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No low End Power other effects of a vacuum leak?

tdubsy

CB750 Enthusiast
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Hey Everyone,

I have a 1978 750K

I've been having trouble getting a decent idle. I can get it down to around 1600 RPM, Any lower and I will get that odd pop hiss sound and the bike will die

But, when my idle is working at that low the bike will bog down and stall if I give it too much throttle off the start even in neutral.

I have to get the idle around 3000 RPM for it to be able roll on its own on flat ground with just the clutch and no throttle. or to be able to accelerate without the engine bogging down.

I just wanted to check to see if a vacuum leak would cause the majority of these issues or if there is something else I should be checking as well?

I'm pretty sure I have a vacuum leak on carb boot#2 (tested it with carb cleaner and revs shoot up)
I have parts to do a full carb rebuild and new carb boots coming in the mail


Thanks!!
 

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Could be the vacuum leak causing a lot of it. Wont really know till you fix it to see if it was your problem. You'll need to do a carb sync when done with the rebuild. Checked compression? Weak engine will never have good power and hard to tune. Do all tune up items...valve adjust, timing chain adjust, clean and set point gap,timing and dwell.
 
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