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1983 Honda GL650I Silverwing Interstate
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Discussion Starter · #1 ·
OK, boys and girls, put your thinking caps on and help me noodle this one out.

1983 GL650I Silver Wing Interstate with 19,000 miles.

SYMPTOMS AS FOLLOWS:

1. Cold engine, choke on full, engine cranks and cranks and cranks. Finally after several attempts the engine fires. (Takes way too much cranking than it should.)

2. As soon as engine fires I have to push the choke just a tad back off to settle the engine idle at 2,000 RPM.

3. Engine idles OK for a bit at 2,000 RPM, maybe for 15 or 20 seconds or so, and then...

4. I hear a fairly loud "click" followed by an immediate increase in the idle speed to about 4,000 RPM ! (Choke still in same position as step #2).

5. Have to then immediately push the choke to about the 1/2 position to get the idle back down to 2,000 RPM.

HERE ARE THE ANSWERS TO THE QUESTIONS YOU'RE GOING TO ASK ME:

1. The carbs have been completely rebuild by me. Been rebuilding carbs on bikes and cars for over 50 years. I know what I'm doing. Carbs first ultrasonically cleaned. All jets then removed from carb bodies, cleaned again, and sized. All fuel and air passageways cleaned/checked again with spray carb cleaner manually after the ultrasonic cleaning to verify open and clear. Used a Randakk's Cycle Shakk rebuild kit. No mods to carbs. Stock jets and everything. Stock airbox and filter.

2. Engine runs like new once started and running. Absolutely no engine performance issues other than the hard starting and the mystery "click" and subsequent RPM increase during starting. Does it every time! The "click" sounds kind of like a switch clicking, and it's loud enough to hear over the noise of the idling engine.

3. New spark plugs.

4. Both of the two TI (Transistorized Ignition) ignition modules (spark units) have been replaced as a check/test. No difference.

SO, HERE ARE MY QUESTIONS:

1. What's the heck is the issue with the hard starting?

2. What in the world is the "click" and the big jump in RPMs after the engine idles for a bit at 2,000 RPM during start up?

Hoping that some CX/GL riders will have some ideas on this or perhaps seen this before.

Thanks for any advice.
 

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1978 CX500 "The Grub", '83 GL650, '82 GL500 Project "AdventureWing", '79 CX500C, '78 CX500 Scrambler
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Assuming you have the original vacuum-actuated petcock, there might not be enough fuel in the bowls for cold starting.
With the kill switch turned to OFF, crank the engine in 2-3 second bursts until the oil light goes out. This will apply enough vacuum to fill the bowls. If the carbs are as clean as described, it should start with no choke.
Also, 2k rpm is too high for idle. Adjust the idle speed adjuster (black knob between the carb bodies) until it's about 1,100 rpm.
 

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To me it sounds like it might be running on one cylinder. The rpm will jump up when both cylinder are firing.
 

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1983 Honda GL650I Silverwing Interstate
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Discussion Starter · #4 ·
Assuming you have the original vacuum-actuated petcock, there might not be enough fuel in the bowls for cold starting.
With the kill switch turned to OFF, crank the engine in 2-3 second bursts until the oil light goes out. This will apply enough vacuum to fill the bowls. If the carbs are as clean as described, it should start with no choke.
Also, 2k rpm is too high for idle. Adjust the idle speed adjuster (black knob between the carb bodies) until it's about 1,100 rpm.
Thanks Randall.

Yes, I do have the stock vacuum-actuated petcock. I'll give that method a try.

Regarding idle speed. I do have my idle adjust knob set for the engine to idle at 1,100 RPM, but that's a fully warm engine. 2,000 RPM is a good cold idle speed for start up while on choke. (I guess I didn't explain that 2K was a cold engine, choke-on idle speed.)

Gonna give your method a try on next start up. Thanks again!
 

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Discussion Starter · #6 · (Edited)
To me it sounds like it might be running on one cylinder. The rpm will jump up when both cylinder are firing.
Right, I know. It does sound like that. That's why I changed out both spark units as a test. And, how the heck does it run so well once it's started. Thing purrs like a kitten!

I have a spark tester for cars that I can probably hook up to the plug wires on the bike. That will tell me if I have a spark upon first moments of cranking.

Thanks for the idea.
 

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1983 Honda GL650I Silverwing Interstate
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Discussion Starter · #7 ·
This couldn't be the starter clutch remaining engaged and the click and subsequent higher RPM are caused by the disengagement?
Thanks for the idea!

I wonder how I could test that? Do you suppose by just holding the starter body I could feel when it was engaging/disengaging?
 

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Maybe you could feel if the starter motor is being dragged by the motor. I don't know. But 650s are hard on starter clutches so it possibly is this.

I had one here that had actually broken the idler gear and was making a lot of bangs and clicks.

Perhaps if you remove the starter you can check starter clutch operation by putting your finger in the hole and manipulating the starter idler. It should move freely in one direction and not at all in the other. I don't know how successful this would be in determining the issue even if it is the starter clutch. Maybe if you start the motor and shut it down while it is still struggling, then remove the starter. The trouble is it may disengage from inertia when the engine stops.

I guess removing the starter, plugging the hole and a push start might tell you something.
 

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Discussion Starter · #9 ·
Maybe you could feel if the starter motor is being dragged by the motor. I don't know. But 650s are hard on starter clutches so it possibly is this.

