Series 3 Where can I find instruction on how to adjust carburator?

85Santana3 · Aug 8, 2019

Good day everybody
I have searched online as well as this forum and can not find a simple guide for adjusting carburetor on a series 3 petrol. Any idea where I can find such info?
My Landy still makes smoke even after engine work and since there are only two screws on the carb I figured I should give it a try.
I know there are two types Zenith and Webber and since nothing is written on my carb and it is possible that is neither I include a picture.
thanks in advance

marjon · Aug 8, 2019

Carbs are pretty basic things but can give big problems.
But that said can be easy to sort. Can’t see you pic to well but this little guide may help.

http://www.glencoyne.co.uk/carbs.htm

Looks like you may have the Zenith carb.
Buy a rebuild kit ( only a few gaskets really I think) take it off and ensure it’s all clean then put back on and set up.
Or try setting it as per the guide it’s not hard

Good luck. Try it an a bike with 4 of the bloody things

Are you sure the smoke is because of fuel and not oil? You mention engine work?

J

85Santana3 · Aug 8, 2019

marjon said:
Try it an a bike with 4 of the bloody things

At the risk of making an ass of myself let me guess your bike:
4 cylinder 4 independent carbs, 1970s Japanese, bigger than 650 so CB 750 or 1000 or could be a Kawasaki 900
close?
I have a weakness myself for old Japanese motorcycles, particularly CX and GL 500s.

By the way thanks for the link. Apparently my carb is a Zenith. I have to play with the two screws based on trial and error. I don't think carb cleaning is needed. It was done last year.

marjon · Aug 8, 2019

85Santana3 said:
At the risk of making an ass of myself let me guess your bike:
4 cylinder 4 independent carbs, 1970s Japanese, bigger than 650 so CB 750 or 1000 or could be a Kawasaki 900
close?
I have a weakness myself for old Japanese motorcycles, particularly CX and GL 500s.

By the way thanks for the link. Apparently my carb is a Zenith. I have to play with the two screws based on trial and error. I don't think carb cleaning is needed. It was done last year.

You did not make an arse of yourself Kawasaki Z1000

It’s not trial and error, you will be surprised once you get the hang of it.

But the engine work and reason is still in question for the smoke?

J

Colthebrummie · Aug 9, 2019

If your engine ticks over nicely, I wouldn't worry too much about the carb. You could take a look at the colour of the spark plug electrodes, a nice tan colour means the setting is good, black and sooty means too rich and white means too lean. Oily plugs mean there's a problem with the engine. Have you done a compression test.

Col

85Santana3 · Aug 9, 2019

Colthebrummie said:
You could take a look at the colour of the spark plug electrodes, a nice tan colour means the setting is good, black and sooty means too rich and white means too lean. Oily plugs mean there's a problem with the engine.

Thanks this is very useful info. I will check that as soon as I can find a socket for plugs.
I have not done a compression test but 2 weeks ago engine was opened and valves and related items were changed (second time in 2 months!)

rob1miles · Aug 9, 2019

Get it rich then slowly make adjustments towards weak driving for a while each time. Too weak can do a lot of damage so you want to get to the correct mixture in small steps from a rich setting.

marjon · Aug 9, 2019

rob1miles said:
Get it rich then slowly make adjustments towards weak driving for a while each time. Too weak can do a lot of damage so you want to get to the correct mixture in small steps from a rich setting.

Please correct me if I am wrong but, the only 2 screws on the carb to adjust only concern at idle running. These have no bearing (really) once you open the butterfly ( push the go pedal)
The richness is controlled by jet size? And float height.

Yes it’s always good to take for a run after any adjustments.

As there has been work done on engine the smoke may not be fuel related. Checking plugs is a good place to start.

J

Colthebrummie · Aug 10, 2019

marjon said:
Please correct me if I am wrong but, the only 2 screws on the carb to adjust only concern at idle running. These have no bearing (really) once you open the butterfly ( push the go pedal)
The richness is controlled by jet size? And float height.

Yes it’s always good to take for a run after any adjustments.

As there has been work done on engine the smoke may not be fuel related. Checking plugs is a good place to start.

J

No, the adjuster screw at the base of the carb, the one with a spring, is a jet. It controlles the richness of the fuel/air mixture. The base setting is about 2 and half turns out from fully screwed in. When you screw it in, don't screw it tight, it has a very fine point on the end. I had a lot of trouble keeping the setting on mine, when I completely removed the screw I found the end was damaged. I replaced it and it has been fine since.

Col

Colthebrummie · Aug 10, 2019

Forget what I just said about it being a jet, I've only just got up. It's not really a jet but does control the mixture.

Col

marjon · Aug 10, 2019

Ok thanks Col. @Colthebrummie .

Yep as I said that’s only a “pointy screw” and acts like a jet, I understand that part.
But was under the impression that was only for slow running/ idle?

Ok I will watch and learn more from you guys who actually run this type

Did find this a minute ago, might be of use.

J

rob1miles · Aug 10, 2019

Your hope is always that the jet size is ok and the crew will adjust enough.

Series 3 Where can I find instruction on how to adjust carburator?

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