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Re: KPaul was right,Take that back 90 deg V-4 is narrower and has perfect primary bal

Uhh, check my post.

I said, and I quote, "Your inline 4 won't have perfect balance. You can get either primary or secondary balance, but not both. That is why you see balance shafts in 4 cylinder engines (in cars). To be balanced, you need it."

I said nothing about the V4. I was talking about your I-4.

The V4 will have perfect primary balance, but not perfect secondary balance. A 90 degree V engine, regardless of the number of cylinders, has perfect primary balance but suffers from secondary imbalances.

So, in trying to claim I was wrong, you were wrong again. You should learn to quit when you're ahead.

BTW, BSME, MSME, PhD EE.

I learned more in my four years at the motorcycle shop then I did in 11 years of college. Some of the most ignorant people I've ever met were well educated. Educated fools. Some of the smartest people I know barely graduated from high school.

NEVER equate education with intelligence.
 

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Re: Not totally true...

Yep... I was PreMed stud until I ran into Organic Chemistry... To me Physics and Math are easy compared to Chemistry... Most engineers have brains wired to understand Physics and Math... Chemistry is a lot different IMHO... I have much respect for Chemistry, Chemists and Chemical Engineers.... Doctors too...
 

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You're the man blitz...

Thanks for the advice and knowledge.... Yep my I-4 doesn't look as good as it did.... :) "Some of the most ignorant people I've ever met were well educated' I am sure my wife would put me in that category. :)

Much Respect blitz

kpaul
 

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Re: You're the man blitz...

Thanks.

Life, like engineering, is all about tradeoffs. I used to view the world as black and white. As i get older (and hopefully wiser), i see way more gray. The gray is what makes it interesting. Problematic at times, but way more interesting.
 

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Re: KPaul was right,Take that back 90 deg V-4 is narrower and has perfect primary bal

blitz, to the best of my knowledge a 90 degree V6 or V12 do not have perfect primary balance. A 60 degree V6 or 12 does have PPB, but only if the crank throws are 120 degrees apart. VWW
 

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Re: KPaul was right,Take that back 90 deg V-4 is narrower and has perfect primary bal

Hi Van,

My kinematics book is in my attic, but I think you can have perfect primary balance with a 90 degree V6, or any V configuration with an even number of cylinders.

As I recall, primary balance has to do with the center of gravity not moving as an engine runs. A 90 degree V with 90 degree crank pins will not have its CG changed. (I just drew this out, and with crank pins 90 degrees apart, this holds true.)

Adding cylinders won't change the CG of the engine. If a 90 degree v twin has perfect primary balance, adding cylinders in multiples of two won't change the CG. It will, however, add rocking moments, therefor not providing secondary or higher order balance.

I'll caveat this again by "I think." It's been 22 years since I took kinematics, but I paid attention that day because it actually hit on something i was interested in. That was the one fact that stuck with me.

Thanks.
 

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Re: KPaul was right,Take that back 90 deg V-4 is narrower and has perfect primary bal

I believe that you are right about the secondary rocking couple ( as a long time BMW rider I of all people should have factored that in) however I am at a loss to explain why a 60 degree V6 with 120 crank throws is so much smoother than a 90 degree V6 if the primary balance is perfect and only the secondary balance spoils the smoothness. VWW
 

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Saw it at the Tokyo motorshow. Also, there's an article with pics on it in one of the more popular bike mags here in Japan (in Japanese, of course). 1800cc and pretty killer looking. Much less cruiser, more like the MT. Personally, I like the old one (get them while they last) for looks with some performance upgrades to boot.
 

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The 2005 Tokyo Motor Show isn't until October 21 so I assume that you saw it at the 2004 show. This is the first that I hear about Yamaha displaying the new 1800 V-Max. Can you provide a link so I can check it out?



Regards,

Doug
 
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