Cam lobe flattening '85 VF500

I interconnected mine, as I said in an earlier post, because it was the easiest way for the time being. Until the next time the carb assembly is removed, this is the easiest way. This was done AFTER there was already surging, not the cause of it. As a matter of fact, I believe the performance of my ride has improved.

I disagree that the performance would be any different with them interconnected because the hocky pucky thingy does the SAME THING. Only the valve opens and allows the vacuum tube coming up from the canister to be open to the ECS ports.

And why would balancing have ANYTHING to do with interconnecting the ECS lines? Balancing is adjusting the butterfly valves in the carbs and the ECS ports are between the butterfly and the slider. No affect on balance - engine vacuum is measured at the ports in the cylinder head between the intake valves and the carb butterflys.

 

someone's gonna kick my ass when I don't get this exactly right....

I'll do my best...

The ECS ports are the vacuum port on the side used to recycle collected fuel fumes from the carbon canister on the front of the bike. Technically I don't know that you'd really call it a vacumm port but it looks like one with vacuum lines going to it.

In my case, the problem was the #90 main jets. If your main jets were clear and clean (along with no vacuum leaks) and you had surging issues you may consider trying a larger main jet. My surging issues were very noticable and HP would drop as rather than build as the RPM's were climbing. I went to a #102 and didn't try any others.

If your surging is not very noticable, you may want to try a (assuming you have a #90 now) #92 or #95. If it's very irritating, try #97, 100, or 102.

Look at your mains and see what number is stamped on the side.

I got mine at a salvage yard for $4/ea if I remember right.

Let me know if you have any other question - happy to help.

 

+1 JamieD

I believe the photo below shows what I have referred to as the ECS port. In my troubleshooting, I removed the vacuum tubes and plugged these orifaces just to eliminate any possible sources of vacuum leak. When the system operates normally, fumes from the carbon canistor would be recycled back to the motor thru this tube. I have California carbs so I couldn't say for certain if 48states are the same way.

notice the vacuum tube on the side of the carb. This photo was marked up with red arrows and used in a previous post to show the pry location to remove carbs.

 

because of how the vacuum sliders work in these carbs, what you describe could still be considered throttle position.

If you're at idle and crank the throttle butterfly wide open, the carb and main jet are still not "wide open". The slide will be in a lower position with the slide needle plugging the main jet.

As the RPM's climb, vacuum increases in the motor, and the slide moves up, further exposing the main jet.

When we refer to throttle position, we really mean "slide position" and around 5000ish rpm would normally be around mid throttle and definately into the main jet circuit of the carb.

If you remember the old two strokes from the 70's and stuff, you'd be at idle and crank throttle and the motor would bog down because the carb would lose vacuum. They always seemed more responsive if you'd ease on the throttle verses dumping it WOT. The carbs with vacuum slides were the fix for this.

My recommendation for you would be to increase your main jet size. If you're at 90, go to 95. If your at 95, try 100. There are sizes in between like 92 and 97 but too small of a change may not result in a noticable enough change to show if you're on the right track.