYONE KNOW HOW THE HELL TO GET THE TORX SCREWS OFF THAT HOLD THE HELIX ON? I TRIED HEATING WITH A TORCH AND STILL BROKE A TORX BIT (T-20).

More heat? Impact driver?

My M7 ones were a ***** but seemed way easier then this!

 

[Coxy]

Awesome man, thanks for the report! Looks like i may be pleased with aquiring this spring like yours! The only way to fly with those torx for the helix was the old M7 technique. Heat them up a bit with a small torch, give them a little shock with a hammer/punch, then get em while they are hot. I got them all out on my M7 without breaking the heads off or a bit. Just be stable, and you shouldnt strip the heads out on em.

 

[Griff]

Great report Glenn and thanks for including the photos for those of us working and wishing we could be riding. Just to confirm, 73g, & stock secondary pulling 7700 in deep powder climb at 9000 ft with stock motor.

 

[GlennRMK]

Correct

All I have is a Jaws can

73 gr in the primary, with 120/340 Team yellow spring, stock secondary

 

[mcfly13]

hey guys just a couple of thoughts
we all have to remember cat's tach is off either way by at least 200 rpm

on the helix removal issue i found that if you heat it up good the let it set for a min and heat again they will come loose also try and get heat in the helix it self
use a snap on torx soket for at least they a re warrentied

 

[dunatyk]

Well have some results. I ran it in the field behind my house with stock can HPS can and Jaws can. All were about the same with the jaws having the highest peak rpm and maybe 30 to 40 more rpm then the other 2. The primary clutch is very hot to the touch after 3 100 yard pulls, the secondary was nice and cool. So my firts question is what is the best course of action? Install a different spring such as Glenn or drop down to 70 gram weights like Phatty? Also these results at elevation corespond with my 07 m8. It pulls 7700 to 7800 down in the valley but up in the mountains 7 to 10k it pulls 7500 to 7600 where they needed to run. Any input would be greatly appreciated. I also remember a thread a couple of months ago about a guy who brought home his new M8 from the racin station and i think he said that they installed a different primary spring that was an SLP but i do not remeber the color on the spring. Going to clean clutch faces and see if anything changes. More to come..........