Harleys and Heat: truth or myth?

[ak85lp]

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.

LOL Well said!

 

[Harpo]

I once saw three Harley Davidsons traveling together down Interstate I-26 going well over 110 MPG with no apparent problems at all.

Of course, at the time they were in crates on the back of a flat bed trailer ..

Did you know seven out of every ten Harleys are still on the road? That means only three out of ten will actually get you back home.

Ever wonder why some Harley riders never wave back? They don't dare take their hands off the grips.

Have you heard about Harley's new octagonal wheel? Not round, but with eight flat segments to each wheel. More noise, more vibration, and more of that unique HD experience.

 

[Sechskant]

Harpo, I'm betting you're a fan of American Angst.
Don't worry mods, I won't link it, does make for some funny(honest, accurate) reading

Jake

 

[bdalameda]

I was a mechinc back in the 70's. The old Harleys from that era had cast iron cylinders and heads. Over heating was a common issue especially when climbing steep grades on hot days. The rear cylinders and heads were a big problem and it was common to have valve jobs every 5-10K miles, blowing the rear cylinder from overheating was common. The valve guides would not last long. I used to run an undersized tap through the guides to created a lubrication pathway to help the guides last. I used to ride with a big club in those days even though I was not a member. I soon found out why. Everyone knew I was a mechanic and they liked having a mechanic with them on rides. There was almost always one or two bikes breaking down on each ride.

Dan

 

[Harpo]

.. and still they persist in the longitudinal V twin with belt drive. They've strayed into water cooling and I applaud them for that, but it needs to become more prominent. They're apparently not capable of more than two cylinders, though .. wouldn't we love to see a boxer four out of Milwaukee .. with a water jacket and a shaft?

Selling primarily an image is what turns me off about HD .. it's like they limit themselves so much in the pursuit of money and not in seeking technological perfection.

 

[hondast1300]

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.

I've got a harley road king to supplement my st in hot weather. It's just nice to not have any plastic in front of me. IMHO niether HD or Honda has a heat problem to fix.
VegasRob

 

[Nevada]

.. and still they persist in the longitudinal V twin with belt drive. They've strayed into water cooling and I applaud them for that, but it needs to become more prominent. They're apparently not capable of more than two cylinders, though .. wouldn't we love to see a boxer four out of Milwaukee .. with a water jacket and a shaft?

Selling primarily an image is what turns me off about HD .. it's like they limit themselves so much in the pursuit of money and not in seeking technological perfection.

Belt drive isn't a limitation. It's actually, depending on the application, an advantage. Frankly, I think every non-dirt bike/non-race bike should either have a belt or a shaft, and since belts are simpler and lighter, I'd go that way.

 

[acedantinne]

.. and still they persist in the longitudinal V twin with belt drive. They've strayed into water cooling and I applaud them for that, but it needs to become more prominent. They're apparently not capable of more than two cylinders, though .. wouldn't we love to see a boxer four out of Milwaukee .. with a water jacket and a shaft?

Selling primarily an image is what turns me off about HD .. it's like they limit themselves so much in the pursuit of money and not in seeking technological perfection.

Owned 11 HD. 95 traded in for 07 RKC. That 95 FLSTC 56,000 miles no problems.
Sporty had 86,000 miles still running.
Leave it go. HD did a lot for motorcyling.

 

[suprdav]

Owned 11 HD. 95 traded in for 07 RKC. That 95 FLSTC 56,000 miles no problems.
Sporty had 86,000 miles still running
Leave it go. HD did a lot for motorcyling.
Well said, Harley has their style and philosophy in regards as to how to build a motorcycle. If everyone made their bikes the same what a dull world it would be. The engine temperature management system (shutting the fuel off to the rear cyl.) is how they attempt to deal with engine heat. Other brands have radiators or different engine layouts. Remember, Harleys are made by stylists and Hondas are made by engineers, neither group is perfect. All I know is that the world is big enough for all type bikes and riders.
Ride Well

 

[Silver Bullet]

Actually the rear cylinder on the touring big inch HD,s do shut down in hot situations and the fuel and spark are both shut down,since they are fuel injected, thus a big cooling air pump.Turns back on when cooled or moving and ,yes it can also be shut off by rolling back the throttle to the stop and a tad more ! Just to clarify ! No I don,t own one ,just read a lot of test !
MIKE

 

[ulyrider]

Belt drive isn't a limitation. It's actually, depending on the application, an advantage. Frankly, I think every non-dirt bike/non-race bike should either have a belt or a shaft, and since belts are simpler and lighter, I'd go that way.

