The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Ctino on July 09, 2013, 01:44:55 PM
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Hi, i started my cafe build in january, im having a few problems with starting the bike. First off i posted a thread with my ultrasonic cleaner back in january, where i foolishly sank the carbs as a whole in them. since then i learned how to strip, clean and rebuild my carbs properly. Having that school boy error off my chest i feel much better..!!!
I think im having a fueling problem with my carbs, the battery takes charge and stands at 12.5 v there is also spark. The diaphram in the carb seems to be working as i blow air in the air hole in the top of the carb it moves up. The reason i think its to do with my fueling is because when i spray carb cleaner in the left hand carb while starting shes fires up then quickly dies. if i continue to spray carb cleaner while accelerating she will run ontill the can runs out. ive checked over the carbs twice now and everything is clear and unblocked even the choke jet in the float bowl. I put new diaphrams, o rings, pins and gaskets when rebuilding the carbs. Petrol flows nicely into the float bowls.
The fuel air mixture is to be adjusted once the motor is running ??
The bike was a hard starter when i got her i had to bump start.
Any help much appreciated.....
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First place I'll go, is the 'choke' assembly is side specific, there is a right and left assembly .
Sounds like both of the idle jets are clogged as well .
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Thanks for your reply... the jets are clear i tanked them in the ultasonic cleaner then sprayed with carb cleaner and replaced the o-ring...
I also rebuilt the carbs one at a time as not to mix parts up. The choke assemblies may have been mixed up previously how can u tell???
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I *see* your problem - you are missing spark plug leads! ;-)
So, when you take the bowl off the left hand carb and look into the small well in the inside front corner, there is a decent quantity of fuel in that little column? When you disassembled the carbs to clean them and re-assembled, you only did (1) at a time or kept them in separate tubs so that you didn't intermix parts from one ot the other? (the "choke" discs parts are left/right handed and the proper one must go on the corresponding carb, and in the proper orientation, or else the enricher will NOT work properly). From your description it does sound like the enricher is not working right, either through blockage or other fuel-feed issue.
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The choke assemblies may have beenmixed up previously how can u tell???
The only way to be certain is to look at and understand how the enricher disc aligns with the orifices in the carb body. The pear shaped hole flows air and should be at the top of the disc with the narrow end pointing towards the cylinder head. The small holes at the bottom flow fuel. Take a look here in our FAQ section
http://www.bmwr65.org/cgi-bin/yabb2/YaBB.pl?num=1291933920
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I think you need to go back and re clean your carb. Since you are able to keep it running when you spray the carb tels me a jet is stopped up. I have seen this too many times by first hand experience and others cleaning carbs.
Don
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[smiley=tekst-toppie.gif] What Don sez.
Totally strip every component from the carb body. Your choice on the butterfly and those tiny screws and o-rings...
Strip a single copper wire from something like 16-18 gauge wire and probe each and every opening you can find. Don't overlook the small holes in the venturi each side of the needle.
You likely have a clog in the idle system...
have you yet confirmed correct enrichener circuit component installs?
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The fuel air mixture is to be adjusted once the motor is running ??
yes, with it good and hot when you sync the carbs... but the engine will not run if your mixture screw is turned all the way in. There is a base setting for the number of turns to back out the screws. Cant recall off hand, but you can try backing out 1/2 turn on each carb at a time and trying to start it.
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Back to my post on cleaning carbs again. I have had my 82 R65 do the same thing to me. Turning the mixture screws and was not seeing any change in running. Went back and cleaned every thing again fixed the problem.
Don
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Thanks for the advice, Ive re-cleaned my carbs, checked my choke discs and everything is correct. With a little adjusting on the butterfly opening and mixture screw, the bike now starts with the choke fully on then after 2 or 3 seconds dies.
What would be the next step to getting the bike running????
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Well, while you are at it, you should check your valve lash if you haven't done so. Tight valves will make a bike hard to start because if they get tight enough you lose compression. Once you check the lash on a cold (hasn't been run since the day before) engine, do a compression test and make sure you have good compression.
When you dunked your carbs as a whole assembly, what did you dunk them in? A strong solvent could have damaged the o-rings on your jets. When you say you "rebuilt" the carbs, does that mean you replaced all the rubber, or just took them apart, cleaned, and reassembled?
For good measure, make sure you have a good, strong, blue spark.
Also, if you don't have an in-line fuel filter, install one. It's possible that you are letting bits of rust, crud, and old tank liner into your carbs after you clean them.
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And, are the vacuum ports on the bottoms of your carburetors plugged, capped, or otherwise sealed to the atmosphere?
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Will have to check the valves also the clearances, haven't done that yet. I presumed since the bike was running before hand they should be ok??
Dunking the carbs as a whole was a mistake i re dunked them stripped. Replaced diaphragms, o-rings, float retaining pins, bowl gasket and choke gasket. I used a tickpour solvent r33 http://www.ultrasoniccleaner.co.uk/tickopur-cleaner-agent/tickopur-r33-2-litre.html .
