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techtalk:ih:engmech07 [2019/10/11 23:40] hippysmack [Breather Valve Alternatives] |
techtalk:ih:engmech07 [2019/12/04 00:51] hippysmack [76< Timed Breather Valve] |
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| Documents from HD Racing from the period show no HP gain between the 2 systems when the breather is properly timed ( which didn't happen a lot). \\ | Documents from HD Racing from the period show no HP gain between the 2 systems when the breather is properly timed ( which didn't happen a lot). \\ | ||
| ===== 76< Timed Breather Valve ===== | ===== 76< Timed Breather Valve ===== | ||
| + | ==== Sub Documents ==== | ||
| + | * [[techtalk:ih:engmech07a|Timing the Breather Valve]] | ||
| + | |||
| The rotary breather valve is timed to open on the downstroke of the pistons. ((1960 HD FSM pg 3a-15)) \\ | The rotary breather valve is timed to open on the downstroke of the pistons. ((1960 HD FSM pg 3a-15)) \\ | ||
| This allows crankcase exhaust air pressure to expel the scavenge oil from the crankcase breather oil trap into the gearcase. \\ | This allows crankcase exhaust air pressure to expel the scavenge oil from the crankcase breather oil trap into the gearcase. \\ | ||
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| |{{:techtalk:ih:engmech:cc_flow_6_by_dr_dick.jpg?direct&300|}}|{{:techtalk:ih:engmech:cc_flow_7_by_dr_dick.jpg?direct&300|}}|{{:techtalk:ih:engmech:cc_flow_8_by_dr_dick.jpg?direct&300|}}| | |{{:techtalk:ih:engmech:cc_flow_6_by_dr_dick.jpg?direct&300|}}|{{:techtalk:ih:engmech:cc_flow_7_by_dr_dick.jpg?direct&300|}}|{{:techtalk:ih:engmech:cc_flow_8_by_dr_dick.jpg?direct&300|}}| | ||
| + | \\ | ||
| + | There are only 3 rotor and tower slot widths for all 1937-76 4-cam engines (45, K, KH, XL, UL), which determine the complete breather timing interval. ((kitabel of the XLFORUM http://xlforum.net/forums/showthread.php?t=2073932&page=87)) \\ | ||
| + | - Rotor .375" (88°) + tower .34375" (81°) = 169°: \\ all non-R 1937-71 engines; the exact opening-closing points vary between engines; 1952-71 K &c. slots are taller than 45 & UL. | ||
| + | - Rotor .594" (146°) + tower .34375" (81°) = 227°: 1972-76 XL; these slots are also taller than 45 & UL. | ||
| + | - Rotor .214" (99°) + tower .269 (125°) = 224°: all 1954-? KR, KHR, XLR (many mods to this) | ||
| ===== 77-78 Breather Valve ===== | ===== 77-78 Breather Valve ===== | ||
