Ideling an engine too long without use of fan

Discussion in 'Airheads' started by AirGsPd, Dec 4, 2012.

  1. disston

    disston ShadeTreeExpert

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    It has been suggested to me that idling for extended periods of time is not good for the engine because the engine does not rid it self of excess heat that well if standing still. Excess heat is bad for engines in general. Maybe the Airhead engine can do this better than some other engine designs but it is still not recommended as a regular diet. I think it prudent to try and not idle the engine for extended periods of time.

    About the only time I might want to have the engine idling for a longer period of time is when balancing the carbs. I am able to balance the carbs with out idling longer than a couple of minutes. If I need more time than this I take the bike out and ride some, then adjust some, then ride some.

    I have been stuck in traffic a few times and the bike did seem to be over heated. I rode on the apron or the break down lane to the next exit. The bike was fine after words but it ran funny while it was over heated.

    The advice about not over heating the engine is not original to me. I have heard this advice from people with much more experience than I have. I have always considered this good advice.

    The box fan may be helpful to some riders sometimes. I don't have one.
    #21
  2. Big Bamboo

    Big Bamboo Aircooled & Sunbaked

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    One more thought; at idle, the oil pump is pushing the least amount of oil through the engine, with the oil at max temperature and it's lowest lubricity. Can't be a good thing...
    #22
  3. Prutser

    Prutser Long timer

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    The only thing I noticed is that some airheads had problems with valve seats comming out of the heads when they got to hot.
    A lot of those times the heads have been overhauled to use unleaded fuel.They just didn't do a good job.
    It did happen even more when they were used for a sidecar.
    On events in the netherlands where sidecars were used to take handicapped people for a ride out, and the bikes were driving slow for a long time it was a common airhead failure.

    My solo bike's have had hours of idling on muddy forest tracks,trying to get through in serious heat.

    Had no heat problems with more than 400.000km....

    Just my experience.:knary
    #23
  4. Airhead Wrangler

    Airhead Wrangler Long timer

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    Who just completed a massive rebuild on their bike because their idiot brother in law used it recharge a battery on a ride-on mower or something stupid like that and left it idling for an hour? I can't remember whos bike it was, but I remember there being a LOT of damage.
    #24
  5. Prutser

    Prutser Long timer

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    That is out here somewhere. I have seen some damage out there too.

    Once a guy came up to me that had a R1200C that stopped idling after 5 min.(so he said)
    But when he brought the bike all the paint was falling from the engine, inlet rubbers had melted the oil in the engine was burned. After I checked the bike the wires from the hall sensor were melted, that was the first thing that stopped the engine.........

    At least we don't have much paint that will fall off :evil
    #25
  6. Airhead Wrangler

    Airhead Wrangler Long timer

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    He got lucky. I've heard several stories of oilheads catching on fire from idling too long.

    Here's the overheated GS thread:
    http://advrider.com/forums/showthread.php?t=645324
    #26
  7. DaveBall

    DaveBall Long timer

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    I think the problem is that a lot of people do not know how long is too long. We have to get real here. There are a lot of things to consider before saying that an airhead cannot sit at idle for a few minutes. And we have to use some common sense. Sure, sitting at idle is going to allow the engine to build up heat. That is expected. Does that mean that we have to turn the engine off at every stop light? No. These engines were designed to be ridden in normal every day traffic. That includes sitting at idle for short periods of time.

    Yes, the reason for the engine failure is due to overheating and the oil not being able to lubricate properly. So to help eleviate that problem, make sure you do proper maintenance. Change that oil and filter on a regular basis. And use a top quality oil that is rated for the application. If you have to commute thru heavy traffic with stop and go situations, change the oil more often. Maybe install an oil cooler. Or if all that will not work for you, commute on a different bike.

    There are lots of us who have gotten well over 200,000 miles out of our engines without major rebuilds or breakdowns. And we ride the bikes as they were originally intended. Don't over load them and do proper maintenance. And learn to use the upper end of the tachometer. Get those revs up and let the oil circulate.
    #27
  8. cycleman2

    cycleman2 Been here awhile

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    Having owned both oilheads and airheads the manufacture advises to not let them idle for more than 10 minutes. That sounds like a good idea to me.

    I always use a fan if I'm adjusting carbs, sync etc as 10 minutes can go by fast if you are preoccupied. If I'm stopped in a long line of traffic, like a railroad crossing, where you know you are going to be there for awhile I will shut the engine off, same as if I'm at a border crossing with long lines of traffic. Traffic lights and other similar type situations I let the engine idle.

    Now if you want to talk heat the oil temp on my Softail has hit 270 F, 2 up in the mountains, lots of stop & go construction, 90 +F air temp. I run synthetic oil but that's too hot in my mind so I put an oil cooler on the engine shortly after that.

    A certain amount of common sense has to be used when idling an air cooled motorcycle.
    #28
  9. jackd

    jackd Long timer

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    That would be 'Jimbee' up here in Vancouver. He had quite the mess on his hands. The saddest part was that he went to the trouble of re-buiding the engine, with much encouragement from the forum members. Eventually he was having problems with the cylinder hold down studs pulling out of the block which led to further repairs. I was wondering if somehow the block had lost its strength where the studs thread in. I'm hoping that it came to a satisfactory resolution at the end.
    #29
  10. crazydrummerdude

    crazydrummerdude Wacky Bongo Boy

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    Try idling up a mountain waiting in line to enter Yosemite during construction of the main road, on a beautiful weekend.

