1995 ZX6R Running Uber Rich - Ram Air?

Folks,

Macca's 6 is in getting tuned and the guy can't make it run anything but uber rich on the dyno .

I've read about airbox hacks and the like on streetfighters but although this bike has race glass it has all of the factory ram air ducting so I doubt we'll have to stoop to that level?

I spoke to John from Mornington and other than offering Google and talking about balance tubes he couldn't tell me how to fix it, has anyone ever had this issue of running rich off the charts and being able to fix it with correct vacuum tubing/switching/something else like that?

From the sounds of it there's something that's not opening in the ram air circuit to let the extra airflow in at high RPM/WOT and it's riching through the floor on the air fuel ratio chart.

Any help? As a last resort I can probably get hold of another early model 6 to look at switches/vacuum line routing but maybe we won't have to stoop to that if someone here can help?

It would certainly be worth checking the balance tubes are connected properly, although I don't think you'd notice it too much on the dyno where the ram-air is doing SFA. They equalise the air pressure in the float bowls to the pressure in the airbox and when the aren't connected, your fuelling gets worse the faster you go on the road.

How much has he done to the carbs to try to fix the issue? It kind of sounds like stuff I've read about worn emulsion tubes where they let too much fuel past the needle and no amount of rejetting will sort it out. Not sure how much of a problem this is on 6's though...

Run a cupla of compressed air hoses into the ram ducts to simulate 200kph road speed just a thought

Run a cupla of compressed air hoses into the ram ducts to simulate 200kph road speed just a thought

I was just thinking that, you cant simulate RAM air on a dyno.. The bike would be expecting a hell of a gust at WOT in any gear above 1st.

where's marty... he raced a 95 ZX6R

Run a cupla of compressed air hoses into the ram ducts to simulate 200kph road speed just a thought

I was just thinking that, you cant simulate RAM air on a dyno.. The bike would be expecting a hell of a gust at WOT in any gear above 1st.

There'd be people who have had bikes dyno'ed with ram air in the past yeah? Don't all the new bikes have ram air these days? And the dyno I'm talking about has big fans on the front of it...

the fans do fuck all in the way of ram air, its just to keep the rad cool.

as micklc said, the balance tubes int he ram air are needed to let the bike run right, if they are not working it will throw it out.

If ram air was the issue, no 6-7-9 on the planet will ever have been able to get a dyno run, unless in a wind tunnel.

So cross ram air off the list of possible issues.

Thanks Wattie, what's a balance tube, where are they, and how will I know if they're fucked? The AFR goes way way way rich could this be the cause?

if you look inot the air intake, you will see these tubey things pointing at you.

Dunno how they how they connect, i have always had FI bikes, since i am a digital/metric baby.

From memory on my old 9 there were two tubes that went from the back of the little tubes in the intakes, to a joiner, then single tube this ran back to the carbs and joined in to them somewhere under the airbox.

But the whole balance tube system is only there to cope with the changing pressures in the airbox with the ram-air, so they aren't doing anything on the dyno....in other words it can't hurt to check them but they aren't likely to be the source of your problems.

When mine came loose one day because I hadn't reconnected them properly after taking the fairing off, the bike would rev fine at standstill and only played up when I was on the move.

We have had the fairings off a few times for various things - so this ^^^^ is a possibility... When I ride it, it is coughing and spluttering in low revs - but once it gets high it picks up and goes no worries... Im not mechanical enough to put that in technical terms but maybe it has some bearing on your opinions?

Based on what I am hearing, it sound like the pollution gear is fitted incorrectly. I could be wrong, but check the plumbing up on top of the rocker cover and make sure it is all fitted properly with no leaks. Blow through the big round thing to make sure it flows. Check to make sure the vacuum tubes are routed to the correct points.

But, if it's horrible off the bottom, but cleans up mid range, then it sound like the needles are either wrong, incorrectly postioned or both, or perhaps the float levels are wrong and it's feulling up at low revs? Could also be too large in main jet size if it's rich at all revs on the dyno.

the pollution gear should effect running should it marty?

90% of bikes have it blocked off with no ill effect.

Based on what I am hearing, it sound like the pollution gear is fitted incorrectly. I could be wrong, but check the plumbing up on top of the rocker cover and make sure it is all fitted properly with no leaks. Blow through the big round thing to make sure it flows. Check to make sure the vacuum tubes are routed to the correct points.

But, if it's horrible off the bottom, but cleans up mid range, then it sound like the needles are either wrong, incorrectly postioned or both, or perhaps the float levels are wrong and it's feulling up at low revs? Could also be too large in main jet size if it's rich at all revs on the dyno.

Thanks Marty. The guy who is doing it knows what he's doing with needles and jets and float levels etc. so we're going to borrow another 6 (thanks Mike ) and see what's not working properly.

I'll feed back to him about the pollution gear as well.

the pollution gear should effect running should it marty?

90% of bikes have it blocked off with no ill effect.

Believe me on a 1995 ZX6R F1, if it's not all set up properly, it runs like shit!