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Appearance isn't everything. Those particular isolators have a metal base, I can tell because they bolt on instead of clamping on, and as such they use an o-ring gasket between the isolator and head. These get squished over time and shrink or even crack and break. I'm not betting the farm it's your problem but worth a look for sure and it's an example of where vacuum leaks can occur besides hoses.
I've had that experience on previous carbureted bikes where the o-ring split causing lean running, backfires etc. It's not always a visual, "that looks fine, the bolts are tight" situation. I also had a crossover hose between carburetors develop a hidden crack where it ran beneath the gas tank. My bike had amazingly developed more power... right up until an exhaust valve seized. :eek:
 

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Discussion Starter · #63 ·
Appearance isn't everything. Those particular isolators have a metal base, I can tell because they bolt on instead of clamping on, and as such they use an o-ring gasket between the isolator and head. These get squished over time and shrink or even crack and break. I'm not betting the farm it's your problem but worth a look for sure and it's an example of where vacuum leaks can occur besides hoses.
Yeah I will investigate that for sure but yeah I'm not 100% sure that's the issue either because it's intermittent I believe if it was a vacuum leak it would be like a constant problem because sometimes it would run perfectly and others it wouldn't and why specifically under 4,000 RPM makes no sense. And also why for some reason jumping that vacuum line over totally solves the problem it is running a little bit more lean now little bit more backfiring but other than that it's been fine for the past couple days so odd....

I think I'm going to take the intake off and investigate and try to see what internally is going on there that moving the vacuum line makes such a big difference in performance!
 

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2022 Versys X 300
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Yeah I will investigate that for sure but yeah I'm not 100% sure that's the issue either because it's intermittent I believe if it was a vacuum leak it would be like a constant problem because sometimes it would run perfectly and others it wouldn't and why specifically under 4,000 RPM makes no sense.
Motors pull less vacuum at higher revs so it makes perfect sense.

All I know from your posts is that it appears you have a vacuum leak issue, you're swapping hoses around and it appears to run better, maybe the swapping is canceling out some of the leak or sharing the leak with both throttle bodies. If you can just find the source of the leak in the first place you'll be golden. That's why I suggested propane or starting fluid, it's a cheap and instant way to detect a leak.
 

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Discussion Starter · #66 ·
Motors pull less vacuum at higher revs so it makes perfect sense.

All I know from your posts is that it appears you have a vacuum leak issue, you're swapping hoses around and it appears to run better, maybe the swapping is canceling out some of the leak or sharing the leak with both throttle bodies. If you can just find the source of the leak in the first place you'll be golden. That's why I suggested propane or starting fluid, it's a cheap and instant way to detect a leak.
Yeah but the odd thing is it wasn't a consistent thing under 4,000 like sometimes it would idle fine sometimes it would work okay? Very odd but yeah I think that idea of It sharing the leak might make sense it seems so weird that just swapping that tube and it magically is better. I really appreciate the input you guys have been very useful here!

I'll take this thing apart tomorrow and see what I find!!!
 
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