The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: DgM on June 06, 2008, 03:13:24 PM
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Riding along, everything aok, engine starts running on one cylinder, coughs, stops. Left carb pouring gasoline on exhaust pipes, ground, right carb no leaks. Tap carb with gloved hand, gas stops pouring. Wait a minute, bike starts up, runs fine, ride home expecting gas geyser, no leaking. Anyone else experience this? What causes this and how to fix? Help!
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float needle stuck open could have some trash under seat of needle.
Don
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Time to clean out the float bowl needle valve seat and check the condition of the carb float... both sides. And here you thought you'd get to ride on Saturday. ;D Not a tough job. Glad you didn't roast your weiner on a blazing saddle.
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Check the condition of your fuel lines. They may look fine on the outside but be cracked on the inside and dropping little bits of junk that makes keeps those valves from closing. A foot or two of new fuel line is a really cheap fix. It may also be a good time to replace those gaskets between the carb body and float bowls.
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I replace my fuel line every 2 or 3 years for this reason alone.
I had mine leak on me once, in 2000. Never since.
You should also take the time to empty the fuel tank and remove the petcock to examine the screen that may be inside.
My petcock also has a second, smaller screen at the bottom, where the hose slips on.
Do you know when the float needles were last replaced?
They have a rubber seal on the tip, and that can harden over time and make it harder to seal.
If the floats are old, they may be starting to absorb gas, and would be heavy and not work so well.
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Thanks for the help. Looks like a weekend with the carbs. Can work be accomplished while carbs are on bike or must they be removed? Super drag, as I just finished install of brembo caliper, pads, disc, splitter, lines, new master cylinder...braking more progressive, smoother, a bit more powerful. Thanks for the parts Montmil!
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I aways liked that fairing (BCW). That is a real pretty bike you have there.
Don't worry about the carbs, after you fix them, something else will likely call for your attention! ;)
I am pretty sure you can remove the pin to drop the floats with the carbs mounted on the bike, but it would be a whole lot easier to do on the bench.
The pin will only move one direction, so examine it closely to determine which way to drift it.
Only work on one carb at a time, so if you forget how something goes back together, you have the other to refer to.
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Lovely, Classic Look! Really special.
Ed ;)
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Thanks for compliment on bike. It's a sweetheart...when it runs! Started it up, engine as usual caught, idled with choke on, warmed up, turned choke off, idled well, no leaks, then began running rough (like drowning in fuel), gasoline vomitorium once again. Removed float bowl from overflowing carb. Inside clean as a whistle. Needle riding on float bowl bracket moves with no sticking, no effort. Gasket between float bowl intact cork, thin. Floats didn't seem fuel logged, white/tan plastic. Reinstalled float bowl, turned on gas tap, gasoline everywhere again. Does this indicate floats filling with gasoline, sinking, float bowl overflowing? Would a too thin gasket between float bowl and body cause overflowing? Or am I going to have to remove carbs and take apart?
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Pull the fuel lines off the carbs, and plug them with a couple of golf tees, or something similar.
Turn on the gas.
Make sure the fuel lines are not leaking.
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Removed fuel lines, plugged with golf tee, turned on gas. No leaks. Hooked up fuel line, turned on gas, so much gas spewing it seems to be coming from every seam of carb Turned off gas. Pulled carb, throat not as clean as inside float bowl, not gummed up. Removed float bowl, checked float and needle again - float not soaked, float needle moving freely - replaced float bowl, reinstalled carb, turned on gas, no leak, no spewing. What gives??? What can be screwing up inside to cause this? Haunted carb?
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It could be dirt in the fuel, getting between the needle and the seat.
You need to empty the fuel tank and remove the petcock and see what comes out. See if you have any filters on the petcock at all.
Some folks like inline filters. I've never found the need, myself.
My petcock has two filters. A big one slips over the two tubes that allow the gas into the petcock.
The small filter is on the bottom of the petcock, just above where the hose slips on.
If you have crap in the tank, and no filters, that would explain a lot.
