crguy's similar Gas delivery problem

[crguy]

Good news Dewane but now I have similar problem: for the first time in 30 years I needed to truck my bike back home last night. It seemed as if it was running out of gas...checked tank and it was close to empty and stopped and filled with 4.3 gallons of fuel..upon starting the right cylinder backfired, occasionally the left as well, never was able to actually fire off cleanly at all, I popped both bowls and they had fuel, pulled the plugs and can see intake and exhaust valves move, grounded the plugs an I can see them spark to ground, pulled timing cover and turned bean can (hall) thinking timing change, no luck, I can't get it to fire off at all.. I brought it all back to initial settings...carb throttle stops just touching, idle mixtures to 3/4 plenty off fuel flow and checked float height...still no fire...yikes any other ideas much appreciated.

[EGRG]

You could pop off the valve covers and check to see if valve are moving in time with the piston checking that both valves closed a TDC.  This to discard a timing chain failure.

[crguy]

Yeah, looked in the sparkplug hole an can see valves move, the chain was replaced last month and ran excellent, I wish it had points ignition so I can static time it, I'll pull the covers and double check lash and TDC as you recommend Doublez thanks...

[Bob_Roller]

crguy, what year bike do you have ?

Do you have the single ignition coil, dual output, possibly black and gray in color ?

Looks like we posted at the same time, I would look your ignition system over, I had the original coil go bad on me 18 years ago, failed just about the way you describe .

[crguy]

83 with 110K...dual coil more brown than blk original

[crguy]

Rob, plugs are sparking, not to sure on intensity, can see it but I recall years ago I would hear it as well..but this could be my age now too.

[crguy]

Sorry Rob, not clear with my answer...I have a dual output coil..thanks Guy

[Barry]

If the bean can has been moved the timing could be so far off there is little chance of it starting easily.

I have points so static timing is easy. I'm sure you can also static time an electronic bean using the right method.   Having points it's outside my hands experience but I've read about it some place. If I had an electronic bean can I'm sure I could devise a method of doing it statically otherwise I'd face the dilema that you have of not being able to check the timing of a non starter.

I'll bet if you turn the engine over slowly by hand and observe the timing marks it will spark but perhaps only if you are careful to have the ignition turned on for the minimum amount of time possible to prevent time out of the ignition module. I would turn it on just before you approach the static timing mark.  Worth a try.

[crguy]

Thanks Barry for interest, when I changed the T Chain a short while back i scribed location marks prior and it fired right... another tidbit is the bike has been having a hard time cold starting lately, I am leaning towards ignition system and / or valve timing, even though I see a consistent spark it wouldn't even fire with starting fluid...need to dig deeper this evening..G

[steven m]

Bad gas?  If you put 4.3 gallons in the tank you were just about dry on the left side of the tank, correct?  You might consider draining a couple of gallons out and restarting the bike to eliminate that possibility.  Drain the lines to the carbs as well.  If that doesn't fix it, clean the petcock and give it another try.  And if that doesn't work then you know it isn't anything fuel related.

Just a thought...

Steve

[crguy]

Yes Steve thanks..when at the gas station i popped the bowls off and they were 1/2 full, also pulled the fuel line off each carb to, after i got it home the next day I bought a clear inline gas filter to see whats up..I will be digging into it this evening...I will report in latter.

[Rob Valdez 79 R65]

[postsmovedhere1] 9 [postsmovedhere2] BMW Technical Q&A, Primarily R65 [move by] Rob Valdez 79 R65.

[crguy]

Ok, back at it: checked valve lash and it's right on, grounded out spark plugs to chk timing and strobe flashes on OT, close enough for now figuring a little retarded is easier on starter motor. I installed a clear fuel filter, never had one before, fuel bowls have fuel, doesn't flood out of overflow, but filter is not filling up completely (normal?)..removed one carb and it is clean..what gets me is these bikes can run on one cylinder, must be something in common, not enough spark?, I even dipped an end of a stick into the gas and lit it with a match...its gas...I just don't know

[Bob_Roller]

What color is the spark at the spark plug ?

[crguy]

White Rob