Vacuum issue?

[motomarv]

Ok, I am new to this bike/engine and really don't have much knowledge about engines in general. I've been doing some reading and trying to figure out some issues I've been having, but so far, no luck. Here is the big one right now:

After running the bike tonight, it still gave me some issues with the hesitation in 1st and maybe 2nd. So, I brought it back home and had it idle. I wasn't able to locate any specific spot with the propane torch, but did spray it again with the starter fluid. Through this, I was able to notice that the RPM's did drop when I sprayed the synthetic rubber feed pipe. Thoughts?

I have a 1977 xs650. Just bought it 2 weeks ago or so.

 

[angus67]

by synthetic rubber feed pipe, do you meen the carb mount boots? if the rpm changes when you spray those, they are leaking. when you spray them, you temporarily 'block' the leak, the rpm drops. need new boots.

 

[inxs]

- and then you run into ethanol compatibility problems
- try contacting jbmindustries for boots, can have a read about them here too

 

[motomarv]

Actually, it's more along the lines of the fuel line, I think. I'll attach a pic of the rubber hose that causes the change when sprayed. No change in RPM when I spray the boots.

 

[angus67]

how old is the hose? how bout some real clamps, too.
If it is leaky hoses, change 'em out. cheap enuf, and you'll know right away.