Karcoma Petcock questions

[brant914]

New day with new questions....
this time regarding the petcocks on my 1971 R75/5

3 questions... these are a mess, they had no strainers, and no filter, and missing some of the pick up tubes


1st question: I don't see the pick up tubes available in the diagrams with Max or Bob's (1 short/reserve, and 1 long). Can I find plastic tubing at the hardware store... or has anyone ever replaced these before?

2nd question: On the same tank tubes referenced above. One side of my petcock's has 2 large diameter tubes sticking out of it. The other side petcock is missing the short tube, and the long tube is a smaller diameter than the first side. Are
the right and left supposed to have different size of tube? I pulled the large diameter from the 1st petcock and it does not fit into the 2nd one... so maybe the 2 different sizes are supposed to be different right to left?

3rd and final question. Upon taking one apart... the spring pictured in the parts diagram is not in mine. Mine has a couple of wavy spring washers stacked under the lever instead of a coil spring. did some years not use the coil? or did a
previous owner "fix" this before I got it?

thank you everyone
I really appreciate the help and education
brant

 

[20774]

Snowbum has a good section on petcocks here:

https://bmwmotorcycletech.info/fuelfltrs&petcocks.htm

The internal tubes have been discussed over the years. He talks about various sources for that...mostly hobby stores. Your model had no internal strainers. And there should be a long and short tube. The heights can be somewhat standard, but they can be "adjusted" to what you want. I don't know the length of the tubes in my /7 tank, but I go on reserve at around 4.6 gallons and I have maybe 0.75 gallons on each reserve. I don't know what that relates to as heights of tubes.

 

[ebeeby]

I can tell you I like the resolute "click" of Karcoma petcocks when they are in working order. Good "clicks" at 12, 3, 6, and 9 positions.

 

[jagarra]

Found some on e-bay https://www.ebay.com/itm/Fuel-Pipe-...ke:BMW&hash=item56cf1636bf:g:fP8AAOSwxs1dynqq

cheers,

 

[brant914]

Found some on e-bay https://www.ebay.com/itm/Fuel-Pipe-...ke:BMW&hash=item56cf1636bf:g:fP8AAOSwxs1dynqq

cheers,

Thanks you..
amazing...

 

[brant914]

Kurt, Everyone,


thanks for the direction
I'll get some new straws on ebay

and do some more reading today

still puzzled that the straws on right vs left petcocks seem to have different diameters
but hopefully I'll be able to figure that out in my reading and research today

thanks
brant

 

[jagarra]

Went to EME site, they are even cheaper there. https://www.euromotoelectrics.com/product-p/fc-pipe.htm

no e-bay fees.

gg

 

[PAS]

Be careful of the bottom plastic nipple they are known to break off!

 

[brant914]

Be careful of the bottom plastic nipple they are known to break off!

One of mine came to me "Pre Broken"
like much of this project
brant

 

[1074]

Strainers

You should find the strainers sort of attached to the plastic nipples.

 

[lkchris]

https://www.bingcarburetor.com/petcocks.html

 

[brant914]

Thanks Kent !

that is great, and I had not found it before

brant

 

[brant914]

More Petcock questions... I'm sorry for bugging you guys


something is a little off on my project
I'm wondering if one of the petcocks has been changed to an earlier or later model?

buying a used one on ebay may be a pathway forward

so here are the pictures
both are clearly marked Karcoma

but the straws inside the tank, are clearly of different size for the R vs. the L
the large straws (I bought new ones thanks guys) do not fit into the 2nd petcock which requires smaller diameter straws

also the 2nd Petcock had no coil spring... but a very thin wave washer inside


anyone have any idea if this is correct, or from an incorrect year?
I assume the straw size and coil internal spring should have been the same right to left

thanks for more input
brant

 

[brant914]

and I just thought of another question

how do I tell which is R and which is L ?
incase I buy a used one, I want to get the correct side
thanks
brant

 

[1074]

If the nipple points straight down then there is no left or right side! The 90 degree petcocks have the strainer inside, covering the long and short tubes. From the factory, the nipples pointed to the rear.

 

[brant914]

If the nipple points straight down then there is no left or right side! The 90 degree petcocks have the strainer inside, covering the long and short tubes. From the factory, the nipples pointed to the rear.

Thank you !


off to ebay and find a match to one of what I already have
brant

 

[edzr60]

no leaks!

Make sure you provide a nice flat surface on the ring on top of the petcock that contacts the fuel tank/gasket before you reassemble.

 

[6322]

Thank you !


off to ebay and find a match to one of what I already have
brant

Be aware, used off of ebay may require rebuilding anyway. I just purchased a new pair from EME with a meter of new fuel line. They are 90's, right and left, but they're new and the new fuel line will give me what I need to make the 90s.

 

[brant914]

Be aware, used off of ebay may require rebuilding anyway. I just purchased a new pair from EME with a meter of new fuel line. They are 90's, right and left, but they're new and the new fuel line will give me what I need to make the 90s.

The Petcock from Ebay came
the threads were gone or nearly gone on the large nut that attaches to the tank
of course I stripped it trying to reassemble... should never have bothered with it given how bad the threads were

a 2nd used ebay petcock is on the way... it showed nice threads in the photo
so hopefully this one will work after polishing 4 total so far.
brant

 

[6322]

This will come together for you. Just stick with it.