 

[EASt]

What kind of applications would make the belt drive superior to chain?

 

[Byron]

What kind of applications would make the belt drive superior to chain?

I recently bought my first belt drive bike, Buell 1125R. The zero-slack belt drive makes the bike's throttle feel like a reostat. Start to twist the throttle and the bike just rolls out, back off and it's like lightly putting on the brakes. The advantages I see are; belts don't stretch, make less noise, don't need lubing, don't need adjustment and I'm guessing the sprockets don't need to be replaced like chain sprockets.

 

[ulyrider]

I recently bought my first belt drive bike, Buell 1125R. The zero-slack belt drive makes the bike's throttle feel like a reostat. Start to twist the throttle and the bike just rolls out, back off and it's like lightly putting on the brakes. The advantages I see are; belts don't stretch, make less noise, don't need lubing, don't need adjustment and I'm guessing the sprockets don't need to be replaced like chain sprockets.

Nice summary. I'm lazy and have little mechanical skills, so I especially like the maintenance side of having a belt

 

[Rossi]

What kind of applications would make the belt drive superior to chain?

Although the ST is shaft driven, I would rather have a belt drive than a chain when doing alot of riding in the rain, like during a trip. Less messy and probably less wear.

 

[Dracula]

yep, they get hot

What he said.

:amflag:

 

[Avtrician]

On one of my trips across Oz in the 70s, I saw a Harley rider sitting on the gutter in a service station at Nullabour (in the middle of no where) looking somewhat p1ssed off. Seams he had two problems, teh secondary oil pump had failed, (dont know harleys very well) and the rear pot was bright iridescent blue.

It was hot out, so he had been checking the front pot with his hand, but not the rear. He was waiting for spares to arrive on a truck from Perth.

 

[TwoBrittanys]

I recently bought my first belt drive bike, Buell 1125R. The zero-slack belt drive makes the bike's throttle feel like a reostat. Start to twist the throttle and the bike just rolls out, back off and it's like lightly putting on the brakes. The advantages I see are; belts don't stretch, make less noise, don't need lubing, don't need adjustment and I'm guessing the sprockets don't need to be replaced like chain sprockets.

During my 3 years as a Harley service writer, I can tell you that belt sprockets do wear out and we replaced a bunch of them. Once the hard surface coating wears through, they deteriorate rather quickly.
Posted via Mobile Device

 

[Harpo]

Chain drive is marginally more efficient than belt drive, due in part to the fact that a belt is stiffer and pulled tighter than a chain, which has slack in it.

Chain drive is lighter than belt drive. The chain is heavy, but that weight is offset by the weight of the more massive pulleys in a belt drive system

Chain can be bought for as little as $18 for one bike on the web and sprockets for as little as $35, making re-gearing to a higher or lower ratio more inexpensive than belts and pulleys. Sprocket teeth don't wear nearly so much if one changes out stretched chain on a regular basis.

Chain is able to handle much more torque than a belt. No race bikes use belts, especially in drag racing.

The down side to chains: slinging lube and frequent adjustments. In other words, they're not for the lazy riders who just want to ride, ride, ride .. and who take their bike in to a real man for maintenance with their wallets held out in front of them.

I prefer the ST's longitudinal shaft drive, even though it's heavy and loses a bit of power in the gear transition at the 90-degree bend .. simply because the ST is a refined, well-dressed bike in a tuxedo. For optimum efficiency, transverse engines should use chain or belt drive and longitudinal engines should use shaft drive. A transverse engine with shaft drive has TWO 90-degree bends in the drive train and is the most inefficient drive made. The Concours, the FJR, and VFR .. they all make this mistake as do all the metric shaft drive cruisers.

 

[Harpo]

Also, that hard surface coating Itsbent refers to on the sprocket is the 'case'. Sprocket teeth are case-hadrened and bear up very nicely so long as stretched chains are replaced regularly and chain lube is used generously.

Some morons have taken to using WD-40 on their chains .. incredibly .. simply because it's "cleaner". Probably raised by their mothers ..