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Eldo Sugar Cube Thread Size?

Tonerjockey

Tonerjockey

High Miler
GT Contributor
Joined
Oct 28, 2008
Messages
788
Location
San Jose
Anyone know what size the thread is on the old Eldo sugar cube fuel petcock? Looks like 12mm with a 1mm/thread ... thread.

Sugar Cube

I want to clean out the gas tank (shaky shaky) w/o the petcocks installed. Thinking a "standard" bolt would fit... maybe.
 
Thanx John.
My monkey wrench with numbers (aka caliper) reads just short of 12mm. My thread gauge shows 1.0 mm/t.
This is an odd combination, so I thought I'd ask if anyone KNEW what the spec was.
As far as I can tell the standards are 1.75 mm/t , 1.5 mm/t, and 1.25mm/t for M12 bolts.

Maybe I'll just make a couple rubber plugs ...
 
Tonerjockey said:
Thanx John.
My monkey wrench with numbers (aka caliper) reads just short of 12mm. My thread gauge shows 1.0 mm/t.
This is an odd combination, so I thought I'd ask if anyone KNEW what the spec was.
As far as I can tell the standards are 1.75 mm/t , 1.5 mm/t, and 1.25mm/t for M12 bolts.

Maybe I'll just make a couple rubber plugs ...
Click to expand...
I'd use tape for the internal threads, and the rubber plugs. If you are on good terms with a machinist, he could make a couple plugs out of hard plastic that would do the job matching the diameter and thread pitch.
 
My lathe will cut 1mm thread. I tried to make some threaded 12mm rod out of plastic rod, then aluminum. ... but I couldn't grind a cutter down enough to establish threads.
So Grainger has some nice pipe rubber plugs
Item 2HCF4
Mfr. Model 269840

They're for 1/2" ID pipe so I hadda grind them down a bit. They worked fine.

Plugs Plugs in Grounds for cleaning
Got the tank cleaned a bit. Not concourse but definitely cleaner.
Hardest part was getn out the little steel screws and washers I used with the alcohol to abrase a little. An extension magnet did the job.
 
If you are going to put in an ethanol resistant liner, it needs to be much cleaner. See if you can get the Caswell kit.
 
Depending on how dirty/rusty a tank is, I clean it with electrolysis or milkstone remover. I only seal the tank as a last resort - pinholes and such. Caswell is the only sealer I'll use. Last I checked they were out of stock until next month.
 
I think I'll reassemble and reinstall as is.
The original symptom was stalling after 5 or so highway miles. The left shut of valve's internal rubber seal had rotated causing very limited flow in Open position. No flow in the Reserve position.
The engine would resume running when the right reserve valve was opened.
I've seen this before, long ago, and now we'll see if the correction of that internal seal's seating "fixes" the symptoms.
If any fuel related symptoms recur, I will look into the Caswell stuff.
I've sealed gas tanks before (V7 Sport etc.) and it can be a bit of a job. So using the right chemicals is mandatory. Caswell looks like the stuff to use.

Thanks for the info's.

~Alex
 
I have extensive experience with the after effects of Caswell linings.

Caswell is OK but know this.

It will come off in sheets eventually.

IMG 2407 IMG 2408

When it does, it looks like clear plastic wrap floating in the gas. Yes, Caswell dies an ugly death when it finally dies; Huge chunks and sheets of it sluff off into the gas.

Literally, you will be pulling out chunks of the stuff from your tank and it will be evident when you are driving down the road and all of a sudden the engine goes to complete fuel starvation as these sheets of Caswell will get sucked up by the fuel pump.

Just realize that even Caswell, has a finite life in gas.

It’s not a panacea fix.

Results are always based upon the meticulous preparation of the substrate metal.

YMMV with Caswell but if it is a motorcycle you want to keep for many years, may I suggest a professional tank restoration service.

I have seen very good results from this outfit in California:

gastanklining.com
 
Last edited:
Tonerjockey said:
I think I'll reassemble and reinstall as is.
The original symptom was stalling after 5 or so highway miles. The left shut of valve's internal rubber seal had rotated causing very limited flow in Open position. No flow in the Reserve position.
The engine would resume running when the right reserve valve was opened.
I've seen this before, long ago, and now we'll see if the correction of that internal seal's seating "fixes" the symptoms.
If any fuel related symptoms recur, I will look into the Caswell stuff.
I've sealed gas tanks before (V7 Sport etc.) and it can be a bit of a job. So using the right chemicals is mandatory. Caswell looks like the stuff to use.

Thanks for the info's.

~Alex
Click to expand...

The new production "sugar cube" petcocks aren't made correctly and the rubber seal inside rotating is a common issue. I don't buy them for that reason. A better idea is the kit that MG Cycle sells - adapters with later "diamond" shaped petcocks.

The first tank I ever sealed with Caswell was the one on my vintage Gravely garden tractor. It had pinholes, but no rust. That was 15 years ago. Sits year round with E10 gasoline in it. That old tractor vibrates more than any motorcycle I've ridden (except maybe the Yamaha XT500). The Caswell still looks like the day after it was done - no change in color, no cracking, flaking, etc.
 
Amboman said:
The new production "sugar cube" petcocks aren't made correctly and the rubber seal inside rotating is a common issue. I don't buy them for that reason. A better idea is the kit that MG Cycle sells - adapters with later "diamond" shaped petcocks.

The first tank I ever sealed with Caswell was the one on my vintage Gravely garden tractor. It had pinholes, but no rust. That was 15 years ago. Sits year round with E10 gasoline in it. That old tractor vibrates more than any motorcycle I've ridden (except maybe the Yamaha XT500). The Caswell still looks like the day after it was done - no change in color, no cracking, flaking, etc.
Click to expand...
Being the owner of an XT 500 I agree !
 
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