Primary Spring? - M8 pipe, port, head

[ItDoAble]

Have an head/port 07 M8 that had an awesome clutching setup for 8-12K altitude. Smooth engagement, snappy upshift at any RPM, held RPM on hill, good/controlable backshift, decent track speeds. Now added an SLP pipe and chasing the optimum setup.

Before;
Primary Spring - AC yellow/Wht
Weights - 68.1gr Cutler adjustables
RKT 36deg secondary kit, red spring, center hole (#4)
7900-8000 Max RPM on a hill pull

With the new pipe, seeing much more top end power but lost low RPM snap. Finished tuning the fuel map .. now chasing the clutch setup. Targeting max RPM 8000-8100.

Leaving the current setup and adding/subtracking to the weights, yet to see over 7940 RPM (per BD box):
1) adding weight, drops RPM into the 7800's but adds back some low end snap (upshift).
2) removing weight, raises RPM into 7900's but no more snap (see#4).
3) tried stiffening secondary spring, while changing the shift pattern a little, not much change to the RPM (of course).
4) <6000RPM, feels like a delay in the upshift. Engine increases RPM, but the clutches do not upshift fast enough to take advantage of the power curve .. if that makes sence ... no snap.
5) >6000RPM, pulls like a madman, but at ~7900RPM max have a few more ponies I'm not taking advantage of.

Thinking I need to go with a higher finish rate on the primary spring.

Any opinions on a Speedwerx H5? Any suggestions for spring rates that have worked in simular applications?

Oh, and I'm going to gear down slightly, so I could probably get more agressive on the engagement, if needed.

Other ideas?

BTW, this engine setup is fantastic for the M8. Just need the clutching setup to take advantage of it.

 

[dmkhnr]

Riding 7-10k
Heavy powder today.

RKT port/head/torsion, SLP pipe boonbox.

75# orange/white, 38-34 with snopro green 3rd hole spinning 8100.

Having a problem with pulling the outer cord in the belt, have wasted 2 belts to overshift. Clutches aligned and I'm thinking it might be the torque of the motor causing my outer cord to pull.

 

[iluv2fly]

I run the speedwerx H5 125/340 spring and 70G cat weights on my 09 M8 with the slp pipe. It will run 8000rpm at 8500-9000K and pulls hard. In another month I will do some porting to gain another 10Hp.

 

[BigRed118]

I have a similar set up to you. The SLP black/red spring fixed it for me. 120/320 spring rate. Make sure when you are comparing springs that you look at how compressed the spring is when they are measured. It changes everything. I tried a Polaris Black/green that is a 340lb shift out and didnt get the rpms I did with the SLP at 320lbs shift out.