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Blake
| | Posted on Wednesday, August 01, 2007 - 10:07 am: | 
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Sloppy,
"To put this in perspective, neither MV, Yamaha or Honda 1000 cc bikes get past 4000 FPM."
That sounded unbelievable to me, so I did some checking.
2007 Yamaha YZF-R1
Stroke = 53.6mm,
Rev Limit = 13,750 RPM,
Piston Speed = 4,836 FPM
2007 Honda CBR1000RR
Stroke = 56.5mm,
Rev Limit = 12,200 RPM,
Piston Speed = 4,523 FPM
(Message edited by blake on August 01, 2007) |
Blake
| | Posted on Wednesday, August 01, 2007 - 10:08 am: |
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Ronald (LimitedX1),
You have email.  |
Sloppy
| | Posted on Wednesday, August 01, 2007 - 07:27 pm: |
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Those are impressive numbers -- I wonder if we're running into the inflated rpm wars when Yamaha claimed the R6 redline was something like 16,000 rpm? Of course they did retract and refund, but they sure sold alot of R6's with that advertising line...
My numbers came from a database from prior years that I made back in '04 (so it's pre-'04 bikes) with information I got from the mfg. site, and if not available, from online reviews:
Yam R1: 58mm / 10,000 rpm - 3791 fpm
Honda 954: 54mm / 11,250 rpm - 3971 fpm
MV1000: 43.18mm / 10,000 rpm - 2822 fpm
Duck 900ss: 68mm / 8,000 rpm - 3556 fpm
Buell XBRR: 79.4 / 8,000 rpm - 4152 fpm (I'd say this is a low "advertised" rpm number...)
Sorry: I should have noted the years of my data!!! Of course, since we're in a Tuber forum, we are talking about this timeframe of metal and mfg. technologies.
Calculation is (stroke in mm * rpm) / 153 for fpm. So by all means DO USE THE MOST RELEVANT AND ACCURATE DATA.
As noted, my data came from the net, so if anyone has anything confirmed different then do use it instead. |
Sloppy
| | Posted on Wednesday, August 01, 2007 - 08:03 pm: |
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Funny, I went to the Yamaha site and they don't have any data as to power or rpm of the engine (not even the '06!).
After a Google search I got hooked up with Sportrider and I did find this for their '07 R1!
stroke of 53.6 mm at 12,100 max hp -- still an impressive 4240 fpm, but it's no 4800 fpm or 13750 rpm!!! Darn those Yamaha marketers are good ;)
So who has the right data???
Only the shadow knows...
Regardless, pushing 4340 fpm on an XL motor by running it to 6775 rpm is an aggressive application of its design... and faster than the latest and greatest design from Yamaha!!! You think about that before you feel like you want to spin your engine as fast as your import buddies. You've got to hand it to those HD engineers - they know what they're doing.
(Message edited by Sloppy on August 02, 2007) |
Rick_a
| | Posted on Wednesday, August 01, 2007 - 10:39 pm: |
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quote:Regardless, pushing 4340 fpm on an XL motor by running it to 6775 rpm is an aggressive application of its design... and faster than the latest and greatest design from Yamaha. You've got to hand it to those HD engineers - they know what they're doing.
Don't say that within earshot of import riders!  |
Blake
| | Posted on Thursday, August 02, 2007 - 04:15 pm: |
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After a Google search I got hooked up with Sportrider and I did find this for their '07 R1!
stroke of 53.6 mm at 12,100 max hp -- still an impressive 4240 fpm, but it's no 4800 fpm or 13750 rpm!!! Darn those Yamaha marketers are good ;)
It's probably not very accurate to use the RPM for peak HP as the rev limit.
The dyno plots on motorcycle.com appear to bear out the rev limits I used. Their R1 plot may be indicating a bit lower limit of 13,500 rpm is all. That would put the piston speed at 4,748 FPM which is still well above that for the Buell XBikes.
I have a very difficult time accepting the ridiculously low rev limit you listed for the MV1000.
Being picky, the precise equation for calculating mean piston speed in feet per minute (FPM) from stroke in mm is...
Mean Piston Speed = Stroke * RPM / 152.4
(Message edited by blake on August 02, 2007) |
Sloppy
| | Posted on Thursday, August 02, 2007 - 07:34 pm: |
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Sport rider has the actual rpm at max. hp vs. trying to interpret it from a graph.
While you can argue on the value of "over-rev", I don't see much other way of comparing engine speeds unless you define it at max. hp... otherwise anyone can claim a max. rpm of upteen million revs until the motor blows or the rev. limiter kicks in. And if they truely wanted to get that much engine speed then they should have picked a cam to actually use the hp that they could have gotten at those revs. The way I see it, unless you actually use max. hp, then you don't have any standard to compare to.
For the brand new, 2007, race ready MV Agusta F4S they now run at an incredibly lazy 3650 fpm at a hp peak rpm of 12,750. So like I said, my numbers are from years past, but MV still isn't pushing any design envelope on their engines!
http://www.sportrider.com/bikes/146_0012_mv_agusta _f4s/index.html |
Sloppy
| | Posted on Friday, August 03, 2007 - 11:31 am: |
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The latest dyno data on the CBR1000RR I could find was '04, which shares the same stroke as the '07 -- it's piston speed is only ~ 4080 fpm with a peak hp at 11,000 rpm. Perhaps another exaggeration of engine performance as what Yamaha has done???
http://www.sportrider.com/bikes/2004/146_04_honda_ cbr1000rr_specs/
So Honda has just gotten into the 4000 fpm barrier with their 1L bikes.
Again, a case of the XL engine being subjected to some incredible forces when compared against a superior designed, water cooled, plain bearing, single piece crank, made for the track bikes...
So you can take your fpm data to what ever rev. limit you want to pick, but unless it's compared to max. power, IMO you can't make a fair comparison as you can likely pass 5000 fpm just by downshifting or just putting in a different rev. limiter into your ignition... |
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