tough to start but fine when warm

[tab1324]

I've got an 82 XJ1100 and when I start it up cold, I have to have full choke and it usually dies once or twice before it will stay running. Even then, it only stays running by feathering the throttle for about 5 minutes. Once it's warm it seems to run fine... I've had it out for several long rides with no hick-ups.

I just can't figure the cold start thing out. I've noticed that the #1 pipe is cold while #2 & #4 are hot and #3 is barely warm. This is at cold start only. After bike is warm they're all firing. I've checked for spark at each location and it's good. I don't think it's the p/up coil thing because it's #1 and #3 that seem to be the problem. I've got new plugs in with no change. Could it be someting with the carbs? Choke circuit? Anyone have a thourough understanding of the "choke" circuit on the XJ?

I've been riding all summer like this but it's getting frustrating when I wanna go for a ride to have to sit there and warm up the bike for 5-10 minutes.


Please Help!

[Bubba1954]

One possibility is that number 1 cylinder may have a lazy float valve that may be alowing gas to leak into this cylinder when engine is parked. When you fire it up, #1 is just too flooded with gas to fire at first. However once the bike engine heats up, this cylinder finally starts to fire and runs just fine.

[dragxs11]

Let me know when you figure this out. I have the same problem with one of mine. I rebuilt the carbs and was pretty thorough. I couldn't really imagine what I might have missed.

[Geezer]

The starter jet system (choke) is plugged up. There is a tiny passage in each float bowl that feeds the jet pick up tube. If that tiny hole is clogged, well it runs like your bike does. Pop the float bowls and clean them passages with a bristle plucked from a wire brush.

Geezer

[Ken Talbot]

Here's where to look for that passage:

[tab1324]

The "choke" jet worked but still probs.

Guys, Thanks tons!!! I pulled the carbs tonight (reluctantly) and checked the choke "jet" as described and photo shows. The number 1 and 3 holes were plugged solid. I couldn't clean them out with a wire - the blockage was hard as a rock. I remember the P.O. said he had a hard time with starting too.... Then the bike sat for 2 years before I got it. So this plugging was substantial. I found the smallest drill bit I could find and with a variable speed drill, drilled into the plugs VERY slowly. Unfortunately, I did remove some brass so the holes are now slightly larger than original but the fix worked. The bike started right up and idled on it's own. Still rough but it stayed running.

I checked the #1 and #3 pipes again and they're actually still running cold! I don't get it. Maybe now with the larger holes those two cylinders are idling rich????????

I saw in another thread something about baking the spark plugs in order to get the coils to "seat"??? What??? Is this something I should try?

I don't want to mess around with the mixtures because they're set pretty good as far as my plug color goes.

Any thoughts?

Tom B.

[Winterhawk]

I just use a single strand of an old cable and keep working at it till contact cleaner sprays out. Nice photo Ken.

[thumperjsa]

At first I was thinking coils. But then I remember that 1 and 4 share one coil and 2 and 3 share the other.

If the pipes are cold, then I believe they are not firing up any mixture. Even rich, the pipes should get hot. Are the plugs wet on those cylinders when you pull them?

Might I suggest check the plugs for spark and checking the wires as well.