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No low end power

12608 Views 12 Replies 4 Participants Last post by  dwhst9
A couple years ago,I purchased a 2001 trailblazer 250 that had recently had a new top end bored to .040. I have since installed a new 38mm(400cc) carb and a FMF fatty gold exhaust . I have also installed a EPI performance clutch kit. The trailblazer had both lower and upper power to spare for about a year. Have lots of hills that I climb, and over the last several months I have noticed a very definite decline in low end power. Barely able to make it up hills, but starts on a dime and has plenty of high end power. I checked compression;was 115 psi, after putting a little oil in, it came up to 120 psi. My service manual indicates 115 psi is spec. Again, starts on a dime, idles like a champ, just bogs somewhat on low end, just doesn't have the same take-off power, can't climb a hill for squat like it once had. Installed a new Ricks CDI box, as well as repacked and cleaned silencer,did not help. Is jetting the carb what I'm missing? I have never changed jets. Is compression too low? new rings in order? Can anyone help, I'm at a loss.


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I agree, look at the clutch. Give it a GOOD cleaning and service the sheaves. Look close at the belt.. it should NOT be shiny.

If your convinced its the motor, have you cleaned the carb? Do you run anything to keep it clean?

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