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| - | Both sides previous revisionPrevious revision |
| - | techtalk:ref:svcproc22 [2024/01/22 05:46] – hippysmack |
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| + | techtalk:ref:svcproc22 [2024/01/22 21:00] (current) – hippysmack |
| @@ Line -40,4 +40,5 @@ | |
| This works on the same principle as using your finger. \\ | |
| The whistle will begin blowing as compression builds in the cylinder. \\ | |
| ==== TDC: Compression Stroke vs Exhaust Stroke of the Piston ==== | |
| In terms of the piston position, there' | |
| @@ Line -62,5 +63,5 @@ | |
| Finding True TDC is a little more tedious. \\ | |
| By using only a dial indicator on top of the piston, the point where the indicator falls off it's high point will be different. \\ (depending on which direction you rotate the engine to find the high point). ((rivethog of the XLFORUM | |
| There will be a few degrees of interpretation before the piston rolls back down. \\ | |
| @@ Line -70,5 +71,6 @@ | |
| |{{: | |
| |For Ironhead and Shovelhead cylinders, \\ pull the head and install the indicator. ((photo by billeuze of the XLFORUM | |
| ===== Find True TDC Using a Dial Indicator and a Degree Wheel ===== | |
| The dial indicator and the degree wheel are used in unison. \\ | |
| @@ Line -76,5 +78,4 @@ | |
| The degree wheel will reflect the degree on each side of the highest point. \\ | |
| Then you calculate the middle of these two points to reach True TDC. | |
| - **Remove both spark plugs**: (or one on each cylinder for dual plug heads). | |
| @@ Line -99,5 +100,4 @@ | |
| * Turn the engine backwards however many degrees of the resulting number to True TDC. \\ (it's best to count the degree marks first, then double check your counting and then make a mark on the wheel before trying to count them as you turn the wheel) | |
| * Re-set the degree wheel to " | |
| ===== Find True TDC Using a Piston Stop and a Degree Wheel ===== | |
| @@ Line -119,5 +119,5 @@ | |
| * Rotate the engine so the piston is well below the top of the cylinder. | |
| * Screw a piston stop tool in the spark plug hole. | |
| * Screw the middle bolt of the tool down just past where you think the piston will be when it's at the top of the cylinder. \\ {{: | |
| * __With the head off__: | |
| * You can make a piston stop with a thick plate or metal strap bolted across the open end of the cylinder using 2 opposite head bolt holes. | |
| @@ Line -127,5 +127,5 @@ | |
| * With the head off, the rings will grab the cylinder and pull it up and out of the case with the piston. | |
| * The 2 long head bolts would need to be installed in the remaining 2 head bolt holes with a PVC fitting as a sleeve or other to hold the cylinder in place. | |
| * If using domed pistons, the middle bolt may not be necessary in the plate / strap if the dome extends past the top of the cylinder deck. ((piniongear of the XLFORUM | |
| * The dome will stop the piston when it touches the plate. | |
| - **Find the pre-TDC hash mark on the degree wheel**: | |
| @@ Line -145,10 +145,11 @@ | |
| - **Re-set the degree wheel** to " | |
| {{: | |
| ====== Finding / Verifying TDC on Compression Stroke ====== | |
| ===== Find TDC (compression) Using the Rocker Arms as a Visual ===== | |
| You can tell the [[techtalk: | |
| However, you must look at the valve train __movement__ to be able to tell the difference. \\ | |
| And just as importantly, | |
| * There are (almost) no visible differences in the position of the valvetrain when you're at compression TDC as opposed to overlap TDC. | |
| @@ Line -158,5 +159,5 @@ | |
| * On the exhaust stroke pass through TDC, both valves are slightly open and both their corresponding rocker arms are slightly raised). | |
| * Just by looking at the rockers sitting still with the piston at TDC, it's hard to tell if they are both down or both slightly raised. ((aswracing of the XLFORUM | |
| * It's an easy mistake to make and a very unreliable way to tell the TDC's apart. | |
| * It's also been the cause incorrect pushrod adjustments. | |
| @@ Line -173,10 +174,10 @@ | |
| * This will most likely shake the bike some so you'll have to watch the rockers carefully. | |
| * With the transmission in neutral, rotate the crank shaft or pinion shaft with a wrench. \\ (no compression to put undue stress on the pinion shaft) | |
| - **Rotate the engine through the intake cycle**: ((aswracing of the XLFORUM | |
| * Watch the pushrod end of the intake rocker arm as you're rotating the engine forward. | |
| * You'll see the intake rocker move up and open the valve. | |
| * Then you'll see the rocker lower and close the intake valve. | |
| * Now stop. | |
| - **Anticipate to stop at the nearest TDC from here while rotating the engine forward**: ((aswracing of the XLFORUM | |
| * This will be your ending point of rotation at [[techtalk: | |
| * You can [[techtalk: | |
| @@ Line -189,11 +190,9 @@ | |
| * Spinning the wheel by yourself, although do-able, can distract your focus on the rockers plus the bike shakes quite a bit making it hard to see movement. | |
| * If you can't see the rockers move while you're turning the rear wheel, you can have a helper turn the wheel. | |
| * If your arm-span will permit, it is possible to put a flat-bladed screwdriver through the timing hole with one hand (flat and lightly against the flywheel), \\ rotate the rear wheel with the other and you can feel and catch the single line mark as it passes the timing hole as you are watching the rockers. ((Mosey of the XLFORUM | |
