Carb problem causes leaking gas?

[MarkAZ]

New to this board, thinking of picking up an R65. Here's a nice one for sale in my area:

http://tucson.craigslist.org/mcy/301719960.html

My question is, does this explanation make sense:

"It runs really well but it needs to have the carbs cleaned and synchronized. The left cylinder bank runs hotter than the right and tends to leak gas out of the carb."

Will dirty or out-of-sync carbs cause gas to leak? Or could this be a symptom of something else? Is cleaning and synching carbs a do-it-yourself job or is this an $800 dealer procedure?

Thanks...

[Clutch]

well, I guess I'll reply simply because no one else has yet.  There are more knowledgeable people on this forum than me.

I would say that dirty carbs could definitely leak (stuck needle valve, stuck bowl float, etc.).  You would probably want to buy some carb rebuild kits to replace the rubber diaphragms and other parts inside that may have deteriorated.  To balance the carbs, you will need something called a "manometer", or another vacuum measuring device to hook to your carbs (they sell instruments specifically designed for this task).  People on this forum have even built their own manometers for cheap!  Balancing your carbs is no big deal with the right equipment.  You'd probably end up buying a Clymer's manual, or other equivalent, which will walk you through these mainenance jobs.

That bike looks pretty nice.  It doesn't say how many miles though.  It may be getting near mileage where major work will need to be done.  Beware that odometers on older BMW's are notorious for failing, and therefore the mileage on the odometer may not be accurate.

[Bob_Roller]

Hi Mark, I saw that R65 in Tucson, and it looks like it is in good condition (better than most), from the picture, the odometer looks like 42,000 miles, but it's not a real good picture. I would view it as a total rebuild of the carbs, not a big job at all. Probably around $100- 130 to do a complete overhaul on both carbs. Other things to consider that probably need attention, are the transmission input spline lube, check steering head bearings and regrease, replacement of brake lines if they are original, a general  going over, as it is 24 years old, and the desert heat will take it's toll on all of the rubber and plastic parts. I moved to the Phoenix area about 14 years ago, and my '81 R65 has shown a lot of degrading in this area, and it is garage kept. If you need any assistance with this bike, just let me know, I've had my bike for 26 years, and there's not much that I havn't gotten into at one time or another.

[Rob Valdez 79 R65]

It does look like a nice bike for the money.  It looks to have been repainted.  No pin stripes.  No big deal.  Try and give the inside of the tank a look with a flashlight.  From the factory they had an orange paint coating.  A "hidden" problem that a lot of bikes have is water will get into the gas, and being heavier than gasoline, it settles to the bottom.  If a tank is not emptied and dried out periodically, it can rust out from the inside.  Check closely around the petcock for any bubbling of the paint.

The carb situation is one that crops up on these discussion boards several times a year.  Normal stuff.
I believe this is the period that the ignition coils were notorious for cracking and needing replacement.
But for $2000, you can drop another $1000 (inc. tires, etc) in it and still be about average, especially if it is as nice as it looks.

Are you comfortable with a wrench in your hand?  While these bikes are easy to work on, they require that you work on them from time to time.  But for some (me included), that is part of the fun.

[Ed Miller]

It could even be fuel line causing the leak, though rebuilding the carbs isn't a bad idea anyway.

Nice looking bike.  Crash bars!  Is that a Brown side stand?  It looks farther back than my stand, which as far as I know is original but modified.  

[Justin B.]

Looks very nice, sounds reasonably priced, and the shape of the stand does look very "Brownish" from that particular angle.

Another thing that can cause carb incontinence is a fuel line deteriorating on the inside.  This produces little hard rubber granules that just love to hang the float needle open and will drive you nuts, BTDT...

[Rob Valdez 79 R65]

Yeah, I replace my fuel lines every 2-3 years.  But then, I like the stuff that has braided cloth on the outside.  I understand there are some "high-tech" hoses that can outlive the bike...

[Semper Gumby]

Yeah, I replace my fuel lines every 2-3 years.  But then, I like the stuff that has braided cloth on the outside.  I understand there are some "high-tech" hoses that can outlive the bike...

Hi Rob,

Where?  In today's alcohol + gas enviroment?  Clear Hose would be nice!

[Rob Valdez 79 R65]

I don't know, I read about it either here or on Boxerworks.  
I was never interested to bookmark the info.  I like my German stuff, and I enjoy the tinker.

[Bob_Roller]

A little tip here that I started doing about 15 years ago, is instead of using rubber fuel line under the airbox, try using a length of 1/4 " steel fuel line. Makes the job go faster than taking the airbox off!

[Ed Miller]

I like Bob's idea, though I haven't done it yet.  When I take off my air box, my cross over fuel line looks squished in a couple of places.  Could it be enough to restrict flow?  I use the 7mm braided outside stuff that Rob is probably talking about.

I remember recently on Boxerworks somebody was insisting that 6 mm was correct, not 7 like everybody else uses.  I haven't looked that up any place else yet, either.

[Rob Valdez 79 R65]

I remember recently on Boxerworks somebody was insisting that 6 mm was correct, not 7 like everybody else uses.  I haven't looked that up any place else yet, either.

I use whatever the dealer sends me.  Lately that has been Matt at Boxerworks.
I haven't measured it yet.

[Justin B.]

Bob, I've been thinking about doing that as well.  I guess since you have been using this method for 15 years it is working out OK for you...

I use clear urethane line and it looks really nice for a few months but then starts to turn a yellowish brown.  You can still see through it and it is still soft, but not really what I would consider attractive.

[suecanada]

I think the steel line would be ideal...it is a big pain to fuss with the air filter box. Has anyone heard of a method to pull the new fuel line through under the air box by somehow attaching it to the OLD fuel line that is being removed???

[Ed Miller]

I think the steel line would be ideal...it is a big pain to fuss with the air filter box. Has anyone heard of a method to pull the new fuel line through under the air box by somehow attaching it to the OLD fuel line that is being removed???

I don't know of a way to do that, at least not strongly enough to let you pull the new line through.

The first time I did the job with the air box in place, I stuck a very long philips screwdriver through the gap, pushed the new fuel line over it, and that helped guide the line as I shoved it through.  I don't know if that would work with the braided covered German fuel line I use now.  The screwdriver was not a real snug fit in the fuel line, it slipped inside pretty easily and just helped me guide the line and kept it from bending in there.