DIY manometer carb sync

[BareKat]

OK after reading a bunch of threads I figured I'd try a DIY carb sync.

I'd love a Morgan Carbtune but one of those would cost about $150+can.

So for $25 worth of parts I rigged up the stuff below.

Piping is 3/8 OD and 1/4 ID.

Quick questions before I pull the tank and attempt the sync I was wondering if anyone knows the size of the vacuum inlet on the carbs?

I hope they are 1/4 so I don't have to rig up some sort of adapters.

Oh ya, one other point I used 2-stroke oil just in case the stuff got sucked into the engine.

Tx Barekat

[mykat]

Funny, I JUST finished syncing my carbs two minutes ago.

I bought a set of vacuum gauges for $50 on ebay, since when I tried to rig up my own device, my carbs were so out of sync that they sucked in the water immediately, so I decided it'd be safer not to use mercury.

I can't help you with the sizes though, I'm on a pre. Sorry and good luck

[akarob]

I'm on a pre as well and just did mine using a board like you have. The inlet is 1/4 OD and it won't be a tight fit. I took some of my handy .020 carb cleaning wire and twisted some on the hose tips to act as a hose clamp, worked perfect. The biggest thing about the setup is to NOT use water. Use oil - thicker the better. 10w worked good but I'd use thicker if I did it again.

[ottoguy]

I made the exact same setup last year. The tube I used just barely fit on the carb ports. I don't remember what size it was though.

In the end I found it extremely tough to balance all 4 carbs at once. I ended up breaking off half of the device so it was only doing 2 carbs at once and balancing them that way.

The tubes weren't long enough to keep the liquid from being sucked up very quickly. With only 2 tubes to manage it was a bit easier, but was still tough. If the sync is out much it will quickly pull the oil out of one side. I think I used power steering fluid.

[GregS]

First, you do have a dual cable system unless someone has modified it.
Second, going by recollection, 3 carbs have small (about 3/32 inch) ports and one has a larger port (it supplies vacuum to the fuel petcock).

[BareKat]

I'll try to do a video capture of the board attached without adjusting anything then I'll do a video capture after I sync'd 'em up.

The last sink was done 35,000km ago...

[Black_peter]

NOT use water. Use oil - thicker the better. 10w worked good but I'd use thicker if I did it again.

Well maybe, actually it's not the thickness of the fluid but visibility.
In this system thickness or even density doesn't matter, in fact you could use a BB.. The thicker fluid might damp the pulses, and I guess since y'all don't install any dampers in the lines, that does make some sense.. never mind...

First, you do have a dual cable system unless someone has modified it.

Umm I'm at a loss why you mention that

Second, going by recollection, 3 carbs have small (about 3/32 inch) ports and one has a larger port (it supplies vacuum to the fuel petcock).

Nope, the petcock port is on the side of Carb #4 not the cap..

[bob393]

Nice, I did mine with the same thing only two channel!
I used transmission fluid, red and kind of thick.
I found that if the carbs are way off or you turn the screw in the wrong
direction that it reacts a bit to fast for me. If you put a spring clamp
on the tube it slows it down a bit and keeps the fluid from foaming too.

[Black_peter]

If you put a spring clamp
on the tube it slows it down a bit and keeps the fluid from foaming too.

That is the damper I was referring to

[BareKat]

OK guys, here is an update.

First thing was that GregS was correct about the vacuum ports being different sizes.
Carb 4 (the one connected to the gas tank) was 1/4 OD and the three other carbs had 3/16 or 5/32 OD... what a pain! I zipped over to the auto parts store with the vacuum cap and was able to pick up 6' of the smaller ID vacuum hose. The reason I got 6 feet was so I could leave them permanently connected to carbs 1-3. When I finished I just plugged the smaller hoses and zip-tied them up out of the way. With the damn choke rail in the way connecting the vacuum lines is a real pain.

The manometer I made had 1/4 barbed connectors so I had to lube the barbed end and "jamb" it into the smaller ID hose to make the connection. Regardless it worked OK.

Instead of explaining everything I'll just post three youtube video clips. They are kinda boring but you can see me adjusting and readjusting the screws.

Video one is the motor unadjusted. Even with the motor warm I had to use a bit of choke to get the bike to idle. You'll hear the uneven idle in the video and see that carb 3/4 were way higher than 1/2. [ame="http://www.youtube.com/watch?v=Hd8vwlSbHbI"]YouTube- carb sync 001[/ame]

Video two is the long video and if you jump to 2:30 you can see where I start making progress. Notice the improvement in engine operation. [ame="http://www.youtube.com/watch?v=2SxARF67lSU"]YouTube- carb sync 003.MOV[/ame]


Video three is just some final tweaking.[ame="http://www.youtube.com/watch?v=fSLjmv9_CyU"]YouTube- carb sync 004[/ame]


I might have been able to do this faster but I was trying to avoid cursing too much! Plus this is the first time I've done a carb sync. This picture shows the difference between the vacuum hose size on carb 4 and carb 3.

[Kreylyn]

Very nice... great visuals!

Krey

[Pyro18t]

So how does it ride now? Can you tell a differance?

Jay

[BareKat]

I finished up late and only had time for a short ride but I can tell the throttle response is much smoother. The idle is no longer 'lumpy' (if that's the right word).

I figured the videos would help others take the leap.

[Black_peter]

Well my apologies to Greg, I had no idea the 98 + carb was so different.

[BareKat]

just a quick question...

will the carb sync be affected by the different OD vacuum ports??