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Old 11-06-2012, 07:56 PM   #586
crazydrummerdude
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Doesn't sound like diaphragms to me - when those tear, the bike runs fine up to 4-5k RPM where it bogs down and won't go beyond 60mph.
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Old 11-06-2012, 10:25 PM   #587
Kai Ju
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Quote:
Originally Posted by crazydrummerdude View Post
Doesn't sound like diaphragms to me - when those tear, the bike runs fine up to 4-5k RPM where it bogs down and won't go beyond 60mph.
The only reason I mentioned diaphragms is because it sounds like the right cylinder isn't pulling at all, as if the slide wasn't lifting. Usually that's the diaphragm.
The check that blaine performed on the carbs seems to eliminate the slides/diaphragms as the culprits but doesn't explain why the right side's not pulling.
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Old 11-07-2012, 12:39 AM   #588
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I have had bad diaphragms that ran poorly much sooner that 4-5 K. Mine was practically running on one cylinder.

New diaphragms, huh? Where did you buy said "new" diaphragms?

The only way to know is take the slides out of the carbs and hold rubbers up to strong light. Stretch the rubber and look for pin holes.
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Old 11-07-2012, 06:49 AM   #589
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I'll check those out tonight. The diaphragms are BMW stock parts, if I recall. They came in the little carb board BMW stamped round container.
One thing I forgot to mention is, unless i've done a proper highway or 20 mile run on the bike to get it properly warmed up, the right side plug will come out dry and black.
My left side is just perfect...I can't even force it to be outside of perfect without trying really really hard haha.
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Old 11-07-2012, 07:13 AM   #590
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Did you try switching ignition wires left to right, right to left just to eliminate that?
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Old 11-07-2012, 07:17 AM   #591
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Did you try switching ignition wires left to right, right to left just to eliminate that?
Yup, that was in the diagnosis steps I took. Granted, I didn't run them on a full warm up crossed. It just immediately blacked out a new plug.
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Old 11-07-2012, 10:11 AM   #592
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It's always possible to swap carbs side to side, though it seems everything else has been eliminated and it's gotta be the carb. These bings are just too simple, and I keep coming back to plugged low speed circuit. I've never run nylon fishing line through the passages, but that sounds like a good next step. It has to be something previously unnoticed, so look closer. Look deeper!
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Old 11-07-2012, 10:16 AM   #593
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It's always possible to swap carbs side to side, though it seems everything else has been eliminated and it's gotta be the carb. These bings are just too simple, and I keep coming back to plugged low speed circuit. I've never run nylon fishing line through the passages, but that sounds like a good next step. It has to be something previously unnoticed, so look closer. Look deeper!
You know...something as simple as swapping the carb sides could bisect the issue right down to a binary "is it carbs, yes/no" answer. That at least would give me something to go on.
Didn't know you could actually do that or if it would have some bad effect.
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Old 11-07-2012, 10:57 AM   #594
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If you're confident it's not ignition, I'd just go after the carb on the offending side with carb cleaner AND compressed air until it decides to work. Mine never worked quite right after a couple rebuilds until Solo Lobo lent me his berryman's dip can and I left them in there about double the recommended time and then blew them out with compressed air.
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Old 11-07-2012, 11:46 PM   #595
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I'm with AW on this. I've been wanting to get an ultrsonic for carb cleans - supposed to be THE best!
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Old 11-08-2012, 06:16 AM   #596
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Blaine, I have an ultrasonic cleaner. It's a little guy, so you have to flip the carbs. But I also have my bings newly rebuilt sitting on the shelf. It where the 50 pilots came from. you could also disassemble the carbs and go visit Nathan and throw them in his big ultra cleaner. Does a good job. Let me know, I'm going out there monday to do some sorting, I could take the bodies and chuck them in for you.

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Old 11-10-2012, 02:13 PM   #597
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Words don't even need to accompany this image.
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Old 11-10-2012, 02:36 PM   #598
crazydrummerdude
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Interesting. I'll have to re-read your symptoms. I had two bikes with torn diaphragms and the symptoms were as I described on this page.

Well, now you know!
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Old 11-10-2012, 02:57 PM   #599
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Progress !!!
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Old 11-10-2012, 03:32 PM   #600
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Progress, but not a resolution.
Upon initial crank, did just fine and felt like I had two cylinders and really smooth and strong pull again.
After warm up on the interstate and slow down back down, it immediately went back to losing a cylinder and back firing (all left side still.) Even stranded me on the side of the interstate for a minute or two while I tried to get her started again.
I still suspect carb issues. I haven't gotten time to swap the carbs and see if the issue transfers, just had to time to swap the flimsy, thin diaphragm in there for a healthy one.

Also, the carb does not rotate when loosening the plastic elbow and just having the engine side tight. Those rubber boots on the engine side are new, too, but I'm going to pull and swap and inspect them.
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