Vacuum ports are plugged and inline filters are installed.
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If the bike came to you hard-starting, don't presume anything.
Airhead valves tend to tighten up quickly, and overly tight valves will make a bike hard to start. They should be checked every 5 or 6k miles. Supposedly some of the R65's had a bad batch of valves that wear out pretty quickly and thus require frequent adjustment. You should get in the habit of checking valve lash fairly frequently at first to see how the valves on your bike are behaving. If they continually tighten up quickly, they should be replaced. A dropped valve will cause serious damage (There is another thread going on in the technical forum about cylinder and piston replacement caused by a valve/piston collision).
We like to say air/fuel/spark, but what we really need is compressed air, atomized fuel, and properly timed spark (in conjunction with properly timed intake and exhaust flow)
So, go back to all the basics. Strong spark, good timing, a clean air filter, good compression, etc.
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cheers, I am gonna have a look at the valves on sat see whats going on.
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Hi CafeRR,
I see you have a automotive inline filter on your fuel line. Get ride of it. The China stuff is crap and restrictive. There is an Emgo filter that is a screen I may try that but I will never put an automotive inline filter on my Gravity Feed bikes ever again.
There is a metal strainer inside of the fuel petcock. That is enough. Just make sure that once a year you remove and clean your tank and clean the petcock strainer out.
Also look at the condition of the fuel hoses. If there are any cracks on the ends of the hose then you are well past due for new hoses. Hose life with todays weird fuels is 2-4 years(?)
The last thing to do is to check your float bowls at oil changes. Look for crap in the bowls and then work your way backwards to the source of the crap. If its red then it's the lining from the tank failing. If its black then its prolly the hoses.
Good luck. We are all counting on you. 8-)
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Not to be rude, but...
The China stuff is crap and restrictive.
It doesn't matter unless it's too restrictive. I've got a more restrictive than metalpaper element automotive inline filter from Autozone on my bike. Not exactly "China crap" --It has "made in Israel" printed on it-- but it wasn't expensive. I can bury the speedo for 20 minutes and the bike doesn't give one hiccough. How much more can you ask for? Besides, there is a very simple fuel delivery test to make sure enough gas is getting to your carbs. The engine doesn't need more than enough.
The last thing to do is to check your float bowls at oil changes. Look for crap in the bowls and then work your way backwards to the source of the crap. If its red then it's the lining from the tank failing. If its black then its prolly the hoses.
...if you find red crap in your carb bowls then clearly the metal strainer is not doing its job
Anywho, his problem is with getting the bike running. As long as he can get clean gas to the carbs it should run for a couple minutes before it runs the bowls down anyways.
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Not exactly "China crap" --It has "made in Israel" printed on it-- but it wasn't expensive.
I remember mechanics when they saw "Made in Israel' would roll their eyes and then would start swearing. It was a long time ago but never-the-less.... :o
Actually I don't think "Made in Israel" or "Made in China" has anything to do with it. Something about the paper elements and the Ethanol fuel is a bad combination. The paper inline filters are restrictive in a *short* time. This is my experience doing daylong rides with the BSA and BMW up and down the east coast. They are a bad idea unless you have an electric pump providing pressure.
This is my experience...
As aways your results may vary.
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Did you replace the carb floats? Did you check that the starter valve discs were not switched left and right (easy mistake to make..)., if that was done somebody may have tried to compensate for weak starting mixture by raising the fuel level through modifying the float tabs. Restoring the correct level will make the engine very hard to start.
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Kriky I completely forgot.
Check the jet that is in the float bowl ( there is a hole in the bottom corner of the float bowl.)
The jet is pressed in the bottom of the tube. So get a can of carb cleaner and put the red end of the plastic tube into the hole in the bottom corner of the float bowl. Point the open end of the float bowl away from your face (and any other paint surface - like a car or another bike). And spray. I fine jet of carb cleaner should come out the tube in the corner of the float bowl. if it doesn't then unclog it. Betcha the bike starts better now.
Some body will know what sized jet it is and the #of the really tiny drill bit you need to unclog it. I have just such a tool for the BSA's as they clog much easier than the BMWs.
Good luck.
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Some body will know what sized jet it is and the #of the really tiny drill bit you need to unclog it.I have just such a tool for the BSA's as they clog much easier than the BMWs.
Bing quote 44-031/66 which must mean a size 66 jet.
That translates to 0.024" or a number 73 drill.
I just use some thin wire but for a really stubborn blockage I guess you might need the drill.
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The small fuel reservoir in the corner of the float bowl feeds the enrichener circuit. The enricheners are actually small carburetors although most everyone refers to them as "chokes". Fuel enters the enrichener circuit reservoir through that small hole in the bottom of the float bowl. No fuel in there, starting will be difficult.
As Barry noted, a small length of copper wire will clear all but the most stubborn clogs.
