Inexpensive Tuning Tool

[Kiwi_Roy]

I finally got around to making a gauge for balancing the throttle bodies.

10 ft of clear plastic tubing and a lump of scrap metal.

I used 10/30 oil as the fluid thinking it would be safer than water if it accidently

got sucked into the engine. at first i thought it might be too viscous but when I

tested it out seemed just right. Without making any adjustment I get about

8" at idle, falls away with some revs.

I looked everywhere for barb fittings to screw into the body. Finally in a rare

flash of brilliance i figured out 6mm grease nipples looked just right.

I ground the back a little to let the spring and ball out, they work perfect. If

I can just find some caps for them they will become a permanent fixture.

Sorry about the sideways picture, just flip your monitor over LOL

 

Cheers

Roy

[Kiwi_Roy]

I used my new tool this evening, It worked like a charm.

I did the TPS RH fully shut I found 102 mV so adjusted it to 150

This gave me a range 150 - 4890 mV.

When I re-connected the linkage I got anywhere from 387 - 440 mV as I wrapped the throttle.

This equates to about 1% of span so I wasn't too worried.

I see several posts saying the mV should be about 500 with the linkage on.

I adjusted the RH stop to give me ~500 mV. The LH body still on the stop

When I attached the balance tool the difference was less than 2" of oil which is a very small error indeed.

The bike was running about 900 RPM so I opened the left and right bypass screws until I got 1100

with both pressures balanced (about 1 turn on each)

Then I ran the engine at about 3000 RPM, the pressure difference was about 4" so I tweaked

the throttle linkage knob ever so slightly (

 

A few observations

I figure that both throttle bodies should be sitting on the stop screws at idle because that's the most

repeatable position 500 mV +/-10 mV.

The 500 mV number is not really fixed like fully closed or WOT because it is effected by bypass screws

and linkage backlash The main thing is to get a steady idle, I figure a repeatable mV should help there.

Oil was a good choice of fluid for the manometer, during the test one of the tubes fell off due to the

plastic softening with the heat, this resulted in some of the oil getting sucked into the other cylinder.

I will find a short length of rubber tubing to modify the setup.

Grease nipples are the cat's pajamas for connecting the tubes, just take the spring and ball out.

 

I am confident that I have my throttle bodies well aligned no load. Next I will figure out how I can

check it while riding with the motor under load. Once I have it to my satisfaction I will try out my

Throttle Position mV offset rig. I cut the TPS wire near the ECU and inserted a M/F spade connector

from here I will run a pair of wires to a mV source at the handlebars, I think +/- 100 mV

(+/- 2% of span) should be about the right range

 

Will keep you posted

Roy

[Tom M]

That gauge looks familiar Roy, but I used ATF.

 

 

One slight problem that I ran into was over time the tubes kinked at the top zip tie because I stored it standing up. I need to fix that before I use it again.

 

I'm surprised you needed to use zerks on the intakes. My '02 has fittings with very small orfices that prevent rapidly sucking the ATF in if the balance tube fell off or, as what happened to me the first time I used it, one of the tubes flops against the exhaust and melts through. Maybe a previous owner ditched your fittings when he removed the vapor canister?

[Skeeve]

Great post, Roy! Looking forward to your updates.

[Kiwi_Roy]

That gauge looks familiar Roy, but I used ATF.

 

 

One slight problem that I ran into was over time the tubes kinked at the top zip tie because I stored it standing up. I need to fix that before I use it again.

 

I'm surprised you needed to use zerks on the intakes. My '02 has fittings with very small orfices that prevent rapidly sucking the ATF in if the balance tube fell off or, as what happened to me the first time I used it, one of the tubes flops against the exhaust and melts through. Maybe a previous owner ditched your fittings when he removed the vapor canister?

Your gauge looks like the Delux model LOL, it even has a scale!

Slide a short length of rod inside or tubing outside and make a right angle bend at the corner, that will take care of the kink.

My bike just had socket head screws but no tube between the bodies as mentioned in the write ups.

Your manometer is much more accurate than using two gauges, I worked for many years as an instrument technician, That's what we used to measure low pressures accurately and where the unit "Inches of water" & "Inches of Mercury" come from. "Inches of ATF" in your case.

A normal vacuum gauge has a range equivalent to a 32 foot tall manometer full of water with an accuracy of +/-1/2% (+/- 1.9 inches Water Column)

so the differential reading could be out by as much as 2 x 1.9. The only thing that will mess your gauge is air bubbles in one side or two different fluids.

Nice clean bench, mine is 3 layers deep in junk.

Regards

Roy

[waspp]

I have a very similar model using clear tubing and a pine board painted white. I also used atf as the fluid and now after several years its time to change out the tubing as the atf has managed to darken it so visibility is a problem. My 03 also has nipples right on the throttle bodies which feed (or used to) into the charcoal cannister.

[Kiwi_Roy]

I have a very similar model using clear tubing and a pine board painted white. I also used atf as the fluid and now after several years its time to change out the tubing as the atf has managed to darken it so visibility is a problem. My 03 also has nipples right on the throttle bodies which feed (or used to) into the charcoal cannister.

Yes, I am a journeyman Instrument Mechanic. Manometers are used to accurately measure low pressures.

A normal Bourdon tube vacuum gauge has a range equivalent to a manometer 32 feet tall so your setup

is far more accurate for a fraction of the cost.

I will leave my modified grease nipples in place and cap them off.

Regards

 

Roy

[gstallons]

My hat's off to you !