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Refinishing (not rebuilding) Carbs

Posted: Sun Dec 14, 2008 1:16 pm
by FirstYearDeek
With little to contribute in the way of experience-backed 'Wing advice, I'm dying to contribute in a way that will benefit all using my knowledge and skill learned elsewhere; that which may not be purely 'Wing related.

Enter "Boss," a fully dressed and sadly neglected 1975 GL1000 currently under the knife. The carburetors, while mechanically and functionally sound, are UGLY. Whatever factory finish may have been left on these poor pumpers is long gone and years of road grit and grime have permanently blemished them leaving no chance for an attractive set, barring total refinishing.

Image

Rebuilding the GL1000 carburetors has been covered on this forum by Octane and professional rebuild kits/videos/advice are available from Randall Washington (Randakk) I have only slightly more experience than the average backyard mechanic in carburetor service, and next to none with respect to these particular units. However, I've reached a state of "Monk-ness" that is not only annoying my family, but causing me to go bald at 30!

Since I need an outlet for my anal-retentive behavior, I will attempt, through this thread and available to all who read here, refinish a set of Keihin 764A carburetors, a central plenum and intake runners for a GL1000.

Follow along as I cover complete strip-down and rebuild of the carburetors for refinishing by painting, powder-coating or polishing. Along the way I'll cover carb cap ("button") replacement, disassembly of the throttle and choke linkages and tips for reassembly after I powdercoat my entire rack in "wrinkle black."

Stay tuned!

-Deek

Not for a 75!

Posted: Sun Dec 14, 2008 1:26 pm
by FirstYearDeek
Astute readers will notice that the carb code (764A) is NOT correct for a 1975 GL1000.

The major differences between the 764A and the 755A are as follows:
The Primary Fuel Jet is smaller (#62 vs. #65)
The Secondary Fuel Jet is smaller (#120 vs. #125)
The CV Needle ID is different (#452301 vs. #302305)

Idle Jets are the same, though curiously the factory specification for opening is different (2.5 turns out vs. 1.375)

When I purchased this bike the PO said he had the "carbs worked over by a professional" and one of the saddle bags had a Wal-Mart sack full of random parts. (bowls, intake runners, caps and CV slides to name a few)

Worked over may be a good description! (in the stereotypical mafia sense)

I'm excited to see what I get into... if the carbs aren't on the right bike, who knows what's inside!

-Deek

Posted: Sun Dec 14, 2008 2:16 pm
by sunnbobb
OK first off Deek, that bench is wayyy too clean!

Posted: Sun Dec 14, 2008 3:35 pm
by FirstYearDeek
sunnbobb wrote:OK first off Deek, that bench is wayyy too clean!
For now...

I've actually been hounding my local metal guy for a sheet of galvanized that I can cover it with... that "veneer" won't last long around carb and brake cleaner!

-Deek

Deek!

Posted: Sun Dec 14, 2008 4:03 pm
by donspicer2
Deek! I appreciate and applaud admitting your knowledge of these bikes is near my level - 'feet of clay"... well written opening statement.

Posted: Sun Dec 14, 2008 4:10 pm
by ElPiloto
See the Eastwood catalog, or website, for several different ways to refinish carbs.

Hey Deek - my bench isn't as nice..

Posted: Sun Dec 14, 2008 5:27 pm
by donspicer2

Posted: Sun Dec 14, 2008 7:28 pm
by Cookie
Is the note from your wife?

ya!

Posted: Sun Dec 14, 2008 8:05 pm
by donspicer2
I'd stagger into the house, stinking to high heaven of B-12, exhaust fumes, WD40, and the odd minor - accidental - dog - flop - step - into: the mud and the blood and the guts and the beer, as it were. Naturally, I'd head for the toilet, then the coffee pot, and try to sneak back to the inner sanctum.

One time, I stepped into a puddle of mud & B-12, tracked it all over.... The dogs, cats, wives, tenant, all of 'em went Ape-S**t. The sign appeared the next day.

I took refuge at my wierd neighbor the photographers house. He has all of his really cool stuff on the second floor of his barn - accessable ONLY by rope ladder, or block & tackle. His wife can't get up there....

Posted: Sun Dec 14, 2008 9:48 pm
by starket
Don,

I like your workbench. I purposely keep mine looking like that. It keeps my wife out of the shop. She is a neat freek. She hates things that are disorganized. When my shop looks like that she stays away. Won't even go in to find a screwdriver. I am the KING of my workshop and want to keep it that way.

Posted: Sun Dec 14, 2008 10:38 pm
by Cookie
Mine gets to be a real mess while doing a fast project. I just had to clean some of it up to find some clips for Gary today, they sproinged off into the mess forcing me to clean up to find them.
I'm not done with putting all the stuff away for the Xmas train and right now I have tarps over stuff in the garage because my roof isn't done and it's pouring.
When my bench is tidy I'm not doing much.

And as for stupid husband tricks... I drained a fuel tank into a fuel container and when it stopped I pulled the petcock. Seems I drained it on main, not reserve out of habit. This left about a gallon to pour pour onto the ground as I struggled to reinstall the petcock.

My wife's office faces the rear and she was less than impressed. After telling my friends I found out I wasn't the only one who had done that trick but for Freddie it was worse. His garage is part of his house. since they have the two daughters his wife only threatened divorce.

My wife has suggested a shower in the garage and a place to leave my clothing.

Posted: Mon Dec 15, 2008 12:02 am
by heraldhamster
Cookie wrote:... My wife has suggested a shower in the garage and a place to leave my clothing.
I gotta say, having a full, finished bathroom in the garage is an absolute and total blessing. I don't have that anymore, but my next house will. and d*mn the expense.

Deek...my appoligies for hijacking

Posted: Tue Dec 16, 2008 12:01 am
by donspicer2
I got carried away, forgive me hijacking and being so silly.

Posted: Tue Dec 16, 2008 12:08 am
by sunnbobb
OK Deek, you may now commence.

Posted: Tue Dec 16, 2008 11:47 am
by FirstYearDeek
sunnbobb wrote:OK Deek, you may now commence.
:lol:

Thanks!

I tore down carbs 3 and 1 last night. Linkages and all. I took tons of pictures and I'm in the process of putting all that together for posting. I'll go carb by carb so I don't miss anything, since each one is a little different!

So I expected to run into weird stuff and I did... Primary and Secondary fuel jets are both wrong for 764A, but are correct for 755A! The needle, however is correct for 764A! :roll:

So; I'm on the lookout for the correct needle for the 755A for reassembly.

One caveat; I may not be able to powder coat the bodies of the carbs; there are quite a few pressed brass plugs, glued-in plastic pieces and whatnot that would be destroyed if disassembled, for sure. Whether or not these parts would hold-up to the oven is a big question.

Expansion isn't a concern for the brass pieces; the differential volumetric coefficient of expansion for brass vs. aluminum is only 15%. Any captive brass part will remain captive. My biggest concern is the CV slide lug.

Does anyone have a ruined carb body I could do some experimentation on? That would put my mind to rest and tell me whether the low-temp wrinkle black powder I've picked out can be applied.

Otherwise I'll paint, which is fine, but in the vicinity of fuel and related chemicals, I would rather PC!

-Deek