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| techtalk:ref:svcproc20 [2024/01/21 23:17] – hippysmack | techtalk:ref:svcproc20 [2024/01/22 05:24] (current) – hippysmack |
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| ====== Test Each Cylinder for Compression ====== | ====== Test Each Cylinder for Compression ====== |
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| - Ride the bike to get the engine up to operating temperature. ((IronMick of the XLFORUM http://xlforum.net/forums/showthread.php?t=48311)) | - Ride the bike to get the engine up to operating temperature. ((IronMick of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/29105-cylinder-compression-and-leakage-tests-for-your-ironhead?t=48311)) |
| - Disconnect the power to the coil to prevent it from firing. | - Disconnect the power to the coil to prevent it from firing. |
| * The extra two plugs (on dual plug heads) need to remain in place during this test. ((IXL2Relax of the XLFORUM http://xlforum.net/forums/showthread.php?t=2005378)) | * The extra two plugs (on dual plug heads) need to remain in place during this test. ((IXL2Relax of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/frame-mount-evo-sportster-talk-1986-2003-models/188118-compression-test-1200s?t=2005378)) |
| * If you can't disconnect power to the coil, ground out all the plug wires. | * If you can't disconnect power to the coil, ground out all the plug wires. |
| - Clean the area around the spark plugs __BEFORE__ you remove them. ((79-85 HD XL/XR FSM pg 3-10)) | - Clean the area around the spark plugs __BEFORE__ you remove them. ((79-85 HD XL/XR FSM pg 3-10)) |
| * If you haven't disconnected the coil, you can insert the plugs into the plug wires and press the plugs against the cylinder heads for grounding. ((IronMick of the XLFORUM http://xlforum.net/forums/showthread.php?t=48311)) | * If you haven't disconnected the coil, you can insert the plugs into the plug wires and press the plugs against the cylinder heads for grounding. ((IronMick of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/29105-cylinder-compression-and-leakage-tests-for-your-ironhead?t=48311)) |
| - Connect the compression gauge to the first cylinder. | - Connect the compression gauge to the first cylinder. |
| - Make sure the **throttle plate is fully open** (and the choke, if present) before turning over the engine. | - Make sure the **throttle plate is fully open** (and the choke, if present) before turning over the engine. |
| * If using a CV carb, **hold the slide up.** ((aswracing http://xlforum.net/forums/showthread.php?t=26208&page=2)) | * If using a CV carb, **hold the slide up.** ((aswracing https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-motor-top-end/15672-four-strokes-and-leak-down-compression-tests-how-they-work/page2?t=26208&page=2)) |
| * If the cylinder can't freely pull in air, the compression reading will be low. | * If the cylinder can't freely pull in air, the compression reading will be low. |
| * **Do NOT pull the enrichener knob** - The enrichener is mis-named a choke ('86-'06) but it is not a choke plate. | * **Do NOT pull the enrichener knob** - The enrichener is mis-named a choke ('86-'06) but it is not a choke plate. |
| - Crank the engine continuously through 5-7 compression strokes. (until there is no further increase in reading at the gauge) ((IronMick of the XLFORUM http://xlforum.net/forums/showthread.php?t=48311)) | - Crank the engine continuously through 5-7 compression strokes. (until there is no further increase in reading at the gauge) ((IronMick of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/29105-cylinder-compression-and-leakage-tests-for-your-ironhead?t=48311)) |
| - Record the readings at the end of the first and last strokes for this cylinder. | - Record the readings at the end of the first and last strokes for this cylinder. |
| - If you get a lower than normal reading, add app. 1/2 ounce of oil into the cylinder, repeat the compression test to see if the reading will increase. Record the oil-added readings. | - If you get a lower than normal reading, add app. 1/2 ounce of oil into the cylinder, repeat the compression test to see if the reading will increase. Record the oil-added readings. |
| - Repeat for the second cylinder. | - Repeat for the second cylinder. |
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| {{techtalk:ref:svcproc:checking_compression_1_by_mathormell.jpg?direct&300|}} ((photo by MatHormell of the XLFORUM http://xlforum.net/forums/showthread.php?t=1976997&page=71)) {{techtalk:ref:svcproc:checking_compression_2_by_mathormell.jpg?direct&300|}} ((photo by MatHormell of the XLFORUM http://xlforum.net/forums/showthread.php?t=1976997&page=71)) | {{techtalk:ref:svcproc:checking_compression_1_by_mathormell.jpg?direct&300|}} ((photo by MatHormell of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-engine-conversions/183888-hammerperf-90-in-the-works/page71?t=1976997&page=71)) {{techtalk:ref:svcproc:checking_compression_2_by_mathormell.jpg?direct&300|}} ((photo by MatHormell of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-engine-conversions/183888-hammerperf-90-in-the-works/page71?t=1976997&page=71)) |
