Won't idle

[herbg]

Craig:

Agreed but it seems that the bike starts only when I can give the carbs a few squirts via the accelerator pumps. That doesn't seem to be happening.

I'm hoping I can try to get this going before pulling the carbs and taking them apart.

Cheers,
Herb...

[herbg]

Steve ... I tried pressing out the pump jets with my thumb but they seem a bit tight.

How much force is acceptable to push them out?

Thanks,
Herb...

[BevHevSteve]

whatever it takes. I use a large screwdriver and push a flat up against the end of the jet and lever it in (pushing it out) when they are really stuck. Its the rubber o-ring on it which has stuck itself in there along with gas that has hardened.

This again tells me the carbs need to be completely disassembled, cleaned and put back together with all new soft parts.

[Craig in France]

Agreed, but it seems that the bike starts only when I can give the carbs a few squirts via the accelerator pumps.

That's because they're compensating for a problem elsewhere in the carbs*, Herb. So, even if you do get the pumps working and the bike started, you're still going to have to strip and re-build the carbs.

So why delay?

Remember: you can run these bikes without the pumps, should the fancy take you. So, IMO, it doesn't make much sense to waste time on them when there are more significant problems to be fixed.

* E.g. Worn/blocked idle jet, blocked air passage, wrong float heights etc.

[abmartin]

Agreed, but it seems that the bike starts only when I can give the carbs a few squirts via the accelerator pumps.

That's because they're compensating for a problem elsewhere in the carbs*, Herb. So, even if you do get the pumps working and the bike started, you're still going to have to strip and re-build the carbs.

So why delay?

Remember: you can run these bikes without the pumps, should the fancy take you. So, IMO, it doesn't make much sense to waste time on them when there are more significant problems to be fixed.

* E.g. Worn/blocked idle jet, blocked air passage, wrong float heights etc.

I usually give the throttle a couple of good twists before starting my SS with 40mm carbs. Normally starts first kick. I would give the carbs a good cleaning and tuning including making sure the jets and passages are clear. Then just ride the bike for some serious distances to get some fuel through it. Hot starting is usually more difficult and I've never been able to get mine to idle reliably. If the float heights are incorrect my bike refuses to start. I try not to let my bike go on reserve as it seems to cause problems getting fuel to the carbs.

Bruce

[herbg]

You're right ... too many red flags on the operation of these carbs. Embarking on a full rebuild of both to make sure all is correct. Already finding lots of problems.

Thanks!

[abmartin]

Retuned and balanced my bikes 40mm carbs using a Morgan Carbtune. At least for the time being I now have a reliable idle albeit at about 2000 revs. Not sure how the guys on Youtube get their big carbed dukes to idle like a harley.

Bruce

[BevHevSteve]

... no air leaks, patience doing the sync procedure and you will get it. Mine idles nicely with big carbs...

[900tlc]

Just been reading the woes of engine idling,I had a problem with my GTS not idling correctly.The RPM would go up and down, so we would assume a problem with carburettors/seals etc.
Quite by chance I was reading" Guzziology",which mentioned the same problem. My GTS has the Bosch ignition ,the same as fitted to some Guzzi's.
and Ducati's of course.
The problem was found to be the setting of the pulser ignition coils,they need to be set very accurately,so if you have Bosch ignition,and you have taken the primary case off and accidently knocked the coils,then they need to be reset.
In my case I got the correct tool,and the engine settled to a steady idle. Hope this is of some help,just thought I would share my experience.

[BevHevSteve]

+ 1 on proper pickup placement being super important....