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Discussion Starter #1
Ok, here's the deal. I bought a set of FAST twins for my sled and all the clutching that I was told to use. Now I have decided to put a 136" on also. What I am wondering is will my stock clutch setup with lower gearing work or will my pipe setup work?pipe clutching-(228 ramps, 18gr. weights, Black primary, beige secondary at 18-20 lbs, 53-47 cam). Either way I am going to be running a 136 with the fast pipes. I am just trying to find the best clutch setup with what I got.
 

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Hey  670ho, Doo doesn't make a solid black primary sping. Look
for the stripes on it - likely purple/ blue. In any case, your clutch combo should be o.k., but I would raise engagement to
reduce the dreaded bog off the line, and you may have to run lighter pin weight to get the rpm that fast wants these twins to run at. What does fast suggest for clutching? I bet they want a heavier rate primary spring, shallower ramps, and less pin mass.
 

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Doo does make a black spring (185 -410). I would try a shallower helix and lower gearing depending on the lug height of the 136. The 53-47 is a hard angle to pull even with the short track on the HO. I had FAST twins on a 97 670 (non HO) and I used 200-320, 145's (similar to the 228's just ground for higher engagement) 17 gram pins and 50 deg helix @ 16 pounds. It liked 24-44 gearing with 1 1/4 short track. 18 grams mat work well with the 410 finsish rate of that spring.

Good luck
 

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Discussion Starter #4
Yeah I was going to say I have the #### black spring right here, anyway the setup I listed is what FAST reccomends with a short track. The 670 should be turning at 8300 with the pipes and engaging at 4800 with this clutching. I think I am going to try it with the long track and if she can't pull it I will maybe put back in the stock ramps or reduce the pins since they are adjustable.
 
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