71 R50/5 petcocks

[jdvorchak]

I have no problem ordering new petcocks for my 71 but I am curious how these come apart. Specifically the black plastic cover with the fuel positions. Does it screw off or pry off? Any other tricks? If they are as bad inside as I think they are I won't attempt rebuild.




Thanks
John

[wookie]

Pry off.

Wookie

[jdvorchak]

Thank you.
The more I look at them the more I think I'll just order two new ones. Don't need some funky old petcock leaking fuel on the exhaust or not flowing enough fuel to keep the pistons from seizing.

[Kurt in S.A.]

Personally, I'd rebuild the old ones. Those are obviously original and the output is directly opposite the input. If you reorder petcocks, you'll get ones where the output is 90 degrees to the input. IMO, I don't like the look of those...prefer the "straight through".

These Karcoma petcocks are really quite simple to overhaul. You might need to consider "fixing" the tall straws as it gives a different reading for main tank fuel amounts. The lengths of the straws seems to vary, but something like 83mm for the tall and 23mm for the short might be dimensions to shoot for. Snowbum has a write up on this on his website.

Kurt in S.A.

[jdvorchak]

I'll check out his site

[Bamboo812]

Good deals, free shipping and they come with the screens: https://www.eubmw.com/collections/carbu ... 8916588613

[sprints@pldi.net]

They aren't bad to rebuild. The plastic cover just snaps on and off and slides down the handle and you can buy new plastics for a few dollars. The important thing is that the spring is very stiff so when you get it apart screw the covers on without the spring and mark exactly where the thread begin to engage because the threads are very fine and easily cross threaded. That way when you compress the spring and turn the cover it immediately engages in the right spot

[jdvorchak]

Thanks for the tip on the screw on threads. I'll give it a shot at rebuild but thanks to Bamboo I now have an inexpensive source. What the pics don't show is how plugged, with rust and grime etc, the inlet pipes are makes me wonder how corroded the internals are. The carbs were so corroded that there were actually holes in some of the towers like idle jet and one of the ticklers has rusted completely through, spring shot it out the top of the carb. Good news is that the tank is still sound and not really that rusty. Surface rust. So I'm guessing the PO drained the tank but not the carbs or there was so little fuel in the tank that it evaporated but in the petcocks and carbs it lingered and collected water.

[Duane Ausherman]

Those aren't stock petcocks. Those actually seal, and hold up very well. Don't bother with originals.

We made a tool that is a sort of screwdriver to fit those slots and press at the same time. Use some Vasoline on the moving parts.

[Bamboo812]

The petcocks in the photo are Karcoma which were stock on the later bikes. The Everbest (?) found on the /2 were only used until the early 1970s...