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General Category => General Discussion => Topic started by: Daniel Kalal on December 10, 2016, 08:57:09 AM
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I took this shot at the Santa Rosa Mile, where this bike won the dash-for-cash.
(http://www.dankalal.net/2016trip20/photo0033.JPG)
For a scratch-built race-only bike, it's really beautiful. It's beautiful without the qualifiers. Per agreement, Indian/Polaris has a limited time to use this bike before they're obligated to build lots more. As for any street application, I don't know that there's much call for a 750cc high rpm twin, but I expect eventually we'll at least see a few (not by the factory).
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Deke , I wondered about the production question . Polaris certainly spent some money hiring the last three champions , but still not what it will cost to build a production version of the engine .
Dusty
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what?
Is this a smaller displacement version of the Scout/Octane engine? De-stroked?
why did they make it smaller? aren't 1000cc production engines allowed to run?
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A short run of FTR Scouts with flat track styling and some handling chops would be a kick-butt machine, how many do they have to build? And do they have to be street legal, or simply track ready customer bikes?
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Is this a smaller displacement version of the Scout/Octane engine? De-stroked?
No; it's all new with nothing (save probably a few bits here and there) from an existing engine.
why did they make it smaller? aren't 1000cc production engines allowed to run?
Production engines can be 1000 cc, but pure race (like the Harley-Davidson XR-750) are limited to 750cc. This is an on-purpose racing engine.
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A short run of FTR Scouts with flat track styling and some handling chops would be a kick-butt machine, how many do they have to build? And do they have to be street legal, or simply track ready customer bikes?
I think technically all they have to build is the motor . Race only engines are limited to 750 CC's , which explains why they built a 750 . The number required is pretty low , XR motors were only built in low numbers , maybe 10 a year , and none by HD for decades .
Dusty
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wow, Polaris made a scratch built race engine? That is serious. If that's the case, I would imagine the Kawasaki will still be the most popular since you can get those out of the junkyard.
I think the last pure race engine was Honda's back in the early '80s (raced by Bubba Shobert, Ricky Graham & Ronnie Jones)?
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Polaris has a serious commitment to this, the engine design almost certainly came from their Swissauto division.
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wow, Polaris made a scratch built race engine? That is serious. If that's the case, I would imagine the Kawasaki will still be the most popular since you can get those out of the junkyard.
Yes; Polaris stepped up and had their new-purchased Swiss engineering company design and build the engine for them. These guys have shown that they can turn out racing engines that are fast from the start without years of development.
Yes; the Kawasaki is probably going to be the most numerous out there in 2017. I can't imagine anybody wanting to make a go of the new XG-750 from Harley (without lots of sponsorship money). It didn't impress this year even with a very good rider.
I think the last pure race engine was Honda's back in the early '80s (raced by Bubba Shobert, Ricky Graham & Ronnie Jones)?
Yes; this new engine is in that class. It's expected to be a game-changer for the 2017 season. And like Honda, Indian has hired the best riders and support crew. The 2016 championship Howerton team (Bryan Smith) is really just changing from Kawasaki to Indian--the team continues.
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Uh fellas , the XR 750 is a purpose built race engine .
Dusty
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Uh fellas , the XR 750 is a purpose built race engine .
Dusty
Of course. And, over the decades it has had every bit of horsepower squeezed out of it--to the point that a rider with an aggressive wrist (Baker) often couldn't finish the race before it let go. If the new Indian can handle Brad Baker, then we'll know they've got a durable engine!
I'm hoping that H-D will find something during the off-season to make their new XG a better bike. Pretty much everybody was able to pull it on the straights.
The annoying part of the 2017 rules is that the Ducati 1100 engine is no longer allowed. You'd think an old two-valve SOHC air-cooled production motor would be allowed at least a little advantage in displacement. Nope.
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👍 on the subject matter Daniel, looking forward to the '17 season!
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Of course. And, over the decades it has had every bit of horsepower squeezed out of it--to the point that a rider with an aggressive wrist (Baker) often couldn't finish the race before it let go. If the new Indian can handle Brad Baker, then we'll know they've got a durable engine!
I'm hoping that H-D will find something during the off-season to make their new XG a better bike. Pretty much everybody was able to pull it on the straights.
The annoying part of the 2017 rules is that the Ducati 1100 engine is no longer allowed. You'd think an old two-valve SOHC air-cooled production motor would be allowed at least a little advantage in displacement. Nope.
True , the XR was at the end of its development cycle , and in mile tune was becoming a hand grenade . Seems like I read somewhere that the tuners were getting over 100 HP at 9800 RPM's in the latest versions , which is pretty amazing considering they were designed in 1972 , or the aluminum ones were . Sad to see the big Ducs get eliminated , maybe someone will develop a race motor from one of the smaller displacement engines .
One thing that does concern me re the new Indian motor , flat track teams operate on tight budgets , wonder what a customer version will cost ? Of course if they will not require very expensive crankshafts every other race that would help mitigate some expense .
Dusty
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Flat track racing in the US is an event for HD to show off their bikes, so of course a competitive Ducati has been disqualified. They can't let some other brand rain on HDs parade...........ex cept maybe Indian, another American brand competitor from back in the day?
As I recall wasn't the `80s Honda-Bubba Shobert race bike a water cooled CX500 motor enlarged and switched sideways to make it inline cylinders?
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Flat track racing in the US is an event for HD to show off their bikes, so of course a competitive Ducati has been disqualified. They can't let some other brand rain on HDs parade...........ex cept maybe Indian, another American brand competitor from back in the day?
As I recall wasn't the `80s Honda-Bubba Shobert race bike a water cooled CX500 motor enlarged and switched sideways to make it inline cylinders?
No , completely different engine . Honda did experiment with the CX 500 , never had any success .
Dusty
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a couple of points.
I think the Howerton family is originally from Tulsa. Jackie was a local sprint car show that moved to Indy. I used to see Jackie race when I was a kid.
So far as the Honda, they originally started with a CX500 based motor but later came up with a race engine. I understand it has the same bore and stroke as the XR Harley but with an OHC lay out. It was successful until Honda pulled out in the late 80s. Ricky Graham won a title in the early 90s with leftover Honda parts.
Looking at that little water cooled Harley, I'd be surprised if that engine went anywhere. It looks cheap and flimsy. They might build a race engine using the same side covers bolted to a new case, crank, cylinders, and heads but......ah I dunno. What do I know? I thought that Indian was street motor like the Kaw. Heck, I even had the Cycle World article on it and haven't read it.
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...CX500 motor enlarged and switched sideways...
The very successful Honda RS750 flat-tracker has far more in common with this NXR750 Paris-Dakar race bike than anything else, including the Honda NS750 (the sideways CX) or the H-D XR750)
(http://www.dankalal.net/wildgoose/NXR750.jpg)
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The RS750 was a SOHC 4 valve per cylinder design , that as Deke says has more in common with the Dakar bike , and as Lowryter stated copied the XR HD bore and stroke ratio . They were developing 110 HP at 10,000 revs when the best XR's were making 95 . Very narrow V angle like the HD also .
Dusty