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I have an inline filter, gas viewed in filter and in float bowl free of grit, dirt, muck. The leak seems to be a carb internal issue, as if floats are sinking and letting gusher of gas into carb which then overflows. Yet floats are light and needle isn't sticking. A conundrum. This issue first came up only after riding, parking bike for a short time and restarting, wondered if heat from engine was cooking fuel lines, now spewing with cold engine. Before big spew, engine runs rough, then dies as gasoline drips drips drips. What could have come loose or get clogged? Can float needle wear out/break/fall apart?
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Have you replaced the lines, floats, etc? I mean, do you know how old these parts are? Baselines are good.
Where do you live? Is there weird stuff in the gas?
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I have had a fuel bowl with some corroision start weeping fuel that looked like it was leaking out the overflow.
Don
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I had this problem recently after a carb overhaul and i couldn't figure what was going on,fuel dripping everywhere,then it struck me!!the floats were touching the side of the bowl!i gently sqeezed them together,and it's been fine since,maybe this has happened to you?give it a go,but be gentle.
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Right on the money. Gently squeezed floats towards center, reassembled carb, no leaks, runs fine. Thanks.
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Right on the money. Gently squeezed floats towards center, reassembled carb, no leaks, runs fine. Thanks.
That's a great result,i'm very pleased it worked for you. :)
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Re your photo:
Wow!!! At first glance, I thought you had photographed *my* bike. It's terrific!
The resemblance between yours and my '81 is striking. Further study showed that yours has the great BMW red & white pinstripes on the fairing (my Shoei cafe fairing, alas, is plain black), you placed your R65 battery cover emblem a bit lower than I did, you have a single front brake (mine is a twin), and I've added BMW Touring Cases and their necessary brackets. Otherwise, they look like siblings.
Query for the veteran riders: What's the story about single vs. twin disks on '81 R65s? It appears that some have singles, and others, twins. The Parts Department folks at Bob's BMW surmise that twin disks might have been a retrofit on the 1981. The parts fiche on the OEM web site seems to confirm this. (What's the correct URL for that site? I forget.) Is this common with 1981 and other years?
Good riding to you. Please, if we ever show up at the same rally, don't park yours next to mine. Too much chance of an honest mistaken attempt to ride off on the wrong bike.
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Thanks for compliment. Doppelganger a go go. Post a picture of yours. Check out the picture of my bike again. I installed a dual disc, brembo caliper setup. Works better, looks better. The stickers on the side covers are as installed by BMW factory. Prior to the LS, R65 models came with dual discs with ATE calipers, after LS, plain old R65 models had single disc, brembo caliper, smaller master cylinder. Haven't gotten around to getting saddlebags yet, just a big tank bag. See you on the road.
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"Post a picture of yours."
That's an ongoing project. I've been fighting gators in other areas & haven't been able to complete a couple computer & communications updates that would make an independent personal site practicable. As soon as I get an AROUNTOIT, I'll do so.
"The stickers on the side covers are as installed by BMW factory."
That's good news, and also bad news.
The good news is the uncertainty that it resolves. There's a topic about a month old somewhere on this forum re the emblems (how to get them, what color, etc.) I spent some time at Morton's on this subject. The sales manager searched the web & could not find a pre-1985 standard r65 photo showing the emblems. Your photo is the first concrete evidence I've seen re the OEM location of the emblems.
The bad news is that I now feel the need to acquire two more emblems, laboriously remove the old ones, and install the second pair in the correct position. Looks like the dealer makes a few more bucks from me.
I'm trying to make my bike more visible for safety purposes, but by hacking into the electrical system no more than necessary. To that end, I've been investing in 3M reflective tape and applying it tastefully (I hope) to the touring cases and unpainted surfaces of the bike. (The tape that's black during the day looks good on the cases, but is a bright silver/white at night is quite effective.) Additionally, I'm waiting for the dealer to receive a backordered drop-in LED brake/tail light module that purportedly fits into the OEM enclosure. (Some Virginia cops reportedly ticket the "progressive" taillights on the theory that only a "steady" red light is permitted under fed regulations & the Virginia Motor Vehicle Code. There has been a lot of recent discussion of that issue on bmwbmw<dot>org's forum.)
