GS1000 CV to slide carb mod.

[Scotia1000]

Hi,

Bought a basket case gs1000e. The head is a 1980 model, with home made plates with rubbers to take slide carbs instead of cv's,  K and  N filters and 4:1 baffled. The bike runs smooth on tick over and clean gear changes (slow build up) at 3500rm up to 80mph then struggles, coughs and splutters. I noticed the jets are 145, would it need this size because of the bigger intake and the modification? The carbs do not have a vacuum supply between 2-3 carbs but the tank fuel tap is not on/off type so I run it on prime with an inline on/off tap, would this make a difference? I don't know whether to try and lower the jet sizes or just source out a set of rubbers and cv carb. I took it for it's first test drive today 50 miles, will check the plugs this evening to see if they are too rich,

any thoughts please,

jim

[Gixer1460]

Some people say the taps 'Prime' setting works good for WOT - i'm not convinced! Why would you need to fill float bowls at max flow rate? A reasonable dribble will do the job in about 30 seconds. If so, fuel starvation is a possibility in your case ie. when you need the flow into the bowls it ain't there! 145 MJ's probably fitted to cope with the free flow K&N's - more air needs more fuel! You could source some screw in nipples to make a vacuum line connection to the inlet rubbers / adapter plates / or even into the carb bodies.

[BigT]

Are the MJ 145 Mikuni?  Because that would be really rich. Should be around 125.

But, are they Dynojet MJ?

Since the carbs aren't stock, some pictures might help

[Scotia1000]

Thanks for your replies, Hope to get some photos in the next day or two. I also bought a 1978 gs1000e which is pretty stock, apart from 4:1, but the carbs are a mess, being stood for 20 years, they have the vacuum pipe between 2-3, I have stripped them right down and have a kit coming, they look like stock 95 main jets, although everything is a bit rusty and faded.

Never felt right leaving bike on prime while running, like the idea of sourcing another vacuum from the intake, 

Changing the subject, I have just seen these carbs off a local marketplace, just says kawasaki mikuni's, don't think they are 650, but seems like a strange box under number 2, would that be an american emisions thing? guy asking 150 euros 

[cnap504]

I think those are 28mm (1979 Kawi).  The hump lump or bump on the number 2 bowl was a cast in “boss” to pump feed 4 venturi nozzles. The ‘76 & ‘77 kwackers had 26mm with no pump.  I think in some cases the the slide cutaway differed for the kawais and Suzukis 

 

 

[Scotia1000]

On 8/13/2022 at 3:05 AM, BigT said:

Are the MJ 145 Mikuni?  Because that would be really rich. Should be around 125.

But, are they Dynojet MJ?

Since the carbs aren't stock, some pictures might help

I will drop the bowls and re check the main jet sizes, will also see if the intake on number 1 will vacuum,

[Scotia1000]

[Scotia1000]

No mixture screw on base, so not suzuki carbs?

[BigT]

On 8/14/2022 at 5:01 AM, Scotia1000 said:

No mixture screw on base, so not suzuki carbs?

Yep, Kawasaki carbs or a mongrel.   Suzuki carbs would have the pilot fuel screw underneath, a plastic covered lever on the choke and the vacuum port on #3.  Does that jet really say Solex 145?  Solex? I have no idea how that converts to Mikuni. Buy some Mikuni 125 main jets and see if it runs better

[Muddy]

Isn't Solex a carb manufacturer?

[Gixer1460]

3 minutes ago, Muddy said:

Isn't Solex a carb manufacturer?

it is, or at least it was! Who knows if its survived the EFI onslaught LOL! Used on Froggy cars a lot so lightly a metric thread compatible with Jap carb as would sizes - still sounds too big though!

[Scotia1000]

i took  a set of mj 95 of my other gs 1000 carbs and tried them, it ran rough, sounded like fuel starvation, although tick over was higher? missing and back firing. i have a good set of cvs of an 83 kawasaki  1000j, i read that they might fit on the 1980 cv gs1000, they look like 39-40mm od on the intake with 35 mm spacing 1-2 +3-4

and 56mm from 2-3, anyone know what size the intake rubbers are on the cv gs 1000? i have seen the conversion intakes, slide to cv but cant get any sizes for stock cv intake rubbers