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Re:Highway gearing
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TOPIC: Re:Highway gearing
#1024326
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Re:Highway gearing 1 Month ago  
ctkog wrote:
It sounds a little like you're trying to fix an uncommon problem of a roadstar pinging bad by chasing it off with different gearing. I agree with the statement if you're having that much pinging something else is probably going on like timing fuel air mixture or it running hotter than normal assuming this motor is stock and not built.

+1...I suspect this is your problem....."I am running premium fuel and octane booster".
 
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#1024327
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Re:Highway gearing 1 Month ago  
I am certain that I am hearing a ping in light throttle high gear situations

Then, I’d check the TPS that controls your timing to throttle settings.
 
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Re:Highway gearing 1 Month ago  
Blew through 1600 miles of steep grades and hard highway running for the M&G 3 weeks ago and not a sign of a ping or knock. What I DO hear from time to time at lower RPM is a little piston slap noise, but again, 4 1/2 inch stroke. That’s a buttload of dwell angle on the crank, and these pistons aren’t exactly useful as shop ashtrays for the skirt length. They can’t be, because they have to clear some giant counterweights on that 42 pound crank. At 72K I dropped the bore scope into my cylinders for a peek and all is golden (an expression, not a color!) inside the cylinders. If you are actually pinging, something is off.

BTW, a 42 flat slide won’t make even one more foot pound of torque come out of your motor and will in fact be less than ideal for frequent altitude changes. The CV carb is self compensating for altitude by virtue of differential pressure actuation.
 
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Last Edit: 2017/10/23 00:06 By jd750ace.
 
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#1024331
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Re:Highway gearing 1 Month ago  
I will certainly check that. I would imagine that it's a 0-5 volt variable tps like cars use that I can sweep with my scope. I have the factory manual on DVD. I will check that in the morning. Vacuum seems good, (over 18" at idle), could not find any vacuum leaks using brakleen. TPS doesn't always set a check engine light in cars so it might not turn the check engine light on my bike either. I thought that it was odd to have to add so much octane for 9.5 compression. CO and hydrocarbon readings are good. (I have a 5 gas anylizer). I don't ride big v- twins that often but my Uncle's 2014 Harley rides great in high gear at 70 so what you say makes sense. Thank you again and I will let you know what I find.
 
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Re:Highway gearing 1 Month ago  
jd750ace wrote:
"Blew through 1600 miles of steep grades and hard highway running for the M&G 3 weeks ago and not a sign of a ping or knock. What I DO hear from time to time at lower RPM is a little piston slap noise......and these pistons aren’t exactly useful as shop ashtrays for the skirt length......"

I think I hear that slap noise when I'm chugging a little slow up hill and using too much throttle in that load demand. I can feel the piston in my seat almost like its wanting to fight the rotation. I try to anticipate and keep it out of that rpm range by down shifting to bring the rpm up into a sweeter spot. With the shorter skirt I imagine that puts the piston at a slightly steeper angle in the cylinder which I've heard can be bad for our roadstars too.
 
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Last Edit: 2017/10/23 00:35 By ctkog.
 

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#1024334
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Re:Highway gearing 1 Month ago  
The TPS is adjustable, so it is possible to have it advanced a tad too much, especially at light throttle applications where spark timing is at its highest. Never really delved into these things as mine is not pinging, but worth a check.

 
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#1024337
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Re:Highway gearing 1 Month ago  
Since the rings are already in contact with the cylinder wall all combustion pressure does is press them tighter. I don't think you would hear this. Pinging AKA detonation happens at the moment of ignition and is instantaneous. The heat when combustion just begins travels at the speed of light and if there is a pocket of gas anywhere in the cylinder that is close to igniting it will do so at that time. The ping is when the two flame fronts meet each other. I don't think detonation will occur in a Road Star with premium gas unless high compression pistons have been installed.

I think you're hearing something else.
 
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#1024338
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Re:Highway gearing 1 Month ago  
I will get a knocking sound in mainly forth gear when lightly on the throttle most all the time, sometimes when it is hot you can hear it in second and third with little throttle. Change the throttle position just a little and the knocking goes away. What's the opinion on these sounds? should I have any concerns? It's been doing this since and bought it. Has 3800 miles on it then now has 14500 mile on it.
 
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Last Edit: 2017/10/23 07:41 By Nocolorbrother.
 
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#1024339
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Re:Highway gearing 1 Month ago  
I notice some pinging on hot days especially after some traffic. It’s not surprising to me since part of the equation for pinging is heat and pressure. Our pressure is relatively low but our engine temp can often be up there a bit and that raises pressure. We just don't see it because we have no temp gauges.
 
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Last Edit: 2017/10/23 09:58 By ctkog.
 

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#1024374
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Re:Highway gearing 1 Month ago  
I suspect that the previous owner already has done some tinkering with your gearing.I have a 99 and as I understand the early models are geared taller.Your set up sounds like your gearing is taller than mine. On a flat road,I normally shift into 5th about 65.My bikes sweet spot for cruising is between 70-80.I don't quite understand how taller gearing will rid you of pinging unless the taller gearing is a separate wish list item. I just moved to Goodlettsville last month and can't wait to get some riding in.
 
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