GS 550 carb re-fitment advice.

[Ian W]

OK. I give up. How the heck am I supposed to re-fit the carbs on a 1981 GS 550 L?

It seems impossible. There's no room to move around at all! It's usually tight on the re-fitment but this is ridiculous!

I am thinking of ditching that ruddy airbox and fit some pod filters. I would need to up-jet the carbs I take it, if memory serves by 10%. They're size 80 at the minute so I'm guessing 90? Could I get away without a re-jet? I'm thinking of running without an airbox at the minute as the carbs just will not fit amd I'm desperate to go out for a ride as I've been off the road for nearly a month now! Ggggggggggrrrrrrrr.

 

[tkent02]

There is more to jetting CV carbs for pods than upping them %10.

Are your boots still floppy and flexible on both the intake and airbox side?

Did you move the airbox back as far as it will go?

Lube them up with some silicone spray or something?

 

[Nessism]

The airbox will slide back about 1 inch if you take out the bolts, not enough to make the job easy, but it's doable. Removing the band clamps also makes the job somewhat easier - but not easy overall.

Basically you just need to stuff the carbs down in there and then fight around with the boots until everything aligns. Not fun on the 550 but after you do it a time or two it gets much easier.

 

[Ian W]

There isn't any room to wriggle the carbs about .

The boots are fine, no problem there. I just don't have the room between the engine and airbox. The airbox is moved as far back as possible and there still isn't enough room!

As for the airbox, I've thrown the bloody thing to one side. Looks like I'll need some advice about fitting the pods though (please).

The bike is fitted with Mikuni VM22SS, according to Haynes anyhow .

I feel like I shouldn't have bothered taking the carbs off in the first place!

A 'quick clean' has resulted in another set of inlet rubbers and carbs as they were knackered.

Trying to put the carbs back on is proving impossible and now it looks like I'll have to spend more money I haven't really got jetting up the carbs etc.

But I do love my GS .

 

[Nessism]

There isn't any room to wriggle the carbs about .

The boots are fine, no problem there. I just don't have the room between the engine and airbox. The airbox is moved as far back as possible and there still isn't enough room!

As for the airbox, I've thrown the bloody thing to one side. Looks like I'll need some advice about fitting the pods though (please).

The bike is fitted with Mikuni VM22SS, according to Haynes anyhow .

I feel like I shouldn't have bothered taking the carbs off in the first place!

A 'quick clean' has resulted in another set of inlet rubbers and carbs as they were knackered.

Trying to put the carbs back on is proving impossible and now it looks like I'll have to spend more money I haven't really got jetting up the carbs etc.

But I do love my GS .

Dude!!! Man up and put the bike together right!!!

"Quick clean" = half A$$ job

Do a full tear down of those carbs and replace all the O-rings inside with a kit from cycleorings.com You also MUST replace the intake boot O-rings if you haven't already done so.

Dealing with the airbox is a pain but trust me, it can be done as long as you don't get all squirrelly in the brain.

Take a break, have a frosty beverage, and then go at it again after you have the O-rings all sorted out.

 

[drejal]

There isn't any room to wriggle the carbs about .
......
The bike is fitted with Mikuni VM22SS, according to Haynes anyhow .

I feel like I shouldn't have bothered taking the carbs off in the first place!

......
But I do love my GS .

odd, but I'd swear the 550 switched to cv carbs in 1980? could this be the problem? If someone switched you to VM carbs without changing the airbox?

 

[Suzuki_Don]

odd, but I'd swear the 550 switched to cv carbs in 1980? could this be the problem? If someone switched you to VM carbs without changing the airbox?

Or swapped the head.

Some pics would help here so we know what you are dealing with.

As said previously the 1980 550 had 32mm CV carbs and not 22mm VM carbs. Find out what you got and don't spit the dummy. More help here than YOU know what to do with. Just be PATIENT.

 

[Ian W]

Quote-Find out what you got and don't spit the dummy.

Too late for that .

I was really looking forward to going out for a spin today. Gutted .

The carbs are back on after chucking that bloody airbox to one side in the shed.

The ol' girl won't start though. That vacuum tap is suspected. I do have two others, I would prefer to dump the vacuum tap and fit a standard on-off jobby.

I've got another GS but the headstock is twisted, she's in pretty tidy condition and was running a little while ago. I'm tempted to swap the running gear etc from that bike to one of the two frames I've got and shove this (censored) GS into the naughty corner as it's giving me a lot of grief.

