Throttle balancing problems...

[Grahamm]

(I've posted this on the Facebook forum too)

I was trying to balance my throttle bodies today on my FZ6-SA 2006.


 I hooked all the gauges to cylinger 1 to calibrate them and worked out the differences in readings. no problems.


 But when I came to actually trying to balance them, I did have a problem.

Here's the set up...
 I'd checked the idle speed, tweaked the adjusters on the adapters so the needles on the gauges were just not jittering, blipped the throttle a couple of times then let them settle, but no matter what I tried and how much I altered the throttle screws, for some reason I simply could not get much movement on the gauges and certainly not enough to get the readings even nearly the same


I don't know what I'm doing wrong. Anyone got any helpful suggestions?

[Grahamm]

More pics...

[Gnasher]

Firstly, check your gauges.  Swap the one with the higher reading with one of the others as see if you get the same reading.  If not the gauge is out of calibration or naff.  Many on the cheaper gauges can't be calibrated, in which case, as long as it reads the same constantly, you just deduct the error.

Once you've sorted the above out, balance 1&2 then 3&4 then bring 1/2 & 3/4 in balance by adjusting the middle 


   

[Grahamm]

Firstly, check your gauges.  Swap the one with the higher reading with one of the others as see if you get the same reading.  If not the gauge is out of calibration or naff.  Many on the cheaper gauges can't be calibrated, in which case, as long as it reads the same constantly, you just deduct the error.

I hooked them all up to #1 cylinder to check how much (if any) they were off from each other.

Once you've sorted the above out, balance 1&2 then 3&4 then bring 1/2 & 3/4 in balance by adjusting the middle   

The problem is that, no matter how much I change the screws, I get very little movement on the needles.

What I might do next is try increasing the idle speed, then turn all the screws down until it's almost on the verge of stalling.

Hopefully with the screws right in, any adjustments would be more noticeable.

[agricola]

Looks odd to me Graham. What are the grey angled things with a threaded cap on them? And then another angled piece further along the pipe?

[unfazed]

It looks like the left ones and not connected to the correct pipes 

[Grahamm]

Looks odd to me Graham. What are the grey angled things with a threaded cap on them? And then another angled piece further along the pipe?

The grey things connect the gauges to the cylinders.

The threaded cap allows you to adjust the flow to stop the needles fluttering.

One of them has an extra connection because that goes to the Scotoiler vacuum feed. AIUI usually it goes off #1 cylinder, but, for some reason, on my bike it was set up to run off #4 cylinder.

[Grahamm]

It looks like the left ones and not connected to the correct pipes 

Well, unless there's another two short hoses on that side with stopper plugs in them which pull a vacuum when attached to the gauges...!

[Grahamm]

PS Nobody's yet spotted my deliberate (yeah... of course) mistake, that the modification value for cylinder #4 should be *minus* 1 rather than *plus* one...! 

[Gnasher]

I hooked them all up to #1 cylinder to check how much (if any) they were off from each other.

If you telling me that every gauge gave a different reading when hooked up to No1?

If that is the case and all the connections are good, the gauges are unusable.  Sorry to say that but if they can't all read within about 0.1Hg of each other on the same cylinder, you've got no chance unless you can calibrate them within 0.1Hg.

The problem is that, no matter how much I change the screws, I get very little movement on the needles.

What I might do next is try increasing the idle speed, then turn all the screws down until it's almost on the verge of stalling.

Hopefully with the screws right in, any adjustments would be more noticeable.

Providing there's nothing wrong with the throttle bodies, or air leaks.  What you're describing is typical of faulty or poor quality gauges.  The gauges you're using I seem to remember were offered (at the time) as a cheaper alternative to Davida, they work but aren't the same quality, in my experience and from feedback over the years they don't last.

Even Davida aren't the same quality, mine are over 30yrs old, they can be calibrated, newer versions I've seen can't be.  Either, you've got air leaks and/or you can calibrate these gauges, failing that borrow or buy some Davida's, or carbtune I think they're called, not a fan of the latter but others like them. 

[BBROWN1664]

Those gauges are like mine. You can calibrate these. With nothing connected, take of the lens and adjust the brass screw until all the gauges read the same. Once all "zeroed" you should try them all on the same cylinder to check the reading is roughly the same on each gauge. Once done, you can connect to the other cylinders to confirm if the cylinders are out of adjustment or not.

[unfazed]

It looks like the left ones and not connected to the correct pipes 

Well, unless there's another two short hoses on that side with stopper plugs in them which pull a vacuum when attached to the gauges...!

Any I saw and/or worked on had the pipes coming straight from the front by the frame. Have you relocated yours?
When you swap the hose of guage on 2 to position I and 1 too 2 I presume it then shows the same as the others around 9? Only asking
Was the engine running rough that you decided to check the throttle bodies?

Check the routing of the pipes too the throttle bodies to ensure they are not kinked especially No. 2. since you appear to have an issue with it. I have seen those type of hoses crack at the edge of the pipe/stub  they are attached to at the throttle body. Common enough issue in cars also.

Picture of the Idle air control valve apart for info, not much in there to go wrong

[Gnasher]

You can calibrate these. With nothing connected, take of the lens and adjust the brass screw until all the gauges read the same. Once all "zeroed" you should try them all on the same cylinder to check the reading is roughly the same on each gauge. Once done, you can connect to the other cylinders to confirm if the cylinders are out of adjustment or not.

Well that's one way of doing it, I suppose But it's not calibration, that's done under various loads of a measured source, that said if you can get these to read the same consistently it will do.

You learn something every day 

[Grahamm]

I hooked them all up to #1 cylinder to check how much (if any) they were off from each other.

If you telling me that every gauge gave a different reading when hooked up to No1?

If that is the case and all the connections are good, the gauges are unusable.  Sorry to say that but if they can't all read within about 0.1Hg of each other on the same cylinder, you've got no chance unless you can calibrate them within 0.1Hg.

If you look at my pictures, you'll see that I wrote down the differences between the readings.

So gauges #1 and #3 gave the same readings, but #2 was 0.75 down and #4 was +1 up.

As long as I remember to add or subtract as required, I can get an accurate result.

A mercury gauge is around £100 or there are digital ones for £400+ !

[Grahamm]

Any I saw and/or worked on had the pipes coming straight from the front by the frame. Have you relocated yours?

I have the FZ6-SA 2006 model.  Below is the page from the FZ6 service manual.

When you swap the hose of guage on 2 to position I and 1 too 2 I presume it then shows the same as the others around 9?

See above for how I calibrated them.

 

Was the engine running rough that you decided to check the throttle bodies?

I'm fitting the 4 degree ignition advancer, so I decided I may as well do the synch as well. I don't know if it was done when the engine was installed a couple of years ago, but it's something that's recommended for regular maintenance anyway.

[Gnasher]

If you look at my pictures, you'll see that I wrote down the differences between the readings.

So gauges #1 and #3 gave the same readings, but #2 was 0.75 down and #4 was +1 up.

As long as I remember to add or subtract as required, I can get an accurate result.

A mercury gauge is around £100 or there are digital ones for £400+ !

Try as BBrown has suggested, it my well work.  Or as you've said, but they need to constantly read the same once they do, then plus/subtraction method should work.


Gauges are expensive, mine which are 30 odd yrs old are proper workshop models, cost me over £250 back then.  I've had many a bike in where an owner or a stealer has balanced carbs/throttle bodies only to find they're a good way out.  They other issue is owners over adjusting, i.e doing them with poor gauges when they don't need doing, but their gauges say they do, or they do them wrong.