1978 CB550 K4 carb choke spring

[Brian Cairns]

The spring in the photograph ( not my carb) is missing and replaced with copper wire hack.
I finally found a replacement spring have hunting one down of eBay.

Can anyone point in the right direction of how to replace this spring i.e. how do you remove and replace choke linkage?
They are PD 46A carbs

Thanks in advance
Brian

[Seabeowner]

If this is a USA import then I believed that the 1978s had PD46C like mine has. But maybe they were just using up bits as it was the end of the line. The main throttle spring is mounted round the throttle shaft on the PD46C.
But back to the choke shaft. I  am not going to be much help. But think the C and A both have the double spring arrangement. When I split my carbs a few years ago I remember that getting that spring wound to give the correct force was a a nightmare so take note how much it unwinds when it lets go.

[Johnny4428]

I’m nearly sure that these have to be separated to replace spring. At least 1&2 separated from 3&4.

[Brian Cairns]

If this is a USA import then I believed that the 1978s had PD46C like mine has. But maybe they were just using up bits as it was the end of the line. The main throttle spring is mounted round the throttle shaft on the PD46C.
But back to the choke shaft. I  am not going to be much help. But think the C and A both have the double spring arrangement. When I split my carbs a few years ago I remember that getting that spring wound to give the correct force was a a nightmare so take note how much it unwinds when it lets go.

Hi
Sorry, you are correct, carbs are PD46C.
Cheers
Brian

[Brian Cairns]

I’m nearly sure that these have to be separated to replace spring. At least 1&2 separated from 3&4.

Thanks

Brian

[Brian Cairns]

If this is a USA import then I believed that the 1978s had PD46C like mine has. But maybe they were just using up bits as it was the end of the line. The main throttle spring is mounted round the throttle shaft on the PD46C.
But back to the choke shaft. I  am not going to be much help. But think the C and A both have the double spring arrangement. When I split my carbs a few years ago I remember that getting that spring wound to give the correct force was a a nightmare so take note how much it unwinds when it lets go.

Hi just wondering what float height and needle position do you use on the PD46C carbs...........since I will be taking carbs of bike I am going to check everything out....can't get bike above 70 mph and am convinced its something to do with carbs. Everything on bike is standard.

Cheers

Brian

[Seabeowner]

If this is a USA import then I believed that the 1978s had PD46C like mine has. But maybe they were just using up bits as it was the end of the line. The main throttle spring is mounted round the throttle shaft on the PD46C.
But back to the choke shaft. I  am not going to be much help. But think the C and A both have the double spring arrangement. When I split my carbs a few years ago I remember that getting that spring wound to give the correct force was a a nightmare so take note how much it unwinds when it lets go.

Hi just wondering what float height and needle position do you use on the PD46C carbs...........since I will be taking carbs of bike I am going to check everything out....can't get bike above 70 mph and am convinced its something to do with carbs. Everything on bike is standard.

Cheers

Brian

I have written down 14.5mm for the A and 12.5mm for the C. Strange really as think they are same carbs. So 12.5mm. Only covered about 75miles though as only got it legal late last year.

[Brian Cairns]

If this is a USA import then I believed that the 1978s had PD46C like mine has. But maybe they were just using up bits as it was the end of the line. The main throttle spring is mounted round the throttle shaft on the PD46C.
But back to the choke shaft. I  am not going to be much help. But think the C and A both have the double spring arrangement. When I split my carbs a few years ago I remember that getting that spring wound to give the correct force was a a nightmare so take note how much it unwinds when it lets go.

Hi just wondering what float height and needle position do you use on the PD46C carbs...........since I will be taking carbs of bike I am going to check everything out....can't get bike above 70 mph and am convinced its something to do with carbs. Everything on bike is standard.

Cheers

Brian

I have written down 14.5mm for the A and 12.5mm for the C. Strange really as think they are same carbs. So 12.5mm. Only covered about 75miles though as only got it legal late last year.

Yes I read 12.5mm for the C. going to check them tomorrow.
I think the wrong main jet size is wrong in my bike, should be 90 but has 98 installed. I was also told that  the needle height on the C carbs can't be adjusted i.e. only has one notch but again will check that also?

Cheers

Brian