harley heat

jim peacock

Contrinuting Member
Apr 21, 2009
450
3
greenfield indiana
There was a post by some one talking about the heat coming off a harley engine and what could be done about it.
I Was watching a piece on speed t.v. about harleys over the week end and on some of the 2009 models when you are idling it shuts off the rear cylinder and it acts as a air pump and helps cool the engine down and as soon as you twist the throttle it comes back on.
 
Air-cooled m/c engines with fore/aft orientation are inherently more difficult to cool. For this reason and because of fast chain wear in sandy conditions, H-D built a couple thousand BMW shaft drive boxer engined knock-offs for the U S Army to use in North Africa during WW11. It isn't clear that royalties were ever paid. <g>
 
Our local Harley shop had one of the opposed twin Harleys in their museum. I'm not sure if they still have it or not. Kinda cool!

Dwight
 
Yes, a VROD makes an excellent trike. Here's the Motor Trike V-Rod...

Agreed. I wonder why H-D didn't base their Lehman based in-house trike on the V-Rod. It would have provided a market for teh V-Rod drivetrain and sidestepped the overheating problem of air cooled fore/aft V engines.
 
Good question...

The 'overheating' of the venerable V-twin is only a very recent problem, thanks to EPA and air/fuel ratio mandates. I've owned 13 Harleys over the years, (still have 4 of them) and none of them overheat. The reasons behind my "Heat and the Harley" article were to benefit a specific group of HD folks who are experiancing this heat thing for the first time, either because it's their first Harley, or their previous HD's were carbureted. The heat problems are easily taken care of, even on an emmissions controlled bike, but it will most likely void a new bikes warantee, something I for one, really don't care about. Should a brand-new bike have to have work done on it immediately to get it to run right? No, it shouldn't, but as I've said before, that's the price you pay for trying to keep a 45 degree, air cooled, pushrod V-twin with all it's 1908 technology going in today's emmissions controlled world. Sad, but true.
 
Good question...

The 'overheating' of the venerable V-twin is only a very recent problem, thanks to EPA and air/fuel ratio mandates. I've owned 13 Harleys over the years, (still have 4 of them) and none of them overheat. The reasons behind my "Heat and the Harley" article were to benefit a specific group of HD folks who are experiancing this heat thing for the first time, either because it's their first Harley, or their previous HD's were carbureted. The heat problems are easily taken care of, even on an emmissions controlled bike, but it will most likely void a new bikes warantee, something I for one, really don't care about. Should a brand-new bike have to have work done on it immediately to get it to run right? No, it shouldn't, but as I've said before, that's the price you pay for trying to keep a 45 degree, air cooled, pushrod V-twin with all it's 1908 technology going in today's emmissions controlled world. Sad, but true.

Would it be more accurate to say that the 'overheating' problem has been made more severe as a result of engines being set up to run leaner? Overheating of such engines predates the EPA by many years. As noted earlier, the engines and chain drives were deemed useless in the WW11 North Africa campaign.
 
Ben, If you'll read the article, the first sentence states:

With the EPA clamping down on Harley® emissions, our V-Twins are running pretty lean, making them run hotter than ever before.
 
Last edited:
Ben, If you'll read the article, the first sentence states:

With the EPA clamping down on Harley® emissions, our V-Twins are running pretty lean, making them run hotter than ever before.

"...making them run hotter than ever before." as I tried to convey, the condition isn't something new but it is, as you noted, worse with the leaner mixtures. H-D is not the only company that has had overheating problems with aircooled engines with a trailing cylinder. Most companies have stopped producing air cooled engines altogether. H-D has an excellent liquid cooled engine of it's own that has been a very hard sell because it looks and sounds "different."
 
Ultraboy also mentioned the oil cooler options and adding extra oil in his overheating article (good read). I have ran a crash-bar oil cooler on all of my bikes over the past 20 years. This adds some extra capacity, does a pretty good job of cooling and is not likely to get knocked-off when you can't dodge the road kill either. I have seen some real sloppy crash bar installations and I have a couple of trick set-ups for anybody wanting to consider this. It's ideal for any EVO and the early twin cams. Later twin cams with the updated engine-to-transmission mating are a bit tricker. I will share with anybody interested and have some photo's also.
 
A long time ago they made a ceramic coating to go on the inside of pipes to keep them from bluing from heat it seemed to make my pan and shovels run cooler on my leg. Hope it helps:
 
Amazing isin't it....... I mean the money we will spend and the things we all will do and go through just to ride an expensive toaster oven that rattles. Harley builds them because we want them. Man....I hope they never quit!
 
Hey 1550 VT. I agree. A Goldwing is much quiter, smoother and cooler (heat wise) ride, but a Harley is a "HARLEY". I think they are a lot easier for the owner to work on. I like riding both of them, but the sound and feel of my Harley can not be replaced.
 

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