Mid-Range Lean or More Twist in Helix?

dnale

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South Lyon, Michigan
I had asked the question in the tech section. I have a 96 600xt with a set of psi pipes on it. I also have the max perf kit for those pipes. I jetted and clutched per the max perf kit. It engages about where the kit says (around 4k) and doesn't over rev per the sheet (like 8800 if I remember right.) It's ok off the line, nothing great, but mid-range is kinda weak. Once I get the rpm's up to about 6k, it takes off.

The suggestions were that I might be either lean in the mid-range or need to twist 10* more with the secondary. I can check the mid-range lean but should I also do the twist too?
 

The twist is simple to do. 5 minutes worth of effort and you might get your answer.

My next time out I am adding another 10* of twist. They recommended 50. I am at 60 now and will try 70 for the next trip (forgot wrench last time).
 
They recommended 60 so a switch to 70 isn't much of a problem to do. As long as everyone else with me is a little patient!
 
With mine they recommended 50 to start with. It was driveable but not like I liked. 60 is much better. I don't know what 70 will get you. I am using their progressive helix so I can't tell you what the angles are for reference.

Something easy to start with at least.
 
Why not run it where it is "weak" and hit the kill switch. Then check the plugs. I would much rather rule out a lean condition quickly. Make you feel really bad to burn it down testing helix changes. Thats just my opinion, and how I would approach it. Maxdlx
 
If it turns out to be a lean condition somewhere in the mid-range, I'd raise or lower the needle jets? That's all based on the clip position right?
 
If you thing it is lean in the mid raising the needle by 1 clip would be good. I just suggested the helix cause it involves much less cussing when out in the cold. What ever you do do 1 thing at a time.
 
is it usually both or just one carb that you need to adjust? I did nothing with them when I did the other adjustments. Mainly becuase I couldn't tell where they were.....
 


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