| Author |
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Hootowl
| | Posted on Friday, February 17, 2012 - 10:40 am: | 
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That's not really a good comparison. It isn't half of that V8, or it would be 3.1 liters, and not 1.7. Different piston sizes, lower reciprocating mass, surely different cams. Other than being a sohc V configuration, what does it have in common with a chevy v8? |
Natexlh1000
| | Posted on Friday, February 17, 2012 - 10:52 am: |
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It may not make as much power as the ST1300 engine but I'll wager it will have a better lump of torque.
If they lose the direct F.I., does that mean they have to back off on the compression ratio? |
Birdy
| | Posted on Saturday, February 18, 2012 - 07:06 pm: |
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But what about power to weight? Seem like that's what it's all about really. 120 HP in a 400 pound bike moves along pretty good...Buell. 120 in a 800 pound bike's a pig...I think they call it a Big Twin.  |
Ft_bstrd
| | Posted on Saturday, February 18, 2012 - 08:38 pm: |
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Bike weight is around the 530lb mark WET, far lighter than similar sport touring bikes in the class.
I believe I read somewhere that the KMV4 engine and transmission weighs around 200lbs. I believe the Buell 12 motor was a similar weight (Correct me if that is wrong.). |
Brumbear
| | Posted on Saturday, February 18, 2012 - 08:43 pm: |
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I was on there sight and looking at the engine and I think they have the cam shaft running the water pump impeller? I don't know if I like that? |
Ft_bstrd
| | Posted on Saturday, February 18, 2012 - 08:48 pm: |
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Does this help:
What do you see as the problem with that set up? |
Glitch
| | Posted on Saturday, February 18, 2012 - 09:01 pm: |
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Forbidden
You don't have permission to access /images/2010/01/motus-v4-exploded-view.jpg on this server. |
Glitch
| | Posted on Saturday, February 18, 2012 - 09:02 pm: |
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Glitch
| | Posted on Saturday, February 18, 2012 - 09:03 pm: |
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More than one way to skin a cat |
Ft_bstrd
| | Posted on Saturday, February 18, 2012 - 09:11 pm: |
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Cant tell whether it's driven off the cam shaft or the crank shaft. |
Brumbear
| | Posted on Saturday, February 18, 2012 - 09:33 pm: |
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It's just that there would only be a seal between water and naughty parts IDK I think an accessory drive would be better. |
Ourdee
| | Posted on Saturday, February 18, 2012 - 09:44 pm: |
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Sure does look in line with the cam shaft though. |
Natexlh1000
| | Posted on Sunday, February 19, 2012 - 01:53 am: |
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Why wouldn't you want the water pump to be driven from the cam?
It couldn't be fast enough to cavitate could it? |
Fast1075
| | Posted on Sunday, February 19, 2012 - 05:38 am: |
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Direct drive water pump is not a new idea. Mercury Marine used the design on their "4" series I/O drive motors.
The cam has a seal, the water pump has a seal. A cavity with a drain hole separates the oily parts from the wet parts. It would take a water seal failure an plugged drain hole and an oil seal failure to do damage.
I saw a couple of water seal failures from lack of maintaining the cooling system, causing grooving/rust on the cam stub. A stainless Speedi-sleeve and it was better than new.
In short, direct drive water pump = great idea. nothing to fail except a seal. |
Brumbear
| | Posted on Sunday, February 19, 2012 - 09:18 am: |
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Thats reassuring indeed as long as it's not 1 seal away from catastrophe. I would still like to see a better breakdown of it before I spent my money. I have seen antifreeze kill a lot of stuff it eats through just about anything.
Thanks for the explanation Fast. |
Blake
| | Posted on Monday, February 20, 2012 - 06:24 pm: |
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An XB12 engine/tranny weighs in significantly less than 200LB, all radiators and such included, about 180 LBs if memory serves. The work done on the XBRR dropped that by a significant amount to around 150 LBs I think. |
Whistler
| | Posted on Monday, February 20, 2012 - 08:15 pm: |
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Saw one this past weekend. I'll wait for the EBR bikes.
(Message edited by whistler on February 21, 2012) |
1324
| | Posted on Tuesday, February 21, 2012 - 12:35 pm: |
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If I were to speculate (hey Wall Street does it all the time with our oil prices), my educated guess would be that there may have been some challenges with the long-term durability of the DI. Some auto systems appear to be pretty robust, but others are plagued with fuel diluted oil and soot/carbon deposits. I'd wager they unraveled that mess significantly later than could be fixed without excessively delaying vehicle launch.
This approach makes sound business sense, in my eyes. There is less risk in implementing a known fuel delivery system. Losing some sales due to a lack of DI sure beats missing the boat entirely. I'm sure they'll attempt to slide DI into the lineup down the road as an improvement, when possible. DI is great, but there is a reason more conservative automakers have been slow with adopting it. Germans don't count as conservative. |
Xl1200r
| | Posted on Tuesday, February 21, 2012 - 02:52 pm: |
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Other than being a sohc V configuration
Take one more step "backward"... these are OHV engines.
Cant tell whether it's driven off the cam shaft or the crank shaft
If you want to be technical, it's driven by the rotating assembly. Yes, it's bolted to and spins with the cam, but only because there's a chain and sprocket set which drives that off the crank, and the impeller sits on the drive system. |
Hootowl
| | Posted on Tuesday, February 21, 2012 - 03:01 pm: |
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"Take one more step "backward"... these are OHV engines."
That is, of course, what I meant. Thank you. |
Crackhead
| | Posted on Wednesday, February 22, 2012 - 10:20 am: |
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While OHV doesn't have the high end breathing of the DOHC motors, it does have an important benefit. The OHV motors are smaller dimensionally then SOHV or DOHV motors. |
