Carb setting

[El__burro]

Good day, I am struggling to do a proper job with carburettors.
Below is a link to a video I posted on utube.
https://youtu.be/9RgCqNbQ1aI
The problem is when I open the throttle.
How can I get from this to the stage below.

https://youtu.be/BmnImCG3jEA
Thanks
El__burro

[mgy66]

Hi... Just a Newbie's view on your post... struggling myself with the idle and carb set up!

It looks to me that you have a gap at the opening from idle. I have noticed that your air screw are deep inside the carb. How many turn?

It looks like you need more full to pick up from idle. Either on notch up for the main jet or 1 notch up for the jet needle. You have probably seen my recent post Idle and Starting Set Up where there is a table on jetting.

That probably needs to be ascertained by the pros out there.
Good luck anyway...

[ST1100]

I suggest either emission checker or use of a ColourTune to find out if you're on the lean or rich side there...

[El__burro]

ST1100, I am looking into ColourTune as it could be a long term investment. (not sure what size though)
Also I guess I must set the float bowl to the proper measurement.
MGY66, with the air screw in any position it will not make that much difference.

Thanks
El__burro

[mgy66]

I would still recommend to keep it at 1 turn just to make sure you are not cumulating issues. Do you have an easy start up? Do you know the size of main and pilot jets as well as position of the needle clip?

As in many cases, there often cumulating issues with something not working well. I just went through a full dismantling of my carbs and I can tell you it is worthwhile at least to make sure this is set up issue. Then it should be a one at a time iterative process to fix it.
Best,
Marc

[El__burro]

Marc, the bike start quite easily, not sure about the jets size, my guess is that they are stock.
Also not sure about the clip position on the needle (just figured out thanks to a Hackaweek video yesterday).
I have set all the floats to 26mm and the Air screw to 1 turn (from fully closed).
I need to set the clip on the needle right for all of them (any suggestion).
Unfortunately to make matters worse I have realised that exhaust 1/3 are not as hot as 2/4 (from a 4/1 system).

Before I remove the carbs I will have to look at this first.

Many thanks
El__burro

[hairygit]

Could be electrical if 1and3 are cooler, they share a common set of points, so check the condition/settings of the points and wiring before ripping the carbs off, far easier to deal with than removing the carbs, which may not be the issue at all.

[mgy66]

Hi... I though 1/3 are 2 different coils? Mine are 1/4 on same coil and 2/3 on same coil, can't recall if it is 1/4 on left or 1/4 on right and vice et versa...
Best,
Marc

[El__burro]

yes, i will definitely check the points first.
I hate having to put these rubber back on the carbs/engine.
this could be the fix to my problem!!??
still need to check the clips on the needles.

thanks
El__burro

[hairygit]

Hi... I though 1/3 are 2 different coils? Mine are 1/4 on same coil and 2/3 on same coil, can't recall if it is 1/4 on left or 1/4 on right and vice et versa...
Best,
Marc

Oops,, you're right about the coils, I misread the original post! Still a good idea to check the points, and the common live feed to the coils.

Sent from my X5 using Tapatalk

[mgy66]

ok, I feel better now... wires are fine but worth checking. then still my advice would be to check the needle clips are in the same position nbr 4. and check your jets are stock...

i went through the exercise and just discovered that i had one cylinder (usually running at 80-90defF coldest) with a clip at nbr 3 where all other were at nbr 4... i have been trying to tune this bike for a year now. went through pilots/mains/float levels. now my carbs are in a ultrasonic cleaning. 1/2 hour 45degC. you would not believe the amount of dirt these things accumulate over the years.

if you are stuck with ideas and have some spare time and do not know your carbs... go for the full mounty clean up. the only drawback is getting the spares to rebuild. cant find the rubber that goes on the top cap cover where the slide rods go through...

cheers
marc

[El__burro]

Today I started off with checking the GAP on both points, its ok (0.3-0.4mm).
Then I removed the carbs and checked the clip on each needle,  they were all on the 4th from the top, then I adjusted the floats to 26mm.
All the jets are stock 40/110.
Eventually it didn't make much difference.
The exhausts 1 and 3 are much colder than the other 2.
(Thinking back aren't the points connected 1-4, 2-3).
I'll check spark plugs tomorrow.
If no success I'll have a look at the valves.

Thanks
El__burro

[Bryanj]

I hope you mean 0.3mm to 0.4mm

[El__burro]

yes, correct.
thanks

[El__burro]

It looks like it's sorted!
Although it's pouring down I have managed to check for sparks plugs and their caps the last being the culprit.
The caps for spark plug 1 and 3 were not properly screwed in so the plug wouldn't make a proper spark, also the 1 plug was arching and that required some gap setting.
To date I haven't heard a nicer sound.
Probably since (almost) completing the bike this is the first time I have fire on all 4.

(ps I'll upload a new video soon)

thanks to all of you for your support
el__burro