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| ====== Interpreting the Readings ====== | ====== Interpreting the Readings ====== |
| | Notes: The recorded results between the two cylinders should be within 10psi of each other.\\ PSI expectations are from HD manuals. ||||| | | Notes: The recorded results between the two cylinders should be within 10psi of each other.\\ PSI expectations are from HD manuals. ||||| |
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| | * Also, pay attention to how many pumps it takes to pump up each cylinder. ((wedge of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/134966-compression-test/page2?t=1457327&page=2)) Both cylinders should be relatively comparable. |
| * Also, pay attention to how many pumps it takes to pump up each cylinder. ((wedge of the XLFORUM http://xlforum.net/forums/showthread.php?t=1457327&page=2)) Both cylinders should be relatively comparable. | |
| * Pumping up too fast means the exhaust isn't opening (pushrod worn too much or loose enough to fall out of place). | * Pumping up too fast means the exhaust isn't opening (pushrod worn too much or loose enough to fall out of place). |
| * Pumping up too slow is the usual suspect list below: | * Pumping up too slow is the usual suspect list below: |
| **Possible Cause**: \\ | **Possible Cause**: \\ |
| Piston ring gap too tight upon installation. ((Jörgen)) \\ | Piston ring gap too tight upon installation. ((Jörgen)) \\ |
| **Full Article**: http://xlforum.net/forums/showthread.php?t=1567509 \\ | **Full Article**: https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-bottom-end/144544-white-smoke-from-pipe-and-ac-rattle-in-engine?t=1567509 \\ |
| **Pics of the Damage**: ((Photos by sep69 of the XLFORUM http://xlforum.net/forums/showthread.php?t=1567509&page=2)) | **Pics of the Damage**: ((Photos by sep69 of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-bottom-end/144544-white-smoke-from-pipe-and-ac-rattle-in-engine/page2?t=1567509&page=2)) |
| |{{techtalk:ref:svcproc:piston_damage_1_by_sep69.jpg?direct&300|}}|{{techtalk:ref:svcproc:piston_damage_2_by_sep69.jpg?direct&300|}}|{{techtalk:ref:svcproc:piston_damage_3_by_sep69.jpg?direct&300|}}| \\ | |{{techtalk:ref:svcproc:piston_damage_1_by_sep69.jpg?direct&300|}}|{{techtalk:ref:svcproc:piston_damage_2_by_sep69.jpg?direct&300|}}|{{techtalk:ref:svcproc:piston_damage_3_by_sep69.jpg?direct&300|}}| \\ |
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| ====== Compression Calculator ====== | ====== Compression Calculator ====== |
| Article by aswracing of the XLFORUM ((http://xlforum.net/forums/showthread.php?t=1441757)) and Hammer Performance site. (( http://hammerperf.com/ttcompression.shtml)) \\ | Article by aswracing of the XLFORUM ((https://www.xlforum.net/forum/vendors/hammer-performance/133947-max-compression?t=1441757)) and Hammer Performance site. (( http://hammerperf.com/ttcompression.shtml)) \\ |
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| [[http://hammerperf.com/ttcompression.shtml|Click here to download a free copy of the HAMMER PERFORMANCE Compression Calculator]]. \\ | [[http://hammerperf.com/ttcompression.shtml|Click here to download a free copy of the HAMMER PERFORMANCE Compression Calculator]]. \\ |
| HAMMER PERFORMANCE assumes no responsibility for what you do with the information presented. \\ | HAMMER PERFORMANCE assumes no responsibility for what you do with the information presented. \\ |
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| {{:techtalk:ref:svcproc:compression_calculator_screeenshot_1_by_aswracing.jpg?direct&400|}} ((screenshot by aswracing of the XLFORUM http://xlforum.net/forums/showthread.php?t=1441757)) {{:techtalk:ref:svcproc:compression_calculator_screeenshot_2_by_aswracing.jpg?direct&400|}} ((screenshot by aswracing of the XLFORUM http://xlforum.net/forums/showthread.php?t=1441757)) \\ | {{:techtalk:ref:svcproc:compression_calculator_screeenshot_1_by_aswracing.jpg?direct&400|}} ((screenshot by aswracing of the XLFORUM https://www.xlforum.net/forum/vendors/hammer-performance/133947-max-compression?t=1441757)) {{:techtalk:ref:svcproc:compression_calculator_screeenshot_2_by_aswracing.jpg?direct&400|}} ((screenshot by aswracing of the XLFORUM https://www.xlforum.net/forum/vendors/hammer-performance/133947-max-compression?t=1441757)) \\ |
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