Sparks plug question

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Jan 11, 2015 | 04:46 PM

#31

98hotrodfatboy

Seasoned HDF Member

Joined: Mar 2010

Posts: 21,116

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From: Poolville

By what I hear 50 psi is the requirement for a dyno run. Keeps the tire from expanding which can create inaccuracies between low and high rpm range.

Quote:

Originally Posted by Schex3x

Pump that rear tire up hard when you put it back on the dyno.

Jan 12, 2015 | 07:33 AM

#32

br549A1

Outstanding HDF Member

Joined: Nov 2013

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I'd go to a different dyno. Aren't all the runs subject to how well the operator knows the equipment? Many years ago I had my cammed 86 gixxer dynod by a well know local guy that built these engines. He came up with 127hp. I knew my bike well and could tell he wasn't even giving it full throttle. Now ten minutes after the run he tried to sell me an 1127 complete and guaranteed it to have 150 at the wheel. I declined. I knew what the bike and engine were capable of and there was already nothing on the road that could touch it. Not saying you have this problem, but I would do a new dyno run at another shop before I did anything.

Jan 12, 2015 | 03:01 PM

#33

johnjzjz

Seasoned HDF Member

Joined: Nov 2006

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From: la la land jerzey

just to keep this on the same page as the real people who actually have done this ---- -- at the road race tracks to keep apples apples jap stuff / Italian and others like buells - race in a HP to the rear wheel classes, like 106 to the tire we were in in 1996, and at the end of a race the 4 top finishers were dyno spun before they left the track - the dyno was right at the exit in the infield if a bike posted more than the 106 it was disqualified and that is how the 4th bike in the span was used as he then posted a 3rd -- NO oNE was allowed to even touch the bike much less blow up the tires - in this case let air out

blowing up the tires is good for as much as another 10 to 12 percent of power /// gimmick

corrected / weather / altitude / like 400 feet below sea level at 55 degrees a PC modding is good for at least 20 percent more power to any sheet

we have a guy in my area who brags he has the bikes with the most power and no one can touch his motors hahahahahahahah really

he also knows how to give you what you think you want and need with a click of the board

dont believe what you your self has not done and tested with the correct equiptment its all about making money and a dyno is like having a license to steal

Jan 12, 2015 | 04:15 PM

#34

98hotrodfatboy

Seasoned HDF Member

Joined: Mar 2010

Posts: 21,116

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From: Poolville

But?

When a tire is blown up to different pressures say 30-50 psi, does that not increase the diameter as well? I can understand how it would change the final ratio of motor to rear wheel but how can it affect the HP rating? I do know that centrifugal force will create a larger tire especially when it is under inflated, sort of like a set of slicks but as the wheel rpm increases so does the diameter creating more speed.

Last edited by 98hotrodfatboy; Jan 12, 2015 at 04:18 PM.

Jan 12, 2015 | 04:23 PM

#35

Schex

Club Member

Joined: Apr 2011

Posts: 5,816

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From: SE Louisiana

don't think ratio, think drag

straping down a car too tight on a dyno will affect #'s

Jan 12, 2015 | 07:13 PM

#36

machinehed

Road Master

Joined: Oct 2011

Posts: 957

Likes: 2

From: Carlsbad Springs Ontario

iridium plugs

Quote:

Originally Posted by Spanners39

I am a professional cynic and tried the Iridiums expecting them to be ho-hum but on both my bikes (Evo and then TC) they did exactly what the hype said they would, so now that is all I use.....although it will be a very long time before I need to change plugs.

My gist :

Take a look at the electrode of an iridium plug and a standard NGK or whatever . You will see that the iridium electrode is not much bigger than a ball point pen . As we are all riding vintage bikes with vintage coil voltages , it follows that the tiny indestructable irridium electrode provides a very low resistance to the coil voltage and gives the best spark . Nuff said.?