Differences

This shows you the differences between two versions of the page.

--- techtalk:ih:engmech02 [2021/08/07 08:09]
hippysmack
+++ techtalk:ih:engmech02 [2023/04/17 21:44]
hippysmack [1957-1976 gear]
@@ Line 120: / Line 120: @@
 ====== Pinion Gear ======
-\\
 **Compatibility**
 -1985 pinion gears have 18 teeth and splines to match the splined pinion shaft. \\
@@ Line 138: / Line 136: @@
 |24061-74 (black)|:::|
-**The 57-76 pinion gear needs to be a tight fit**. However, it's a common problem to find them loose on a used engine. ((Dr Dick of the XLFORUM http://xlforum.net/forums/showthread.php?t=1072235)) \\
+Click on any pic below to enlarge: \\
+|  1957-1976 Pinion Gear. ((photo courtesy of Ebay seller, Evil Genius M/C Parts. [[https://www.ebay.com/str/evilgeniusmcparts?_trksid=p2047675.l2563|Link to Ebay Store]] ))  ||
+|{{:techtalk:ih:engmech:pinion_gear_pic2_24011-37_by_evilgeniushd1936.jpg?direct&300|}}|{{:techtalk:ih:engmech:pinion_gear_pic1_24011-37_by_evilgeniushd1936.jpg?direct&300|}}|
+|1977-1985 Pinion Shaft Timing Mark ((photo by IronMick of the XLFORUM http://xlforum.net/forums/showthread.php?t=239641&highlight=cam+positions&page=3))|
+|{{:techtalk:ih:engmech:pinionshafttimemark_by_ironmick.jpg?direct&200|}}|
+|  1977-1985 Pinion Gear (24057-74) ((photos courtesy of Ebay seller, Robison Motorcycles [[https://www.ebay.com/str/robisonmotorcycles?_trksid=p2047675.l2563|Link to Ebay Store]] ))  ||  1977-1985 Pinion Gear (24056-74) App. Dims ((photos courtesy of Ebay seller, Robison Motorcycles [[https://www.ebay.com/str/robisonmotorcycles?_trksid=p2047675.l2563|Link to Ebay Store]] ))  |
+|{{:techtalk:ih:engmech:pinion_gear_24057-74_pic2_by_robisonmotorcycles.jpg?direct&300|}}|{{:techtalk:ih:engmech:pinion_gear_24057-74_pic1_by_robisonmotorcycles.jpg?direct&300|}}|{{:techtalk:ih:engmech:pinion_gear_24056-74_app_dims_by_robison_motorcycles.jpg?direct&300|}}|
+===== Pinion Gear Fit on Shaft =====
+==== 1957-1976 gear ====
+These are OD measurements of 3 OEM pinion shafts as measured by needspeed (.7844", .7840" and .7840"). ((http://xlforum.net/forums/showthread.php?p=5991474#post5991474)) \\
+Comments by Dr Dick; \\
+Installing a tight gear: If you tap the gear on the shaft you are tapping on your flywheel assembly in a direction not supported by anything. NOT recommended. \\
+You should utilize the 5/16"-24 left hand threads tapped in the pinion shaft to counteract installing force (press it in). \\
+The 1957-1976 pinion gear needs to be a tight fit and was a factory press fit. However, it's a common problem to find them loose on a used engine. ((Dr Dick of the XLFORUM http://xlforum.net/forums/showthread.php?t=1072235)) \\
 The trick in selecting the right fit part during assembly. The gear is supposed to be "size for size" with the major diameter of the shaft splines. \\
-The press actually is between the sides of 1 male shaft spline and it's matching female in gear. \\
+The "press" actually is between the sides of 1 male shaft spline and it's matching female spline in gear. \\
 There is 1 bigger spline so the gear can index for cam timing. The press spline is the one opposite the bigger one. \\
 The bad news is the shaft wears before the gear. The XL gear is beefier where the pump drive gear hits the back of the pinion gear. \\
 It's beefier because HD also had these failures. \\
-However, leaving the gear loose makes you 1 of 80% of Ironhead riders. Worse side effect is non stop "tappet noise". It can be heard even just pushing the motor over with kicker. \\
+However, leaving the gear loose makes you 1 of 80% of Ironhead riders. Worse side effect is non stop "tappet noise". \\
+It can be heard even just pushing the motor over with kicker. \\
 It's usually not "destructive" problem to leave it as is and you can't use an adhesive to "glue" the pinion gear on. \\
