The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: farmer on May 04, 2009, 08:17:23 AM

Title: Carb Leak - Always A Mistake To Assume All Is OK!
Post by: farmer on May 04, 2009, 08:17:23 AM
I always seem to relearn this the hard way. Finally got my 79 R65 out for first run of the season. I keep it in heated garage on charger year round. Started right up so I took off for a ride. About a block later I get a wet cool sensation on my left foot - look down and gas flowing from carb float bowl on my tennis shoe. Hurry up and shut down and lean over to keep gas off hot exhaust. Back home in garage, removed float bowl to inspect. Float and float needle appear to be working properly. Will clean and install a new float bowl gasket next. If that doesn't work I guess carb will have to be removed and thoroughly checked.
Title: Re: Carb Leak - Always A Mistake To Assume All Is OK!
Post by: williamemack on May 04, 2009, 09:07:14 AM
HI Jim, I've had this happen too. I shut down, drained bowl, held up the floats to flush out carb fuel intake and all has been well eversince.

Will
Title: Re: Carb Leak - Always A Mistake To Assume All Is OK!
Post by: Justin B. on May 04, 2009, 10:28:15 AM
I would seriously suspect rubber fuel lines disintegrating internally and the rubber bit's will flush down the line and sometimes intermittently prevent the float needle from seating.

This could/will be an ever increasing problem as government enviro-nazis mandate an ever increasing ethanol percentage in fuel.  Rubber bits meant for gasoline generally don't take too kindly to high levels of alky-hol which is why I started switching to urethane fuel line a few years ago.
Title: Re: Carb Leak - Always A Mistake To Assume All Is OK!
Post by: montmil on May 04, 2009, 12:16:32 PM
Maybe I'll figure a way to mount a fuel filter on each carb's brass fuel line pipe.

Bowl gasket may have dried out and shrunk up on you. A bit of junk could hold the float needle off its seat.

You've received good advice here, Caddy Jim. Probably ain't no big deal. Your sneakers already stink anyway...

Monte
Title: Re: Carb Leak - Always A Mistake To Assume All Is OK!
Post by: Bob_Roller on May 04, 2009, 12:21:02 PM
Justin,
Any common suppliers sell  urethane fuel lines ??
Last time I installed clear fuel line, I had problems with it kinking.
Title: Re: Carb Leak - Always A Mistake To Assume All Is OK!
Post by: Justin B. on May 04, 2009, 12:28:49 PM
I get mine from Aircraft Spruce.  Oh, and they now list a blue Bing alcohol resistant line...
Title: Re: Carb Leak - Always A Mistake To Assume All Is OK!
Post by: farmer on May 04, 2009, 12:32:05 PM
Thanks for the suggestions everyone. Will check out fuel lines and rubber bits in float needle area tonight. I did replace fuel lines 2 seasons ago. Can they go bad in 2 years?

PS: The wife banned me from entry into house until offending sneaker and sock discarded in garage garbage can. Also have this problem with grease on hands.
Title: Re: Carb Leak - Always A Mistake To Assume All Is OK!
Post by: montmil on May 04, 2009, 12:46:20 PM
Quote
...PS: The wife banned me from entry into house until offending sneaker and sock discarded in garage garbage can. Also have this problem with grease on hands.

Save 'em, Jim! Wear them to the next family reunion and you'll probably get lucky and never be invited back again.

If I liked these people, I'd go see them on my own time...  ::)

Monte
Title: Re: Carb Leak - Always A Mistake To Assume All Is OK!
Post by: vestandpants on May 04, 2009, 02:00:46 PM
now ive heard from many sources that the left carb is always prone to leaking.

i had a leaking left carb 5 years ago and i couldnt work it out. the float was fine and correctly set, float needles changed and it still leaked. a friend of my dad's made a comment about it whilst supping a pint in his local 'left carb leaking? you have to make sure they are level'. the next day i did as he said and its never leaked since.
Title: Re: Carb Leak - Always A Mistake To Assume All Is OK!
Post by: MrRiden on May 04, 2009, 07:10:55 PM
Google up Tygon. Its a type of fuel line that the ultralight folks have been using. Looks interesting.
Title: Re: Carb Leak - Always A Mistake To Assume All Is OK!
Post by: farmer on May 04, 2009, 08:58:24 PM
Just finished working on the left leaking carb and no more leak! Here is what I did (not sure which one fixed the leak):

1. Put my trustee pocket level on it (the flat top bings make this easy) and sure enough not level by about 10% - so I leveled it.

2. Removed float bowl and sprayed float needle area with carb cleaner and dried with compressed air.

3. Float bowl gasket is bad (in pieces) - I think there may have been an unsealed gasket area - carefully placed the gasket back together and installed float bowl. Ordered a new set from realgaskets.com. I did remove float bowl to make sure it was dry last fall before storing - I bet the gasket got messed up then.

Just happy that no rebuild was necessary now.  [smiley=clap.gif] [smiley=clap.gif]

Thanks again for all the ideas.
Title: Re: Carb Leak - Always A Mistake To Assume All Is OK!
Post by: Rob Valdez 79 R65 on May 05, 2009, 07:04:00 PM
Quote
Google up Tygon. Its a type of fuel line that the ultralight folks have been using. Looks interesting.

