Gas cap

[trat]

My bike, 83 GL1100, seems to have too much vacuum in the fuel tank after a ride. If I open the fuel cap at idle after the engine has run for a while the engine seems to actually idle smother and the idle speed increases slightly and there is a noticeable whoosh sound from the tank. I went to Honda to get a new cap because I figured the vent in the cap isn't working correctly. The cap is no longer available from Honda (thanks Honda). Does anyone know of a good aftermarket cap?

[chrisz]

I believe there are is a way to 'refurbish' the existing gas cap. I believe I've seen some folks here do exactly that to solve the similar issue. Else looking at eBay may be required.

[olchris]

HI and welcome.. There is a vent/hole it the cap to compensate for the fuel being sucked from the tank... It is common after 40 years for it to get blocked with rust, crud and an occasional tea bag ..

If you have the time! drop it in a cup full of vinegar/ lemon juice/coke, rust killer whatever, for a few days and then with lots of compressed air blow it to bits.. The cap has to "breathe" to equalise air pressure.. This maybe, will dislodge and clear the vent hole!!

[maintainer]

Yep,
What they said.
This is caused by a blocked cap vent.