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5,378 Posts
^All good to do it, just take note of the original pilot screw settings, I reckon half the Ciblets are running rich to get that easy cold start, but yeah don't touch the mixture screws :D Unless you have a carb balancer.

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370 Posts
Got the bike back together awhile ago. I put the settings to factory spec and managed to get it started, ran but was very rough. Took it to rb imports to get the carbs looked over and balance as i don't have the tools and this is my first time playing with carbs. They said one of the pilot screws was off as well as mixtures off and they synchronized it so now suction is equal in all carbs.
I changed the spark plugs, air filter, cleaned the fuel strainer and put on new carb rubber boots/insulators.
I took it for a test ride before i paid and it seemed great. Got home, parked it and didn't touch it for a few days. Started it today to get to work and it took while to warm it up (kept stalling). Got it going, seemed fine but when at idle the revs tend to slightly move. its set at 1500rpm but now and then jumps to 2000rpm. This is when its at temp.
I haven't changed the oil or filter yet, was planning on doing that soon (tomorrow).

Is this jumpy idle normal?, i can't remember what it was like before i pulled the carbs off. If not, what could be causing this?

My first thought is the spark plugs may be fouled so i'm planning on pulling them out and inspecting them and while i'm at it might as well change the oil and filter.

any ideas?[hr]
Also, the second time i started it today was 2hours after i turned it off and it need choke or slight acceleration to keep it from stalling. Got home at 11am, at 1pm took it for a ride for an hour just running through the revs parked it at 2pm and now at 5:30pm i went to start it and it would not stay on without accelerator. After the 3rd attempt i stopped.
The bike is fine when moving its just when idling there problems.

again any ideas?

· Registered
5,416 Posts
mine does the jumpy revs thing, i haven't touched the carbs on this tho.

as for the stalling and having to rev it to keep it going it might just be cold.

i didnt ride mine for a week and it wouldnt start this morning (had to get a lift to work with the boss)

but it runs fine when its used freqently (still needs choke and a bit of revs to start most times) so it might just be lack of use?

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6 Posts
Hey all noobie here to forums, but not affraid to get into it. Carbs needed a good clean and have not been done since i got my baby.
I had the problem of loseing power in 1st-4 gear, and its only just started this week, so Carb clean.
Never done this by myself b4 and it was all easy thks to this site and some good clear pics. The only prob i had was the boots and getting the whole carb off, but the flatwood was good leaverage :) and work real easy. After cleaning carbs and parts, i found no probs with any components from carbs, guess i was lucky. no need to replace anything apart from some seals. I did find a BLOODY COCKROACH in No4 carb.

This guide helped heaps. Cheers and good forum.

· Registered
1,312 Posts
Quick question. How many turns for the idle screw. after cleaning i think its too lean stopping it starting again. set at 1 1/2. Manual says 1 3/4 but understand 2 helps with cold start. can 1/4 really have that much an impact? And could this be the reason why it wont start? And fyi have spark and fuel. and read the thread on starting bikes. and did a search...

· Registered
6 Posts
Hi again, carbs got cleaned and put back together, Came to start the bike and had fuel coming out the Air vent overflow pipe between carb 3-4
Checked a few things again today, pulled carbs apart again, checked diaphram, check floats. any ideas would help

· Registered
6 Posts
Lane said:
Do you have the float valves seated correctly?

Are the float valves rubber seats all good and intact?

Are their brass seats clean and smooth?

Don't laugh, I've even seen them in upside down before.
Ok cheers, took carbs out, check said above things^^^^
The pic with the insulator BOOT still left on, that pipe is full of fuel??


· Registered
45 Posts
Hey guys.. if anyone wants a video of cleaning the carby.. here's the video of me first time cleaning it.


Hope it helps anyone trying to attempt this in the future, espesh if its their first time.