Don't you have a source you use that you could link us to?
Lots of hits on Google.  This is just one of them.
Yellow, eh?  I suppose I could find something black to wrap it with...

http://www.willardssmallengines.com/shop/2-cycle-carburetion/tygon-fuel-line-/page1.html
Title: Re: Carb Leak - Always A Mistake To Assume All Is OK!
Post by: Rob Valdez 79 R65 on May 05, 2009, 07:07:28 PM
And I recommend riding boots over tennis shoes.  

If foot injuries are anything like hand injuries (http://www.pbase.com/tomfarr/image/107192088/medium), I want to minimize the risk at all costs.
Title: Re: Carb Leak - Always A Mistake To Assume All Is OK!
Post by: MrRiden on May 05, 2009, 08:11:58 PM
Don't you have a source you use that you could link us to?
[/quote]
Yea Rob ya got me. I know I link to lots O stuff but I'm still runnin my trusty Black rubber NAPA fuel line. I have seen Tygon in charcoal. I'll tell ya what, if you run the yellow I'll run it too! Even go in half for 6';D
rich
Title: Re: Carb Leak - Always A Mistake To Assume All Is OK!
Post by: rob650 on May 10, 2009, 12:22:14 PM
level the carbs - on what axis?

i also have the "left carb peeing on my foot" problem.  pulled the bowl and bent the floats down a bit for a short term fix.
Title: Re: Carb Leak - Always A Mistake To Assume All Is OK!
Post by: montmil on May 10, 2009, 12:31:42 PM
Believe Jim the CadMan leveled his carbs as I've seen suggested on a couple sites.

With the bike on the centerstand and parked on "level ground" (my quotes!) when viewed from behind, the carburetors should be positioned vertically. Any serious tilt could possibly let float bowl fuel weep past an old, hardened gasket.

Right, Jim? [smiley=thumbsup.gif]   Monte  
Title: Re: Carb Leak - Always A Mistake To Assume All Is OK!
Post by: msbuck on May 10, 2009, 05:10:10 PM
My turn with the leaking carbs.  My left side leaked while Graham was doing maintenance - he found trash in the bowls and cleaned them out.  We went out for a ride yesterday and when I stopped at the local Honda shop, my right bowl was leaking...and I had wondered why my foot slipped off the brake earlier.  So, more trash in the bowl.   >:(

I think it's time to replace my fuel lines...now where was that link for Yellow fuel lines?...  8-)

Title: Re: Carb Leak - Always A Mistake To Assume All Is OK!
Post by: montmil on May 10, 2009, 05:15:51 PM
Could be debris in the float needle seat causing fuel to vent out the overflow tube. Does sound as if your fuel lines are in less than ideal condition. Simple and economical chore to replace.   Monte
Title: Re: Carb Leak - Always A Mistake To Assume All Is OK!
Post by: Justin B. on May 10, 2009, 06:33:53 PM
Aïda,

We had tons of grief on the '80 R65RS when we firt got it.  Seemed like every other time Suraklyn took it out he came back with wet-boot syndrome.  I went through needles, new floats, lapped the seats, etc - no good.  I finally pulled the worst offender and decided to clean it real good.  When I put some pressure to the needle seat (blowing back upstream) a bunch of hard black granules blew out.  I then took off the other carb with like results.  After this, no more leaking.  I am taking a WAG that the little hard black granules were decomposed fuel line...
Title: Re: Carb Leak - Always A Mistake To Assume All Is OK!
Post by: farmer on May 10, 2009, 06:56:42 PM
Yes I leveled carb as described by Monte above. Have since received and installed new set of gaskets from Real Gaskets Corp. No more problems with leaks. Fuel lines were only 2 years old and seems fine.

Rob: Good point about riding boots, just have to overcome sticker shock when I shop for them!
Title: Re: Carb Leak - Always A Mistake To Assume All Is OK!
Post by: Justin B. on May 10, 2009, 07:28:59 PM
I just ordered some of this:

http://www.aircraftspruce.com/catalog/appages/bingfuel.php

and some of this:

http://www.aircraftspruce.com/catalog/appages/fuelline.php

I have been using this:

http://www.aircraftspruce.com/catalog/appages/polyurethanetubing.php

The regular poly tubing seems to turn brown with age but I have had it on my '81 R100 for probably 4 years and it's still soft...
Title: Re: Carb Leak - Always A Mistake To Assume All Is OK!
Post by: Bob_Roller on May 10, 2009, 07:31:34 PM
I emailed the Bing agency in Kansas, and they wanted $2.59US per foot.

Looks like it's Aircraft Spruce, for the next fuel line replacement, for the R65, and the oilhead.
Title: Re: Carb Leak - Always A Mistake To Assume All Is OK!
Post by: msbuck on May 10, 2009, 10:10:52 PM
Graham's already been through the trash in the carb syndrome from deteriorating fuel lines on his R100.  I think he still has some fuel line laying around - oh yeah, he replaced his vent tube with the extra fuel line, so that is now his 'spare line' that he carries with him at all times...

I'm pretty sure that's my problem, so it's on the list now.