TOPIC:

question for you guys that really know
is it possible to synch the carbs of a '81 kz1000 ltd with a single manometer gauge, maybe im wrong but if ( i beieve the #3 carb is the benchmark carb) i base the remaining 3 off the reading of that carb and match them (making sure everything is clean and in working order) then the carbs will then be in synch... correct or wrong
and if wrong please guide me to smooth running as i really dont want to spend lots of $$$ for the specialty tool.....
just trying to get the bike running and ridable for now till i get more $$$ to completely restore it

appreciate all the help anyone can give

You have started with a "bench sync" first, right?

Read 4th article from the bottom here .

Theoretically it's possible, but very difficult in practice. The engine vacuum varies greatly during the sync when you blip and let the motor settle. It's just way faster and more accurate to see all 4 at once.

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We talked alot in this thread about a 4 way sync from tubing and oil.
But this is what I initially did:
I made a gauge that measured one cylinder,
I measured each cylinder, took the average and set all of them to that average. It seemed to work ok, but I always wondered if I could get it closer. The PVC tube acts as a damper, but you still need a small clamp on the black tube to get the needle steady, I used visegrips and adjusted the knob to get what I needed.

Then I made the $1.55 Carb Synchronizer. .
Intended for two cylinders it got me closer in synch compared to the single gauge. On my 650 I adjusted carb 1 to 2. Keeping #2 as the master, I connected the hose from 1 to #3 and set #3 to #2. Then I unhooked #3 and hooked it to #4 and set #4 to #2. You need to shut the engine off before you unhook any tube or the oil gets sucked into your engine. I used bright red tranny fluid.

It worked just fine.

If you use this gauge on the bigger fours I believe there is an adjuster on the carb rack that connects 1-2 with 3-4. In this case you would set carbs 1-2 equal, then set carbs 3-4 equal, then connect carbs 2-3 and use this adjuster to equal the whole carb bank.

Post edited by: OKC_Kent, at: 2007/03/15 12:16

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H1Vindicator wrote:

I tried the 2 hose jobbie, but it seemed too fiddly, so I made the one with the 4 hoses. OKC does bring up a good point there at the end: be sure to understand the shop manual procedure for balancing prior to synching them (which ever tool is used). JMK.

Fiddly? I guess so,there's more hooking up and un-hooking, and engine stopping/starting, and it does take a bit longer to do, but nothing that should stop anyone from trying it.

One thing about using oil in these setups versus the commercial units that use steel rods or mercury: The oil is lighter weight than mercury so you will see greater variations compared to a mercury/steel unit. With proper damping on the tube you can get the oil levels to pulse very steady, or no pulsing at all and still be able to move. Basically it means you can get the carbs synched closer together. Is it going to change performance that much? Probably not that we would notice on the street. I got my oil levels about an inch apart. If I hooked up a mercury unit I bet the levels would be dead even.

OKC_Kent wrote:

H1Vindicator wrote:

I tried the 2 hose jobbie, but it seemed too fiddly, so I made the one with the 4 hoses. OKC does bring up a good point there at the end: be sure to understand the shop manual procedure for balancing prior to synching them (which ever tool is used). JMK.

Fiddly? I guess so,there's more hooking up and un-hooking, and engine stopping/starting, and it does take a bit longer to do, but nothing that should stop anyone from trying it.

One thing about using oil in these setups versus the commercial units that use steel rods or mercury: The oil is lighter weight than mercury so you will see greater variations compared to a mercury/steel unit. With proper damping on the tube you can get the oil levels to pulse very steady, or no pulsing at all and still be able to move. Basically it means you can get the carbs synched closer together. Is it going to change performance that much? Probably not that we would notice on the street. I got my oil levels about an inch apart. If I hooked up a mercury unit I bet the levels would be dead even.

Thank you OKC_Kent. Your comment reflects my opinion.
I built the single line manometer while my bike was down. I will try the synch procedure as soon as I get my fouled plug issues ironed out. When I read the write ups, I just liked the idea of matching/tuning all the carbs to one, more or less. Won't go into logic/reasoning, but I am glad to hear you have the same train of thought.
Man, I sure miss George, do you?

Why do you miss me? I am about to tell you something you don't want to hear... I am not a fan of the single or double gauge sync tool used on a 4 cylinder.

Next time you bench sync a set of carbs, notice how when you change one slide height, another will change. The four slides are linked on a single arm and if one is holding the other three up, when you raise it some, the other three will drop... what this translates to is that when you sync, you have to see where all four slides are simultaneously. The easiest way to do this when the carbs are on a bike is by looking at four separate meters.

I suspect that when folks talk about "good enough", if they viewed the four levels simultaneously they would notice some significant differences in vacuum levels. Hey, the bike will still run fine, just not as well as it could. It is probably better to just bench sync rather than use a single or double gauge on a four cylinder.

wiredgeorge wrote:

Why do you miss me?....

Now _THAT's_ a good question.
Well, let's see, because,, uhmm,,,errr,,,anybody?
Just jump right in here any time!!

Post edited by: JimatMilkyWay, at: 2007/03/18 12:16