Another Heat Management question

Discussion in 'General Harley Davidson Topic' started by R_W_B, Apr 6, 2011.

  1. R_W_B

    R_W_B Senior Member

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    Would appreciate any input or opinions on the following. (I already have a Lenale fan)

    After reading all the posts on HD Heat management and Lenale fans, I was going to have my HD dealer make sure my Heat Management (rear cyl. shut down) was activated (since he said they would do it for free).

    However I've been reading some other input about HM on the net and there is a consensus among some that the HD HM (the rear cyl. shut down) is primarily for rider comfort rather than engine protection. They claim that while the rear cyl. does in fact cool down (along with the rider's thighs) the front cylinder is still suffering high heat.

    So this sounding logical, I would think that just relying on on the (other) less documented dropped idle speed/mix cooling scenario, ECM activated by default (that Smitty's old post spoke of) would actually do more good to preserving both cylinders (not discounting the air that a fan would supply).
     
  2. Porter

    Porter Junior Member

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    I just recently had the dealer turn on my heat management system. I didn't even know I had it until Hoople enlightened me, and with the weather as it is, have not had a chance to see it activated.

    My thoughts:
    So, you are driving along and come to a traffic jam.
    The rear cylinder is hotter from the heat of the front cylinder blowing by it, it makes sense to shut down the rear first. The assumption is that the front is shortly behind the rear (in temp) and at this point there is a relatively short period of time before deteriorating conditions occur in the front cylinder.

    1.) Many veterns suggest HD's are made to run hot, but we all know there are limits.
    2.) Good synthetic oil helps.
    3.) I don't think there are that many HD's seizing up. I keep looking for credible info, but I can't find it. They should be all over the road in Florida, Texas, Arizona. Maybe I am wrong, but I'll keep looking.
    4.) Heat Mangement is simply a warning system above all else. If I can't get moving quick, I am either going to ride up the shoulder to get some air moving or pull over and shut it down.
    5.) I guess you could keep a spray bottle of distilled water with you and mist the engine while you are sitting....but then that is the whole water cooled thing...
     
    Last edited: Apr 6, 2011
  3. mat 60

    mat 60 Senior Member

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    Does it half to be distilled?? Will city water work:D..How about a back pack with a big water jug and hose with lawn sprayer?..:bigsmiley23:
     
  4. Porter

    Porter Junior Member

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    Heeeheeee!:newsmile100:
     
  5. R_W_B

    R_W_B Senior Member

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    Thanks for the replies but before the topic gets construed here, I am aware or all the tuner mix, parade fans, modes, synthetic oil etc.

    My question is do you think the (Parade mode) Heat Management is worth even setting it up (in the ECM) since it only cools the rear cylinder, and of course your thighs which is a good reason I will admit, but by that time I would have probably turned my engine off.

    Porter submitted a valid theory in that the rear one runs hotter than the front so this does shed some light in a functional direction. But I am just not sold that it's gonna help that much in keeping me engine any cooler than the default idle speed condition (not parade mode) that Smitty told me about (which also depends on leaving the throttle alone)

    In other words I am debating if I even want to turn on HM (parade mode) .
     
  6. Dr. Dolittle

    Dr. Dolittle Experienced Member Staff Member Moderator Contributor

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    Can you enlighten me, and maybe others, and give a brief description of how this works and exactly what you mean by a "hotter plug?"
     
  7. Dr. Dolittle

    Dr. Dolittle Experienced Member Staff Member Moderator Contributor

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    Thank you, oh wise one! :worthy

    Is there much price difference? Are they available at the HD dealers or do you have to seek them out elsewhere?
     
  8. Hoople

    Hoople Account Removed

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    I agree that killing the rear cylinder won't buy you much extra time. I use it more as an indicator to make me aware of the situation. If heat mode kicks in, and I clearly see I won't be moving any time soon, it tells me that I need to make some kind of decision. My heat mode kicks in when the temp sensor (mounted in Front cylinder) hits about 310*. Killing the rear cylinder does not stop the heat from rising. Extra fuel can only do so much. On a normal day, my air fuel ratio at idle is about 13.2- 13.4. I have not measured it, but when heat mode kicks in, I am sure the front mixture goings into the low 12's maybe even in the 11's. Trust me it is rich, and the temp still rises. These engines are air cooled, not ambient cooled. Unless there is air flow around the fins, the temp will continue to rise. When exhaust gases are 950*, there is no stopping it.

    I have experienced (not with HD engines but with other air cooled engines) needless engine damage caused by excessive (uncontrolled) engine temperatures. At the very least I have seen piston rings de-tension or loose spring tension which results in compression lose and oil control. Not seeing an engine seize does not mean your engine escaped damage. Who's going to really notice a small amount of compression lose or a little more oil usage. I also feel that if you don't have a current 96 or 103, you have a lot less to worry about as far as heat goes.
     
  9. R_W_B

    R_W_B Senior Member

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    Thanks for the replies, I think they have pretty much told me what I was fishing for. So for me it's really academic whether I have the HM activated or not. All it would do is let me know it's time to shut my engine off and I think I can judge that myself by other factors involved.

    It was interesting reading Tbones reply. I was not aware the hot plugs could reduce engine heat. I did know that a hot plug retains more heat in the plug tip. It does this by having a bigger ceramic insulator contact than a cold plug, thereby holding the heat in the tip as opposed to transferring the heat out to the engine head with a (cold) lesser ceramic insulator.

    You don't (or at least I don't) hear much about hot or cold plugs anymore. I remember them from my teenage years. Then we were told for normal use, the selection of a spark plug heat range is a balance between keeping the tip hot enough at idle to prevent fouling and cold enough at maximum power to prevent pre-ignition or engine knocking. I believe they had a number on them to designate the hotness or coldness.
     
  10. R_W_B

    R_W_B Senior Member

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    You know as a side note, what is you guys take on this scenario. After I bought my bike (used) I communicated by phone and email with the previous owner whom I located by old tickets in the bags.

    He told me once my bike (when he had it) overheated with him in a parade and quit on him. He said he had it towed to the shop and they replaced the crank position sensor. I'm wondering if the engine really over heated or this sensor just quit on him.

    Would overheating damage the CKP sensor ?