No vacuum

[Guest]

Hi there guys and gals. Need some help. I recently cleaned and resealed my bs34 carbs. They're on an 81 gs400x . It's a Canadian / Euro bike. I don't seem to be getting any vacuum from the vacuum port. If I manually suck on the hose I get fuel from the petcock if not I get nothing. Any ideas?

[Cipher]

is this a vacuum petcock?
Check your hoses
and yes the hoses can age and collapse internally.

[Cipher]

oh and no vacuum? man that sucks!

[chuck hahn]

Got it on the right nipple?? Brass nipple at the rear of carb 2 ?? Place your hand over the face of carb 2 and crank the engine...does it make suction on your hand??? If not theres a problem with the cylinder..otherwise you should feel the in take suction on your hand.

Was the bike running before this clean up??? The more details you provide the better the answers youll get.

[Rijko]

if sucking on the hose gives gas, and stop sucking cuts gas off, i'd say
it's a vacuum petcock and it seems to work.
Hose seems fine, too.

Seems to be an issue with the carbs, maybe the vacuum hose on the wrong carb ?

If set to pri, does the bike run ?
If yes check if one of the other hoses sucks air.
Can't be more specific, i do not know which carb the vacuum hose should
be connected to on a gsx400 but there are people here with way more
knowledge of that bike than me...


edit : Chuck posted just before me .. did not see it until after i posted

[Anfoman76]

Thanks everyone. Very new to bikes. Had it hooked up to the wrong nipple. Now thats working onto the next issue. It starts on choke runs for a 30 secs and dies. If I try to give it any throttle it dies right away. It wasn't running when I bought it. I pulled the carbs and petcock and used my ultrasonic to clean them afterm I pulled them apart. Put all new orings in and put them back together. Sorry for the lack of info last time.

[Cipher]

airbox on>?

[Anfoman76]

No airbox came with pods

[Anfoman76]

Sorry and they weren't on

[chuck hahn]

review this rebuild tutorial and see what / if you missed anything.

http://zeus.mtsac.edu/~cliff/storage/gs/mc_maint/GS_CV_Carb_Cleaning_Series.pdf

Store this for future use and for service manuals etc etc.

http://members.dslextreme.com/users/bikecliff/

[Cipher]

assuming it was jetted and running fine pre storage
then the pods however non restritive they are should be on
otherwise your lean

[Rijko]

assuming it was jetted

yep, i'd take off the carbs and check jet sizes to be sure.
They should be bigger than standard.

[chuck hahn]

It should at least start and idle without the pods..but trying to run it up will make it die. Put the pods on a see what it does then. If it will idle and still die then cut up some old socks and slip a sleeve over each pod to richen it up. If this solves the problem youll need to rejet up on the main jets. I would go up two sizes above whats in the now for my starting point..if the added restriction makes it better that is.

another way to see if its too lean ( with the pods on ) is to apply about 1/4 choke and then try running it up. The choke will richen the mix a bit. If it doesnt solve the problem, or makes it worse, then your too rich already and will be going down in jet sizes.

Also at the top of the carb forum is a STICKY about CV carb tuning proceedures...see that read also.

[Anfoman76]

They were hard to read. But it should run even if not jetted right? Have ordered some bigger ones overstock numbers so I can tune it once it's running.

[chuck hahn]

CV carbs will IDLE without an airbox or pods...not rev up though. The CVs need some restriction form the airbox or pods to work right. Thats why i just typed all the quicky ways to do a crude symptom diagnostics in my previous post.