Slight hesitation at steady throttle? Lean?


Information and questions on GL1100 Goldwings (1980-1983)
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driven
Posts: 7
Joined: Tue Apr 30, 2013 7:18 pm
Location: Hampden, ME
Motorcycle: 1981 GL1100 Standard

Slight hesitation at steady throttle? Lean?

Postby driven » Wed May 08, 2013 6:54 am



Just finished my '81 GL1100 winter project about a week ago which included a complete carb rebuild. Starts and idles very smooth. Acceleration is fine. But at a constant throttle, specifically cruising at 2500 to 3000 rpm I am getting a slight hesitation or hitching. Sync looked good, valves are properly adjusted, nothing else amiss. It feels like it's lean, though my plugs look normal (see pic below). According to what I've read the idle circuit is in play throughout the entire rpm range, so I'm thinking of going to 2 turns out. They are at 1-1/2 now. Also want to recheck float level as I know that could also cause these symptoms. Any other suggestions? Thanks!!
Plug pic
Plug pic



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virgilmobile
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Location: Denham Springs,La.
Motorcycle: 1988 GL1500 I
Previously owned
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81 GL1100
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Re: Slight hesitation at steady throttle? Lean?

Postby virgilmobile » Wed May 08, 2013 7:14 am

One way to verify if it is "lean" is to operate the bike in the suspected RPM range and add a bit of "choke".This adds just a bit of fuel without changing the throttle setting.As you add the choke fuel it normally will begin to load up and run worse.if it picks up and runs better,it is running lean in that rpm range
If it is lean in just the 2500 rpm range,lift the main jet metering needle 0.10" with a washer.Thats inside the slide.
If the "choke"cleans it up in the lower rpm range also (1500-2000 rpm) double check the float measurment.Low by a few mm. Can overall lean out a engine.

driven
Posts: 7
Joined: Tue Apr 30, 2013 7:18 pm
Location: Hampden, ME
Motorcycle: 1981 GL1100 Standard

Re: Slight hesitation at steady throttle? Lean?

Postby driven » Wed May 08, 2013 7:34 am

Thanks! I never would have thought to shim the needle. Good call.

I have tried the choke trick. Even when warm if I pull the choke all the way out while riding it stays at 3000rpm with no throttle applied. Choke when warm should cause it to stall in my experience, so it does indicate a lean condition. Just not sure what the cure is - idle screw, float level, or needle shim. Wish I could try the shim without pulling the carbs! But the frame is in the way... Guess the carbs are coming back off.

driven
Posts: 7
Joined: Tue Apr 30, 2013 7:18 pm
Location: Hampden, ME
Motorcycle: 1981 GL1100 Standard

Re: Slight hesitation at steady throttle? Lean?

Postby driven » Wed May 08, 2013 8:11 am

Any chance you meant 0.010" ? 0.10" is pretty thick for a needle shim. The copper washers I have are about 0.030". Not sure where I'd find 0.010 washers unless I made them out of shim stock.

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virgilmobile
Posts: 7663
Joined: Sun Sep 19, 2010 5:39 pm
Location: Denham Springs,La.
Motorcycle: 1988 GL1500 I
Previously owned
78 GL1000
81 GL1100
82 GL1100 I
83 GL1100 I
83 GL1100 standard
84 GL 1200 I

Re: Slight hesitation at steady throttle? Lean?

Postby virgilmobile » Wed May 08, 2013 8:59 am

My bad 0.010".my bike fluttered at 2500 rpm and just a little choke smoothed it out.
I removed the needle from the slide and added the max. Ammount of spacers.Measured them and replaced with a flat washer.Too thick and the needle wont lock back in.

driven
Posts: 7
Joined: Tue Apr 30, 2013 7:18 pm
Location: Hampden, ME
Motorcycle: 1981 GL1100 Standard

Re: Slight hesitation at steady throttle? Lean?

Postby driven » Wed May 08, 2013 4:11 pm

Took the carbs off. Nothing looked amiss. Turned idle screws out half a turn and raised the float level 1mm. Also did a bench sync.Test ride showed marginal improvement but still a slight hesitation at a constant throttle. Also checked for vacuum leaks but found none. I also tried holding it at 3000 rpm while parked in neutral and didn't notice anything obvious. Seemed smooth without a load. I am starting to wonder if what I'm feeling is in the drive line and not the motor. Like a bad u-joint or something. I'm borrowing a carb sync tool tomorrow. That's my last try as far as carburetion goes.

driven
Posts: 7
Joined: Tue Apr 30, 2013 7:18 pm
Location: Hampden, ME
Motorcycle: 1981 GL1100 Standard

Re: Slight hesitation at steady throttle? Lean?

Postby driven » Wed May 08, 2013 4:22 pm

I will try shimming the needles if the sync doesn't help. Where can I get shims? Regular washers are too thick.

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virgilmobile
Posts: 7663
Joined: Sun Sep 19, 2010 5:39 pm
Location: Denham Springs,La.
Motorcycle: 1988 GL1500 I
Previously owned
78 GL1000
81 GL1100
82 GL1100 I
83 GL1100 I
83 GL1100 standard
84 GL 1200 I

Re: Slight hesitation at steady throttle? Lean?

Postby virgilmobile » Wed May 08, 2013 7:12 pm

I was lucky.My work has a lot of leftover hardware. I found a drawer with a bunch of washers.I can suggest a few things.
Turn the slide upside down,lift and push the needle.Measure the available space.Go to a hobby shop,Ace hardware,electronic shop to search for a washer.Take the needle with.
Iffin you don't have any option,let me know,I can drop a handful in a envelope for you to play with.

driven
Posts: 7
Joined: Tue Apr 30, 2013 7:18 pm
Location: Hampden, ME
Motorcycle: 1981 GL1100 Standard

Re: Slight hesitation at steady throttle? Lean?

Postby driven » Wed May 08, 2013 7:18 pm

Thanks man! Just started another thread about a loose driveshaft. This may be what I'm feeling. We'll see...




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