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fi196.photobucket.com%2Falbums%2Faa1%2Fmontmil%2FBMW%2520Carbs%2Fbowlvent.jpg&hash=38300e8a3038588d19bd27366129db6a328c37c4) (http://s196.photobucket.com/user/montmil/media/BMW%20Carbs/bowlvent.jpg.html)
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Cheers for the replies,
Got at the bike for a few hours this evening, still no luck with getting her running.
@constillation, The floats were not replaced and the choke discs have been checked.
The small jet in the float is unblocked and tested. The ultrasonic cleaner took care of that.
I done the valve clearances today right side was a bit tight. Also done a compression test, which had to be done on a cold engine nothing i could do there. Both cylinders are running at the same around 155 psi, i dont know if thats good or bad??
After all this put it back together went to start again with the coke fully on. whined for about 5 seconds started and cut out after two. Tried a second third and fourth time nothing, pulled the carbs off to see wtf is going on. On the intake there seems to be a puddle of fuel just before the valve opening. Took the spark plugs out to see whats going on inside the cylinder there was mist or smoke not sure which.
Any advice on what could be going on??
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I had similar issues with my '81 R65 .
Here's what happened to me, couldn't get the bike to start, removed all of the parts and put them in an ultresonic cleaner for 12 hours, thought that evrything had to be clean .
I checked the idle jets with aerosol carb cleaner, I placed the plastic tube up against the end with the screwdriver slot, sprayed cleaner into it and it sprayed out .
What I didn't realize at the time, is that the carb cleaner was coming out of the two sets of holes drilled into the body of the jet about half way down .
The very end of the jet has the metered orifice that controls fuel flow, on both of my idle jets this orifice at the end was clogged .
Had a devil of a time getting them cleaned out without opening up the hole any larger than it should be .
Once they were clear, no more problems .
Even when this hole is clear, it's very difficult to tell its clear just by looking at it .
It may or may not be your issue, but it's a quick check type item on both carbs .
Hope this helps you out !!!!!!!!!!!!!!!!!!!!!!!!!! ;) ;) ;) ;) ;)
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Both cylinders are running at the same around 155 psi, i dont know if thats good or bad??
I wouldn't worry, that's a very good figure. Be worth checking again when hot. Anything above 145 psi on a hot engine is classed as excellent.
What I didn't realize at the time, is that the carb cleaner was coming out of the two sets of holes drilled into the body of the jet about half way down.
Those are the air emulsion holes. Air is supposed to go in through those holes mix with the fuel and the air/fuel mixture then should go out the hole in the top of the jet - which in this case was blocked.
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Good and bad news...
I took the carbs back off blew out the holes in question. Put it all back together, went to start her with the choke fully on. Fired up perfect holding at about 2000 rpm, just as i was about to celebrate she died. It was the longest i had her started for, she went for about 20 seconds. On subsequent start nothing, nothing, nothing and nothing!!!!!
Any ideas???
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I'd check the plugs to see if they are wet. They don't like full choke for long especially at this time of year. Well mine doesn't like the choke at all until it's well below 10 Deg C. I Haven't used the choke since last March/April and probably won't until October/November.
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Any ideas???
My thought is you picked up another piece of sediment.
Replace the fuel lines and filters if they aren't new.
Use carb cleaner to blow out your carb passages and follow with compressed air.
Make sure the air filter is clean. I've never heard of this happening, but maybe it's possible to get grit, fluff, etc. into one of the small air inlets at the mouth of the carburetor.
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Ok, so there was a mix up in my shed with gas canisters and it turns out i was trying to start the bike with diesel.... :-/
Good news is the bike runs perfect starts with no choke,every time so far...
Sorry to have hounded you all over this....
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Glad you found out before you did any damage.
Although if you did not start it.......
Rev. light
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Well !!!!!!!!!!!
I'd recommend that you flush out the tank, float bowls, and possibly replace in line fuel filters to ensure that lingering pockets of diesel don't remain to cause future 'mystery' issues.
I make sure that all my diesel/kerosene containers are marked with a big "D" or "K" on them too!
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That was a learning experience !!!!! :D :D :D :D
Don't know if they are available in your part of the world, but I have seen yellow fuel containers for diesel fuel locally .
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Much worse to run a diesel on gas than a gasser on diesel ;) Glad the bike runs well now. Sounds like it did run for a few seconds on the diesel with clean carbs, so your plugs are probably fouled.
Gonna have to add that to my poor starting checklist! I'm surprised you didn't notice the fumes when you took the carbs apart.
As long as most of the diesel is out it should be fine... after all, the R65 manual calls for draining the gas tank and coating the inside with motor oil for winter storage! Anything left will dissolve in the gasoline. Might even give you a little extra lubricity ;D
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That was a learning experience !!!!! :D :D :D :D
Don't know if they are available in your part of the world, but I have seen yellow fuel containers for diesel fuel locally .
They're mandatory here. Stations won't sell you diesel to put in red gas cans.