Harleys and Heat: truth or myth?

EASt

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Please don't think of this as bashing. Let me fill you on the background of this question.

I worked with a guy years ago who was formerly in a biker gang called 'BPM'. Anyhow he always used to wax on about how the Harleys he used to ride (we're talking 1970s) would always stop running on really hot days and he would drive around helping fellow club members haul their motorcyles home in his truck. He'd always ask if my Honda had the same problem.

Anyhow, I just rode to my girlfriend's house, which is about 10 miles via interstate. It's currently 95 degrees out and very humid. In that 10 miles, I saw four HDs stranded on the side of the road. I stopped to help the two that were in the same direction I was heading. Both riders stated that their bikes just suddenly sputtered and died. I offered a cell and a ride for help but they said they were okay.

I know there are several owners here who do (or did) ride Harleys too. Is the heat issue still common or is it pure myth?
If it's truth, what's the fix to suggest to them next time?
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Please don't think of this as bashing. Let me fill you on the background of this question.

I worked with a guy years ago who was formerly in a biker gang called 'BPM'. Anyhow he always used to wax on about how the Harleys he used to ride (we're talking 1970s) would always stop running on really hot days and he would drive around helping fellow club members haul their motorcyles home in his truck. He'd always ask if my Honda had the same problem.

Anyhow, I just rode to my girlfriend's house, which is about 10 miles via interstate. It's currently 95 degrees out and very humid. In that 10 miles, I saw four HDs stranded on the side of the road. I stopped to help the two that were in the same direction I was heading. Both riders stated that their bikes just suddenly sputtered and died. I offered a cell and a ride for help but they said they were okay.

I know there are several owners here who do (or did) ride Harleys too. Is the heat issue still common or is it pure myth?
If it's truth, what's the fix to suggest to them next time?
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I owned a 2000 Wide Glide and a 2001 Deuce, heat never stopped either from running. Now the Deuce in traffic could really throw off some heat due to the oil tank right under your bean bag. That is true of all HD "Softails" due to the oil tank location.
 

Blue STreak

Bob Meyer
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Any aircooled bike is going to have more trouble in extreme heat that a liquid cooled one. And a front-rear vtwin has even more problems keeping the rear cylinder cooled because the front cylinder blocks most of the airflow to the rear. So a Harley, especially one with a carb, is a lot more likely to have issues with detonation in hot weather. But that's not enough to cause it to stop running.

I suspect the problem had more to do with the "customizations" made. Poor carb tuning, old points, overheated coils, etc., and I can see problems with weak spark, vapor lock, and the like causing lots of dead bikes.

Back in the mid 70's, I used to ride with a bunch of guys on Harleys. On a typical weekend ride, with maybe 8 or 10 bikes, at least one would go home in a pickup truck every time. My favorite was the guy who didn't use fuses. "Because he could always tell what circuit the problem was in by searching for the burned wire."

I kid you not. :nuts1:
 
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I have owned and been riding Harley's for the last twenty years. Never have i had one stop running because it was too hot. They stopped running for numerous other reasons :), but never due to temperatures.

The last one I owned for four years in South Georgia, where the temp was continuously in the 90's in the summer time, with no evaporative cooling effects due to the high humidity. It was an '03 Electra Glide. The engine oil temperature would get up to 270 degrees in the GA/FL summer and would ping every now and then, but it always kept running. Same holds true for my 2002 Sportster that I rode in the same temperatures for 3 years before that.

The old pan and shovel head motors were very finicky but always kept running when it was hot.
 
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EASt

EASt

Streuselkuchen
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Okay. Thanks for the input guys. I'm gonna chalk it up to the 'myth' side. I didn't figure it would be a common problem these days.

I mean, manufacturers will listen to riders who complain about heat issues, right? ;-)
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scootac

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Any aircooled bike is going to have more trouble in extreme heat that a liquid cooled one.
Sure about that one????
There's an awful lot of AIR cooled BMW twins running around with a lot of miles on them that are ridden under hot conditions.
BMW was just smart enough to stick the jugs out in the wind to get more cooling, not hide one behind the other!
 

punk rocka

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Yup, pure myth for the newer ones anyway; I can't speak for anything made back in the 70's though. I rode the wheels off my Harley in Texas summers for 9 years and it never once had any issues with heat.
 

Gug

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I don't know about the newer ones, but the Evos's, yes the will cease up under excessive heat and speed. Just stop, let cool and take off again. It was only symptomatic with that motor that I know of.
 

Rossi

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I thought I read somewhere that HDs have a system on the newer bikes that cut ignition, alternating between front and rear cylinders when running in high heat situations.

Can anybody confirm that?
 
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And a front-rear vtwin has even more problems keeping the rear cylinder cooled because the front cylinder blocks most of the airflow to the rear.
No heat related problems with my Buell. Of course, it has a fan that kicks on to help draw air across the rear cylinder to cool it faster. Some people find the noise the fan makes obnoxious, but as a fellow Bueller's t-shirt reads:

Loud fans save lives

:D
 

Follow

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Coincident that you ran into them after your friend told you that story.

Personally, coming from a family that has had HD's (and many other types of bikes) I also have a lot of friends that have HD's and I have an HD, no one that I know have ever mentioned that, but they have mention breaking or blowing something, even vapor lock which did stop them.