· Registered
22 Posts
K916 said:
If a spark plug change and air filter replacement do not have the desired effect on your bikes performance, the three golden steps you need to follow to get your bike running smooth are

- Clean your Carbs
- Set the Float Heights
- Get them Balanced

For Cleaning the carbs

Items needed

1. Aerosol Carb Spray Cleaner
2. Clean Petrol in a Plastic “Squeezy” type bottle
3. compressed air (if available)
4. new screws for the top and bottom carb covers (check for correct length)
5. new fuel filter
6. soft brush and toothbrush

Tools needed

1. Very long (12 inch) Phillips screwdriver
2. Stubby flat and Phillips screwdriver
3. 8,10 and 12 mm spanners (ring preferred), and 2 fixed 10 mm spanners
4. pliers (to undo the clamps holding the fuel pipes)

Getting to the Carbs

1. Disconnect the fuel / vacuum pipes from the tank
2. take off the tank after making sure that the tap is off and place it gently on a discarded car tyre – the edge of the tank will rest on the sidewalls of the tyre while the tap can hang safely in the middle
3. undo the air filter box from the carbs
4. loosen the screws holding the carbs to the manifold – you’ll need the long Phillips head screwdriver for this.
5. pull the carbs out firmly but gently (this is the first hurdle – get ready for some bruised knuckles)
6. undo the accelerator and choke cables with two 10mm fixed spanners and screwdriver (choke cable) making note how they should go back in.
7. the carbs should be free now – wash them from the outside liberally with petrol and a soft brush and toothbrush
8. tap each screw on the top and bottom of the carb gently with a hammer
9. mark the top and bottom of each carb with numbers from 1 to 4 to ensure that you don’t mix the internals / covers up.

Opening Process

1. Open the screws from the bottom of each carb – do this one at a time (this is the second hurdle – have someone experienced at hand and an impact driver if possible) make sure you don’t “round” the heads of the screw.
2. take the cover off and place the screws in it
3. gently slide out and remove the float pin, needle and float and place them in the bowl
4. with the correct ring spanner (8mm I think) and flat screwdriver undo each jet gently !!! the metal is very soft !!! – place it with the respective carb cover
5. repeat this over all 4 carbs
6. turn the carbs over
7. maintain the same sequence – don’t turn it around else you will interchange the order – ie . from left to right (look at your earlier number markings for a confirmation)
8. undo the screws
9. place the top covers with the respective bottom covers
10. remove the diaphram, needle and spring and place each with the respective top cover.
11. wash the carb bodies liberally with petrol, a small paint brush and toothbrush. Spray carb cleaner everywhere very liberally – let them stand for a while – and wash once more with clean petrol
12. wash each jet with carb cleaner and petrol, blow air through them but don’t insert any pins or sharp objects through them – this will damage them.

Closing up

1. fit the jets back and tighten them gently – not too tight (use your brain here – not your muscles)
2. wash the floats, pins, etc with carb cleaner and clean petrol and fit it back on carefully – refer to Shadows manual for specifications if you want to be a perfectionist (I do it just by sight cause I don’t need performance in India)
3. fit the bottom on with new screws and gaskets if possible.
4. wash the carb tops, diaphrams (don’t pierce them by mistake) and springs and fit them back together.
5. its dicey getting the spring back in the MC-17 and 19
6. make sure that the diaphram is not kinked or sticking out of the cover at any place.
7. make a final check to see if all the screws are in – nice and tight.
8. push each slide up gently and release – they should smoothly slide back into place
9. fit the carbs in the manifold – apply a light layer of grease and slide them in after connecting the throttle cables, choke.
10. tighten the clamp clips, connect the fuel pipes with a new filter
11. fit the air filter[hr]

Thanks to RPM's for the write up and pictures

First, some decent pics of the carbs (finally!)
(you may want to set your screen res to 1024x768 or higher for viewing this)

This next pic is of the rear of the carbs, if you could get your head where the rear shock absorber is.
Simply undo the clamps indicated to get the carbs off.
Note I have replaced the crappy screws with torx heads as the heads do not stuff up as easily.
Also I wrapped teflon tape around the threads to make it easier to undo them.