I had one here that had actually broken the idler gear and was making a lot of bangs and clicks.

Perhaps if you remove the starter you can check starter clutch operation by putting your finger in the hole and manipulating the starter idler. It should move freely in one direction and not at all in the other. I don't know how successful this would be in determining the issue even if it is the starter clutch. Maybe if you start the motor and shut it down while it is still struggling, then remove the starter. The trouble is it may disengage from inertia when the engine stops.

I guess removing the starter, plugging the hole and a push start might tell you something.
Mine's not making any kind of noises at all from the area of the starter.

Thanks for the troubleshooting ideas. I'll see what I can do to investigate.

Wish me luck!
 

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Its likely the two questions are unrelated. The slow starting can be a slight vacuum leak to the petcock, starter rpm supplies much less vacuum than idling rpm. Cracked ends on vac tube are common on old tubing. Low float level can also cause delayed starting, that can also deprive engine of the rich mixture needed to start.
 
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Do you park it on the side stand or center stand? On the side stand, the Silverwing has a pretty extreme lean. You'd have more gas in the left bowl, so it would fill, and fire, first.
 

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'84 CX650E that is evolving into a GL500
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Even when parked sitting upright like mine (not enough lean to matter with the sidecar) it is pretty common for it to start on one side and then have the other side kick in after a few revolutions but I've never noticed a click when the 2nd side starts.

I was thinking along the lines of a vacuum petcock problem too (you didn't say how long it has been sitting when this happens), but it wouldn't hurt to check the pulse generators.
 

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Sounds like it may be one cylinder is firing to begin with and then then other one kicks in.

To see if this is the case then from cold try starting and the instant the rpm increases stop the engine.

If one exhaust is hot and the other not you have your answer. If they are both hot at least you know they are both firing from the start and it must be something else. Good Luck!
 

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Discussion Starter · #15 ·
Do you park it on the side stand or center stand? On the side stand, the Silverwing has a pretty extreme lean. You'd have more gas in the left bowl, so it would fill, and fire, first.
Thanks for the idea.

I always park it on the center stand. Also always start it either on the center stand or vertical with me sitting on it.
 

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Discussion Starter · #16 ·
Its likely the two questions are unrelated. The slow starting can be a slight vacuum leak to the petcock, starter rpm supplies much less vacuum than idling rpm. Cracked ends on vac tube are common on old tubing. Low float level can also cause delayed starting, that can also deprive engine of the rich mixture needed to start.
Thanks for the ideas.

I've actually rebuilt the OEM petcock. Not easy since the rivets have to be drilled out, but I've done the same operation a lots of old Honda petcocks that were not made to be rebuilt. Also replaced the vacuum hose at the same time.

Carbs have been completely rebuilt and float level checked at that time.

It's makin' me crazy, I tell ya! :oops:
 

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Discussion Starter · #17 ·
Sounds like it may be one cylinder is firing to begin with and then then other one kicks in.

To see if this is the case then from cold try starting and the instant the rpm increases stop the engine.

If one exhaust is hot and the other not you have your answer. If they are both hot at least you know they are both firing from the start and it must be something else. Good Luck!
I guess that's actually a possibility... one cylinder firing and then the other one later.

Gonna try your "feel the exhaust" during start up test, and see if I can tell whether or not that's what's going on.

It it WAS running on one cylinder first, wouldn't that cause a fairly noticeable vibration?
 

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When starting the bike have you tried cranking with the kill switch in the off position, choke knob pulled out, until the oil light goes out then turn the kill switch to run and start normally?
 

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Discussion Starter · #19 · (Edited)
OK, MORE TEST RESULTS: I THINK WE'RE ON TO SOMETHING!

As suggested, I checked the header temps when starting the bike to see if perhaps it was running on just one cylinder until the mystery "click" happens and the RPMs jump way up.

BINGO!

When the engine starts up, the left side header stays COLD until the "click" happens and the RPMs jump! I mean COLD. I could wrap all four fingers around the header pipe while the engine was running. So, the left cylinder is NOT running during initial start up.

I guess that means the mystery "click" is something in the ignition system that finally gets the left spark plug to fire. As soon as the "click" happens the left side header starts getting hot.

As mentioned, I have already replaced both of the two TI (Transistorized Ignition) ignition modules (spark units), so it doesn't seem that they are the problem.

FSM says this could be a pulse generator issue. If it is, I guess I'm in for a real "treat" since I just read in the FSM that you have to remove the swingarm to get at them!!! AAARRRGHH! However, the pulse generators are electronic devices, which means they usually are either good or fail completely. Hmmmm?

FSM also says it could be:
+Faulty ignition coil
+Faulty spark unit (already replaced)
+Poor connection or broken or shorted wires between:
-spark unit and engine stop switch
-spark unit and ignition coil
-spark unit and pulse generator
-ignition coil and spark plug

So, at this point, I'm on the hunt for why the left spark plug doesn't fire until the mystery "click" happens. Hopefully, it's one of the spots that a poor connection or bad wire is the cause and not a failed pulse generator that will require the disassembly of the entire back end of the bike.

Question: Does anyone know which spark unit (top or bottom one) is for which cylinder? FSM doesn't say.

THANKS TO EVERYONE FOR TAKING TIME TO NOODLE THIS OUT WITH ME. Now I just have to fix it.
 
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