Jdub goes there 1981 650e rebuild

[Rich82GS750TZ]

Took me to a clip from the old Carol Burnett Show. Harvey Korman and Tim Conway were so funny together.

[melchiro]

I clicked your Facebook link. It didn't go anywhere. It says, " This content isn't available right now".

I am a Facebook user.

[jdub6092]

I haven't put the rubber dampers on the engine. Wondering if that might help.

[jdub6092]

https://www.facebook.com/share/v/14Z6fMgwuf/?mibextid=qi2Omg

I'm not an active facebook user, but wanted to share a video to see if anyone can recognize this sound.

[Nessism]

One step forward, and one step sidewise. Sounds normal to me...

Check your cam chain tensioner. They like to jamb. When rebuilding an old GS, it's time well spent to break it down, and make sure the plunger is moving freely. Not sure this is the issue at hand, but hopefully something simple.

[jdub6092]

I attempted to start the bike last night. Got the oil circulating, checked compression (150,150,140,145), checked spark and then hooked up the tank. Nothing happened. Tried for about an hour. Found one of the not replaced spark caps fell apart when I pulled the plug out. Replaced it with another of the cheapo Amazon caps while waiting seven days for the OEMs that were shipped UPS second day air. Still no luck.
This morning I started grasping at a few straws. Noticed that one of the coil mounts was not grounded due to chassis due to powder coat. Filed part of the tabs to bare metal. OK, dont know what that will do other than maybe reduce EMI. Readjusted carb mixture screws to two turns out. Stuffed a rag at the air intake.
Tried again and heard my first pop of combustion.
A few cranks later, it started and the revs went towards infinity. Scared the crap out of me. Shut it down as fast as I could. Checked the Idle screw and somehow, it was substantially open. Cranked it back down until it barely moved the fuel rail.
Started back up with half choke and it roared to life. It was smooth except for a pronounced clacking rattle sound coming from below the valve cover. Shut it down. Started back up, let run for about ten seconds. Again fairly smooth, but the noise prompted me to shut it down. All four exhaust pipes were warm. Not the normal GS sound.

[Griffin]

I have a set on my Yamaha 750 Seca. They work fine. Inexpensive, too. About $6-$7 each.

[rphillips]

Good to know, I knew NGK had quit them. I've used a lot of K&S turn signals and stalks and always been very impressed with their quality.

[Griffin]

Put new OEM plug caps on order. Apparently NGK has discontinued these over a year ago and they will be very hard to find in the near future, especially the 120° long type...

Just an FYI for future reference, K&S is now offering NGK-style resistor caps.

When there is a demand, the market will respond.
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[Griffin]

Looking fantastic! The GS650E is one of those sleeper UJMs that got overlooked, and it's a shame.

Almost as fast as the KZ/XJ/GS/CB 750s, but much smaller and more nimble.

My '82 is one of my favorites. It's been in sleep mode for about four years. Maybe this is the year I break it out as one of my riders for the year.

[Nessism]

Hi jdub,

You did a right fine job there! Puff out your chest, take a bow, and be proud!

I hope it runs as good as it looks.

[jdub6092]

20241230_195719.jpg Getting there. At least cosmetically.

[jdub6092]

Put new OEM plug caps on order. Apparently NGK has discontinued these over a year ago and they will be very hard to find in the near future, especially the 120° long type.

All that remains before attempting to start is repair of a broken exhaust clamp that Ive put off since the beginning of this rebuild. So I drilled four holes on one broken piece, inserted toothpicks, cut off flush and put drops of paint on each. Then carefully pressed the pieces together to transfer drill locations and drilled four more holes on the mating piece. Drill holes heeded to be 90° to the surfaces in order to press fit metal dowels for reinforcement.

20241230_045828.jpg ex

[jdub6092]

Was hoping to attempt a start today, but did a last few checks. Found 35 kohm resistance between #1&#4 spark plug caps which is in spec. Then found an open circuit between #2&#3. Pulled off the caps and found one to be bad. Then measured across the two wires and got about 14 kohm coil resistance. Since the resistance of the caps is 5 kohm nominal, that would give a total of 24 kohm from cap to cap which is below spec. Concerned that #2 & #3 coil is on the way out.
I know I can still get OEM caps, but can anyone recommend a coil replacement? I've seen a bunch of them online, but many comments about them not fitting.
How about non-OEM plugs that I can get fast for a test?

The last time I had this running, it did not act like a cylinder was dead, but just had a surging RPM after it warmed up. Did have gas in the airbox though.

[jdub6092]

I moved the gas and vent hoses on the other side of the rail. Not that it matters, but because two sets of photos in the sevice manual show it that way.

After four rounds, including thread repair, I finished shimming the valves. Results as follows:
#1 exhaust: 2.50 - 0.05
#2 exhaust: 2.45 - 0.07
#3 exhaust: 2.40 - 0.09
#4 exhaust: 2.45 - 0.07
#1 intake: 2.35 - 0.09
#2 intake: 2.50 - 0.07
#3 intake: 2.55 - 0.07
#4 intake: 2.45 - 0.09

Understand that .09 is technically out of spec., but saw in several places that this OK and even preferred. I don't actually have a .07 or .09 feeler blade, but the .06 and .08 blades slid in easily and the next blades up (.08 and .10 respectively) did not clear.

Back to installing the carbs and air cleaner, followed by exhaust and valve cover. Getting close to seeing what I have.