The fluid hangs in the tubes on the new unit didn't cause any problems for me while adjusting either of my bikes. Even Motion Pro says they're not an issue. After doing an initial sync adjustment followed by a pilot screw adjustment I fine tuned the sync a second time. Now my ST runs smooth as glass. After removing the sync tool I swing it like a pendulum to get the fluid that hangs in the tubes back into the reservoirs before screwing the four screws out to seal them. I prefer this new Motion Pro sync over my old mercury one. I think it's more accurate.
First time carb sync
- Thread starter maximark
- Start date
Many people are having poor results with the new Motion Pro unit due to they're not setting it up correctly in the beginning. All four tubes attached to the #4 carb to equalize the fluid in the tubes is a must BEFORE you try to sync the carbs.
Is there a carb sync video showing the connections and procedure for an ST1100? Also, if I'm looking to open up the high speed jets (sorry if I've got the nomenclature wrong on these bikes...just that other bikes I've had did have a "high and low" speed jet), how exactly do you do that. I'm a bit confused when I look at the carbs and when I compare to the drawings. I'm not what you'd call a proficient mechanic, but I do try and move cautiously when doing these things. Just can't seem to find the clarification I need to make myself content.
Apologies if this has been asked previously (I'm new to the ST1100)...............
............but since all carbs are balanced to the #4 carb, could a simple balance manometer be used in place of an expensive Motion Pro or other unit?
What I mean by this is a device built with tubing and ATF fluid. It's a closed system in the shape of a very large "U" (the tubing uses a yard stick for support to form the "U" using about 18 inches of ATF on both sides damps the fluctuations pretty well).
One end goes to one carb, the other end to the other carb. (the system is closed to atmosphere). It just compares vacuum from one side to the other by balancing the two ATF columns.
I've used this for years on my Transalps and BMWs and it works great on twins.........so I'm thinking that if every carb on the ST is "indexed" off the #4 individually (which differs a bit from most 4 cylinder systems) and effectively you're only balancing two carbs at any one time, I could use this tool rather than spending $100 on Motion Pro or equivalent.
Whatja think?
Ray
............but since all carbs are balanced to the #4 carb, could a simple balance manometer be used in place of an expensive Motion Pro or other unit?
What I mean by this is a device built with tubing and ATF fluid. It's a closed system in the shape of a very large "U" (the tubing uses a yard stick for support to form the "U" using about 18 inches of ATF on both sides damps the fluctuations pretty well).
One end goes to one carb, the other end to the other carb. (the system is closed to atmosphere). It just compares vacuum from one side to the other by balancing the two ATF columns.
I've used this for years on my Transalps and BMWs and it works great on twins.........so I'm thinking that if every carb on the ST is "indexed" off the #4 individually (which differs a bit from most 4 cylinder systems) and effectively you're only balancing two carbs at any one time, I could use this tool rather than spending $100 on Motion Pro or equivalent.
Whatja think?
Ray
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Johnny,
The ST1100 uses a CV (constant velocity) carb. that has a pilot (slow) jet, a slide/needle jet/jet needle (two parts to the same system), and a main jet.
The pilot is used for idle to 1/4 throttle (approximately), the slide/needle combination fo the mid-range and the main jet for full throttle.
With the power of the ST I'd bet your almost never using the main jet.
The "problem" with jetting is that all the different parts of the system overlap so the pilot jet size affects mid-range and the main jet size has some effect at lower throttle openings.
That being said, most bikes of this era were set up from the factory to be a bit lean at idle and just "off-idle" since that's how they were tested for emissions.
Opening up the mains should only be considered if you've done considerable modifications to the intake or exhaust system of the engine.
My ST seems to carburate perfectly with no evidence of lean-ness even down low when pulling one or even 2 gears higher than I should.
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Yes, people have used homemade manometers before to do this. I was thinking it is cly 1 that is tied to the idle adjust though not #4. It is clear when you get in there as 3 have adjustments on the carb and the other one goes to idle adjust.
You have to go from the fixed carb to each other carb matching them up and then I think people go between the ones with adjustment just to see that they are the same as well. Can it be done, yes. It just is more work and takes longer since you can't see all the carbs at once.
