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techtalk:ref:engmech04 [2020/02/11 03:51]
hippysmack [Sub Documents]
techtalk:ref:engmech04 [2020/09/21 21:11] (current)
hippysmack [Sub Documents]
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 **Cruise** (low load test): Typical RPM most riding takes place in (2500-3000 RPM). \\ **Cruise** (low load test): Typical RPM most riding takes place in (2500-3000 RPM). \\
  
-===== Testing with a Slack Tube by bustert =====+===== Testing with a Slack Tube (Manometer) ​by bustert =====
 ==== Sub Documents ==== ==== Sub Documents ====
   * [[techtalk:​ref:​engmech04e|Building Your Own Slack Tube]]   * [[techtalk:​ref:​engmech04e|Building Your Own Slack Tube]]
-  * [[techtalk:​ref:​engmech04f|Using / Diagnosing with a Manometer ​Slack Tube]]+  * [[techtalk:​ref:​genmsr04#​using_diagnosing_with_a_slack_tube_manometer|Using / Diagnosing with a Slack Tube (Manometer)]]
   * [[techtalk:​ref:​engmech04g|Slack tube testing on a 1998 1250S model]]   * [[techtalk:​ref:​engmech04g|Slack tube testing on a 1998 1250S model]]
  
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 Other factors are involved so results will vary. \\ Other factors are involved so results will vary. \\
 ===== Why Oil Pukes Out the Air Cleaner ===== ===== Why Oil Pukes Out the Air Cleaner =====
-Wet sumping is a term usually used when oil spits out the breather vent / air cleaner. ((Hippysmack of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​p=5757523#​post5757523)) \\ +Wet sumping is a term usually used when oil spits out the breather vent / air cleaner. ((Hippysmack of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​p=5757523#​post5757523)) \\  
-However, engine breathing and wet sumping are two different ideas. But they are tied together as much as air and water. \\ +However, engine breathing and wet sumping are two different ideas. But they are tied together as much as air and water. \\ See [[techtalk:​ref:​engmech04#​wetsumping|Wet Sumping]] below. \\ 
-See [[techtalk:​ref:​engmech04#​wetsumping|Wet Sumping]] below. \\+Oil puking and oil seepage out the air cleaner are different conditions. \\ 
 +You'll know it if it pukes as there will be a good puddle of oil on the shop floor or gobs of oil running rearward of the A/C all over the bike. \\ 
 +Oil seepage (or the oil filter getting saturated with oil over time) may be perfectly normal. \\
  
