Sucking noise from filler cap.

[joebloggs]

[quote author=joebloggs link=topic=18161.msg209376#msg209376 date=1441607434]
[quote author=Skippernick link=topic=18161.msg209296#msg209296 date=1441543652]
Ah, ok ill investigate.
Rode it 100 miles today and was ok, but may explain the hard starting, which has been an issues since it was serviced which involved valve check and card sync. Thought it was idle was too low.

Theres an old saying that everyone should remember. If it aint broke, don't fix it.
Every bike I've every had would do as you described in your first post and not once has it caused me or the bike an issue. And if it's the cause of your idle issue I'll eat my hat.

A great acronym when trying to resolve an issue is KISS (keep it simple stupid) See hundreds of problems can cause low idle but the chances are its just the idle adjuster so start there.

Simple first......
[/quote]


I agree and know its idling to low and how to fix that. The problem i mentioned was that since its service it seems to be harder to start, i.e. it spins over for a while before catching. In 5 years of ownership it has never failed to start, but i have never quite got the knack to start it first time regularly.
[/quote]

I still think you need to be looking elsewhere. If, by chance, there is an issue with a partially blocked tank vent causing starvation issues its more than likely that your problem would be at higher rev's when the engine requires more fuel.

If its running well generally then try different throttle/ choke settings when starting from cold and see if that helps. If its hot starts that are the problem it could be down to evaporation due to heat from the engine. Either way, if it never fails to fire I'd be inclined to just leave it alone.
Your choice of course