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Author Topic: Yikes! V12 CBX !  (Read 2762 times)

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Online Magpie

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Yikes! V12 CBX !
« on: November 11, 2009, 08:46:01 AM »
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Offline Bob Wessner

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Re: Yikes! V12 CBX !
« Reply #1 on: November 11, 2009, 08:51:44 AM »
Wow is right! That cowling surrounding the gauges looks like a great little guillotine.  ;D
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Offline kenolds

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Re: Yikes! V12 CBX !
« Reply #2 on: November 11, 2009, 07:04:03 PM »
So, I know that VW, Porsche, and Subaru do it, but how does oil get back to the pan form that bottom cylinder head?  Looks like it would "fill up" and the rockers would be running partially submersed?
Also, is it just me, or does his throttle work backwards?  Is a CBX clutch and gearbox up to taking double the HP? 
Very interesting find.

Kenolds
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Offline jhasewhite

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Re: Yikes! V12 CBX !
« Reply #3 on: November 11, 2009, 07:06:29 PM »
Scavenger pump from a dry sump ferrari engine. I built this bike with Andreas...
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Offline jhasewhite

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Re: Yikes! V12 CBX !
« Reply #4 on: November 11, 2009, 07:11:02 PM »
the cbx clutch and gearbox are taking twice the power, but there are very few "power pulses" transmitted through the primary chain and jackshaft. The limitation of speed on this bike is simply the rear tire- you could put 300hp through a cbx tranny and it still wouldn't blow because the stress on the components is a constant equation of rear tire grip, not engine hp and torque.


It has been gusseted, heat treated, undercut and some parts case hardened with a drag racing clutch to beef it up a bit.


cheers,

j
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Offline wannabridin

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Re: Yikes! V12 CBX !
« Reply #5 on: November 11, 2009, 10:32:18 PM »
throttle isn't backwards, it's just the slight lag on the video and sound.  mine did it too
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Offline Hasenkopf

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Re: Yikes! V12 CBX !
« Reply #6 on: November 12, 2009, 03:43:43 PM »
oohhhh that is  SO sick,   I love it !!
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Online CycleRanger

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Re: Yikes! V12 CBX !
« Reply #7 on: November 12, 2009, 05:22:14 PM »
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Offline Don R

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Re: Yikes! V12 CBX !
« Reply #8 on: November 12, 2009, 07:30:33 PM »
what is the crankshaft?
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Offline jhasewhite

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Re: Yikes! V12 CBX !
« Reply #9 on: November 14, 2009, 01:12:25 PM »
stock cbx crankshaft, machined for Siamese con rods for each journal, then balanced and case hardened.The con rods are forged racing bits that have been decked down so 2 will fit on each crank journal. The new oil passages were wire EDM drilled by me to feed the 2 plain bearings. The second bank of cylinders sits about 1/2" to the left so it all lines up.
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Offline mec

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Re: Yikes! V12 CBX !
« Reply #10 on: November 14, 2009, 01:49:03 PM »
awesome work.

we raced the cbx in the 80ies. it took 70 laps (and a few practice sessions) and the crank broke.
engine had approx 1340ccm, race cams........

mec
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Offline kenolds

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Re: Yikes! V12 CBX !
« Reply #11 on: November 16, 2009, 06:51:19 AM »
How did you drive all of the cams?
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Offline bill440cars

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Re: Yikes! V12 CBX !
« Reply #12 on: November 16, 2009, 10:57:15 AM »


      WHOA! :o 8) Just riding MY 80' CBX is a real blast, to me! I can only imagine what it would be like to just SIT on THAT one and rev the engine a bit, much less actually RIDE it! :o  And to have jhasewhite here to give us insight on the bike, is a REAL treat! ;)
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Offline jhasewhite

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Re: Yikes! V12 CBX !
« Reply #13 on: November 17, 2009, 11:01:51 AM »
cams are driven by a second stock honda chain, with a second sprocket and a second tensioner.The cams were actually cut apart, flipped around and re-welded on a jig to correct the cycle order when we changed the rotation of the second bank of cylinders. It was tricky to fit all of that in there, but it works.
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Offline oldfett

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Re: Yikes! V12 CBX !
« Reply #14 on: November 17, 2009, 12:14:52 PM »
If I may ask (and this may sound stupid) but what brought about this mechanical undertaking? I mean its not like you see a Honda CBX everyday so the concept of taking two of their engines and putting them together and vastly modifying one of the frames had to be a very scary undertaking! Was the engine out to be rebuilt and someone went, you know I bet we could fit another bank of cylinders on here! I'm just curious, I like hearing the story behind the project.
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Offline Laminar

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Re: Yikes! V12 CBX !
« Reply #15 on: November 17, 2009, 01:22:24 PM »
Quote from: wannabridin on November 11, 2009, 10:32:18 PM
throttle isn't backwards, it's just the slight lag on the video and sound.  mine did it too

I'm not sure that it's lag in the video as much as it's lag in real life. When you crack the throttle open, it takes time for the rotating components of the engine to accelerate and for the engine's RPM to increase. Once the RPMs start increasing significantly, you let off the throttle so that you don't overrev it. It feels natural when you do it, but when you're watching it on video, because you're closing the throttle as the revs come up, it looks as if you're closing the throttle TO BRING the revs up.

If you look at the mouths of the people in the video, there isn't any significant lag between speaking and hearing their voices.
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Offline jhasewhite

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Re: Yikes! V12 CBX !
« Reply #16 on: November 25, 2009, 11:31:58 AM »
Quote
Quote
"I'm not sure that it's lag in the video as much as it's lag in real life. When you crack the throttle open, it takes time for the rotating components of the engine to accelerate and for the engine's RPM to increase. Once the RPMs start increasing significantly, you let off the throttle so that you don't overrev it. It feels natural when you do it, but when you're watching it on video, because you're closing the throttle as the revs come up, it looks as if you're closing the throttle TO BRING the revs up.

If you look at the mouths of the people in the video, there isn't any significant lag between speaking and hearing their voices."


The electric fuel pump coupled with our guess on jetting was causing that problem, it's all sorted now and the revs rise and fall instantly.
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