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Discussion Starter · #1 ·
I recently added a jet kit to my Shadow VT750DC. After putting it all back together I took it for a ride and now it seems like once it hits certain rpms it loses power until I let off the throttle and give it more gas. I took it apart and I inspected the floats. The only thing that I noticed was the one if the covers for the vacuum piston/chamber and a ding in the top of it. Once I put it back together it’s not as bad it’s more of sputtering in a way. Could this be affecting it or do you guys have any ideas? I’m not sure if it’s a vacuum leak or it could be something else. I posted a clip of it on YouTube to get an idea of it
https://youtu.be/eWkxq9XjcDM
 

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With the work you did it's likely either a vacuum leak or the bike didn't like the jetting changes you made. What prompted you to do the jetting changes?
 

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Discussion Starter · #3 ·
It was running lean because it has an open exhaust on it. They come from factory running already a little lean so it was causing a lot of backfire with the aftermarket open exhaust that was put on it by the previous owner.
 

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Ace Tuner
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Well I can't get to the YouTube but jet kits rarely work correctly when a person goes by the instructions only.
What brand of jet kit was it?
I only ask because some brands have you change some things seemingly just for the sake of change.
I like Factory Pro brand kits over most others because they are straight forward, no BS.

Anyway, the only (or best) way to dial in a jet kit is by reading the spark plugs.
As best that I can recall... those bikes used two spark plugs per cylinder.
At this point if I knew what year model the damn thing is I might be able to help... :plain:
 

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Ya, not uncommon when jetting a bike to have to try a few different combinations. Did they send multiple jet choices with the kit? Plug readings, mileage tracking, and butt-dyno are usually what I go by. It takes a bit, but I can narrow down a combination I'm happy with within a few rides.
 
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