Digital tach hour meter from OZ-USA - Page 2 - Honda Rebel Forum
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post #11 of 20 Old 11-25-2019, 04:52 PM
 
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The tach is only reading sparks from one cylinder.
So does one cylinder fire once per rotation.....or does one one cylinder fire fire twice per rotation?
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post #12 of 20 Old 11-25-2019, 04:56 PM
 
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Quote:
Originally Posted by flitecontrol View Post
Once per rotation, twice for all four strokes. It fires on compression and exhaust.
So one cylinder will fire twice in one rotation?
One rotation equals one rpm?
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post #13 of 20 Old 11-25-2019, 05:23 PM
 
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while one cylinder is at top dead center of compression stroke the other cylinder is at TDC of exhaust stroke.. At this point Both cylinders fire at the same time.. Wasted Spark Ignition
both cylinders fire one time per rotation..

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post #14 of 20 Old 11-25-2019, 08:06 PM
 
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Quote:
Originally Posted by SoakedKarma View Post
while one cylinder is at top dead center of compression stroke the other cylinder is at TDC of exhaust stroke.. At this point Both cylinders fire at the same time.. Wasted Spark Ignition
both cylinders fire one time per rotation..
How does one measure RPM while only using one of the cylinders of a 2003 Honda Rebel CMX250C?
How many sparks per rotation of just one of the cylinders.
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post #15 of 20 Old 11-25-2019, 08:11 PM
 
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I was confused for a time.
One cylinder...one spark...one rotation. Got it now. Thank you.
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post #16 of 20 Old 11-26-2019, 05:32 PM
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The recommended idle speed, 1,400 rpm plus or minus 100, isn't set just to provide smooth engine performance, it also ensures adequate oil circulation. So going below the recommended idle speed could damage the engine due to oil starvation. Those engineers may have learned by trial and error, which I doubt, but we disregard their guidance at the risk of damaging something.

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post #17 of 20 Old 11-26-2019, 06:35 PM
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As stated before, travelling at 20 mph in fifth gear lugs the engine, which isn't good for it. This explains why:

Minimum cruising speed in fifth gear, per the Rebel owner's manual, is 30 mph. And should you need to accelerate quickly at that speed while in fifth, a downshift is recommended to avoid lugging the engine. Lugging the engine isn't going to improve fuel economy; it will be worse.

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post #18 of 20 Old 11-26-2019, 10:23 PM
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Originally Posted by 1Surfrider View Post
Well, I don't know what else to say, flite. My experience is "improved" ride quality and engine stability with a wider range of deeper carburetor throttle..... How about if I get over 88mpg, then will you believe me? :^)
There are limits to what the engine is capable of. Getting 88 mpg doing 20 mph in fifth at full throttle isn't possible, even assuming the engine wouldn't die trying.

We had a member here a few years back that claimed increased top speed (like well over 90 mph) and mileage (over 100 mpg) with extremely high gearing. I don't think anyone here believed him.

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post #19 of 20 Old 11-27-2019, 10:52 AM
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Quote:
Originally Posted by flitecontrol View Post
There are limits to what the engine is capable of. Getting 88 mpg doing 20 mph in fifth at full throttle isn't possible, even assuming the engine wouldn't die trying.

We had a member here a few years back that claimed increased top speed (like well over 90 mph) and mileage (over 100 mpg) with extremely high gearing. I don't think anyone here believed him.
I think that member was doing all his testing on a long steep downhill. Many have tried, none have succeeded in installing higher ratio sprockets AND maintaining top end speed.

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post #20 of 20 Old 11-28-2019, 12:24 PM
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He was in Miami, FL. There were no hills anywhere near him.
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