"Check out the picture of my bike again."
Oops. My deadlined ojos, again. :-[ (I'm on nonriding status this week because of retina surgery last Friday, with another round to go in future weeks.) :(
I think you're correct, but I've read a lot of confusing stuff on the "official" sites about the history of the single/dual brakes on the 1981-84 standard r65s. Everyone seems to agree that '79 and '80 are single, though there's an '80 running around our area with dual (probably that retro kit that I mentioned). The '81 had dual, according to the official sites. Nonetheless, there are some '81s with singles. (Possibly using parts from another model year.) There seems to be little confusion about the post-LS "standard" R65.
My hunch is that if the r65 ever becomes a "hot" vintage model, this phenomenon of mixing and matching parts across model years will become a major valuation issue in the resale market.
Like you, I love my bike, and it seems to be running fine at the moment. It's the perfect balance of weight, agility, and power/torque curve for dense suburban traffic and comfortable non-superslab highway riding. I hope it keeps going as long as I keep riding.
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I bought a 1982 R65 brand new in 1982 and it had the stickers on the side covers same as my 'new' 1983. My 1982 also had the old style centerstand which I have been told ceased to be utilized in 1981...I agree about your views on the bike - light, balanced, perfect mix for mountain passes, highways, urban, and suburban travel, a bit light for all day 85+mph blasts down superhighways.
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Gas puking returned after a couple enjoyable trouble free rides. Floats still light as air, needle moves freely - with bowl off and me moving floats. Puking only occurs less than a couple miles after bike has been ridden for a while, is parked, restarted on hot days. Heat soak from engine a factor? BMW service tech mentioned carb body may be worn, allowing needle to rattle around, get stuck, requiring entire new carb of course. Out of state for a week, then carbs off bike, poke around, no riding. Uhh...
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I have an inline filter, gas viewed in filter and in float bowl free of grit, dirt, muck. The leak seems to be a carb internal issue, as if floats are sinking and letting gusher of gas into carb which then overflows. Yet floats are light and needle isn't sticking. A conundrum. This issue first came up only after riding, parking bike for a short time and restarting, wondered if heat from engine was cooking fuel lines, now spewing with cold engine. Before big spew, engine runs rough, then dies as gasoline drips drips drips. What could have come loose or get clogged? Can float needle wear out/break/fall apart?
It only takes a speck of dirt to upset the needle jet. You may not even see it! Also the needles wear and form a minute ridge which allows fuel to pass. Some are solid brass and some have a rubber type tip which can harden/crack with age. If you take the bowl off and open the tap (fuel will flow-be prepared to catch the spill) then manually and carefully lift the float to see if the fuel stops dripping. It should completely stop with no drips. Also check that the float does not have any holes. I would replace the needle valves as a matter of course. They do wear so just replace them as a service item.
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This may be stupid but make sure there is a stand pipe inside the float bowl and that its not broken off. You might try bending the float arm that presses against the needle. I think my carb manual says that the float arms should be horizontal to the base of the carb when the little arm in the center just touches the needle. Somebody please correct me if I'm wrong...
Have you replaced the needles? Might be time for new...
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This may be stupid but make sure there is a stand pipe inside the float bowl and that its not broken off. You might try bending the float arm that presses against the needle. I think my carb manual says that the float arms should be horizontal to the base of the carb when the little arm in the center just touches the needle. Somebody please correct me if I'm wrong...
Have you replaced the needles? Might be time for new...
You are correct, SG.
There is a tab on the float that contacts the float needle. The tab can be bent in either direction to effect how much fuel is allowed in the bowl before it shuts off.
I think the stand pipe you mentioned, that goes down in the hole in one corner of the float bowl, is for the enrichener circuit. One does need to make sure that the small hole that allows fuel into that cavity is clear, but that wouldn't be causing an overflow problem.