Intake Equalization

[cberkeley]

Been playing around with the following idea for an Intake Equalization scheme:

Suppose we were to sync our four CV carbs in the usual manner, then
when were done, we manifolded the four vacuum ports together. This could be as simple as a couple of tees and some vacuum tubing. Maybe even, four restricting orifices if it became necessary (see diagram below).

Would this not equalize the vacuums and mixture intakes to all four cylinders evening out the power produced by all cylinders. Should also ensure a smooth idle and smooth transition from idle all the way through top end, as any variations at the intake would be equalized?

Maybe a stupid idea but I'm very curious.

I intend to try it, I’m just waiting to verify that my carbs are within the sync ballpark and it would be a few weeks till my sync gauge arrives.
Unfortunately a lot of the result evaluation would be subjective unless I can find measurable means to document the findings.

I threw this proposal out to Keith Krause and got his grey matter itching. Would like comments on this from the group and would appreciate anyone experimenting along with me and comparing the results.

[drhach]

Equalization

Aren't the vacuum ports already "manifolded" to the air box? Assuming you have one. It looks like what you are suggesting is to run the vaccum lines in parallel so that they all have the same source. It seems that that is already happening though. Maybe you could elaborate more on what it is you are talking about.

[t3rmin]

Aren't the vacuum ports already "manifolded" to the air box? Assuming you have one. It looks like what you are suggesting is to run the vaccum lines in parallel so that they all have the same source. It seems that that is already happening though. Maybe you could elaborate more on what it is you are talking about.

You're talking about the back end. He's talking about between the carbs and the motor. Things are much different once you get past the slides and throttle flappers.

I like this idea, especially since it seems easy to implement. Eagerly watching this thread!

[t3rmin]

Suppose we were to sync our four CV carbs in the usual manner, then
when were done, we manifolded the four vacuum ports together. This could be as simple as a couple of tees and some vacuum tubing. Maybe even, four restricting orifices if it became necessary (see diagram below).

What's your thinking on the restrictors thing? Seems like the orifices are pretty small already.

[isleoman]

Not really a new idea, my Kawasaki Z1 has been set up with cross over tubing between 1-4 and 2-3 cylinders since 1974 when I first bought it. I also ran a cross over system on my 2001 FZ1 for awhile but it didn't make much difference so I took it back off.

In principle it makes sense to coordinate the vacuum pressures to help smooth things out but you'll be hard pressed to notice a difference between a well adjusted rack of carbs.

[t3rmin]

but you'll be hard pressed to notice a difference between a well adjusted rack of carbs.

...makes sense...

[cberkeley]

What's your thinking on the restrictors thing? Seems like the orifices are pretty small already.

My thinking on the restrictors is, in the event pulsations from one cyl cause turbulence and degrade performance of the other cyl(s). My intention is to try first without restrictors.

[cberkeley]

Not really a new idea, my Kawasaki Z1 has been set up with cross over tubing between 1-4 and 2-3 cylinders since 1974 when I first bought it. I also ran a cross over system on my 2001 FZ1 for awhile but it didn't make much difference so I took it back off.

In principle it makes sense to coordinate the vacuum pressures to help smooth things out but you'll be hard pressed to notice a difference between a well adjusted rack of carbs.

Makes sense indeed. That's the sort of feedback I was looking for ....Thanks Dude!

[cberkeley]

Makes sense indeed. That's the sort of feedback I was looking for ....Thanks Dude!

I also intend to try it with different levels of out of sync between carbs and noting the performance with and without the EQ manifold. This bike is turning into a laboratory on two wheels :-D

[Mike_H]

You got too much time on your hands man...thou it is an interesting idea.

[tconroy]

idle variations after romping on it?

Do you get a little idle gain after romping all over it and then coming to a stop?After hauling a@# in all gears and hitting 90+ then slowing down to an idle I seem to gain about 200 rpm's.This is all in about 1/4 of a mile.It goes from about 1100 to 1300 but settles back down if I ride around some more.If I blip the throotle it also comes back down. Would this be considered normal? Is it because of more heat being produced by the engine when going fast then slowing down.I hope i made myself clear.I have new o-rings boots and no air leaks.Just changed o-rings in the needle seats and switched to a 5/16th's fuel line with no in-line filter,also running high octane premium.

[isleoman]

Not really a new idea, my Kawasaki Z1 has been set up with cross over tubing between 1-4 and 2-3 cylinders since 1974 when I first bought it. I also ran a cross over system on my 2001 FZ1 for awhile but it didn't make much difference so I took it back off.

In principle it makes sense to coordinate the vacuum pressures to help smooth things out but you'll be hard pressed to notice a difference between a well adjusted rack of carbs.

For a nut by nut, tube by tube instruction on how to see also: http://www.cartestsoftware.com/fz1/c...nmanifold.html

[cberkeley]

For a nut by nut, tube by tube instruction on how to see also: http://www.cartestsoftware.com/fz1/c...nmanifold.html

Thanks for the link. That's truly interesting. I knew it was too simple not to have been done before. I will certainly give it a try.
So much for originality :-D

[drhach]

By definition, synching the carbs should do all of what you are trying to do with this method. In thinking about it, the place where you might see improvement is off idle. There may be differences in the rate and distance that each slide moves with respect to the others. In that case, the equalization would probably smooth everything out. On the other hand, it seems doubtful that there is enough of a difference in tolerances from one slide to another for an unbalance to occur when the slides move. But if there is, your method should correct for it. I doubt very seriously that you would notice it. If you did notice a difference, there probably is something wrong with your carbs that needs to be addressed/repaired.

[isleoman]

Those doing this mod on the FZ1 board were more interested in eliminating vibes in handlebars than anything else. Like I said earlier it didn't have much benefit for me, but others swear by it.

As far as I'm concerned the FZ1 has some of the best sorted carbs in the business. Funny thing was many on the board hoped and prayed for fuel injection from 2001 through 2005 and finally in 06 Yamaha gave it to us, and it sucks. Now everyone reminisces and fondly remembers the great Gen 1, carb version of the FZ1, or they spend $500 to have Ivan or Power Commander fix the fuel injection problems. Careful what you wish for.