![]() |
![]() |
![]() |
![]() |
![]() |
![]() |
![]() |
![]() |
![]() |
|
![]() |
#1 |
Semi-reformed Squid
Join Date: Nov 2008
Posts: 531
|
![]()
Mechanically the push-rod style motor is less simple just because there are extra parts & geometry involved vs. over-head cam designs. P/R valvetrains have more parts/sub-parts (typically lifter, pushrod, rocker-arm & all the associated bits), and more parts = more mass & friction/deflection/hot-spots/wear-points = generally less rpm/surface-speed attainable than more efficient OHC designs. But the geometry of the blocks & heads (both casting & required machining - really factors-in when considering oil-passages, I think) & cam-drive mechanism, and adjustment of valve clearance are generally simpler & more easily accomplished (or automatic, with hydraulic lifters/lash-adjusters). As for making torque - p/r don't increase the torque a motor produces, they're just generally used in large-displacement relatively low-rpm motors which tend to have more & are tuned for bottom-end torque. All that said, p/r technology still does a hell of a job in many applications, has for decades and will for many more - it's just not as well-suited to very high-rpm operation & is *relatively* 'old-fashioned' technology. Some of the best things are though!
O/H cam & shim-under-bucket is about as mechanically simple & efficient (fewest parts, least reciprocating mass/energy wasted) as you can get, but the manufacturing tech & precision required is a LOT higher to produce the parts (block & heads, mostly). Can be a real PITA to deal with clearance adjustment also, of course - what with having to pull elaborate air-boxes/hosing & throttle-bodies & shit just to *start* removing the camshafts (and usually cam chain/tensioner) + having to measure/calculate/replace shims which MUST be meticulously & correctly done. Believe me, sometimes I've *wished* I could just slide a couple tubes up & be done with a couple wrench-twists, without having to take much if anything off to get to them! ![]() Last edited by Kerry_129; 02-12-2011 at 02:16 AM.. |
![]() |
![]() |
![]() |
#2 |
RIP REX
![]() Join Date: Feb 2008
Location: Murfreesboro, TN
Moto: 2008 1125R
Posts: 7,467
|
![]() |
![]() |
![]() |
![]() |
#3 |
Trip's Assistant
![]() Join Date: Feb 2008
Location: Imported from Detroit
Moto: 2009 HD Street Classic
Posts: 12,149
|
![]()
Thanks kerry for a much better detailed post. It was more better. I heart pr and have had it on many motors both bike, car, truck, and tractor. I love em.
I luv this whole idea and concept. I wish them the best and hope to see this in a showroom. Hopefully they make good alliances. They should start talking to erik being he's getting ready to bring a non-hd street buell back to the market. |
![]() |
![]() |
![]() |
#4 |
Hold mah beer!
Join Date: Feb 2008
Location: 80 Miles South of Moto Heaven
Moto: 08 R1200GS
Posts: 23,268
|
![]()
Never going to do anything. I don't get my panties wet when I see Ehmurican on shit though.
Dey took our jubs! |
![]() |
![]() |
![]() |
#5 |
DILLIGAF?
Join Date: Nov 2008
Location: Austin, Texas, USA, Earth, Sol, Western Spiral Arm, Milky Way
Moto: 1993 K75SA
Posts: 483
|
![]()
I'm their target market.
![]() If its a solid bike, WITH ABS, I'll definitely consider it. ![]() (As in what idiots would even contemplate building a "sport tourer" without ABS currently?)
__________________
"Quis custodiet ipsos custodes?" "Learn to do the counter-intuitive things that may one day save your ass..." "... Love Much, Laugh Often..." - Amanda Kay Corso (January 18, 1980 - April 15, 2008) |
![]() |
![]() |
![]() |
#6 |
DILLIGAF?
Join Date: Nov 2008
Location: Austin, Texas, USA, Earth, Sol, Western Spiral Arm, Milky Way
Moto: 1993 K75SA
Posts: 483
|
![]()
RE: 90 Degree opposition crankshafts...
Yes, they do twist / lift the bike's chassis a bit. It varies by design. Having had both Boxer and K-Brick engined bikes (both having crankshafts rotating perpendicular to the rotation of the wheels), neither design is "startling" in this respect, even with violent applications of clutch & throttle. Yes, its there. Will you notice it after more than 30 minutes riding the bike? No. ![]()
__________________
"Quis custodiet ipsos custodes?" "Learn to do the counter-intuitive things that may one day save your ass..." "... Love Much, Laugh Often..." - Amanda Kay Corso (January 18, 1980 - April 15, 2008) |
![]() |
![]() |
![]() |
#7 | |||
Chaotic Neutral
Join Date: Feb 2008
Location: Cherry Hill NJ
Moto: GV1200 Madura, Hawk gt
Posts: 13,992
|
![]() Quote:
Quote:
Quote:
![]()
__________________
TWF Post whore #6 |
|||
![]() |
![]() |
![]() |
#8 | |
RIP REX
![]() Join Date: Feb 2008
Location: Murfreesboro, TN
Moto: 2008 1125R
Posts: 7,467
|
![]() Quote:
i mean we can armchair race a new engine, but if its not ment to be racing arent we just spinning our wheels??? right tig? lol ![]() |
|
![]() |
![]() |
![]() |
#9 | |
Moto GP Star
Join Date: Mar 2008
Posts: 14,556
|
![]() Quote:
![]() |
|
![]() |
![]() |
![]() |
#10 |
Semi-reformed Squid
Join Date: Nov 2008
Posts: 531
|
![]()
I'd speculate their decision to go with pushrod design was based on 1) cost/complexity of casting/machining, 2) Overall simpler (considering no ohc drive) & more compact motor, especially with the heads hanging out either side of the bike, ala MotoGuzzi. The heads have to be considerably taller with OHC, especially with a relatively small budget which wouldn't allow for repeated prototyping & material minimization. Way easier, esp. in a V-design, to just stick a cam in the valley right over the crank & with a simple chain or gear drive. Works just fine to, as long as you're not trying to spin it way up. Maybe a distant 3) it's 'murican.
The counter-torque is just nature of the beast & a reaction to the inertia of the crank/flywheel spinning-up. I've felt it on a boxer, and though noticable it wasn't a big deal. That's a V4 mounted relatively high vs. the very low-slung BMW design - and did you see the size of the flywheel in the video?! I bet it has a good bit of counter-torque, but that might just add to its character. Wouldn't be a big handling factor so long as you're changing rpm drastically in a curve - also side-ways V design would lessen the gyroscopic resistance to side-to-side transitions too, vs. typical transverse crank mounting. All technical BS aside - it does look pretty bad-ass, producing their own engine in-house is impressive, and kudos to them for doing *something* to produce a sporting American motorcycle. I hope they do well & we see good things come of their efforts! ![]() |
![]() |
![]() |
![]() |
Bookmarks |
|
|