Time to replace the coil packs?

Shdwdrgn post=927688 userid=41747Think the carbs are ready to test, but when I went to check the (dry) float heights, they're supposed to be at 18.6mm, however every one of them was actually about 5mm higher than that.  I have had a constant issue with fuel flooding into the air intake chamber and suspect this could be a cause?  However when I first built the bike I did in fact have a rig on the workbench and took the time to adjust the floats using a clear tube from the drain nipple.

I can't find the old coffee can I had rigged as a temporary gas reservoir, so I'm getting a small fuel tank ordered off Amazon that has the same 1/4" connector on it, hopefully will arrive tomorrow.  Then I can see where the fuel actually sits (and confirm all of the valves are still working correctly).

   That sounds like the tiny spring loaded pins in the float needles are stuck in the depressed position.  Confirm that the needle pins are free to move before proceeding with clear tube adjustment.

   That said, we don't pay much attention to float height measured on a scale.  Those crude old floats with flexible metal frames don't have the consistency of stiff, modern floats that are relatively quite precise by comparison.   +/- a couple mm at the dry float bulb should be well within in range of clear tube fine tuning.  "...supposed to be at 18.6mm, ..."  Trying to split into tenths of a mm seems futile.  The differences in stationary fuel level will be insignificant between say, 18.5mm and 18.6mm dry float height.  Fuel is constantly moving around in the bowls when being ridden, so a rough average is the best that can be expected.

   Aftermarket float needles and needle seats can have a surprisingly large effect on fuel level too.

   No one has mentioned choke plungers yet.  Plungers leaking when closed will contribute to rich running when when fuel level is correct.

   Vintage carbs offer many lessons for the vintage bike enthusiast.  Patience and tolerance of frustration have been two of the most important for us.

   We documented our development over the past few years of a process that eases setting wet fuel height.  It's a variation of clear tube fuel level tuning that makes fuel level easy to visualize and adjust and, adds safety by using a less-volatile gasoline substitute when working in an indoor shop.  It's a fairly long thread.  Something within may be of help:
www.kzrider.com/forum/3-carburetor/61368...n-setting-fuel-level

Good Ridin'
slmjim & Z1BEBE

bound wrote:

I believe that an old bike just needs some time and elbow grease. I really hope that you are able to get the float levels figured out. I had the same problem!!!

Looks like my browser crashed before it saved my reply here last night...  But yeah, it's a good old bike, I practically scratch-built it combining parts and frames from two bikes that had been chopped up, so I already adjusted the floats once years ago.  I don't know if I simply didn't do it right or if the valves needed time to "break in" to get an accurate measurement, but I was surprised at how far off they seemed to be.  I'll get it figured out though.

@slmjim+Z1BEBE Yeah I also thought it was odd that this would be given in fractions of a mm, especially when the tolerance is supposed to be 1-3mm below the gasket?  So it's not THAT critical and I'm certainly not going to get them accurate down to 0.1mm  I save that nonsense for the 3D printer where 0.02mm actually makes a difference.

Anyway, just came back in from checking the fuel level in the bowls.  All four valves seem to be working correctly and shutting off the flow when full.  I thought it was odd the measurements were all in a line but the last one broke the trend.  In order from left to right they measured at 1mm, 2mm, 3mm, -2mm (this one was above the gasket line).  But that means the roughly 22-23mm height the floats were originally at is definitely way above the line.

So now the bowls have been drained again and I left the bank of carbs laying on its side to air out, and tomorrow after work I'll try to get the bowls off again so I can make a final adjustment of the floats.  I think #1 and #2 are in pretty good shape, just need to touch #3 and #4.

And maybe someone can check my process here, but I think it's pretty straightforward?  On each bowl I hooked the clear tubing and opened up the bleed screw a couple turns while keeping the other end of the tubing above the carbs.  This allowed a little fuel into the line but trapped an air bubble each time right at the drain nipple, so I raised up the end of the tubing a little which forced the bubble back up into the bowl.  Then as I dropped the tubing back down again making sure it stayed full of fuel with no air.  At this point I held the ruler up to the side of the carb and dropped the end of the tubing down another inch or so, then held it in place for a moment as the fuel level filled up and stabilized, and that's what I measured against the bottom side of the gasket.  Does that sound about right?

   If the results are repeatable over multiple tries you're on the right track.

Good Ridin'
slmjim & Z1BEBE