Or maybe the CB 650 could be dragged into service .

 

[Guest]

They are probably CVs.
This is not a straight on fit. It's a game of angles. Angle the engine side of the carbs down and fit the airbox side into the boots. While sitting on the bike pull the engine side of the carbs up and over the intake boots. If either boot (engine and airbox) are hard and shrunken good luck.
Don't forget to put the throttle cable on the carbs first.
Slicken the boots up with silicone lube.

 

[Steve314159]

I have taken the carbs off of my 1980 550L about six times now and sadly am going to do it one more time. It's a pain. What you need to do:

- Like they said before, move the airbox as far back as it will go.

- Take the airbox hose clamps off or loosen them as far as they will go and push them back out of the way. Same with the intake boot clamps.

- Lube the intake manifold boots and airbox boots with a lot of silicone spray.

- Bring the carbs in at a 45 degree angle looking only at the intake manifold. Ignore the airbox boots; you can't fit them both at the same time. Connect the throttle cable and hoses when you get the carbs close to where they're supposed to be.

- Position the top intake part of the carbs into the intake boots.

- Use a giant screwdriver or prybar at the back of the carbs to jam them into the intake boots. You may have to go from side to side a few times since they don't want to go in there.

- After you do this the airbox boots may be squished under the carbs. Use a screwdriver or other tool to work them around to where they are supposed to be.

I am pretty sure the carbs are BS32SS CV. I'll try to take pictures next time I do this.

 

[Ian W]

Tried all that. Won't have it. I'm used to the daft designs of millimeters to spare to fit carbs, that's why I usually dump the airbox and fit filters .

Never in my life have I had it as impossible as this one .

The bike is an 1980 'L' model. But aha! The carbs according to Haynes, are Mikuni BS32SS. Not VM22SS . Jet size should be 92.5, they are 80 fitted at the minute. They were that size on the carbs that were on the bike originally, so they weren't even correct in the first place!

They are the correct carbs. They are the same as the knackered ones that came off before.

Pod filters are go I think as I have tried everything within my (admittedly limited) patience.

So may I ask advice on re-jetting the carbs? 10% on the main and do I need to up-jet the main air jet 10% too?

Thank you for the advice.

 

[hampshirehog]

80 main jet is the standard for VM carbs. Have a look here: http://www.thegsresources.com/gs_carbrebuild.htm and here: http://www.thegsresources.com/files/vm_carb_rebuild.pdf

to see what type you've got. It makes a lot of difference! If they're CVs fitted with 80s it would have run like poo.

If you've got the CVs don't go for pods - the thing will be a swine to get to run right. If you've got VMs it's a lot easier. Having said that, once you've mastered how to use the original airbox it isn't so hard.

 

[Ian W]

They're BS carbs on this ol' girl. CV's. 92.5 main jets according to Haynes. The replacement carbs when I fitted them had 80's in them, but I have fitted the larger jets now. The bike has no airbox fitted, an absolute pig to start at first, but easy on the button now hot or cold but runs poo.

I'm getting conflicting information on the fitting pods/ up jetting advice.

Some people are saying that I may get away without up-jetting, as sometimes on the older bikes you don't have to. Others are saying fit 98-100 main jets. Others are saying don't do it!!

I'm confused .

I've ordered some pods so I will least try them and see what happens. If not bugger it I'll break her up and put the bits on greedbay! It's got to the point where I really can't be bothered messing about with it anymore. A test ride showed that the front brake decided it doesn't really want to work and the clutch has started slipping! I have another GS 550 (with VM carbs) and a CB 650 I can play with instead .

Thanks for all the advice. It is much appreciated.

 

[hampshirehog]

It depends on the pods and your bike whether you'll need to change the jets and the needle height. Some of those K&N lookalikes actually flow worse than the airbox and she'll run rich on standard settings.

You're now entering the territory of plug chops and loads of fiddling. The guys on here will help guide you through it but give it a try and report what happens.

 

[Ian W]

It's a gamble for sure. I want to build a GS hardtail chop though, so I may just pinch the handlebars and tank off the 550L and break the rest.

I have another GS 550 on an 'S' plate but the headstock is twisted, and she has slide carbs! So hard tail that frame .

The only thing is that she also has the ugly mag wheels, I want wire wheels.

There is the CB 650.....

With wire wheels...

Hmmmm....

Should I defect to, dare I say it, H*nda.