The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Tv on March 01, 2009, 10:44:52 PM
-
G'day. My name is Tony and I'm new to the forum. I have an 84 R65 which i bought in December 08 and I'm trying to fix a power problem. I since purchased a 81 R65 (in probabl;y better shape then my 84) as a donor bike and have been using it's components to try and find a solution using a process of elimination.
I've searched the forum but have been unable to find an answer so maybe someone can help. BTW - great forum.
My bike seems to lose power at about 4-5k revs. More when under load such as riding uphill. Down hill it doesn't seem so bad. Occaisionally it just flys like I imagine it should go all the time.
When it dies it sort of bogs down, splutters and groans and if I hold the thottle full open it seems to do it more. Sometimes it'll get through its fit and take off to full revs. It's done this with both sets of carbs and both coils so:- I've overhauled the carbs and set them up as specified in this forums tech hints and links to other technical help (jet needles set on 2nd notch). I replaced the coil, checked the valve clearance, adjusted the head bolts, relaced the air filter, high tension leads and spark plugs and even blew up the tyres.
I cant seem to find any info on ignition timing adjustment for the electronic ignition so I wonder whether it needs to be done? Do you think ignition timing could be the problem?
Thanks a lot!
REgards
Tv
-
If you hear pinging from the motor the timing is too advanced. If it runs hot and lacks power all the time it retarded. You have intermittent power loss so the timing is probably not it. Unless the advance weights in the bean can are shot ( jerky engine). How's the compression? Does it do it when cold or hot? All the time? Clean fuel screen, filter? Is this fun or what?
-
Did you replace the diaphragms?
-
The engine is not jerky. It runs smoothly to 4 or 5k revs then starts to break down. Sometimes if I tickle the throttle it helps to get it to run at full power but I've tried blipping the choke just a bit to see if a bit of extra fuel will help it lets me know that's not it. Plenty of power down low. Does it cold and hot. I've renewed the fuel filter,however, the tank did have a lot of crap in it when I cleaned it out.
When I overhauled the carbs I put a full kit thru, including new jets, needles, diaphrams and o-rings. It does feel like a diaphram issue but couldn't be as the problem exists with both sets of carbs.
I dont have a compression tester
-
Ignition coils breaking down?
-
Does it eventually pick up again and go on, or can you accelerate through it on full throttle?
If so, you might find that you are running a little rich at that point in the rev range. I would try dropping the needle a click or two to lean it out a bit and see if the situation improves. You can do a spark plug check at this rpm as well, to see - ride the bike to the appropriate revs and then shut the bike off, coast to a halt and then immediatly check your plugs - if they are dark, then it is running rich at this point.
Is the bike standard otherwise or do you have aftermarket exhaust or air filters?
SteveH
-
It does eventually pickup and if I get to the 5.5k+ rev range. I've checked the plugs after my ride and the top of the insulator and electrode seem to look normal but the rest of the plug looks a bit black and furry. The air filter is standard but I'm not sure about the exhaust. They look normal but sound bit louder than other bmw's I've heard. Does it seem odd that I would have the same problem with two sets of carbs? When I installed the jet needles (they are the twist in type, not the screw in type) I've clicked them in to the second position so are you suggesting I take it back to first poisition to lean the mix? I tried changing the needle position with the original carbs and that didn't seem to fix the problem so thats why I overhauled my other carbs hoping that would solve it.
AS far as the coils go, it's done the same thing with both coils so that seems unlikely.
Thanks a lot for your help
REgards
Tv
-
Have you checked your fuel filter and petcock?
-
How old are your sparkplug wires. I had my 82 R65 act like it had a fuel problem. I turned out to be plug wires.
Don
-
The plug wires, caps and plugs are all new. The fuel filter is new. I checked and cleaned the petcock and the tank filter before I overhauled the carbs. The tank was full of crap when I cleaned it out so I might check that again. I'll get another new fuel filter and try the other tank also.
I once had a 1958 Hillman Minx car that used to die every time I went up a hill so I overhauled most of the engine stuff and it turned out to be rust and rubbish inside the fuel tank. Once I cleaned it out it went like the clappers.
