Cold Starting Issue

[Spartanman]

My XS1100 has always been cold blooded but is getting really tempermental in her old age. I've rebuilt the vacuum block, replaced all the octopus fuel lines, new plugs etc.... But even on a warm morning, it can be 5-10 minutes before she'll finally start up, sometimes on full choke, sometimes on half choke, never with no choke. Once warmed up, she runs like a champ and starts up no problem the rest of the day. I think the carbs are OK, only because the plugs look really good and it idles and accelerates without a hiccup. One thing I have noticed is that it starts much easier when the tank is full. After struggling the other day to get it started with about a quarter tank, I filled it up and waited a couple days. This morning, it started on half choke on the second try.

So, this may be an idiotic thought, but those fuel lines into the octupus have some tight bends. Is it possible that one or more are bent so much they are restricting fuel flow and that the full tank adds just enough pressure to force the fuel through them? Any other thoughts, suggestions are welcome.

Thanks

[DiverRay]

Yes, that may be part of it, but it usually keeps the bike from running properly at 55mph as well. I would think the problem is the holes in the float bowel used for the enrichment circuit. Also, do you have ethanol free gas available? If not, that is probably your biggest problem.Ethanol gas in a tank that is NOT FULL will start to go bad and change colors within two weeks. A full tank will go about one month before starting to change. When I know I'm going to park my bike for even a little while, like two weeks, I turn off the fuel and run the carbs dry. When I go to restart, put the petcocks on PRIME for a minute and then turn to on. The special will not flow gas until the engine is running, so you need to start it on prime.

[Spartanman]

Yes, that may be part of it, but it usually keeps the bike from running properly at 55mph as well. I would think the problem is the holes in the float bowel used for the enrichment circuit. Also, do you have ethanol free gas available? If not, that is probably your biggest problem.Ethanol gas in a tank that is NOT FULL will start to go bad and change colors within two weeks. A full tank will go about one month before starting to change. When I know I'm going to park my bike for even a little while, like two weeks, I turn off the fuel and run the carbs dry. When I go to restart, put the petcocks on PRIME for a minute and then turn to on. The special will not flow gas until the engine is running, so you need to start it on prime.

Thanks. I don't think it's the ethanol. I run a fuel stabilizer year round, and when I take the bike out of storage after 6 months of Michigan winter hibernation, it's not any harder to start than it is now. But I've never used the prime setting on the petcocks. Will give it a try.

[bikerphil]

Yep, make sure the starter jet is clear down the carb bowl tunnels...

[DEEBS11]

This sounds like a classic case of valve adjustment issues. The gap on the lash is closed and the valve does not sit tight on the seat. You might actually have low compression issues. No gas is getting sucked into the cylinders on the first stroke. Seen it many times. Check those valves and then do a sync.

[Socer4m]

Howdy Spartanman,,,,I second with DiverRay,,,,,turn the petcock to prime, wait a few moments,,maybe check the inline fuel filters, hope you have them installed, otherwise put them in,,,,,then turn over and see if that helps,,,,I do it all the time with my 81 venture and it really helps cold start,,,keep us informed,,,,,Mike in S.DIego and Pa