XR-750 c. 2015: Team Latus
XR-750 c. 2015: Engine left
XR-750 c. 2015: Engine right
XR-750 c. 2015With limited time and money in 1969, Harley-Davidson's racing manager Dick O'Brien and his team used elements of existing designs to put together a new OHV racer, but rather than start from scratch they decided to modify their existing OHV racer: the Sportster-based 900 cc (55 cu in) XLR magneto-equipped race engine with a 3.0000 in (7.620 cm) bore and a 3.8125 in (9.684 cm) stroke. It was too large to be legal, so a modified version was created using the same basic upper end parts (iron heads and cylinders) but with a drastically shorter stroke and shorter connecting rods to reduce the displacement to the 750 cc (46 cu in) legal limit.
[8] These iron head XR-750s of 1970–71 were prone to overheating (humorously called "waffle irons") as well as having insufficient power. The engine was again re-designed for 1972 with an all-aluminum head and cylinder package with bigger bore and shorter stroke for the same 750cc displacement. The frame and the running gear were held over from the KRTT racer, with a Ceriani front fork and two Girling rear shocks.[8] The fuel tank, fenders, and rear seat/fender combination were fiberglass, with a snap down seat cover over a foam cushion.[8][9] To comply with AMA homologation rules, two hundred examples were made and could be had upon request at Harley-Davidson dealers, at a price of US$3,200, which today with inflation would be about US$ 22,329.[9]
Not unlike other Harley-Davidson engines, the unit construction left and right engine cases split vertically, and formed four cavities: a center front crankcase, a center rear gearbox, a right side cavity gearcase for the timing train, where the four camshafts are housed, and a left cavity for the three row primary drive chain.[8] A row of four camshafts had also been used on the KR racers, inherited from the sidevalve Model WL, and even earlier Model D of 1929.[10] While the single camshaft of other Harley-Davidson designs was cheaper to manufacture, and quieter, four cams allowed better performance, such as greater flexibility in adjusting the cam timing, and the short single camshafts are durable, and give the pushrods a straighter path to the rocker arms.[11]
Yet to address the fact that the Evo got Alloy Jugs... Shovelheads already had Alloy Heads..But the valve configuration was Unchanged.. Therefore... Evo, Must be a Shovelhead!!!
The closest thing a Sportster ever got to an XR...was Unitized Tranny...with two rear heads (the Ron Trock SR. X-Head... which is decidedly Not what the XR got..
Easier to turn yer Shovel into an Evo, than to turn yer Sportster into an XR
So... by that logic... All H-D's are the Same!!!
The first XR750 was Sportster-based, right down to the cast iron heads and cylinders with single carb manifold and all. AKA the Waffle Iron on account of how hot it ran.
The engine was straight from the XLR 900 racing model Sportster, cut down to 750cc.
Yet to address the fact that the Evo got Alloy Jugs... Shovelheads already had Alloy Heads..But the valve configuration was Unchanged.. Therefore... Evo, Must be a Shovelhead!!!
The closest thing a Sportster ever got to an XR...was Unitized Tranny...with two rear heads (the Ron Trock SR. X-Head... which is decidedly Not what the XR got..
Easier to turn yer Shovel into an Evo, than to turn yer Sportster into an XR
So... by that logic... All H-D's are the Same!!!
I sold my Sportster and bought a Dyna . The proud new owner of my Sportster is a girl . So there it is , irrefutable proof that I used to own a girl's bike .
Just joking . A Sportster is anybody's bike who is prepared to take it on . Compared to modern Japanese bikes it is brutally basic particularly in the suspension department . It takes time and patience to coax the best performance out of the engine and some degree of mechanical empathy before you master the art of being in the right gear at the right time . The bike makes a fearsome racket with anything but stock pipes and the whole thing wobbles and quakes like a broken washing machine . You've got to stop to put fuel in it every 90 miles or so but that's ok because your **** will have gone square from sitting on a seat like a plank . So there it is , if that sounds like a girl's bike to you , just go on repeating that tired old mantra again and again etc .....
Hey ! I thought that was an honest and reasonably well written contribution to this discussion . Does anyone read anything I write ?
This is my BITCH Sportster and my Girly Girly - Bitch: Trixie Hells Bells. Looking down her nose at everyone because no one is good enough for her. If you care to argue she's not prejudice she hates and will bite anyone. MY bitch will bite the hand that feeds her if provoked enough. She at least tolerates me.
I have a Dyna Wide Glide but the older I get the more comfortable I am on my Sportster. I have nothing to prove, especially to anyone who rides a Honda.
Why do you think they call them bitches?
10-15-2022, 12:23 PM