I have always used a SK flow meter on my 1100. I which is a device that measures air flow through the snorkel. When using this you take a reading off the fixed carb and go though and match it up. It also takes a while as you make your adjustments it throws off the reading on the fixed carb. The same thing will likely happen with the ATF manometer. So work your way around a few times until everything is balanced. I have now since bought a Motion Pro but haven't tried it out on the 1100 yet to see how it compares to the SK Flow Meter I once used. It would be interesting to do a comparison. I will probably still use the SK for a spot check when I open the air box.
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Nevermind about the Cly1. I guess it is 4. It has been a while since I have done this to my 1100. Either way you adjust to the cylinder that is tied to the idle adjust as I mentioned and your homemade 2 channel ATF Manometer will work fine. Just a little slower but it isn't like it is something you do once a week. I haven't checked mine on my 1100 in about 3 years.. I only bought the Motion Pro because I can't use the SK on the 1300. So I needed something. I opted to spend the money on the MP.
I also have one of these:
I used it years ago to balance carbs on a MG.
It never worked on bikes since it was never convenient enough (or small enough) to get down to the carb mouths.
But with the "periscope" snorkles on the ST, I bet it would work just fine.......or am I nuts
Ray
I used it years ago to balance carbs on a MG.
It never worked on bikes since it was never convenient enough (or small enough) to get down to the carb mouths.
But with the "periscope" snorkles on the ST, I bet it would work just fine.......or am I nuts
Ray
I also have one of these:
I used it years ago to balance carbs on a MG.
It never worked on bikes since it was never convenient enough (or small enough) to get down to the carb mouths.
But with the "periscope" snorkles on the ST, I bet it would work just fine.......or am I nuts
Ray
You could always try it. I don't think I have ever seen one of those.
Here is what that SK looks like.
http://www.cbperformance.com/ProductDetails.asp?ProductCode=6537
You just open up the air box and stuff it in the snorkel. Super easy to do a spot check. More work if you need to actually adjust things but they are super easy to use to see where things are at.
They're kinda old-school but the same basic principle.
The circle bit in the center (with the spring) screws up and down to vary the size of the opening.
You just hold it on the carb (or snorkle) mouth and spin the center bit down until the little red ball in the tube comes up about 1/2 way in the tube......then move the device to the other snorkels to see if the reading matches.
I'll give it a try this weekend but I'm thinking a manometer (of any type) would be a bit more accurate. The advantage to these is that you can use larger throttle openings.
It's all in the name of science, you know
Ray
The circle bit in the center (with the spring) screws up and down to vary the size of the opening.
You just hold it on the carb (or snorkle) mouth and spin the center bit down until the little red ball in the tube comes up about 1/2 way in the tube......then move the device to the other snorkels to see if the reading matches.
I'll give it a try this weekend but I'm thinking a manometer (of any type) would be a bit more accurate. The advantage to these is that you can use larger throttle openings.
It's all in the name of science, you know
Ray
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A manometer of some sort is gonna get you the best running results. A flowmeter on each snorkel is only cheating yourself out of a good sync. The absolutey best type of manometer uses mercury, but EPA has shut that off. The next best thing, and have compared to my mercury 'stixs' is the MorganCarbTune. Same ones who make the ColorTune plug. Uses four stainless pistons inside a clear chamber. Comes with carry case and nothing to spill. On the ST 11's, this has to be done with air filter andhousing in place, and goes for ALL multi carb bike motors. Honda even specifies all air intake has to be in place. The vacuum hoses already exist on the bike, with the use of a couple tees your hooked and ready to read all four carbs vacuum draw, to be done at the lowest smooth idle(800rpm). Some have stated above idle sync has little or no effect. An urban/internet myth at best once a peson realizes just how little the throttle plates are open at a 4000rpm/80mph cruising speed. Some may see this as JMO, but my 21yr.old ST11 speaks for itself with its consistant 50-52mpg at 75-85mph continious slab speeds and rolls on smooth as silk from idle in any gear.