-The 79-85 pinion gear slides up on a timing mark on the pinion shaft and corresponding to a timing mark on the pinion gear. These must line up. ((IronMick of the XLFORUM http://xlforum.net/forums/showthread.php?t=239641&highlight=cam+positions&page=3))
+(1) - A loose gear doesn't mess with breather timing too much. A correctly positioned gear sits .312" above the gasket surface. ((Dr Dick of the XLFORUM http://xlforum.net/forums/showthread.php?p=4332256#post4332256)) \\ The cover bushing face sits .312" below gasket surface. So the gear clears the bushing by 1 gasket thickness. \\ A loose gear rides on the bushing face. There is virtually little breather timing difference between the tight position and the loose one. \\ A shim between gears can make up for the loose position. This shim mustn't self destruct and get caught in cam train. \\
+(2) - A loose gear will make a valve tapping type noise. No mechanical problems, just a tad noisy. Looser = noisier. \\
+(3) - The gear press isn't diametrical. Its lateral. When loose both gear and shaft wear. \\ When a loose gear is removed you will see the wear on shaft spline flanks. \\
+{{:techtalk:ih:engmech:1957-1976_pinion_gear_press_fit_pic1_by_dr_dick.jpg?direct&400|}} ((photo by Dr Dick of the XLFORUM http://xlforum.net/forums/showthread.php?p=4332256#post4332256)) \\
+) Bikes using stock valve springs can use a 45" flat head gear to regain some fit. \\ I have done this many times. Probably 50 times. \\
+These gears are OEM WWII surplus (-29 pn). Many times marketed as XL but they are not the real XL gear. The real xl gears have been obsolete for decades. \\
+**Warning**: I also had two 45" gear failures. Both big bore strokers. Both heavy springs and cams. Both bikes ridden extremely hard. \\
+Both gears very tightly fitted to unworn shafts. Broken pinion gears make a serious mess of your motor. $$$$ \\
+Worst case scenario, you will be looking at new cylinders, pistons, heads, valves, guides, pushrods, cams and cam cover. You don't wanna go there. \\
+I suggest never to use the 45" gears on unworn shafts. Or with cams that require heavy springs. \\
+{{:techtalk:ih:engmech:1957-1976_pinion_gear_press_fit_pic2_by_dr_dick.jpg?direct&400|}}
-Click on any pic below to enlarge: \\
+==== 1977-1985 Gear ====
-|  1957-1976 Pinion Gear. ((photo courtesy of Ebay seller, Evil Genius M/C Parts. [[https://www.ebay.com/str/evilgeniusmcparts?_trksid=p2047675.l2563|Link to Ebay Store]] ))  ||
+The 79-85 pinion gear is a slip fit and slides up on a timing mark on the pinion shaft and corresponding to a timing mark on the pinion gear. \\
-|{{:techtalk:ih:engmech:pinion_gear_pic2_24011-37_by_evilgeniushd1936.jpg?direct&300|}}|{{:techtalk:ih:engmech:pinion_gear_pic1_24011-37_by_evilgeniushd1936.jpg?direct&300|}}|
+These must line up. ((IronMick of the XLFORUM http://xlforum.net/forums/showthread.php?t=239641&highlight=cam+positions&page=3))
-|1977-1985 Pinion Shaft Timing Mark ((photo by IronMick of the XLFORUM http://xlforum.net/forums/showthread.php?t=239641&highlight=cam+positions&page=3))|
-|{{:techtalk:ih:engmech:pinionshafttimemark_by_ironmick.jpg?direct&200|}}|
-|  1977-1985 Pinion Gear (24057-74) ((photos courtesy of Ebay seller, Robison Motorcycles [[https://www.ebay.com/str/robisonmotorcycles?_trksid=p2047675.l2563|Link to Ebay Store]] ))  ||  1977-1985 Pinion Gear (24056-74) App. Dims ((photos courtesy of Ebay seller, Robison Motorcycles [[https://www.ebay.com/str/robisonmotorcycles?_trksid=p2047675.l2563|Link to Ebay Store]] ))  |
-|{{:techtalk:ih:engmech:pinion_gear_24057-74_pic2_by_robisonmotorcycles.jpg?direct&300|}}|{{:techtalk:ih:engmech:pinion_gear_24057-74_pic1_by_robisonmotorcycles.jpg?direct&300|}}|{{:techtalk:ih:engmech:pinion_gear_24056-74_app_dims_by_robison_motorcycles.jpg?direct&300|}}|
 ====== Tappets (Lifters) ======

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