 The real reason these things like to spit oil out the breather is because they'​re a common crankpin 45° design. ((aswracing of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​p=110375&​highlight=variable+volume#​post110375)) \\ The real reason these things like to spit oil out the breather is because they'​re a common crankpin 45° design. ((aswracing of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​p=110375&​highlight=variable+volume#​post110375)) \\
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 ===== Aftermarket Breathers / PCV Valves ===== ===== Aftermarket Breathers / PCV Valves =====
-==== Sub Documents ==== 
-  * [[techtalk:​ref:​engmech04a|Dissecting the Hayden KVP38 Crankcase Breather Valve]] ​ 
- 
-There is a product called a Krankvent that can be plumbed into the lower, 6 o’clock position as an alternative to a stock foo-foo valve. ((Hopper of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=518948&​highlight=cam+chest+breather)) \\ 
-But they are not cheap. Automotive PCV valves are not really made to handle the revs or air volumes of a Harley. \\ 
-While a car engine is bigger, it has one piston coming down while one goes up. \\ 
-So there'​s not much change in internal crankcase volume, so not as much breathing to be done. \\ 
-A Harley has two pistons and rods on one crankpin, so is one giant air compressor. \\ 
- 
-Some guys have found that plumbing in a 77-78 foo-foo valve on the later model engines improves breathing. \\  
- 
-**Finding a better breather valve**: ((bunny32 of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=15705&​page=2)) \\ 
-The breather valves that work best on crankcase breathers have several features: \\ 
-  * Low-inertia,​ i.e. they don't take more than a breath to open and close. 
-  * They operate at low pressures ~1-30psi. 
-  * They preferably have a floating type seal. 
-  * They should be transparent,​ so you can see if they block up with blowby, solids, bugs etc. 
-  * They should be easy to open and clean occasionally. 
-  * They should push-fit into your breather line. 
- 
-Metal diaphragm valves with e.g. springs are hopeless. \\ 
-Also avoid other types of valves designed to work at high pressures e.g. plumbing valves. \\ 
-Avoid car PCV valves as they are metering as well as non-return valves and are unsuitable. \\ 
-Automotive PCV valves are designed to let some air back in. \\ 
-The ball and spring valves will not be able to work fast enough to keep all the air out. \\ 
-When air is allowed to be drawn back into the engine, it creates a mass that must be compressed by the pistons on downstroke as it is being vented out. \\ 
-This robs some power and will cause the engine to work harder (creating more internal heat at higher RPM). ((Deimus of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=67658&​page=18)) \\ 
- 
-Aftermarket PCV's: ((electronbee of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=72099&​highlight=reed+valve&​page=10)) \\ 
-  * Mercedes Benz P/N# 271-018-00-29 ~$13. 
-    * Reed type PCV valve. Fast acting. Used for their C 230 Kompressor engine. 
-    * Dims: 2-1/2" long by 1-1/8" with an I.D of 1/​4"​. ​ 
-  * McCaster Carr P/N# 4610K17 ~$6. 
-    * Umbrella valve. Vacuum check valve. 
-  * Autozone P/N# PCV1174 (PV272) ~$5. 
-  * Ball/spring based PCV valve. 
-    * Makes a clicking noise during operation. 
- 
-|  Here is a 2-stroke reed valve. ((photo by norseXL of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1386341&​highlight=reed)) ​ | 
-|{{:​techtalk:​ref:​engmech:​reed_valve_by_norsexl.jpg?​direct&​300|}}| 
- 
-|  Mercedes Benz P/N# 271-018-00-29 ((photo by electronbee of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=72099&​highlight=reed+valve&​page=10)) ​ |  Reed Valve ((photo by Bluto of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​p=5761290#​post5761290)) ​ |  Doherty Power Vent ((Photo by goblin_dust of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=72099&​highlight=wet+sumping&​page=23)) ​ | 
-|{{:​techtalk:​ref:​engmech:​mercedes_benz_pcv_valve_by_electronbee.jpg?​direct&​300|}}|{{:​techtalk:​ref:​engmech:​reed_valve_by_bluto.jpg?​direct&​300|}}|{{:​techtalk:​ref:​engmech:​deimus_mod_2_by_goblin_dust.jpg?​direct&​300|}}| 
  
 ==== Regarding horsepower gains from different breathers ==== ==== Regarding horsepower gains from different breathers ====
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   * Now add a vacuum pump with Z (-1) amount of pull. \\ Now you get X+1=Y-Z... seems the balance (to zero) is restored even though positive pressure is compiled of blowby. \\ But the lower the negative pressure is at the beginning of the downstroke, the lower the next positive pressure will be.   * Now add a vacuum pump with Z (-1) amount of pull. \\ Now you get X+1=Y-Z... seems the balance (to zero) is restored even though positive pressure is compiled of blowby. \\ But the lower the negative pressure is at the beginning of the downstroke, the lower the next positive pressure will be.
   * If you are generating 2 psi of positive pressure on downstroke but reduce it's beginning surge to -1 psi (Z), \\ the result will be only 1 psi of positive pressure during downstroke. \\ -1 (+) + 2 equals +1.   * If you are generating 2 psi of positive pressure on downstroke but reduce it's beginning surge to -1 psi (Z), \\ the result will be only 1 psi of positive pressure during downstroke. \\ -1 (+) + 2 equals +1.
 +
 +Another example:
 +{{:​techtalk:​ref:​engmech:​crankcase_pressure_cycle_by_hippysmack.png?​direct&​400|}} ((drawing by Hippysmack)) \\