-
A little information on the OEM ignition coils, it's highly unlikely that both would cause the same problem.
But if you have the gray and black coils, they are commonly referred to as the 'crack-o-matic' coil , they are a problematic part, and if they are not giving problems now, they will in the future.
BMW upgraded the coil some time in the early '90's, to a red and black part, I replaced my original gray and black coil with the upgraded part, and it only lasted 10 years before it failed again.
Just a little heads up info.
Have you replaced the fuel lines yet ?
I had a problem of one of the lines would kink on me and restrict fuel to the right carb.
Seeing as how you have a 'donor' bike, if you run out of places to go, you may want to try and swap the ignition canisters ( commonly referred to as the 'bean can') , located under the front cover of the engine.
If by chance the can is the problem area, there is a pictorial guide to taking the unit apart on our FAQ section, under the heading 'Bean Can Overhaul'.
Also there is an ignition control unit under the tank, it has an aluminum heat-sink bolted, or riveted to it, they usually work, or don't work, but it's a quick swap over.
From the looks of your profile, you appear to reside in saltwater coastal area, I don't know if corrosion is an issue with your area, but it would be a good idea to disassemble the electrical connections in the wiring harness, and check for corrosion and security of all of the connectors.
Welcome to the world of 28 year old motorcycles !!!!
-
Welcome to the world of 28 year old motorcycles !!!!
Thanks - I sold my Harley because I felt I couldn't tinker with it and it was costing me too much to own. I bought these new (old BMW) bikes for a fraction of the cost and have been fiddling ever since - much more fun, still, I wouln't mind solving this problem. I'll take the advice given so far and let you know what happens.
-
Is it always RPM related, or does it happen rather intermittently (and you end up revving the engine to try to get it to recover ? What I am thinking of is that if this is happening with (2) sets of carbs and (2) sets of coils, it is more likely to be something that you haven't changed yet, so what could it be..
1. What type of fuel filter did you install? Perhaps you can try flushing out your fuel tank to make sure it is really clean, and run without your aftermarket filter - perhaps it isn't flowing fuel well enough and you are getting a fuel starvation issue - or - you might have a gas tank venting issue.
2. It could be the"bean can" ignition trigger unit, but it might by the ignition control unit. I'd take it off and renew the heatsink paste that goes on the metal back of the ICU where the aluminum alloy heatsink plate presses against it - it these get too hot they can misbehave. You could also try swapping the ICU from the 81 to the 84 to see if the problem follows the part or not.
Best of luck - we'll stick with ya until you get this solved. So far you've been going about it in the right way !
-
It may just be the fuel cap not venting at high revs, try loosening the fuel cap tp prove me wrong.
-
Thanks fellows. I'll try all the suggestions one at a time and let you know the outcome.
Update - Changed the tank including petcovk and the electronic module and still the same. I tried the old 'switch the system down when the fault occurs' trick then checked the plugs. They were blackish and bit furry so looks like the mix is too rich. I better try moving the jet needles. Do I need to make them shorter or longer?
-
The position of the needle needs to be moved down, which means the clip needs to be moved up.
The needle position will effect the mixture at 2/3 to 3/4 throttle - and will move fully out the way at full throttle - at that point it is only the main jet that is in play. I think there are on 4 positions on the needle. If the mixture is too rich at this point then the motor will bog down - some people notice it as a 'flat spot', for others it is worse....But you do not want to run too lean, but then you only have 1 or two positions to move to...
I also had an after market exhaust - it looked the same but sounded different.
I had this issue when I first had my bike - took me years to figure it out - I went rich (and made it worse) long before I went lean - even bought bigger jets >:(. I am now using standard jets and needles. Just positioned my needle in a slightly leaner position.
I hope you have success. ;)
Steve H
-
Success, sort of. I moved the needle position to what I think is the leanest ie, the very first position on the fat side of the needle. This way the needle sticks further into the jet??????? I now have a flat spot around 3k but if I gas it it quickly pulls through then through the 4-5k range and onto redline (not that I take it that far but it seems it'll go)
Got back from a quick test ride around the block and noticed oil coming from between the block and the cylinder head.