| * If you can't physically see the rockers moving, you can put a finger tip on the end of each rocker pair and feel them move. | |
| * When you are at TDC (compression) and rotate the engine forward from there, the exhaust valve (and rocker) are the first to move. Then the intake. ((Hippysmack of the XLFORUM | |
| ==== Another Visual ==== | |
| - Rotate the engine to stop on (any) TDC. | |
| * Then turn the engine (slowly) back and forth a 1/4 turn or so passing thru that TDC on both sides. | |
| @@ Line -237,5 +236,5 @@ | |
| * You can use [[techtalk: | |
| * You can also use a [[techtalk: | |
| * The window in time where both valves are completely closed begins on the compression stroke, with the closing of the intake valve. ((aswracing of the XLFORUM | |
| * Both valves stay closed through the rest of the compression stroke, and then most of the following power stroke, at which point the exhaust valve opens. | |
| * Compression TDC sits just about half way in between those two events. | |
| @@ Line -245,5 +244,5 @@ | |
| * This will be your ending point of rotation at [[techtalk: | |
| | This can be removed with a 3/8" Allen hex wrench ((photos by Phillober of the XLFORUM | |
| |{{techtalk: | |
| @@ Line -251,10 +250,9 @@ | |
| * While installing the plug, set it in the hole and turn it backwards until you feel thread engagement before attempting to use any force to turn it into the hole. \\ You should be able to install it by hand as mentioned above to snug. Do not over-torque. \\ See also [[techtalk: | |
| | When you take out the timing plug, \\ this is more than likely what you see ((photo by Phillober of the XLFORUM | |
| |{{techtalk: | |
| ===== Find TDC (compression) with the Rocker Box Off - Cams In ===== | |
| Without the valves going up and down, the cylinder will simply push out air on both [[techtalk: | |
| It's the action of the valves that reduces that to just the compression stroke. \\ | |
| @@ Line -317,7 +315,4 @@ | |
| * For more assurance, you can roll the engine backwards and forwards from here to verify the piston rise and fall on each side of the dwell. | |
| * Pick a spot in the middle of this range and you're done. | |
| |Straw in plug hole for single or dual plug heads ((photo by Hippysmack))|Alternative location with dual plug heads \\ (better location, less binding of the straw). ((photo by Hippysmack))| | |
| @@ Line -327,5 +322,5 @@ | |
| Basically, you just plug the hole with their finger and wait for pressure to blow past it. \\ | |
| There is a distinct difference you can feel between the 2 TDCs from your finger. \\ | |
| The only drawback using this method is that it only works when disassembling. ((aswracing of the XLFORUM | |
| (or rather only works if the pushrods are installed) \\ | |
| It doesn' | |
| @@ Line -355,5 +350,5 @@ | |
| * You'll here the compression building the more you rotate the engine. | |
| * Once the pressure blows past your finger, the piston has risen toward to the top of the bore on the compression stroke. | |
| * Press as hard as you want on the hole, the pressure will be stronger than you as it builds. ((Hippysmack of the XLFORUM | |
| * You may need to roll the engine over several times until you have a good feel of air being forced out of the hole. | |
| * Be careful not to rotate the engine past this TDC. | |
| @@ Line -365,8 +360,6 @@ | |
| * This will be your ending point of rotation at [[techtalk: | |
| | Using the " | |
| |{{techtalk: | |
| ===== Find Compression Using a TDC Whistle ===== | |
| @@ Line -407,4 +400,5 @@ | |
| |{{: | |
| | 14 mm and 12 mm TDC whistles ((photo by Hippysmack)) | |
| ===== Confirming Which TDC You're On Using the Timing (rotor) Cup ===== | |
| It is possible to confirm whether the piston is on [[techtalk: | |
| @@ Line -414,5 +408,5 @@ | |
| Therefore, the cams turn 1/2 the times of the crank. \\ | |
| The rotor cup needs 720° rotation of the crankshaft to a complete 1 revolution. ((conv90 of the XLFORUM | |
| \\ | |
| 360° + 360° = 720° \\ | |
| @@ Line -420,6 +414,4 @@ | |
| So, the rotor position on TDC (compression) and TDC on (exhaust) strokes will be different. \\ | |
| - **Rotate the crankshaft to position the piston to TDC by which ever method available**: | |
| @@ Line -428,5 +420,5 @@ | |
| * Find TDC using a dial indicator and a degree wheel. | |
| * Use a drinking straw through the spark plug hole and it will stop rising when the piston is at TDC. | |
| - **Decide which stroke your at by inspecting the position of the timing rotor cup**: ((conv90 of the XLFORUM | |
| * Let's say the first rotation stopped with the TDC mark in the observation hole at [[techtalk: | |
| * When looking at the notch in the center of the rotor, you'll see it is pointing up to the left. | |
| @@ Line -435,5 +427,4 @@ | |
| * The #2 cam slot is now pointing down to the right. (180° compared to the position when you were at TDC compression). | |
| * To return at TDC compression, | |
| Click on a pic to enlarge: | |
| @@ Line -458,7 +449,7 @@ | |
| * Try letting the clutch out between gears while rotating the rear wheel. | |
| * You can also see if your transmission will upshift without letting the clutch out, | |
| * You can use a Velcro strap as an assist to hold the clutch lever in while turning the rear wheel by hand. ((Shadowdog500 of the XLFORUM | |
| * Remove the strap when your in high gear (4th or 5th respectively). | |
| * If you don’t have a jack or center-stand handy, you could just push the bike in (high gear) ((Shadowdog500 of the XLFORUM | |
| * On a 5-speed transmission, | |
