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1985 GL1200 LTD Idle Problems

8793 Views 11 Replies 6 Participants Last post by  linux2

My 1985 LTD Goldwing has always had this weird idle problem, but I haven't really taken the time to figure out what it is. It runs fine once warmed up for the most part. However, when it's idling or cold it doesn't seem to be consistently firing on all cylinders. Sounds like one of the left-side cylinders is firing late or getting too much fuel (sitting on the bike facing forwards). That doesn't bother me too much, but I have a feeling it's connected to why the bike has trouble idling in the cold.

Anyways, I took a video of this and here is a link to it:

In the video it's at 900rpms cause the engine is still cold, but before I fiddled with the screw I mentioned in the video and the idle screw in the center of the bike it was just stalling out. It comes up to around 1,100 rpms now when warmed up.

Let me know what you think or if you have any ideas. I did change the timing belts when I first bought the bike, but it's been pretty much the same since day one so i don't think the timing is off. When I bought it the idle was actually set a bit high around 1200-1300 rpms so I figure maybe they had done this to prevent it from stalling when cold. There are no error lights coming on on the computer under the trunk. It has 43,xxx original miles.

Any ideas or things to try is greatly appreciated. Also, as a side note, the exhaust smells pretty bad, like it's pure gas. A very rich smell. Almost enough to make your eyes water. Also, when the engine is above 3,000 rpms it seems to vibrate. Pulling the clutch in and letting the RPMs drop down makes the vibration disappear. It's more like a buzzing vibration which might be normal but I've never ridden any other Goldwings. Maybe related? It vibrated the same before and after changing the timing belts as well as changing the u-joint and lubricating the driveline and seems to be completely engine related.

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Maybe she is running rich and drowning the spark plug? Sticking/dirty injector could cause that. Have you tried running Seafoam or similar through the tank?
I've had the injectors out before but I didn't get them checked. Any easy way to check them?

I do know that the cylinder is firing from time to time. Maybe every other time... I did replace the plugs when I first bought it and I guess it never crossed my mind that one could be bad. It does have spark, at least there is current through the cable to the plug. I'm assuming the plug is actually firing (checked that not too long ago). I haven't tested compression though but I could check that fairly easily. The exhaust pipe gets hot about just as quickly as all other other cylinders (right at the header of course).

I'll have to test compression and check that plug to see if it's got good solid spark. Just need to know how to test that injector as well.
Your air control may be stuck and/or sticking. When the engine is judged "cold", the injector duration is increased causing more fuel to be introduced. This is done by the control unit. At the same time, the air valve/aux air valve/air control valve (whatever you choose to call it) allows more air in, increasing your idle speed. Your idle speed is not increasing. A cold fuel injected bike should idle @1500 rpm or so. As the engine warms, the injection rate is cut back and air valve closes resulting in less air and fuel. Consequently, the idle drops and smooths since the mixture is closer to what the ecm thinks it should be. Check and clean your air valve. I suspect you're fouling plugs because there isn't enough air introduced when it's cold.
Oh interesting. I was always wondering why my idle wouldn't kick up. Where is that valve located? I'll pull it out/clean it if it isn't too hard to get to. When I bought the bike I remember it having the idle set wrong, but it never miss-fired. I've only put on maybe 1000 miles since then.

I do remember thought when I was with a friend of mine and we pulled onto the highway and I really let the throttle open (probably all the way) and he said there was a huge amount of black smoke. I suspect it was built up carbon in the pipes, but probably caused by the constantly low idle when cold.
first thing i'd want to do is changeout to new plugs and then try to get the throtlle plates synced,because i have a feeling that someone may have tweaked the wrong screw when trying to adjust the idle at one time or another
if you've had this for awhile what kind of miles do you put on this bike and is it just local intown driving or on highway at 3000+rpms etc
but there are lots of things that may be going on here

whoa after listening to the video and you talking about adjusting the idle,i think you have definitely been trying to adjust the idle incorrectly and as such most definitely have the throtlle sync way off
Hey, Thanks for the info. I'm going to swap out the plugs tomorrow/take a look at the ones in there and see what's going on. I'll update this tomorrow with my findings. Hopefully swapping the plugs will improve things a bit and then I'll see about syncing the throttle plates. I have adjusted the idle using the idle screw in the center, but I also adjusted that screw in the video since I read somewhere to turn that to adjust the syncing, but yep probably just made it worse.

I really do a combination of around town and highway. I bought it last march and have put in maybe 1,500 miles since then. I've done the timing belts, rear swing arm bearings (a complete pain), replaced ujoint cause the engine vibrated and a lot of people seemed to think it may have been that, but it was just the engine vibrates above 3,000 rpms.
Just an update, here is where I'm at now:

Runs a whole lot better with new plugs and the best balancing I could do for now (need to pick up some tools which I ask about in the video). Namely I need some kind of fitting to go into the screw hole so I can hook up the vacuum hose correctly. Even without being able to hook it up correctly I was able to get fairly decent results. the automatic choke seems to work somewhat as well.

Will update once I can actually balance it correct.
Try Wal-Mart's, aquarium section for the vacumn line adapters. Remember: the engine balances left to right. There is no front to rear adjustment on a Fuelie... And set the idle @ 1000 rpm + 50 rpm.


"The automatic choke seems to work somewhat as well."

Trust ol' Ros on this one... You DON'T have a choke on that bike.....:grin:
Haha. I should have put "choke" in quotes. The idle comes back down one it warms up so we'll see how it is tomorrow once I let it warm all the way back up and make some final adjustments. I would have never thought of Walmart in the aquarium section. I'll take a look there probably tomorrow. Thanks.
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