HONDA GL1000 1975/6 Called Merlin.

[Adamc]

MERLIN CARBS AGAIN!! - Idle Adjustment Screw

Managed to get two hours down the workshop yesterday.
One job that has been on the back burner is the problem with the Idle Adjustment Screw. The screw is only threaeed half way along its shank and It is a fine thread guage. I was unable to screw it in sufficiently for it to open the butterflies slightly to get the bike to fire up and idle. I tried to find a longer screw locally and on the web to no avail; what to do.

The screw end pushes against a button insert in the fixed bracket on the carb body. The button is an interferance fit that is peened over on the back side. I decided to remove the 'peen' and drift the button out from the rear.

I just about had enough butterfly movement now but the button was only just holding in the hole. I could have used some fixing product to secure it, or solder it, but went a different route. I removed the button pin entirely.

I then drilled the hole the pin went into and run an M3 tap down the hole.

An M3 Allen Head Screw was inserted from the rear and secured with some mild loctite and bolts.
All the above is reversible if required.

Job worked a treat and I now have ample adjustment of the Idle Screw.
It cannot be seen when the carbs are on the bike so Happy Days!

Now need to fluid test the carb assembly for leaks before re-installing on the bike.

 

[Raymond]

Ads, that is great work, the figuring out as well as fitting it. If I may say, a fair bit more than you would have done back when you first acquired Taffy?

 

[Jim]

If I may say, a fair bit more than you would have done back when you first acquired Taffy?

Was jus' thinking the same. Nicely done, Adam!

 

[Mailman]

What a great work around Adam! Very satisfying to find a solution like that!

 

[Adamc]

CARBS CONTINUE TO TROUBLE ME.

After rebuilding the carbs with new brass etc; at long last I can install them.
First off a schoolboy error. Mounted the carbs in the bike and connected everything up.
Throttle & choke cables are a pain to install but half an hour of swearing later I hooked up the new fuel supply hose.
Switch on and........ Fu(kin' flooded the block from one carb overflowing!

Take it all back out and reset the floats using my Heath Robinson test rig.

On the bike these carbs work under pressure from an electric fuel pump.
My solution was to add height to my remote fuel bottle and hopefully supply enough pressure.
First time No1 carb leaked as before. No problem after the float reset.
No time to reinstall on Merlin today; and I didn't fancy the cable install at the time anyhow.
Try again in the week ahead.

 

[Mailman]

After rebuilding the carbs with new brass etc; at long last I can install them.

Man! Nice work, that’s quite the carburetor set up! I’m guessing that the four cylinder Goldwings never had fuel injection.

 

[AUTOMAN]

I just can’t believe how nice that bike looks Adam!

I think this is what’s going on with your coolant leak,
View attachment 329345

weep hole is indication that primary(rotary) face seal has leaked. Spring loaded flat to flat ceramic discs stops the coolant.
Secondary seal is for bearing for the shaft.

 

[Adamc]

weep hole is indication that primary(rotary) face seal has leaked. Spring loaded flat to flat ceramic discs stops the coolant.
Secondary seal is for bearing for the shaft.

I have a rebuild kit for the water pump from David Silver Honda.
Next job once the bike is running.

 

[jetmechmarty]

Man! Nice work, that’s quite the carburetor set up! I’m guessing that the four cylinder Goldwings never had fuel injection.

I believe the 1984 1200 Limited was fuel injected.

 

[Its been a long time]

I believe the 1984 1200 Limited was fuel injected.

I think you're right on that.

 

[Adamc]

Merlin Gets its Lungs Back.

Above images show no carbs installed

OK so I rebuilt the 4 x block of carbs back at the end of last year. All new jets and seals sourced mostly from David Silver Spares a Honda specialist.
Since then no time to do further work on Merlin until yesterday.

Basically the plan was to get the carbs reinstalled and cables connected. Check for fuel delivery from the mechanical pump, and then look for any leaks and / or seepage into the plenum chamber; something I was plagued with when I first got the bike.

Fitting this large assembly into the frame is a pain in the butt. Access is difficult and you have to disassemble the air cut off valve to shimmy the block half way in; connect the control and choke cables, then reassemble the cut off valve before you can push the set of carbs through.

Checking down the intake bores I find a piece off O ring seal that must have dropped down there when I took off the Intake tubes.
Glad I checked.

Clean up all intake surfaces to ensure a good seal with the new Honda O-Rings.

Why are all Honda parts so expensive compared to other Jap bike makes?

Lots of swearing and bashing knuckles and eventually all is in place.
Some lube down the bores and a few turns to get some oil pressure (Plugs out) and all seems good.
Final check over and time for a test start. It took quite a few turns to clear the lube and get some action, but eventually Merlin came alive.

Merlin Running after first fire up.

Happy to say the smoke cleared quickly and the engine ran much better than before.
Throttle control cables need adjusting and the idle speed also needs some attention; but I'm happy for now.

Ads.

 

[Its been a long time]

Terrific result! Well done.

 

[Raymond]

Always joy when they start up after major surgery.

 

[Jim]

Jus' took a little magic...

 

[Wingedwheel]

Awesome job. It’s a good feeling when they fire up!

 

[TX650A Van Islander]

Congrats Adam!!!
What a great story. I hadn't seen this thread before and just read it start to finish. You are one persistent dude! Those old naked Goldwings are cool looking bikes, and you found a beauty. I had no idea the carburettors were so complicated and intricate. Lots of PO issues that's for sure. Patiently waiting in Victoria for the next installment.

 

[Adamc]

Congrats Adam!!!
What a great story. I hadn't seen this thread before and just read it start to finish. You are one persistent dude! Those old naked Goldwings are cool looking bikes, and you found a beauty. I had no idea the carburettors were so complicated and intricate. Lots of PO issues that's for sure. Patiently waiting in Victoria for the next installment.

Thanks Van, The next instalment will be addressing the water pump rebuild as its weeping.

 

[Its been a long time]

Thanks Van, The next instalment will be addressing the water pump rebuild as its weeping.

Maybe you already have, but I'd say don't call the carbs completely done until you've balanced them with a manometer or vacuum gauges. The difference that well balanced carbs makes on the flat four Goldwing motor is amazing. If the carbs are a bit out of balance, you might not even notice the clutch rattling until you get the silence resulting from a good carb balance! And the motor goes from being smooth and responsive to virtually turbine like.

If you already did that, apologies for teaching granny to suck eggs. All the best.

 

[Adamc]

Maybe you already have, but I'd say don't call the carbs completely done until you've balanced them with a manometer or vacuum gauges. The difference that well balanced carbs makes on the flat four Goldwing motor is amazing. If the carbs are a bit out of balance, you might not even notice the clutch rattling until you get the silence resulting from a good carb balance! And the motor goes from being smooth and responsive to virtually turbine like.

If you already did that, apologies for teaching granny to suck eggs. All the best.

You got the right. I still have to sort the Idle, adjust the throttle control cables and choke.
I have bought a 4 way manometer just for this very job, and some 'barbs' to fit to the inlet tubes.

 

[Its been a long time]

You got the right. I still have to sort the Idle, adjust the throttle control cables and choke.
I have bought a 4 way manometer just for this very job, and some 'barbs' to fit to the inlet tubes.

Oh, you're in for a treat when you do that. I can't think of another bike engine that responds so well to carb balance. And it looks a terrific example of an early Goldwing too.

Happy memories of long European trips on my GL1100.