Ideling an engine too long without use of fan

[mattcfish]

Originally Posted by crazydrummerdude

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.

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".

[mark1305]

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. 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.

[batoutoflahonda]

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.



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.

[dm635]

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.

[DaveBall]

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?

[AirGsPd]

Originally Posted by cycleman2

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.

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.

[jimbee]

Originally Posted by jackd

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.

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.

[Schlivitz]

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.