M7 rk tek secondary

[flapdoodle]

Ok. Trying to make my sled better. Grab a coffee, I'm going in depth to describe everything in detail.

Was told by lots of people, and lots of forum threads the sweet spot for an M7 is an Orange primary spring, with OEM recommended weights for my altitude I ride. Also a 10.4" secondary, and further to that a torsional conversion.

So I got the orange primary spring. Left the 68g weights in it as I ride 6-9k ft.

Then I picked up a M1000 10.4 secondary with an RK Tek torsional conversion. It has a blue spring that I think is the Speedwerks spring, and a 34 degree helix which RK Tek says is what I want.

Now the issues. Mid throttle.. if I punch it. I get a bog / it breaks up. If I wik the throttle up into RPMs I get to the 7850 - 7900 rpm sweet spot im told the M7 likes.

Now, in deep pow.. rpms spike.. and I get NO track speed... again.. If I wik the throttle and build up track speed.. it works ok.. but then I get going too fast for boondocking.

So I adjusted the secondary tension to the lowest setting, and then a little further by taking the whole cover a bolt back (90 degrees) and going a little tighter on the adjustment hole which was the equivalent of going back another notch or two. It got marginally better, but the issue persisted.

I swapped back to the OEM yellow/white primary spring and the mid throttle bog / sputter is gone.. but in pow I still lose track speed and the RPM spikes.

Lastly I have checked belt deflection. Seems that even with the adjustment backed right off.. and the cogs of the belt sticking up out of the clutch i still have more than the 1" RK Tek suggests in the instructions.

I am at my wits end. When it works.. I can feel how much better this setup can be.. Pulls hard, GOBS more bottom end. But in the steep and deep it's a pain.

Any suggestions would be muchly appreciated

 

[Vern]

Have you tried tightening the pre load on the spring? Sounds to my like it might not be back shifting right. I don't know how the newer rkt kits differ from the earlier ones other than they include a helix, but when I first got my m7 I tried the older version of the rkt/ovs tortional kit and didn't like it. Never felt right and the rpms were constantly bouncing up and down with no consistency no matter what spring or preload I tried. I went back to the compression set up found a spring I like, dropped about a gram in weight via cutler adjustables and she's been rockin away for the last 5-6 years. In my experience with my m7 figuring out my own set up gave me better performance than all the "must have" set UPS I've tried off the forums, and alot of times was the complete opposite of what everyone said needed to be done.

 

[Desperado]

Clutching

I've had many of the same problems as you with my RKT setup on my M8. At times it worked well, but was very undependable from ride to ride. I finally gave up with the setup and called MDS. Put the secondary back to stock and installed the weights in the Primary. Much happier now and very consistent from ride to ride. The only thing I would look out for is the bushing in the secondary. If it wears you will have problems

 

[flapdoodle]

When I got the clutch, it was already in the second tightest position.. So I started going back from there.

I just picked up a manual. Going through it to make sure things are setup right, offset, center to center, etc.. Gotta be a reason this is acting funny.

 

[Phizzer]

X2 on the back shifting not engaging smoothly. How many miles are on the primary spring? I'd be checking the bushings on the sheaves as well. If they are original, they might be worn and will bind slightly.


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[flapdoodle]

Orange primary spring is brand new. Has trail up miles on it before i swapped back in the oem one.

 

[mbcat]

Sounds like your dealing with binding clutches. Get a new bushing & rollers in secondary, cut spider & cap cups on primary. Get some cutler adj weights & their gold/white primary spring. Get a Thunder ABC kit. Adjust belt to sheave to .020. Take all the shims out behind your secondary and just put in a .030 shim. This gets the clutches in line under load. Put all new engine mounts in and stopper under oil tank. I use a Formula x-1 secondary set up and Mel rebuilt my secondary with a steel hub and bigger bushing. Take what you like works great for me!