Rebuild petcocks?

[robertklee]

Can karcoma petcocks be rebuilt? If so, where do I get the parts? Thanks again.

:usa

[20774]

Sointently! Parts are available at dealers, guys like Ted Porter, places like Bob's BMW, etc. I bought parts for the Karcoma on my /2 from Vech at Bench Mark Works.

[lkchris]

Rebuild them with the knowledge brand new ones are only about $30.

[20774]

Rebuild them with the knowledge brand new ones are only about $30.

Knowledge is good...but skills and confidence are priceless...

http://www.bmwmoa.org/forum/showpost.php?p=442689&postcount=16

[crazydrummerdude]

Knowledge is good...but skills and confidence are priceless...

http://www.bmwmoa.org/forum/showpost.php?p=442689&postcount=16

+1.

[Isamemon]

rebuilding will save money, Ive done it many a time.
however like posted above new or not that much, plus they come wiht a new plastic cap (on/off etc) another advangtage is that you can update to the ones that exit to the side then straight down. I like that feature myself

[Boxerkuh]

The only thing that I would ever consider rebuilding in the petcock is the back, rubber washer. That washer alone costs $8.00 last time I replaced it. Otherwise, I would buy a whole new petcock. Why do you need to rebuild it? Is is leaking? Is the nut tight?

[gfdunn]

I was going to rebuild mine on my 84 R100 with 51K but chose to get new with new screens. They were about $45.00 each with screens. The new detents feel much better and they sealed right away. This was best for me. Cleaned the tank real good but I have some flaking of the orginal lining. I need to do a tank kit to reseal. Down time is about four days for the process so I will ride and do it later.


Catfish

[abe456]

Having been there, done that, I recommend replacing them. I boogered the originals up trying to rebuild them, finally just ordered new ones and new hoses. They look better, increased bike top end speed by over 15 mph, and i was able to win the Harley burn-out contest at daytona this year.

Seriously, some things just aint worth tinkering with, petcocks being one of them in my book. I must have re-installed those things 5 or 6 times, they would always leak somewhere.

[AnnapolisAirhead]

I've just rebuilt all of mine. Its not that hard.

I did it mostly because I couldn't feel the detent on one of them and figured I'd just clean both of them and use new screens (#4 and #12) which you can do without taking the petcock apart. If you do take it apart, the hardest part for me was getting the #9 unscrewed because of the pressure on the compression spring, but even still with careful use of a vise, its not that difficult. The part that was usually buggered up on mine the most was #11 in this diagram:

http://maxbmw.com/fiche/FicheZoom.asp?image=Diagrams/B0000386.png

If your are leaking, make sure that you have new fiber washers and I wouldn't use teflon tape or anything. The washer (#5 in the picture) is what seals it, not the threads. Careful not to hamfist it and strip the threads on the tank--that gets costly.

[tjfriedmann]

Spring loaded petcocks can be a pain...I know I just refurbished a couple.

If anybody else is doing this for the first time, this might be helpful:

http://maxbmw.com/fiche/FicheZoom.asp?image=Diagrams/B0000386.png

My method for getting the screw face plate (#9) off was a simple set of vice grips. No trouble. Helps if you put a little WD40 on it before hand, or soak the petcock in a little hot water. Then:


1
Change out any internal rubber that's no good, you can get the parts at the usual places.
2
Grease the internal rubber screen with silicone grease per Snowbum (http://bmwmotorcycletech.info/fuelfltrs&petcocks.htm)'s suggestion.

3
Getting them back on is slightly more difficult, but be patient...

wrap up the lever in a little tape so that when you're turning the face plate with the vice grips and they push against the lever, it won't nick the metal.
While you're screwing on the plate, you can push the lever, it's fine with the tape on there. This especially important with a new petcock, unless you want a couple nice jags on there!

4
Next seat the threads by pushing the plate gently against the housing, and turning clockwise. Use uniform pressure so the plate is level against the housing. One side up will cross thread pretty easy. Rotate around, pushing through the engagement points until you eventually you've got the plate snug.


Anyway, hope that saves you a little time!

t.

[Weasel]

I bought one new one, long ago, and I rebuilt the old in spare time. That way I always have one rebuilt one on the bench where it's handy when I need it.

[DOINTHETON]

not really much to rebuild, just give 'em a good cleaning. the hardest part is getting the knurled metal ring off and on. i'm a self admitted mechanical hack, so if i could do it anyone can.
mine were brutally bad. sat with fuel in them for four years. full of a dark brown almost black tar like substance. the plastic tubes were completely full. carb cleaner, elbow grease, and voila, nice and clean a little grease on the rubber disc/gasket, wire brushed all the metal parts and back together. look like new, nice solid detent clicks for every position.
cost=$0 dollars. satisfaction=priceless. give it a shot before you spend your hard earned dough.