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Failed Sportster Prototype

PostPosted: Tue Jul 16, 2019 11:45 pm
by MTaylor
Help me out. I'm trying to find something on the failed Sportster prototype Harley built in the 50s. I've read at least one article on it before, but I can't figure out a search criteria to find the article or one like it again. Here's what I remember. In the mid-fifties, Harley developed a high performance bike meant to replace the K model. The project was eventually abandoned, and a less radical design--the Sportster we all know and love--was pursued. If you have a reference or more complete knowledge, let me know.

Re: Failed Sportster Prototype

PostPosted: Wed Jul 17, 2019 8:43 am
by hennesse
Do you mean the KL ?

kl-800x492.jpg
kl-800x492.jpg (91.92 KiB) Viewed 2139 times

Re: Failed Sportster Prototype

PostPosted: Wed Jul 17, 2019 8:56 am
by wz507

Re: Failed Sportster Prototype

PostPosted: Wed Jul 17, 2019 3:43 pm
by MTaylor
Thanks guys.

Re: Failed Sportster Prototype

PostPosted: Wed Jul 17, 2019 4:10 pm
by mikeslemmon
the KL was a 60 degree, high cam 45 cu. in. dual carb. ( direct to head), engine with aluminum heads and barrels. developed in the late 40's and early 50's . it's nick name was the "high cam K" in the mid "60s the factory said it over heated so they had to return to a 45 degree 45 cu. in. flat head. it's real problem was racing, it was 45 cu.in. and over head valves , too big for class c ama sanctioned dirt track, and road racing. the only legal ama racing would be TT.

Re: Failed rrSportster Prototype

PostPosted: Thu Jul 18, 2019 2:50 am
by EKHKHK56
Yes, because rules were 500cc OHV or 750cc SideValve.

Re: Failed Sportster Prototype

PostPosted: Thu Jul 18, 2019 3:28 am
by EKHKHK56
Amazingly against the onslaught of 2, 3, 4 cylinder OHC machines the KR prevailed through 1968, 1969 winning Daytona both years with a 40 year old design blueprint. Cal Rayborn set the First over 100mph average in 68. In 69 he lapped the Field. #FlatheadPower

Re: Failed Sportster Prototype

PostPosted: Thu Jul 18, 2019 8:05 pm
by hayleyl
And also remember, OHV 500cc engines had to run lower compression and were not allowed to burn methanol. AMA rules were obviously tilted towards US manufacturers. One of the factors for the KR longevity. While all K series machines are beautiful things, I don't see any Grand Prix trophies against G50 Matchlesses or Manx Nortons or Gileras or MV Augustas for any KR's. Just giving a global comparison that's all. Cheers Hayley.

Re: Failed Sportster Prototype

PostPosted: Thu Jul 18, 2019 9:33 pm
by hugoct
No one has ever been allowed to burn methanol in US Class C racing nor were the racers in Europe which was a "World Championship" in name only. The G50s and Manx SOHC bikes competed in the US and were competitive but were no better than the US tuned BSA Goldstars and Triumph 500s which won Daytona 3 times.The AMA rules for Class C racing were designed to be an everyman series not an exclusive "Factory Team" series as was run in Europe. The series began in 1933 and was an equivalancy formula of 500cc overhead valve engines of which there were very few and 750cc side valve engines which were the most popular bike in the US. As of 1951 there was a minimum number available requirement and a claiming rule which kept out the factory unobtainium for many years. The formula worked. Many people raced and unlike European races many of our National Championship races were won by privateers running home tuned bikes. It was a Golden Age which we are unlikely to ever see again. I'm just glad I got to race at the highest levels when it was still available to the average guy.