With my bike it came from the factory tuned lean, so it did get real hot which would cause it to ping if I was to push it real hard and I mean hard(climbing mountains at a good speed) even melted my rainsuit. I had a race tuner installed and Dyno'd, now it runs cooler. A few of my friends have put oil coolers on and they all swear by it.
 

Smallville

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I thought I read somewhere that HDs have a system on the newer bikes that cut ignition, alternating between front and rear cylinders when running in high heat situations.

Can anybody confirm that?
Not srue about running in high heat, but some models have a rear cylinder cut off that kills the rear cylinder while idiling to keep the rider cooler.
 
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When the weather starts warming up out here, we start getting calls from guys stranded on their HD's. They end up in stop and go traffic, and the bikes simply overheat from the really slow going. Harley offers oil coolers and a large fan for just these reasons.
 
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My 1970 74" Shovel does fine at speed on the highway for about 100 miles but starts to sputter when I get into town and run in start/stop traffic. The rear jug drops out until it cools. The 1980 80" does fine in all temperatures, it's just a little cold natured after intially starting up.
 

Blue STreak

Bob Meyer
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Sure about that one????
There's an awful lot of AIR cooled BMW twins running around with a lot of miles on them that are ridden under hot conditions.
BMW was just smart enough to stick the jugs out in the wind to get more cooling, not hide one behind the other!
Yep, but the oil heads run cooler than the old air heads. I rode cross country and back with a guy on an airhead Bimmer, and going across the Mohave at 120 degrees, he was definitely dealing with pinging issues. So was my air-cooled Suzuki, for that matter. The BMW design is definitly better than Harley's in terms of cooling, but a liquid cooled engine will still handle the heat better.
 

Harpo

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Overfilling the fuel tank on the HD in summertime is worse than with other bikes primarily due to the jugs heating it up and expanding the fuel. The oil tank heat is also considerable just under the seat and can bake the inner thighs on really low saddles. The rear cylinder eventually takes on an oval cross-sectional shape (not visible to the naked eye) due to higher expansion rates at the exhaust valve.

All in all, the longitudinal air cooled V-twin is a faulted design and the manufacturer must undertake extraordinary measures to compensate for the heat. Ducati was wise to tilt the jugs forward and share the airflow much better than the HD ever could. Moto Guzzi likewise embraces better engineering with their Vees and the metrics are smart enough to pump water through faux finned jugs; only HD, Victory, Indian, and Yamadog continue to make a big bore longitudinal air-cooled twin and all are aimed at the same unsophisticated crowd.

You either want a motorcycle or you want an image. The vast majority here in Dixie want the image; it's no surprise at all, really. I always see them in large numbers around here .. usually in my rear view mirror.
 

Tyrbrnr

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I rode HD for years out in LA traffic everyday. In stop and go traffic on really hot day the engine heat will crack the ingintion module and the bike stop running. This happened to me 3times on 2 HD. Being stuck in LA traffic in 100 plus degree heat is why I don't own a Harley.
 

Harpo

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I look for the new waterpumper HD mill to move into mainstream bikes once they
get "the look" perfected for it. Probably with faux fins. They'll always offer
the antique air-cooled mill, of course, for the image riders, but I think more and
more folks in hotter climes will require a waterpumper.

I can see a fat boy with waterpumper in it .. lots of chrome oil lines and phony
fins around it .. and the radiator up underneath, perhaps .. or back behind the oil
tank with a fan .. in the not-too-distant future.

Then, again .. maybe NOT. Harley rakes in billions with their current old-time
technology and really doesn't need to fix the heat problem. It still pays the bills
in Milwaukee.
 
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From Kawi's advertising department:

"The motorcycle enthusiast interested in the cruiser lifestyle faces the daunting task of selecting a brand and model—which isn't an easy decision with so many to choose from. Fortunately, the Kawasaki Vulcan™ 800 makes the decision simple with its traditional styling, modern technology and affordable price. With standard features that include a stepped seat, raked-out front end, wire wheels and torquey V-twin engine, the Vulcan 800 can also be customized to suit any rider's personality with Kawasaki's extensive line of Fire & Steel™ accessories.
The heart of the Vulcan 800 is a powerful 805cc V-twin engine, which benefits from years of Kawasaki technology. The motor incorporates liquid cooling for exceptional temperature control and engine longevity, but its radiator is hidden between the downtubes of the double-cradle frame, giving the bike a stylish air-cooled look. The overall result is an attractive, high-torque motor that makes loads of power and emits the distinctive exhaust note associated with a V-twin.

Like the engine, the Vulcan 800's chassis is the beneficiary of high-tech design and is
. Kawasaki's own UNI-TRAK? rear suspension system is hidden away to give the triangulated steel swingarm a clean, hardtail appearance. But in actuality, the linkage system applies progressive damping and spring forces as the single shock is compressed to provide a smooth ride."

Harpo, have you recently had sand kicked in your face by a local "unsophisticate"?
 

Harpo

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My Vulcan's still running strong five years later with 35K on it and I love the bike.
Just replaced wheel bearings, seals, pads, rotors, chain, and rear wheel and did
all fluids .. the engine barks with Roadhouse pipes.

As to sand, nope. I just watch the machismo show going on day in and day out
and wonder how so many folks can be duped into paying so much money to any
company for such a limited product. Is the image really that important?

But, then, they also pay good money in droves to have ink injected into their skin
to change the color and become living billboards.

The appropriate sentiment: Dismay
 
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