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Connecting the Intake Vacuum Ports

  • Thread starter Thread starter SteveR
  • Start date Start date
S

SteveR

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Good morning All,

Do any of you see a problem with connecting the intake vacuum ports to each other.
I read a post here and it looks like a good idea.
I'm thinking it would fine tune the balance of the carbs.
I am also interested in a setup like this because I am tired of removing the bolts and inserting the barb connectors to check the sync.
 
Once you have the sync set, it should be good for thousands of miles. I think you are thinking to hard on this one. Just leave it stock.
 
You are right...
I know how smooth my 850 is when it's just right. It's the mirrors and the pegs that tell me what I want to know. I think ( there I go again) that the carbs (my 27 year old carbs that I have worked on) do not stay in perfect sync and mixture at all throttle settings and maybe by interconnecting the ports this slight imbalance can be minimized. I have some patience left...
 
Linking 1-4 and 2-3 use to be the tip for the old Z1's in fact mine still has the cross over tubes
connected.

The FZ1 folks went through a few years ago. The theoretical benefit doesn't really result in something you'll be able to feel. So from my perspective it doesn't hurt but it also doesn't help that much either.
 
I think mine are like that, I'd have to go check to be sure though.
 
It's still early and maybe my brain isn't warmed up yet, but how can connecting the four intakes at each manifold, change, let alone help, anything?
I don't see how a length of tubing can "equalize" or change intake flow among different cylinders.
Even if there is some change, you're just complicating a design and possibly altering a procedure (synching) that if done correctly, will give optimum results.
 
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KEITH KRAUSE said:
It's still early and maybe my brain isn't warmed up yet, but how can connecting the four intakes at each manifold, change, let alone help, anything?
I don't see how a length of tubing can "equalize" or change intake flow among different cylinders.
Even if there is some change, you're just complicating a design and possibly altering a procedure (syncing) that if done correctly, will give optimum results.
Click to expand...

well using just the intake sync ports there would be very little to no benefit as the lines are to small. but the practice of cross connecting intake ports has been done before with good results.
the V-max had cross over tubes with butterfly's that would open under wide open throttle at about mid/ upper RPM allowing each cylinder to breath through two carbs, it worked pretty good.
it allowed them to get more power without going to bigger carbs.

prior to the V-max Yamaha used a system called YICS it served some sort of function related to smoothing idle and or fuel economy, I don't remember what exactly, other than it only was active from idle to about 1500rpm it was a small passage machined into the head and connected the intake ports together and had a vacuum actuated module that cut it off under throttle.
to sync carbs on a Yamaha with it you have to make a tool that slides down the main gallery and blocks the ports.

it wasn't liked by very many and didn't last very long before Yamaha stopped using it.
 
BSA seemed to think it made a difference on the twin carb A65. The rubber pipe connecting mine split and I temporarily sealed the intakes off separately - didn't notice any difference.
 
SteveR said:
I am also interested in a setup like this because I am tired of removing the bolts and inserting the barb connectors to check the sync.
Click to expand...

I don't know what year your 850 is, but if you have the VM carbs on it, you can use Kawasaki carb boots which have the tubes built in with caps on them. I got tired of burning my big fingers and dropping those tiny screws. Plus I don't have to worry about whether those screw-in tubes are sealed good against the head.

100_6784.jpg
 
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Bruce, just curious...
What does the purple California and Colorado and green Nevada mean on your map?
 
that he has visited (ridden in?) those states. those are the default colors for them on the map.
 
KEITH KRAUSE said:
Maybe not, but you just impressed hell outta me.....jumping a bike from Nevada to Colorado?:shock:
Click to expand...

LOL! I trailered my 1150 out to Kabonkie's house in Denver to pick up my Skunk (I bought it on ebay and he kept it for me). I rode around awhile with him, then trailered both bikes back home.:-D

100_0693.jpg
 
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I've done this to two GSs with noticeable smoother running and slight low-end power increase. Both bikes were accurately vacuum synced beforehand. It's standard procedure for me now after seeing the benefits and since it's so easy.

I pick up permanent barbs for the sync ports for cheap from casporttouring.com. Install them with a little Loctite thread sealant. Connect 1+4 and 2+3 with some tubing and fogettabouttit. If you don't like it, no harm done; cap 'em off again.

It's the same idea as the Yamaha YICS system used in (I think) later model XS1100s and V-Maxes.
 
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