1983 Spectre 1100

I got the fuel problem fixed on the KZ1100, which was fixed by a new float valve and needle.
Now I have an issue with the Spectre 1100. After I fill it up with fuel, after about 45 to 55 mikes on that tank, it starts cutting out like it is running out of fuel. If I flip it to reserve, the bike runs fine, and I get to the nearest gas station to fill it. I have gone alot more miles (near 100, I think) previously before switching to reserve on the Spectre. I have removed the fuel tap twice now and find no crud or anything amiss (that I can see). One thing I notice is the plastic fuel strainer that attaches to the fuel tap, it appears that the on position flow gets its flow from pretty high in the tank, with the reserve flow section being rather high up also. The strainer looks like new with no noticable issues. My question is, has any other owners of these bikes had similar issues, switch to reserve at 50 miles? Any ideas what might be the issue? The bike does not appear to be dumping fuel any point, starts, idles, and runs great. I don't remember how many gallons it took to fuel after switching to reserve at about 50 miles then topping it off.
The tach has been jumping recently, are the odometer miles an electrical input? And could they be erratic also? I thought the odo was a mechanical connection to the wheel, correct?
The speedo reads steady and appears to be correct...to 85mph anyhow...

You sure you don't have a vacuum leak? The tap is vacuum driven unless you have it straight up and down in the on position.
Another possibility is the tap needs a rebuild.

ODO is cable driven along with speedometer. I can go atleast 100, usually 130 miles without hitting reserve on my KZ1100 shaft

According to Partzilla, the Spectre D1 has an electronic speedometer like the LTD, while the D2 has a mechanical (cable driven) speedo.
Either way, 50 miles to reserve is way too soon.
Is it the factory correct petcock for that year and model?

the petcock appears to be original...it looks the same as the one on my kz1100 of the same year...what wears out on the petcock to require rebuilding...and if it runs fine after switching to reserve wouldn't a vacum issue still present itself? the speedo and tach look the same on both bikes.

Generally only two things wear out in em. One is all the rubber bits, ant the other is the seat that the little oring seats on. Typically, they do not cause the kind of problem you are having.
I wonder if it is possible that the main diaphragm or the vacuum hose has a tiny little pinhole leak that allows the valve to slowly close?
How many miles have you been able to ride on reserve?

I cant say for sure about miles on reserve because I always get gas ASAP after I switch it to reserve. It happened to my son when he rode it the other day, and he said it happened at 45 miles and he switched to reserve, then it had 85 miles on the resetable when he was done, still on reserve, so I don't think he fueled it. I always reset the odo when I fill it up. I am pretty sure it took 1.7 gallons to fill the first time it happened, so at 50 some miles, the mpg is about normal. I will inspect all the vacum lines and components more closely.

If he rode 40 miles on reserve, that blows my leak theory. A clogged gas cap vent can cause those symptoms, but usually a a LOT fewer miles.

so a vacume issue would affect the reserve also? I will check the cap also. the bike is still rideable and i suspect it would run on prime position if need be...

You might try running (not necessarily ride, just idle) with the cap open once it needs switched to reserve. That might be a way to confirm if the cap is the problem.

tthunderdan wrote: so a vacume issue would affect the reserve also? I will check the cap also. the bike is still rideable and i suspect it would run on prime position if need be...

The vacuum line pulls on the large diaphragm to allow fuel flow in both RUN and RES positions. When the engine is off so there is no vacuum, the valve shuts so there is no flow in those two positions. The PRI position bypasses that business so fuel flows all the time.
As Matt said, the next time you ride and it starts to act up, open the cap and see if that cures the problem. It is best to do that when the tank is not completely full. If that does not do it, try running on PRI. Do not leave it in the PRI position when you park it, just in case one of the float valves does not seal perfectly.

So I figured I would look for another issue on the cutting out . I was going to check the coils this morning and this is what I found...a loose connection on one of the coils...it was just hanging there, getting contact most of the time...I will take her out n see how she behaves in a bit...