81 GS1100 with 29 smoothbores.

[Don R]

I rode it today and got some mid range A/F numbers. It's still fat in the middle although a bit better with the 120 jets than the 125's. I'm going to pull the carbs and drop the needles a notch or two. While apart, I'll catalog the slide number, jet needle and pilot jet sizes.
I went to the industrial park by my buddy's dyno shop, where I keep my hot rod stored in winter, there is a few block long street with no driveways or side streets, I hammered the gs a little and was amazed at the sound of the Kerker echoing off of the warehouse buildings.

[Don R]

I went to the storage unit and traded a Honda for the GS. The petcock stuck or the inline filter must have plugged, It was extremely lean so I just got it home. Later I tried it again and it ran fine, still too rich though. I pulled the carbs and checked the slow jets, I ordered the next smaller two sizes before I noticed the slides are 1.5's, everything I've read says the Suzuki wants 2.0's. which I can buy for $75 each. That's a deal breaker so I'm going to list the smoothbores for sale and hopefully buy a set of 36's. I did buy a set of Sudco carb adapters to put the 29's on a CB750, they may be the next to last set in captivity. Z1 enterprises has one more set.

[Don R]

I got the new jets from Z1 ent. right after I found a nice box of them in my brothers tool box, I dropped the mains and pilots both 2 sizes and left the 1 size over air jets. It's a happy GS1100 now, the air fuel ratio never got fatter than 12-1. I wrote down the Greg Cope jet suggestions from the APE web site.
I'll likely keep the 29's on it unless someone wants them badly enough to pay close to what they are selling for. I did finally find and buy a set of the intake rubbers that fit the Kawasaki - Suzuki carb spread to a cb750 SOHC engine.

[Don R]

Apparently when it went lean leaving storage it was out of gas, When I got home and it ran good I must have slopped some from the right side over to the left side. When I left tonight it ran out and picked up when I got the petcock onto reserve. No odometer and I didn't think the gauge was on empty yet.
Anyway, I'm getting a kick out of the afr meter. I can see the fat area of the fuel metering caused by the 1.5 slides. It certainly runs better than it did going full rich. Still no air filters from APE. Jegs held my money for a month with no filters.
A fill-up from reserve was 3 gallons. I used 5 gallons of evaporust in it. so reserve is pretty deep.

[Grimly]

Still no air filters from APE. Jegs held my money for a month with no filters.

Might be something to do with the passing of APE's founder.

A fill-up from reserve was 3 gallons.
I used 5 gallons of evaporust in it. so reserve is pretty deep.

Reserve should only be about a gallon or so. I had a running-out symptom on mine long before it went onto reserve, turned out to be varnish on the sieve filter on top of the pick-up pipe.

[Don R]

It's a new K&L petcock, I can barely turn it bare-handed. This bike loves to mess with me. I'm enjoying learning about it, thanks for all feedback.

[Don R]

I see I needed to make an update.
All of the data from my exhaust probe was corrupted, so what I believed then, was bad information. I also got a set of RS36's and the exhaust probe said they were also rich, the plugs didn't agree but I dropped a needle slot and a jet size.
Recently I made a 2.5" stainless steel O2 sensor adapter that fits between the 4-1 header collector and the muffler on the Kerker. Now the AFR readings are more consistent and after living with the gauge for a while I can see that the "as delivered" carb settings were probably correct.
I've now returned the jet and the wide-open throttle numbers look good, part throttle was still lean so yesterday I returned the needles to the middle slot, where they were and am hoping for some dry weather for a last good ride before winter puts an end to it.
I also got a set of Oval K&N's for it, I'm looking forward to watching the AFR changes in a side wind. If needed, I'll make an air-box type of wind control for them.
Why did I do all of this? Even this old dog enjoys learning and fabricating. I still have not been to the drag strip on it. Am I Chicken? Probably yes. I have made the clutch slip iin second or third gears on an industrial road so with traction I'll probably find that it needs some work.

[KiwiAlfa156]

Today I rode with the wide band O2 sensor and again the A/F ratio was nearly 2 points different depending on if I was going into or with the wind. With the wind from the front-left it read 12.2 to 12.5-1 when I turned around and rode with the wind at my right rear the ratio got over 14-1. I can only attribute it to the effect of the wind on the pod filters on the 29's. I can see where the factory airbox is a solid design. Next, I may make a removable wind shield just as a test.

Pod filters and open bell mouths are notorious for this. I remember tuning my 83 GSX750E (16" front wheel) back in the day after fitting a nice set of chrome cap oval K&Ns and an air jet correction kit, and being amazed that I could effect the mixture at cruise by changing the position of my knees. Then in a rainstorm the K&Ns got soaked and it blubbered until they dried up enough to pass enough air. I swore off fitting pods after that. The minor top-end improvement that I'd occasionally access wasn't worth the grief.