That wasn't supposed to happen!!!! Better get the tension wrench out :-[
-
I feel your pain. I replace to pushrod seals and now it leaks more! And just to pile it on, I left the petcock on for a couple of days (duh) and now it won't idle and i's fowling plugs. Aargh, I work on this bike way more than I ride it. >:(
-
TV - It sounds like you might be onto the problem, there - I didn't think from your description that your exhaust system was different enough from stock to impact the mixture, but apparently it is.
Goo - maybe you have a leaking seat in your carb jet, or you've got a stuck float, from having the bowls overfilled with gas when the petcock was left on. Also, check your engine oil to see if you ended up with fuel getting into the cylinder and down into the crankcase. IF you smell gas from the dipstick /fill hole or the level shows that it is somehow higher than normal, you gotta drain and change the oil and oil filter or risk damage to the engine.
-
Have you a Haynes manual?
As far as jetting goes, I know the jetting recomendations are different for UK/European bikes than those in the US. I forget which side of the pond is leaner. Are you still running the air bleed pipes? Or have you removed them?
How old are your needle/jets? If they are originals, and you have any sort of mileage on the bikes, then a new set of standard needle/jets might be in order. They do wear, and when they do they will make the bike run richer. At least we are getting there though.
You might also find that changes in gasoline might also be implicated? - a wild stab in the dark, I know. But there is no doubt that gasiline from the early 80's is different to that we are running today. For better or for worse.
-
Welcome to the world of 28 year old motorcycles !!!!
Thanks - I sold my Harley because I felt I couldn't tinker with it and it was costing me too much to own.
Harley "a way of life",
because you spend your life fixing them ?
;D
-
The needles and jets are new. The exhaust has a connecting pipe on the headers at the front of the bike but not underneath. The 81 has the connecting pipe underneath. Which is standard? I've been running High Octane 98 Unleaded fuel so I might try standard unleaded and see if that makes a difference.
I have a Haynes manual but it can be vague in some areas.
-
OK WAG* time. Wadda ya think of too large of a main jet and a float set too low. Yea I know 2 carb sets were tried but were the jet sizes ever verified as correct? From experience I found once that floats I was 'dead sure' were correct were too low to a more practiced eye. So a rich main makes the plugs black but the low floats cause fuel starvation at high [sustained] revs in top gear. Once the high speed is attained the float bowls have a chance to catch up and the motor runs OK again.
rich
*Wild @$$ Guess :D
-
All good theories, BTW what are the air bleed pipes which you refer to Steve?
Hey Darwin, I had that Harley for over 2 years and so far it was the most bullet proof bike I've ever had. Never let me down, went like a scalded cat and never used, sweated or dripped oil - pretty boring huh? At least with these BMW R65 bikes I can muck around with them and if I mess something up it's no big deal. How's that Valiant go?
-
Tv - its an American do-hicky for emissions. Some complicated pipe-work between the airbox and exhaust.
You probably wont see it in Oz - I should concentrate more.
I would check you float heights as MrRiden suggests as well.
Its a fiddly job but worth persevering with.
-
Apologies, did not read the second page before posting.
My vote is for floats and/or fuel flow too low.
Ok all, correct me if I am wrong.
No mention of abrupt stalling or dying of engine, leads me to believe problem is in the fuel system. Most probably the float level is a bit low.
While adjusting the float level is a good time to check fuel flow. If the flow can't keep the bowls filled it'll starve.
I had similar experience after rebuilding carbs. 1mm up or down makes a big difference. I went up untill it started dying on me when braking, because the high fuel level was sloshing into the venturi. Then slowly backed it off untill not stalling at all.
If ignition is the cause I have experienced a back fire usually.
The black fuzzy looking plug may be from raw gas entering the venturi.
Just throwing this out there as even with new floats it is possible they are not set just right. Or not enough flow to keep the bowls filled.