This is basically everything dismantled,
but the intake trumpets and plastic bit in the above photo are not shown.
The perspective is if you had your head where the engine is,
looking back up at the carbs.

This is a pic of the vacuum chamber and all associated parts:

This is a pic of the float chamber and all associated parts.
The carb on the left still has the cover on,
the next one is with all the parts as they will look once you undo the cover,
3rd +4th carb from the right is with the jets taken out:

Last pic is where the two jets + pilot (air/fuel) screw goes.
I noticed the pilot screw and drain screws all had anti-sieze compund on them,
so I assembled them with some more of that stuff...

[br]Okay, I did this, I'm a defintite noob, here's what to avoid:
As mentioned previously, all the vaccum slide things got mixed up (what are they called anyway? the four black things that look like female contraceptives[?]), as I couldn't write on them. [B)]

Somehow, I managed to mix up the float bowl covers too,
despite the fact that they were all numbered properly.[:I]
Someone was talking to me when I assembled the carbs.
The worst part is I only figured this out when all the carbs were back on the bike, and the accelerator + choke cables were attached (and that took a while[B)]).
I peered into the bike and saw that all the float bowl drain screws were all pointing inwards!! "Oh fer chrize-sake" was my first thought.
I'm leaving it that way until I have to take them off again for whatever reason.[B)][B)] *shrugs*

EDIT: Oh yeah at about this point, a good jet of carby cleaner spray ricochet(ed) off the carbs and DIRECTLY INTO MY EYE![B)]
Fuck! You shut your eyelid really tightly by instinct & it feels like your eyeball is vaporising from the inside out. Run to the tap, flush my eye... omg I can still see![hyp]

The bad/good news is that there was one sticking vacuum slide thing
-- turned out to be a very tiny raised bur (sp?).
I fixed that myself with a bit of 1000 emery paper in less than a minute.[HB]

It took 4 to 5 attempts to get the hang of balancing the carbs.
This was because the 3rd balancing screw works the opposite way to the other two.[B)]

I spilled a load of mercury (three times) from the stoopid gauge trying to get rid of the "bubbles", and once the toxic shite ended up in my shoe of all places - and I only deduced that it ended up there after the entire bike was put back together, and I thought "Geez where'd all that mercury from the second spill go?
Kinda went near my trouser leg. Let's have a look in my shoe".
Sure enough it was in my foot for at least half an hour.[xx(]

I thought I did a good job of balancing the fourth or fifth time...
I go up the street and there appears to be a flat spot at roughly 6-8k.
I'm not too sure about this though, as I could only ride in peak hour and it was difficult to tell.
As soon as I hit the powerband the acceleration was decent enough.[^][:S] It idles better than before, but I think it could be even better.

EDIT: more photos of carbs here:
Dunno why his floats are so white...[:S]

really useful post @K916 - thanks for the detailed info bro! Cheers :)

· Registered
7,374 Posts
^Its not water, its a special solution. You could just dunk the whole thing, better off tkaing the jets and needles out and having them cleaned and jsut spraying out the bowl and body quickly yourself. Otherwise you'd need to dismantle everything and use all new gaskets.

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20 Posts
I had my bike MOT'd today and the mechanic said my CO2 levels were high on the emissions test. They were 7.8 when he would expect 3.5ish. He said this was down to my bike running rich. My spark plugs are a little sooty but i wasnt bothered about it. I suspect a past owner has had an aftermarket exhaust on the bike &must have rejetted to suit. Then when the bike was put back to standard the carbs were'nt. Do you guys think fitting a high flo air filter will sort this out or should i rejet my carbs? Am i right in thinking it would just be the main jets that were changed?

· Registered
7,374 Posts
Don't confuse your mixtures even further by changing your intake. You'll end up with a headache that runs like a dog. Pull the carbs down check jet sizing and pilot screw settings. It may just be running rich at idle due to pilot screws. Most people don't rejet for a slip on since it isn't necessary and is just extra coin.
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