    I'd say that was excessive idling, and definitely the hottest my bike has ever run.
    #30
  11. mattcfish

    mattcfish R90X

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    Yeah, that's exactly what scares me. Traffic and road construction on hot days. No lane sharing in this state, and you get a ticket if you drive the shoulder. Even if you don't care about tickets, other drivers will actually pull there vehicles in front of you to block you from getting "ahead".
    #31
  12. mark1305

    mark1305 Old Enough To Know Better

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    The only things I can add are that (1) I live in Floriduh where it can get hot. (80F this afternoon and more of the same for the past week and the upcoming week). (2) Because its warm here most of the time I use a shop fan in front of the bike when doing tuneups. And (3) On a ADV road trip a couple of years ago I got stuck in Friday afternoon downtown Atlanta I-75 stop and go traffic - due to my own poor timing. At the time I was doing an experiment to quantify oil loss and blowby on long highway trips, which my ST doesn't like in warm weather. I had routed the central breather hose out through the side of the airbox and into a catch bottle. Over about a 600 mile run both at speed and the stop and go, the engine blew out about 8 oz of oil, but only about 2 cc collected in the bottle. :huh At the hottest and worst of the stop & go in ATL I could see the blowby vapors literally shooting back out of the catch can. Strictly as hot oil smelling vapors.

    Oh yeah, the motor did and still does pull 150 psi/146 psi when fully warmed up. Somewhere in the mid 40K mileage range on the bike/motor.

    I was amazed at the increase in blowby at high temps and all rpms from idle on up, and the fact that most oil seemed to be lost as vapor. Doesn't do it much at all under less strenuous riding conditions.

    But like many airheads, it does tend to oil the left carb a bit.

    Nothing earth shattering in these observations, but interesting to me.
    #32
  13. batoutoflahonda

    batoutoflahonda Long timer

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    Remember guys and gals. These bikes competed in the ISDT (ISDE). I cant think of any thing harder than pulling high rpms to get through/over obstacles, then going slow over technical sections for long periods. Riding enduros on 4 stroke aircooled dirt bikes has often left me in awe of what an aircooled engine can withstand and happily fire up and do it again.

    [​IMG]

    Being an ex Californian living in "progressive" WA state. Don't get me going on lane splitting. These people will kill you to prove a point. Be careful if you're not used to the retaliation that comes with it.
    #33
  14. dm635

    dm635 I Roll

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    My thought process could be way off track here, But I'd imagine that BMW really put these engines through the paces while testing. Wouldn't surprise me if these engines idled for hours if not days during testing. How could they sell bikes if the engine would cook itself after a short time. Would I sit my bike out to idle for an hour or so, absolutely not. 10 minutes would be too long. But there are areas where massive traffic jams are normal. I lived in Houston for 11 yrs & down there the sun sure does shine. I did ride an old '74 Yamadog 750 down there & it never fried.

    I know these engines are decades old now & certainly not as durable as when new taking that kind of abuse.
    #34
  15. DaveBall

    DaveBall Long timer

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    You see, that is just the issue. People go looking for a cure to a problem that really does not exist.

    I sometimes wonder if people that live in hot parts of the world install box fans and long extension cords on their lawn mowers. Not all of them actually have fans built in. Ot, how about their compressors sitting in the garage?
    #35
  16. AirGsPd

    AirGsPd Dream Rider

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    This is actually the answer that I was looking for. Since I am not the first owner of the bike, I have no manual. For me it is a no brainer when the manufacturer states that the engine should not idle longer than ten minutes, not to let the bike idle too long. I agree with most here that one should use common sense when doing that. Thanks for the good info.
    #36
  17. jimbee

    jimbee Airhead Intermediate

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    Appropriate thread timing - this is about the 2 year anniversary of the "incident", and I'm still sorting out the damage from the bike being left to idle on its centre stand until it died (estimate 45 min). Want to emphasis the encouragement and help I have received!

    As a point of reference for this thread, couple details about heat and damage:

    Think the saving grace in my case was the plastic bearings on the rocker arm - as the oil burned off and stopped flowing to the rocker arms, the plastic bearings started to chip away until the end play on the rocker arms was so much that valves weren't being acuated fully, thus killing the engine.

    During that time the bike got so hot that the plastic crankcase breather valve thingy below the starter melted into a pile of plastic and both the oil and neutral swtiches began leaking.

    In terms of damage to the engine after being heated to plastic melting temperature:

    - there was some wear on the cylinders but it didn't apear that the actually engine seized
    - the big end bearings looked good (thus I have assumed main crank bearing is good too)
    - two lifters showed some pitting (could possibly be from before - never looked at them before)
    - had to replace all of the rocker arm bearings - many broken cages due to severe end play
    - several of the cylinder studs pulled out upon reassembly, but not sure how much the combination of past weakness from possible overtightening from PO plus any lateral expansion of the cylinder and head due to heat played a role vs. actual weakening of the cylinder block as a result of heat

    - after all of this, despite new rings and perfect compression measurments (132 and 127 psi), still I ended up with serious oil consumption (~1L/800km). Not knowing where the oil was going (other than out the exaust), I have since honed the cylinders, sent heads to Tom Cutter, and reinstalled w new rings. Now waiting to sort out a charging issue before breaking in the new top end and reporting back.

    All it all, I suppose it could have been worse.
    #37
  18. Schlivitz

    Schlivitz Mercury Freefall

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    These motors will obviously take alot of abuse. But wouldn't you rather be having some fun when you perform all the stress tests? It's not that hard to point a fan at your motorcycle in the garage. And it sucks working around a bike that's hotter than 40 hells anyway. In traffic...... well, sometimes you just gotta do the best that you can.
    #38