Motus Motorcycles - Page 3

Kerry_129 · 02-12-2011, 02:12 AM

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!

dReWpY · 02-12-2011, 03:32 AM

http://www.youtube.com/user/motusmot.../0/X1V7CfB96Bk

Gas Man · 02-12-2011, 07:43 AM

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.

Trip · 02-12-2011, 08:05 AM

Never going to do anything. I don't get my panties wet when I see Ehmurican on shit though.

Dey took our jubs!

JoshuaTree · 02-12-2011, 12:59 PM

I'm their target market.

If its what it claims to be, I'd consider it. The F800ST is a little anemic, the VFR has never done anything for me, and the other tourer choices are two wheeled cars. :/

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?)

JoshuaTree · 02-12-2011, 01:03 PM

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.

Dave · 02-12-2011, 01:52 PM

Quote:

Originally Posted by goof2

An engine's valvetrain does effect low end torque through their size and timing, but their method of actuation is irrelevant. Pushrod engines are typically designed to produce low end torque only because a normal pushrod engine's valvetrain cannot hold up to high RPM. An overhead cam engine could easily be designed to make that same low end torque, but without the RPM restrictions there isn't any reason to do so. A Hayabusa engine generates almost as much torque as this engine and makes significantly more horsepower with less displacement. The new ZX-10R engine also generates almost as much torque and more horsepower with even less displacement than the Hayabusa. Motus is leaving power on the table by going the pushrod route.

That seems to be the trend. Whichever magazine had the all electric issue recently was littered with companies following that business plan.

1) Develop a gasoline powered motorcycle.
2) Try to take deposits on it.
3) Realize deposits aren't rolling in for a Desmosedici priced piece of vaporware no one has heard of.
4) Make a shitty electric version.
5) ???????????????
6) Profit!

bingo. like i said before it was likely done for cost reasons if not the retarded philosophy that pushrods are 'murican

Quote:

Originally Posted by goof2

The engine will try to twist the bike over to the side when the crankshaft is accelerating. I've heard Guzzis aren't great about it, but at the same time I haven't heard many complaints about BMW's boxer engined bikes which should do the same thing.

dont forget drivetrain losses. did you see the way the tranny is laid out? theres gonna be a bigass diff in there somewhere chewing up the power.

Quote:

Originally Posted by JoshuaTree

I'm their target market.

If its what it claims to be, I'd consider it. The F800ST is a little anemic, the VFR has never done anything for me, and the other tourer choices are two wheeled cars. :/

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?)

hey remember me?

dReWpY · 02-12-2011, 06:27 PM

Quote:

Originally Posted by JoshuaTree

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.

and its not like this bike is being touted as a track weapon where your angled over and at 99% of usable traction is gone already...

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

Amber Lamps · 02-12-2011, 06:38 PM

Quote:

Originally Posted by drewpy

and its not like this bike is being touted as a track weapon where your angled over and at 99% of usable traction is gone already...

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

Adspeak, "We are building a sport-touring bike with the emphasis on SPORT".

Kerry_129 · 02-12-2011, 02:45 PM

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!

02-12-2011, 02:12 AM	#1
Kerry_129 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..

02-12-2011, 12:59 PM	#5
JoshuaTree 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 what it claims to be, I'd consider it. The F800ST is a little anemic, the VFR has never done anything for me, and the other tourer choices are two wheeled cars. :/ 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)

02-12-2011, 01:03 PM	#6
JoshuaTree 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)

02-12-2011, 07:43 AM	#3
Gas Man 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.

02-12-2011, 08:05 AM	#4
Trip 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!

02-12-2011, 02:45 PM	#10
Kerry_129 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!