-
Looks like I better have a go at the floats (have been dreading touching those)
I was riding last night after tightened the head bolts and re-checked the tappets and realised that 0.01" is NOT 0.1mm (der!!!) and set them right then re-adjustied and balanced the carbs. It runs very smooth until it gets to the dodgy rev range then stutters a bit but powers on through, then I ran out of petrol. Once I sorted that out it behaved a lot better but it's still not quite right.
With all the fiddling I'm convinced it's a fuel thing and floats are the only thing I haven't messed with so here goes :-?
-
One other thing to check - the metal insert at the top of some of the bing carbs can leak air around the edge and mimic a diaphram problem. Sometimes you can just catch a fingernail at the edge of the disk. Bike will run fine up to a point and then run out of power for the last 1/3 of the throttle movement.
Fix - run some thin epoxy around the edge of the disk sealing the slot. Some riders glue on a coin or a BMW logo.
Easy fix to try - minimal cost and nothing to take apart!
-
Did we ever get to the bottom of this?
Have you managed to fix your issue?
-
G'day Steve, sorry about the delayed response but I've been busy with work and putting the old '81 back together and have been neglecting the troublesome '84.
I checked the float levels and they seemed OK to me. I still cant get the thing to run right. It idles fine, I take off and it glides to 3k revs and dies then splutters for a second and, because I have to give full throttle, eventually takes off. Very annoying in traffic. When cruising at between 80-120 kph it seems to fade so i give it some gas and it goes ok again. Erratic behaviour - makes it tedious to ride.
When I tuck in and give it the full bore on the open road it seems to be starving at full throttle but when I back off a bit it'll accelerate so I've got used to tickling the throttle until I reach the desired speed then wrestle with it to 'stay'. Seems to go to 140+ no problem usingthis technique
It does also sound like it gurgling when I back off, maybe a bit of a back fire.
I've reassembled the original 84 Bings and I am refitting those in the near future. I have a timing light stored away under the house somewhere and I'm going to see if I can check the timing. Will need to find out how to do that; and I think I may need to seal the exhaust system properly as it may be leaking a bit. Only a few things huh? [grin] but I am determined to figure it out. I'm still trying to find that level playing field
Hope you are all well and life treats you good
-
Good luck with it.
Steve H
-
As for checking the float levels - so how much fuel is in the bowl (either depth from the bottom, or distance to top of fuel level measured from the top of the bowl with the bowl carefully removed and set on flat surface)? If the fuel level is either way too high (floats may have degraded and become too heavy) or too low you may have a starvation issue, or it may be running too rich at partial throttle opening which could also cause ti to "bog" - but I don't initially suspect that you are running too rich, but maybe..
How far out have you adjusted the air/fuel mixture screws at the bottom of the carbs? You might try turning them about 1-2 screwdriver blade's thickness counterclockwise (richens mixture) and see if it has any change on your partial throttle (1/8th to 1/2 throttle) performance. If the sputtering situation slightly improves then it maybe a a lean/starvation problem - if it gets worse then you're really into an over-rich situation, which could be too high of a fuel level in the bowl or saggy floats.
I think (cannot recall) that the target for float bowl fuel level is somewhere around 6mm below the top of the bowl, though I may be thinking of carbs on another bike...
-
You mentioned that you are using a fuel filter, what kind is it, specifically for motorcycles, or is it an automotive filter ?
-
I got the filter from the local BMW workshop so I assume it's OK. I will adjust the mixture screws and measure the fuel level in the bowls.
Thanks, see how I go this time
REgards
Tv
-
I've tried (nearly) everything. Adjusted the float levels and readjusted the idle mixture screw with no change. Out of curiosity I changed the carb needle jet position from 1 to 3. The breakdown started to occur around 5000 revs and I had no top end power. Set needle to position 2 and back to where I began at the start of this thread. I've got bottom end power and the most usable power range at position 2; So needle position 1 dies at 3000 rev, 2 at 4000 and 3 at 5000.
