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I own an auto repair shop here in sunny(now) California. I am overhauling the leaky carbs on my newly purchased GL1500. I have veiwed the carbbalancing article and video several times. We have a four gas tail pipeanalyser (CO, HC O2,CO2) at the shop that I used to dial in the mixture for every thing from old Afla's to MGB's, as well as for emissions testing. Has any one used one on a GL1500? I am hoping to set and balance theidle mixture for both sides by moving my probe from one tail pipe to the other. I am expecting the mixture to come in some where around 1-2% CO with HC around 100-200, which would be typical for a Honda car using the "lean drop" idle mixture adjusting procedure. I will make sure the air injection is disabled soo it won't dilute the mixture. Looking at the path of the gases through the mixing chamber in the exhaust I suspect that the left tail pipe will reflect the right bank and right tail pipe the left, but I don't know yet how it will come out.



My goals are low emissions, good fuel economy, and smooth pickup off idle. Has anyone tried this before? I plan on taking some pictures and posting my results if successful.

Thanks!
 

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It aint rocket science
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There is a collector box behind the headers and in front of the mufflers where gases from both sides are mixed together. So no, it is not strictly a one pipe one side deal.

I might be wrong.:ssshh: Others will chime in.

JD
 

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So in reply to my own post, after a series of misadventures getting the carbs sealed up - they were leaking gas, which started me off on my adventure, I have the carbs leak-free, balanced and adjusted very close to ideal. There is a correlation between the two pipes and the carbs, but it is a bit fuzzy- if one carb adjustmentis way off, the reading in the opposite tail pipe will also be off, just not by as much. The left pipe corresponds to the left carb and vice versa.

To establish a base line, I checked the compression and replaced the plugs. One cylinder came in at 140 psi, the rest at 150 psi. The one with 140 came up to 150 on the second check, but there was a slight ring of rust on the business end of the plug, which makes me think it may have a slight head gasket leak. The previous owner had straight water in the cooling system, and not enough of it, so I am concerned. However, after getting it running after the carb work, it hits solidly on all 6 cylinders and doesn't over heat, so I am not going to stress about it just now.

After cleanling the carbs and replacing the float bowl 'o'rings, metering needles and diaphrams and then taking them back apart and putting the original metering needles and diaphrams back in (the replacements poured raw gas out of the main circuits at idle- not good)I used a "smoke" machine to check for vacuum leaks. This tool produces a durable, non-toxic smoke at 2-3 psi and allows me to fill the intake tracts with smoke to see if any leaks out through split hoses, leaky intake gaskets, etc. All was good.

I have several vacuum guages, including one that has a small hand pump on it. I used it to calibrate another guage right at 15 " of vacuum and then used the two of them to balance the carbs.

After a short test drive to warm it up with the plastic still off and bits hanging in the wind I stuck the sniffer in the tail pipe to see what it looked like

The center pipe is the only one that goes into the interior of the muffler



The "smog" machine reads HC- hydrocarbons as parts per million- usually unburned fuel; CO- Carbon Monoxide-high CO is indicative of a rich fuel mixture; CO2- Carbon Dioxide, the higher the number the closer to 'ideal' mixture; and O2 - Oxygen, generally there will always be some, if there is very little, it will generally be too rich, too much and it will be so lean it is actually misfiring slightly (HC will be high too). The CO, CO2, and O2 are percentages. My initial reading before adjusting the base idle speed but after balancing:



HC way too high, CO, CO2 too low, O2 too high.

After an initial adjustment things were looking better:



However, the CO is too low- it is right on the edge of incomplete combustion as you can see from the 514 ppm HC. My final adjustment came out like this:

The HC is still a little high, but on a vehicle without a catalytic converter, it is acceptable, as is the CO2. What I was aiming for was the highest CO2 with the lowest CO, HC, and O2. As I turned the mixture adjustment screws in and out the ratios changed- this was about the best I could get. When I unplugged the pulse air injection (this is a California bike) the O2 rose and the CO and HC fell by more than half. If this were a car I was performing an emissions test on, it wouild have been very close to passing. I suspect that there may be some carbon build up on the backs of the intake valves, leaky valve stem seals, etc that is making a perfect adjustment impossible. The bike has 166000 mile on it after all.

