hard starting

[jeffro1954]

Need some trouble shooting suggestions on a 1978 XS1100 that starts hard. needs to crank for quite a while (with charger on since it takes a while) with throttle held wide open. Takes awhile then it will fire, not on all cylinders but after maybe 10 seconds or so they all fire. runs a bit rough at low speeds and idle (some small backfiring in pipes) but twist the throttle and it runs great. I did mess with idle mixture (oops) and some synching, but need to do it again. wondering if its combination of idle mixture and synching or if it sounds like an obvious float issue. Thought I was pretty careful with float height. plugs look pretty wet after it turns over a few times. Seems to me since I have to crack the throttle wide open to start something is throwing too much gas in the cylinder right away and flooding it.

[DGXSER]

Could be, but remember it takes vacuum to raise the slides. Even at full throttle if there is no load, the slides do not raise up. So it is still only drawing so much air with the throttle plates open.

The plugs are wet and not firing does imply to much fuel to fire it up. Since you have vacuum operated petcocks, have you tried putting the bike on prime and let it set for a few minutes? See if you get fuel flowing out the air box or back of carbs as in floats not sealing. This could be the problem, and let the fuel level be very high in the bowls. JAT

Otherwise, are you sure your getting consistant spark? Have you checked the pick up coil wires? An intermittent miss can sound like it goes away at higher rpms.

[soccer4m]

starting

Try these
1. change oil and smell to see if there is a scent of gas in the oil, if so, your carb float and seat are leaking
2. check to see if you have the right spark plug
3, try a quick spray of instant start in the carb intake, or air filter intake to see if that helps it catch quicker
4. are you using the choke knob when its cold?
these are the things that I would try first with this bike to narrow down the problems,,,,,keep us informed, Mike in Sun Diego

[jeffro1954]

hard starting

I do try starting in prime position since I don't trust the petcock vacuums, plus there is usually only a gallon of gas in the tank. New plugs put in seemed to help it run a bit better, but not much improvement in starting. I keep thinking I should try the starter fluid method.
I have thought about the coils and the wires, one of the wires is showing lots of wear. Not sure I know how to check those, may need to take it to a shop to check that out to be sure. once I've started it, I can come back 2 hours later it will start right up, but if I wait overnight..............I'm starting all over. Haven't noticed any gas coming out of the air box. Have tried the choke with no results. I wonder if the gas can get into the crankcase without the gas also coming out the airbox?

[DGXSER]

Gas can get into the crankcase and not come out the airbox, but your oil level would be high. Also oil will smell like gas as Mike suggested.

If it starts fine when hot but not when cold, it is a choke /fuel issue typically. Try this, crank the engine over just a few times and look at the plugs, see if they look wet then. I am almost wondering if the choke it way lean, but then the plugs get to wet ti fire before the mixture gets right?

As tot he wires to test. Test the high tension wires by removing the end caps, unplugging coils from the low wires (wiring harness connectors). Then read ohms from end of one plug wire to the other. IIRC, should be 15k ohms +/-10%. Then check the low side, should read 1.5 ohms +/-10%.

As to the pick up coils, you can disconnect wires from harness and measure resistance across them. Then wiggle the wires all around moving your fingers around on the wire as well. If the resistance changes, you have a bad wire.

[Ken Talbot]

Most likely you've got some plugged jets in the bottom of all your float bowls. Search for articles about 'float bowl spooge hole', or go into the middle of a thread here. You should not need to crack the throttle at all when starting.

[SFerinTEXAS]

May I ask if you or anyone else has removed the cam chain tensioner recently? I jumped a chain tooth that way and it would only start with the throttle wide open.Ran pretty rough too . Doubt I could have drove it tho.

[newc4]

My 78E was a hard starter too. Found that my plugs were almost crusted shut, which yours aren't. After I cleaned and gapped them it was still a hard start. Timed it and it starts at a touch.

[CatatonicBug]

Most likely you've got some plugged jets in the bottom of all your float bowls. Search for articles about 'float bowl spooge hole', or go into the middle of a thread here. You should not need to crack the throttle at all when starting.

+1 to that. Those jets are easily plugged, since any gunk that falls into the carbs will get sucked through there first.

[jeffro1954]

DGEXSER is correct, a few turns and the plugs are wet. sometimes it will pop once or twice when cold like it's going to start and won't. After long cranking I can get it to fire. After it's been started, it will start at the touch of the button.

Clearly appears to be a fuel issue then. I've had a timing light on it and that was spot on.

No fun to pull the carbs again, but sounds like only way to correct this. Actually the carbs aren't as bad as trying to put the bottom of the air filter box back on. Hate that thing.

[CatatonicBug]

Actually the carbs aren't as bad as trying to put the bottom of the air filter box back on. Hate that thing.

Why? It's 4 wing bolts, held in with retainers. As long as you don't remove the upper screws, they should go back together almost all by themselves.

[SFerinTEXAS]

I've had a timing light on it and that was spot on.

Not suggesting I think a jumped t/chain is for sure the problem but a timing light will not tell its not.

I do not believe a stopped up jet will make it too rich

[jeffro1954]

Didn't touch the upper screws, seems as though either the new air filter is too tall but it's for a xs1100, or somehow what it screws into got wedged too high. Mine is far from a simple put back into place.

As far as timing chain, if it jumped wouldn't it be pretty rough all the time?

[SFerinTEXAS]

I would think so but hoping isn't knowing. Just need to take the valve cover off to make sure. If it was running good before and no one has messed with the adjuster for certain then its not likely the problem. In my case it was running good and I didn't know not to mess around with the chain while the adjuster was removed so when the same symptoms you have appeared it was obvious.Good luck and strive to persevere.

[soccer4m]

starting

So, try sticking a long skinny stick in the oil hole, pull out and smell the oil, if it has any gas smell, change the oil asap. When the oil is thinned out with gas it starts hard.

Also try the quick spray of instant start in the intake and see if that helps.

If its oil in the gas then the float valve, needle is not sealing correctly and should be cleaned and or get a cheap rebuild kit. When I redo mine I clean the carbs and turn upside down so the float seals, then blow into the gas intake hose,left side pair and right side pair.... if any air goes in, one or more of the carb float needles are leaking......I can usually hear which carb it is by the whooshing sound.

How does the bike run once it fires up and it warm? Does it run down the street ok??

Keep us informed