Would this indicate the carbs are working OK and the poblem is elsewhere? (I have been following clousea's thread about the same problem)
I found I could get to 5500 travelling about 100k in top gear and as soon as I tried to get more power (either going up a hill or giving it the gas) the bike started to blop-blop-blop-blop as if it was running on one pot and seemed like it was misfiring. I've changed coils, leads, plugs, ignition module. If anyone else has encountered this symptom I'd be interested in your cure.
Tomorrow I'm buying a new timing light. Will any type of automotive timing light be OK?
REgards
Tv
-
I have always used just a regular inductive pickup light. You probably don't need the fancier models with the advance knob, just a regular one.
Quite often when the bike just sorta runs outa beans at a particular RPM a diaphragm is at fault. But, if all of that stuff has been addressed...
-
Is the left cylinder the one that is misfiring when you develop this problem ?
Or can you even tell which one is giving you the problem ?
Have you tried running the bike without the fuel filter installed ?
-
Today I re-checked the float levels including measuring the fuel in the bowls and they seem Ok. Both sides are the same.
Got a new timing light and ckecked the ignition timing. The timing seemed to be set correct but I advanced it a bit - test ride with no change to my existing problem, retarded it a bit with the same result.
Tommorow I'm changing the bean can - let you know what happens
Thanks
-
I've read each post in this thread. Early on, I had a very similar problem with my '81 R65. Very similar. So...
Have you replaced the diaphragms and the floats? What technique are you using to set the float levels?
Monte
-
It's not the bean can.
Monte - I have only replaced the diaphrams. To check the float level I turn the petcock to 'off', remove the float bowl, push the floats right up, turn the petck to 'on', slowly let the floats down until fuel starts to flow and at that point, check whether the top od the float is parallel with the bottom of the carb body. Then i let the float go so petrol pours out and slowly raise the floats til the fuel stops and that point looks to be the same spot the fuel starts as described above.
-
I'd recheck your diaphragms to make certain that they are in there properly and haven't popped out of position - there is a small tab on one edge that must fit in its little slot properly or all bets are off.
Our brit friends have also discovered that the moto-bins replacement diaphragms (not Bing brand) are much thicker and heavier and more stiff than the stock ones - this has sometimes caused issue with getting things running right. The thread on that is relatively recent in this tech section somewhere..
-
I just checked all the fuel fiters and lines from tank to carbs and all ok. I am confident I have the diaphrams in correctly as I have had those carb tops off at least 20 times during this exercise. The locating tags are in the right spot. Now that the timing is set, tappets done, I'm going for a ride to warm up then re-calibrating the carbs and that's about it for this session. I've scored a pile of work so the bike goes in the shed for a while, however, I'm going to seal the carb cap metal inserts with epoxy before I put it to bed so next tiem I ride - who knows - maybe that's it.
Thanks and best regards
Tv
-
PROBLEM SOLVED!
Whilst researching all the possibilities I was reading an article by Snowbum about 'Intake and Exhaust tuning' and the intake theory pointed me to the airbox. There was another article concerning the restricted flow of air . One thing led to another and I checked the two air box lids I had and the one fitted had smaller snorkel holes than the spare so I fitted the spare and BINGO, no more mid range flat spot.
The difference in size of the snorkel tips, measuring across the oval dimensions are 25mm x 15mm as against 35mm x 25mm. Thats a fair bit more air getting sucked in.
It looks as it may be running a bit lean now but at least I've overcome the problem issue and I can get down to tuning it more accurately
Thanks to all who helped me through the problem and I'll try to help others in the future also
Here are the links to the articles
http://bmwmotorcycletech.info/InExTuning.htm
http://bmwmotorcycletech.info/R80,%201980+,%20Airboxmods.htm
Thanks again - I'm going out riding - Yeeeee Haaaarrrrrrr!!!!!
-
I don't recall anybody here ever having that issue before! Glad you finally figured it out and maybe this might help somebody else down the road...
-
Just did a quick search on RealOEM parts catalog, and there are a number of different airbox tops for the later style airboxes that use the flat air filter, what the differences are, I don't know, but they have different part numbers, something to keep in mind, if you buy one second hand .