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Tuning Confusion
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I recently bought a Shadow VT600. The previous owner installed a velocity stack and new pipes at the end of last season. The bike didn't run when I bought it due to a rich air fuel condition (smelled of raw fuel + carbon fouled plugs), however, I bought it anyway, thinking that it was a simple issue with the carb.
I cleaned the carb, replaced the old gas with ethanol-free gas, charged the battery, and it fired up great, but would choke out and die at the top of first gear. While in the carb, I noticed he had been running a larger set of jets (he also gave me all the components of the single carb performance kit sold on TJBC website). At first, I thought these larger jets could be the reason for running rich, however, that wouldn't make much sense due to the velocity stack and open pipes.
Once I got it running, I replaced the spark plugs, only for the new ones to be immediately fouled again (in addition to black smoke from the exhaust). At this point, I decided to revert to stock jetting and resume tuning from there to avoid constant guesswork. I used a tach to tune the idle to 1200 rmp. The bike ran best at this new baseline (still choppy in first gear), but once I grabbed second, it ripped.
While out for my ride, I began adjusting the air fuel screw to hopefully solve my rich condition (still seeing black smoke). My pilot friend (actual pilot, not referring to the jet) told me to turn the screw in until the rpms raised, then back out a little because that typically works on the plane. Later in my ride, after doing this, the engine began to surge when letting off the throttle. It felt like I had lost all progress, since it was running fairly decently before.
Today, when I tried to take it out and tune in first gear, I noticed excess fuel on the carb (like it was leaking). Additionally, I lost power, and the engine surged once again. This seems more like a lean condition now, but even after cleaning the sparkplugs with a wire brush, they once again fouled immediately.
I also did an oil change if that changes anything 😂
I think maybe the boot may be worn from taking the carb on and off so many times (maybe causing a vacuum leak), or the choke cable is causing the issue (starts fine without choke), or something else is causing the carb to leak (wasn't an issue until today). I also know that I should rejet, but as of right now, I am a bit lost and don't know where to start. I want to learn more about the bike I am riding. Please Help!
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TJ Admin Staff memberModeratorMember who has the rights to delete posts, and ban members form forum if they violate the rules.
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TJ Admin Staff memberModeratorMember who has the rights to delete posts, and ban members form forum if they violate the rules.
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