annoying and strange start problem

[POULSEN]

Hi Group,

I have searched and followed the site, but not found a start problem quite similar to mine.
It is a GS550 from 1977 with VM carbs.
Air intake is stock.
Carbs are clean with new o-rings.
Intake rubber new.
Dyna-S ignition set correctly.
Valves within spec.
Compression in the lower end, but within spec.

It runs sweet, and I have no complaints.
After it has been running, It can stay for 24h and start within a few seconds.

But if i leave it for 48h or longer, the starter must run for a total of app. 30s before it reluctantly starts, 1, 2, 3 and finally 4 cylinder.
Not a big problem, because it will finally start, if enough power at the battery - but quite annoying.

Now for the strange part:
If i leave it for 48h or longer, but empty the carb bowls and prime until they are filled again, it will jump in almost immediately.

Only explanation i can give, is that the gas in the bowls deteriorate - but to be honest after 2 days only?? anw why does the same not happen with the gas in the tank?

Anyone with same experience, or even better with an explanation and a solution?

I have lived with it since i bought the bike 5 years ago, and it has been the same whatever I have changed.

Best Regards

Stig

[BassCliff]

Hi,

Make sure your carb vent hoses are clear, as well as the drain hoses. You shouldn't have to drain the bowls just to prime them again. Prime should work without draining the bowls first.

Why not just ride every day?


Thank you for your indulgence,

BassCliff

[Big T]

Most VM carbs have the problem you describe, the gas in the bowls evaporates out

Just turn the gas to Prime for 5-10 seconds and it should fire right up

No need to empty the bowls, it's not the gas

[POULSEN]

Bowls are full, and prime alone doesn't help


Quote:"Why not just ride every day? "

Easier said from sunny California, than from rainy Denmark

BR
Stig

[tom203]

Next time, after 48 hrs of rest. don't drain bowls, but put on prime and tap gently on carbs to wake them up in case floats are sticking closed for some odd reason and blocking new fuel.

[POULSEN]

Hi Tom203,
you could have a point - will try - thanks.

/stig

[azr]

Holy cow, you've been living with this problem for 5 years! if someone on here solves it for you you're going to owe them a prize for sure. You are far more tolerant than I good sir, hope you sort it all out.