Cough please !

[simonk]

Hello Kind folks, just a quick question, my 82 1100 has a cough , I was setting the idle up, with an auxilliary tank when I noticed a hot puff out of the vacuum pipe, so I'm thinking bent valve? I have checked for leaks on boots and exhausts ..does anyone have any other ideas about what could cause it ? I am going to check shims , but the bike has done literally no miles since the last time. Thanks.

[Rijko]

When using an auxilliary tank, the vacuum pipe on the carb should be plugged, so how would you notice ?

Could it be you did not plug the vacuum pipe on the carb ?
That would lean out the mixture on that 1 carb, and lean mixture typically produces a cough or spit.

In that case there's no problem, hope that's it ...

[Who Dat?]

Please explain what you are calling "vacuum pipe". Rijko has (correctly) mentioned that if it's the vacuum line from carb Forum to the petcock, and it's not plugged, there will be a very lean mixture there, which can lead to erratic firing.

[unfocused]

If you mean the breather tube comming from the valve cover, a puff of blow-by is common. Constant smoke means your engine is loose and you most likely are buring oil as well