Can't sync the carbs...

[Zenuwlijer]

 

[Screwloose]

Since I'm a really nice guy I've pulled mine out for you just to show you the flaps.

Just kidding, got this image online a minute ago LoL. You need to set these flaps below, before they go on the bike, it will give you a fighting chance of fine tuning them with the Carbtune. The Vboost lnkage and the throttle linkages are easier than they look to disconnect. I leave the throttle linkages on the carbs and disconnebt them at the plastic junction box inside the left scoop.

 

[Parminio]

The first thing I would look at is the linkage itself. You can see it much better from the bottom than the top. Here's a pic for reference:



The big box on the left is what you really want to look at. That is where your problem is going to be more than likely. For some reason, when you let that screw out, it's not moving the linkage. There is either something binding it up or something slightly bent. It doesn't take much at all.

Examine both ends of that rod that goes across the carbs. (Note the red box on the right.) Make sure the clips are on, that there's not a lot of slop in it and that it moves freely back and forth when you operate the linkage.

 

[Screwloose]

The first thing I would look at is the linkage itself. You can see it much better from the bottom than the top. Here's a pic for reference:


The big box on the left is what you really want to look at. That is where your problem is going to be more than likely. For some reason, when you let that screw out, it's not moving the linkage. There is either something binding it up or something slightly bent. It doesn't take much at all.

Examine both ends of that rod that goes across the carbs. (Note the red box on the right.) Make sure the clips are on, that there's not a lot of slop in it and that it moves freely back and forth when you operate the linkage.

I had a problem with that exact linkage.

There was a plastic washer/spacer (end float) on mine that was worn and caused a twist that ultimately caused a delay on the response of the other bank, I sorted it with another washer, but the assembly all tightened up after that. This ended up with me setting all the physical carb levels on a surface table, using spacers where needed, and this worked. I've aslo just realised why it says in the manaul to set the carbs up on an even surface.

If the mechanic that dismantled the carbs in question never paid attention to the movement of this mechanism after rebuild, then this may well be the problem and should be focused on as a potential problem at the earliest opportunity of inspection.

 

[patate657]

This is a simple check. But I'm a simple guy. Anyway when I was syncing mine, I had the same problem. So I switch the hoses around to see if the problem were the Carbs or the Gauges. For me it it was the gauges. I found a pin hole in one hose and another had to much of a bend. I don't know as much as you guys, but sometimes it's just a simple fix. My 2 cents worth....

 

[Screwloose]

This is a simple check. But I'm a simple guy. Anyway when I was syncing mine, I had the same problem. So I switch the hoses around to see if the problem were the Carbs or the Gauges. For me it it was the gauges. I found a pin hole in one hose and another had to much of a bend. I don't know as much as you guys, but sometimes it's just a simple fix. My 2 cents worth....

I wish my life could move a bit more towards simplicity. Poor old Trigger nearly got the 'Heave-Ho' last year over these carbs, furlough saved him from the knackers yard.

 

[Zenuwlijer]

It's out. Gotta eat now.

 

[patate657]

It's out. Gotta eat now.

View attachment 78328

Don't know the correct term for them, but the Slide covers look really good. Where'd you get them?
Thank You
Phil

 

[Parminio]

Here's what I see:



With the carbs on the bench there, you should be able to loosen that screw (which would be the front screw on the right side with the carbs on the bike) and that spring should open up as the tension is taken off it.

If it doesn't, then something is very badly wrong.

 

[Zenuwlijer]

and that spring should open up as the tension is taken off it.

It does!

 

[Zenuwlijer]

Linkage is working as well.

I also checked the idle speed screw. Seems to work.

 

[Screwloose]

Well there you go mate, first problem solved.

If you open all those flaps slightly (and kinda evenly), using the screws mentioned above by Perminio, and the tickover screw, you are on your way there. Not forgetting to check the brass flaps are opening and closing smoothly, and all the connecting bars, cables, and asociated parts are running smooth also.

 

[Parminio]

Now I'm lost then because it should have worked on the bike syncing it out.

Here's something to try: crack open the throttle a bit where the butterflies are slightly open. Then turn that screw all the way in and out. It'll be tricky to hold it steady but you're wanting to see if the two right side carbs butterflies open and/or close slightly as that screw goes all the way in or out.

 

[Screwloose]

Now I'm lost then because it should have worked on the bike syncing it out.

Here's something to try: crack open the throttle a bit where the butterflies are slightly open. Then turn that screw all the way in and out. It'll be tricky to hold it steady but you're wanting to see if the two right side carbs butterflies open and/or close slightly as that screw goes all the way in or out.

I think what may have happened is Zenuwlijer started too far away from standard settings, then tried to fight his way towards a sync, but being too far out never showed any improvement on the balancing, it only got worse by not knowing which way to turn the screws. Plus pushing the driver in whilst trying to balance (and not blipping the throttle after each adjustment would generally end in a merry-go-round.

 

[Zenuwlijer]

As you can see, the valve on carb 2 is slightly opened (see picture), the same goes for carb 1.



I assume this is the reason for the (very) high reading on the Carbtune as you can see in my first post?

How do I set this to close / decrease?

I don't understand the "drill bit" explanation. What exactly do I do?

(Edit: added mentioned photo.)

 

[Parminio]

I don't understand the "drill bit" explanation. What exactly do I do?

Please don't start drilling your carbs.

 

[Zenuwlijer]

Is this also a good moment to set the pilot screws to 2 1/4?

I have them at 2 3/4 now.

 

[Screwloose]

As you can see, the valve on carb 2 is slightly opened (see picture), the same goes for carb 1.

I assume this is the reason for the (very) high reading on the Carbtune as you can see in my first post?

How do I set this to close / decrease?

I don't understand the "drill bit" explanation. What exactly do I do?

Hi mate.

No bother. What you want is the brass flaps all moving together and evenly, and when they fall back to your screw settings on each individual carb there will be an even gap between all flaps and carb bodies, this is where the air goes through.

So start by moving the idle screw so that there are gaps between all the brass flaps and the carb bodies, then using the screws mentioned by Perminio use a drill bit shank to adjust each gap to the same.

Does that make sense?

 

[Screwloose]

Is this also a good moment to set the pilot screws to 2 1/4?

I have them at 2 3/4 now.

The screws you mention can be adjusted to a fine level later. You may find running at temp, the individual carbs differ slightly from each other. I've got one at 2 3/4, and another at 2 1/4 turns. Old age!

 

[Zenuwlijer]

use a drill bit shank to adjust each gap to the same.

Do you mean I use the "behind of the drill" as a gauge? If so, mine are to thick for that use.