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I have a 94 ZR 580 that’s kicking my butt. The thing runs great for few minutes. Maybe a mile or so. Then it Boggs and won’t go any faster than about 45. It acts like it’s not getting fuel but I’m having a hard time believing that. Both carbs have been cleaned twice. The float setting is ~.88”. The main jet is a 370 as best I can tell.
other than a good cleaning, nothing has been changed in the carbs. When I bought the sled the guy said it needed a primary clutch. I bought a new clutch and made sure the spring was correct (red) and that the weights were right (46.5 gram). I decided that as long as I was at it I might as well replace the buttons in the secondary as well. When I took it apart, the spring ( yellow) was in the fifth hole (tightest). Everything I found said the spring should be in the middle hole so that’s where I put it when it was reassembled. Alignment was checked when everything was reassembled and is correct.
My question is could moving the spring from the fifth hole to the third hole be causing my issue? Do the springs loose tension over time and the previous owner moved it to the fifth hole to compensate for it?
Neither cylinder appears to be lean, but could it be crank seals?
I’m totally out of ideas and need your input. TIA.
 

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Yes springs wear out and yes moving it tighter should have increased your shift RPM
Have you removed the air screws and the jets (pilot up the tube) and sprayed all those passages
 

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Discussion Starter #3
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Yes springs wear out and yes moving it tighter should have increased your shift RPM
Have you removed the air screws and the jets (pilot up the tube) and sprayed all those passages
I’ve had the carbs apart so many times they should have zippers on them. Everything has been sprayed, wiped, blown and cleaned multiple times. Nothing I’ve done makes any difference.
 

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Discussion Starter #6
Could it be a fuel delivery problem? Something like a rotting pickup tube in the tank or a marginal fuel pump could cause your symptoms... That's at least a couple things more to check and rule out...
The only thing that hasn’t been replaced/rebuilt is the fuel line inside the tank. It’s worth a try.
 
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