I have a Chevy Suburban with a 45 gal tank that will reliably go close to 400 miles on a tank (And that's towing a 20' trailer) so I don't sweat it when I pass the sign that says "Next Services 175 Miles" (CA highway 6 going NE out of Bishop). However, on my Goldwing, I really want to know, as I like the "blue highways" andhitch hiking is not my strong suit. I am hoping to get a reliable 40+ MPG after my work.
 

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overkill here...muff has a mix chamber and once you get the carbs right and ready to go its just a 1 screw setting that you can practically do by ear.
 

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True, but look at how much fun I had playing with my toys:banana:
 

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yeah!...i guess your right!....when i have nothing to fix i dont know what to do with myself on weekends(winter weekends)
 

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Numbers look good - Back when we had a 4-gas we'd just plug one of the pipes and tune for best CO & HC dip after working the idle drop for baseline (the incerease in backpressure is insignificant at idle...)

I've got an old-school single-gas here now, but still work more with the idle-drop then off-idle driveability... MPG from the carb will come more from proper jetting, so often it's better to clean-up the feathered cruise speed (2.2-3K range) with rod/jet combinations before going back to work the idle mix (followed by WOT, of course) since the circuits are cumulative (idle still bleeds at WOT).

It'll be fun to hear what MPG you're getting once it's all back togetehr and you're a few tanks in... ;)

Nice work!
 

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Thanks for the reply- it's always good to have feedback when venturing into unkown territory. I have a few other things to do to it before putting it on the road on a regular basis, including having a look at the splines on the pinion gear, changing the brake and clutch fluid, checking the fork bearings for play, etc. I see you have a GL1500 with a lot of miles also. What has gone wrong (if anything!) with yours, and what kind of fuel economy do you get?
 

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By the look of your pipes, I'm guessing that your bike is about 10-years newer than mine, and there hve been a few changes tot he fuel delivery and emissions packages, but...

Really, not much has gone wrong... The factory electroluminescent lighting on the saddlebags failed, and ... well the damned headlamp was burning bulbs... Alternator dropped a little after 60K, nothing more than worn brushes (changed brushes, re-trued/ cleaned slip-ring, changed bearings; full output was restored) Fork sealsleaked due to shagged fork bushings at about 50K (still had factory fork oil, according to all records). Aside from that -- a few dirty switches and some serious bug-strikes are about all that's 'gone wrong'... I'm hoping the headlight-bulb issue relates to the broken reflector fulcrum piece (in all fairness, I get about 2.5-years outta a set of bulbs, which is better than the same bulbs to in my small car)

I'm on my 5th set of the little chrome acorn nuts that hold the pads onto my highway boards up on the engine guards though... :action:

I can get 24mpg (and strangely my rear tire wears out about 5k-8k miles early) one-up no trailer or I can see 40-42 (2-up & towing) when touring below about 72mph (aero-drag sucks mileage to about 35-37 for higher touring speeds)

Plenty of guys here can offer feedback on the 150K mile bikes... I'm sure they'll post-up with some of their experiences.
 

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grambo wrote:
overkill here...muff has a mix chamber and once you get the carbs right and ready to go its just a 1 screw setting that you can practically do by ear.
Yes the GL1500 is reasonably forgiving. But it's a good thread, interesting to see how grambo got there.
 

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I took the bike on it's first big trip yesterday and got the answer to my concern about the head gasket when it began blowing coolant into my face as the overflow tank filled up from combustion gasses getting into the coolng system and forcing the coolant out past the radiator cap. This only happened on long hills at 70-75 or after a hard run at 75-80, however it put enough of a damper on our trip that we decided to return home rather than risk getting stuck out in the boonies. I would stop and add about a cup of water directly to the radiator, but couldn't suck coolant out of the overflow tank, so my solution was to place my windsheild cleaning towel over the cap area of the resivior- no more coolant in the face. In 400 mi I only added a pint to the cooling system. The temp guage never even got to the middle of the guage (Average air temperature in the 30-60 range- may have helped). Any advice on replacing head gasket(s) at 167,000 miles? Should I just replace the engine?Or just the one head gasket?
The good news is that my fuel economy is better than others have reported- 38.1 MPG low, 41.5 high, running at 65-75 to 80 on mixed freeway and winding roads. This gives me a theoretical range of 240 mile before runnning on fumes- not bad.Thanks for all your help!
 
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