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Thread: Overheating/electronics on a r69s & oil breather

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  1. #1
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    Overheating/electronics on a r69s & oil breather

    OK, so probably the last sunny day in fall today, go on a ride to a restaurant that has a history for me - years ago, I ran out of gas on my R50/2 on this road. Damned if I didn't run out of gas today in the exact same place! I felt it getting low, so I switched to reserved, it got me maybe 2 miles before it was bone dry.

    Turns out a fellow BMW rider lived about 300 yards from where I stopped, so he set me right.

    But then, about 40 minutes later, I'm on a main drag, and the bike just dies.

    Acted like no spark, no fuel.

    The bike cooled off for about 30 mintes, push started, got it running again.

    I remember hearing something about overheating coils. Can anyone fill me in on this?

    I also have a question about the oil breather. This bike tends to burp up a nice mist from the breather tube. What does this signal?

    Thanks for all the help and advice, and I hope all of you had weather like I did today (but better luck!)

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    The situation with the lack of spark on the older coils, especially when hot, is due to the breakdown of the winding when hot. There should be one long winding which results in the most energy when the field coils are saturated and collapse (slightly different with the magneto setup). Once the winding becomes sets of multiple shorter sets, the energy drops off. That's why the bike will usually start OK cold, but be much harder when hot. Solid state coils are available that are form/fit/function and do a great job.

    Oil/mist coming out the breather pipe might be a signal of crankcase overpressure, likely caused by worn rings and excess blowby. The breather is trying to relieve the pressure bring some mist with it. Engine seals also take a beating in this situation.

    You're not overfilling the bike with oil are you? Sometimes that could cause windage and more churning of the oil, creating excess mist. Too much oil also decreases the internal air volume in the case, further creating more overpressure.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

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    Breather & spark

    No, definitely not overfilled with oil. And I'm pretty sure that I'm not over-revving, simply becuase I can't get the bike to go over 70 on a good day. I'll have it up to 60-65 in Third, then once in 4th, I can barely maintain that speed. I pretty much rode in 3rd today anyway, as I didn't go on any highways.

    I'm thinking that all of these things are somehow connected. I haven't pulled the carbs yet and I haven't re-checked is the valve clearances.

    The Coil seems to be a new black one from the Emerald Isles, or something like that. It looks new to me.

    Remember, I bought this bike fully restored, got it from a reputable place, was given a list of what was done, and who did what, and i've been finding things that were simply not right on it, that don't make sense in light of the work that was done on the bike that cost some serious coin...

    Appreciate your help!

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    Quote Originally Posted by 166926 View Post
    The Coil seems to be a new black one from the Emerald Isles, or something like that. It looks new to me.
    Emerald Island, I think is what it is. I recall that the first series of these coils had an issue with proper grounding. The second series added another grounding wire which took care of the problem. I bought one from Vech maybe in 2009 and it had the second wire. No problems to date.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

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    There may not be any problem there. Something is happening that kills the motor got a good 30 min...hmm...what are some of the more common things to look for? Btw, the misting isn't constant, it usually happens before the shutdown. Is there someone in the Detroit area who wants to have a look? Coffee is on me!

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    Next time you begin to loose power, try slightly unscrewing the gas cap. It should vent. Maybe you're getting a vacuum that prevents fuel flow.

    When this happens again, quickly shut off the petcock and safely coast to a safe area on the side of the road. Pop the top off the float bowls. Is there fuel in there?

    Do you have the brass floats? They can crack and fill with gas, thus sinking. This would be a permanent problem, though, and not necessarily cure itself in 30 minutes.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

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