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| techtalk:ref:xmodels11 [2025/07/02 14:38] – hippysmack | techtalk:ref:xmodels11 [2025/07/03 03:56] (current) – [1972 XR-750] hippysmack |
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| ====== REF: Extra Models11 ====== | ====== REF: Extra Models11 ====== |
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| ====== XR-750 Engine Mechanicals – Top & Bottom End ====== | ====== XR-750 Engine Mechanicals – Top & Bottom End ====== |
| ===== 1972 Specs / Features ===== | |
| New redeigned 750cc engine with aluminum cylinders and heads. Also had new valves, pistons, rods, flywheel assm, "E" cams, carbs and tuned exhaust, 7/8" dia handlebars with an aluminum ball end clutch lever and a fiberglass seat/fender with with a foam cushion. | ====== Engine Case Pics ====== |
| * Engine Type: OHV V-Twin | ===== 1972 XR-750 ===== |
| * Carburetion: Dual 36mm Mikuni carburetors and specially designed air filters | This is a set of XR cases from Dr Dick of the XLFORUM. \\ |
| * Exhaust System: Tuned duals with reverse-cone megaphones | |
| * Bore and Stroke: 3.125" x 2.983" | {{:techtalk:ref:engmech:1972_xr-750_engine_cases_pic1_by_dr_dick.jpg?direct&400|}} ((photo by Dr Dick of the XLFORUM)) \\ |
| * Displacement: 45cu, 750cc | |
| * Compression Ratio: 10:1 | {{:techtalk:ref:engmech:1972_xr-750_engine_cases_pic2_by_dr_dick.jpg?direct&400|}} ((photo by Dr Dick of the XLFORUM)) {{:techtalk:ref:engmech:1972_xr-750_engine_cases_pic3_by_dr_dick.jpg?direct&400|}} ((photo by Dr Dick of the XLFORUM)) \\ |
| * Max RPM: 8000 | |
| * Clutch Type: Multi-plate dry clutch | {{:techtalk:ref:engmech:1972_xr-750_engine_cases_pic4_by_dr_dick.jpg?direct&400|}} ((photo by Dr Dick of the XLFORUM)) {{:techtalk:ref:engmech:1972_xr-750_engine_cases_pic5_by_dr_dick.jpg?direct&400|}} ((photo by Dr Dick of the XLFORUM)) \\ |
| * Primary Drive: 25 tooth engine sprocket, 59 tooth clutch, triple row roller chain | |
| * Rear Drive: 16 tooth transmission sprocket, 40 tooth rear wheel sprocket | {{:techtalk:ref:engmech:1972_xr-750_engine_cases_pic6_by_dr_dick.jpg?direct&400|}} ((photo by Dr Dick of the XLFORUM)) {{:techtalk:ref:engmech:1972_xr-750_engine_cases_pic7_by_dr_dick.jpg?direct&400|}} ((photo by Dr Dick of the XLFORUM)) \\ |
| * Overall Drive Ratio: 5.90:1 | |
| * Transmission: Constant Mesh, 4 speed | ===== 1975 XR-750 ===== |
| * Transmission Gear Ratios: | This is a set of XR cases from mofosheee of the XLFORUM. \\ |
| * 1st 2.09:1 | |
| * 2nd 1.51:1 | {{:techtalk:ref:engmech:1975_xr-750_pic1_by_mofosheee.jpg?direct&400|}} ((photo by mofosheee of the XLFORUM)) {{:techtalk:ref:engmech:1975_xr-750_pic2_by_mofosheee.jpg?direct&400|}} ((photo by mofosheee of the XLFORUM)) \\ |
| * 3rd 1.14:1 | |
| * 4th 1:1 | {{:techtalk:ref:engmech:1975_xr-750_pic3_by_mofosheee.jpg?direct&400|}} ((photo by mofosheee of the XLFORUM)) {{:techtalk:ref:engmech:1975_xr-750_pic4_by_mofosheee.jpg?direct&400|}} ((photo by mofosheee of the XLFORUM)) \\ |
| * Weight: 295 lbs | |
| * Tires (front and rear): 4.0 x 19 on aluminum rims | {{:techtalk:ref:engmech:1975_xr-750_pic5_by_mofosheee.jpg?direct&400|}} ((photo by mofosheee of the XLFORUM)) {{:techtalk:ref:engmech:1975_xr-750_pic6_by_mofosheee.jpg?direct&400|}} ((photo by mofosheee of the XLFORUM)) \\ |
| * Front Forks: Ceriani with 4.40” travel and aluminum fork bracket | |
| * Rear Shocks: Girling hydraulic racing shocks | {{:techtalk:ref:engmech:1975_xr-750_pic7_by_mofosheee.jpg?direct&400|}} ((photo by mofosheee of the XLFORUM)) {{:techtalk:ref:engmech:1975_xr-750_pic8_by_mofosheee.jpg?direct&400|}} ((photo by mofosheee of the XLFORUM)) \\ |
| * Gas Tank: Fiberglass construction with 2-1/2 gallon capacity | |
| * Oil Tank: 3 quarts | {{:techtalk:ref:engmech:1975_xr-750_pic9_by_mofosheee.jpg?direct&400|}} ((photo by mofosheee of the XLFORUM)) {{:techtalk:ref:engmech:1975_xr-750_pic10_by_mofosheee.jpg?direct&400|}} ((photo by mofosheee of the XLFORUM)) \\ |
| * Electrical: Fairbanks-Morse magneto | |
| * Color: Jet Fire Orange | {{:techtalk:ref:engmech:1975_xr-750_pic11_by_mofosheee.jpg?direct&400|}} ((photo by mofosheee of the XLFORUM)) {{:techtalk:ref:engmech:1975_xr-750_pic13_by_mofosheee.jpg?direct&400|}} ((photo by mofosheee of the XLFORUM)) \\ |
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