The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: BooG on December 14, 2009, 04:21:00 PM
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I have spark. I have compression (approx 175 psi in each cylinder). I have fuel in the carbs and cylinders. I have no startup at all...not even a stutter of ignition. Battery is performing valiantly (Oddessey),
Valve clearances are good... .10 at intake and .20 at exhaust, points set at .40....so what am I missing?? Driving me nuts!!
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First observation that I have, is the compression reading .
When my bike was new, the compression was 145 psi .
Is your exhaust system open, I know it's a long shot, but your compression reading just seems way too high for this engine .
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The gauge is an old one, and of questionable quality. It may well be giving false readings. How do I know if the exhaust system is open? Wouldn't it give a higher reading if it was shut off?
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A crude method, is to hold your hands behind the muffler, while someone is cranking the engine over with the starter, you should get a good puff of air on each exhaust stroke .
If that seems normal, time to move on .
Seeing as you have everything necessary to run the engine, fuel, spark, compression, is everything happening at the correct time ?
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I haven't done the timing yet. I guess that'll be my next job. It'll have to be tomorrow though, coz London has gone to sleep and it won't thank me for cranking up!! Would the bean can be a possible culprit?
Thanks for your responses!
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Again, a long shot, if the centrifugal advance mechanism in the 'beancan' was stuck in the full advance position, due to lack of lubrication, and/or rust, broken or missing return springs, ignition timing may be off .
No real good answers to your problem, just possibilities .
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Is it possible to squirt some lube into the beancan? Is that an acceptable (albeit temporary) fix?
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Members here, have done this, and had some positive results, I'm not familiar with the points type beancan, but on the electronic ignition, there is a small oval plate on the housing, and if I'm not mistaken, it is a press fit, after removing it, you have access to the advance mechanism .
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That all sounds like a plan to me!
Thanks Bob.
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Oval access plate on all bean cans.
Do you know your condenser (capacitor that sits on the side of the beancan) is good?
Go to this link, scroll down half-way (plus). Look for the word 'before' in red highlighted in yellow: before
http://bmwmotorcycletech.info/ignitionsingleplug.htm
and read that paragraph.
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I would also be ready with a spare set of points and condensor as a bad condensor will kill all hope of starting anything even if all is is perfect. and start with checking the static timing - look for the T or S in the timing window and verify that the points are in the proper position with the cam. If that looks OK, proceed from there as proposed above.
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I actually replaced the condenser as the first suspect! So there are new points and a new condenser in. New plugs, new leads, Dyna coil, and a big fat blue spark! Thats why I'm somewhat baffled! Great leads to follow however, and I'm on the case right now!
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Have identified the timing marks on the flywheel. I have a line (OT). Below that is the recessed dot, and below that is the embedded sphere. I have lined up the OT line with the groove on the left hand side of the window: should my eyeline be level with the carb or up slightly to take in the angle of the viewing hole itself? It is quite obscurred no?!
However, the points do not appear to be opening at TDC. I have a light rigged up to two croc clips: one to earth, one to condenser terminal on the outside of beancan...no light when rotating. There dosen't seam enough adjustment in the beancan to take up the advance in the right direction. Something going on here...
First time I've done this stuff...........
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Boo
Have you never been able to start the engine since your last thread? If not you must be getting seriously fed up with it by now.
Given all that has already been covered the only new thing I can think of is the petrol. How old is it ? Winter fuel at the pumps has a more volatile blend which starts more easily or alternatively a can of easy start might help.
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Your telling me!!
I'm a stubborn git though, so she will run again. I think I'm on the right track with the timing thing. That was the only other variable that wasn't checked. [smiley=stare.gif]
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Timing is probably the issue here, and the first time can be a bit frustrating. Take a deep breath and read the instructions several times. The little guy wants to run for you, just be patient and you will get the timing right. What spark plugs are you using and are they fresh? Heat range can make a difference if it's too cold, or if the plugs have been fouled.
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Plugs are BP6ES NGK, and have changed to the NGK caps also.
Should the lighting clip go on the condenser spade terminal and the other side to ground (fin)?
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Without consulting my Haynes manual, I believe that is correct. I used a test light, attached one end to the condenser, and put the bike in gear (on the centerstand of course). Touch the other end of the test light probe to a good ground as you rotate the back wheel in the forward direction. When the test light comes on look and see where the timing marks are.
Here's where my memory serves so consult the directions. The marks should be on either the OT, or the S - the manual will tell you which is correct. If you can't see any mark then you must adjust the points or the bean can.
Sorry to be so vague but at my advanced age I always keep the book handy to make sure I'm doing it correctly.
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Here is the bit I don't get. Setting the static timing. So, points are gapped at .40, TDC line in timing window. Now, at TDC, the test light should light up to show that the points have opened. If not, then the beancan can be adjusted to deal with this. However, at TDC, my points have not even opened, and I cannot adjust them so that they do (at the beancan). Interesting....
Obviously the engine will not fire if the spark is in the wrong place. If I squirt some carb cleaner in and turn over, it coughs. This implies that the compression is ok(?). I can feel pulsing at the exhaust pipes. The cylinders are wet inside, as are the plugs. So this could be it.
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Sorry Boo I hadn't seen your post on timing.
You can do quite an accurate static timing check. I disconnect the wire from the Bean can and connect an ohm meter between the bean can spade and earth (effectively across the points). With an allen key in the alternator bolt wind the engine VERY SLOWLY towards the OT mark or TDC. The OHM meter should indicate when the points open and this should coincide with the S mark which is 6 Deg BTDC.
Your method with the bulb should work just the same. You will need the ignition on. The bulb will light when the points open and the points must be opening or you wouldn't be getting a spark. From memory the points gap should be .016" It's not critical 1 or 2 thou either side of this. 0.4 mm = .016"
I know rotating the rear wheel in gear is the recommended method but I find it near impossible to do an accurate check that way. If done very slowly and carefully with the plugs out I see no harm in in using the alternator bolt to rotate the engine.
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+1 with Barry I did mine static with a Ohm meter it seems spot on runs as sweet as a nut.
Lou
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Ah! Ok then....so the TDC (OT line) on my flywheel dosen't correspond to
the widest section of the points cam...indeed, its only just as the points separate...6 degrees before TDC. So you can't set the points at TDC.
So assuming this is done, and the other two variables are in place, (compression and fuel/air mix), then I should at least get the engine coughing. The compression seems OK, so maybe its back to the carbs then??!!
My timing marks are the Line...v diff to make out the OT inscription...got my little finger stuck trying to clean it! The recessed circle below it, and the embedded sphere an inch or so below that. If I'm setting the points, which circle should be in the viewing window?
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This is what you should see just as the points open The S mark aligned with the notch on the window edge which in my case is just below the middle of the window. The line on the flywheel at the top of the window is the lower part of the OT Mark
BTW I forgot to mention if you are using the bulb test method with the ignition on don't leave it on more than a minute or two as the coil will overheat. That's why I prefer to use an ohm meter.(http://)
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Great shot! Thanks! My timing marks are not that clear, but I can make out what's what.