Harley 45 Engine Teardown and Inspection
Text and Pictures by Mark Trotta
Purchased as "parts only, non-running", this Harley 45 flathead engine was locked solid - no flywheel movement at all. But the VIN number was unmolested and belly numbers matched. If the motor came apart cleanly and without damage, it would be worth the effort.
![Harley 45 engine teardown and inspection harley 45 engine teardown](http://www.classic-motorcycle-build.com/image-files/xharley-wla-engine-rebuild-45.jpg.pagespeed.ic.hogu4gURF3.jpg)
Missing pieces included cylinders and heads, generator, timer, intake manifold, and carburetor. But overall, what was left of the motor looked good considering it's age.
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Visual inspection of the engine cases revealed no cracks and no broken bolts. Also encouraging was unstripped factory screw heads--something uncommon for an 80-year-old engine!
![Harley 45 engine teardown and inspection vintage Harley engine teardown](http://www.classic-motorcycle-build.com/image-files/xharley-45-engine-teardown-41.jpg.pagespeed.ic.a-tMseLJ9p.jpg)
According to the previous owner, the motor "sat outside for awhile". As a precaution before starting disassembly, I decided to soak the engine in oil for a while. This would allow every nut and bolt to come off as easily as possible.
![vintage Harley engine disassembly Harley WLA 45 rebuild](http://www.classic-motorcycle-build.com/image-files/xharley-wla-flathead-rebuild-45.jpg.pagespeed.ic.Ts7ci1mcab.jpg)
After removing the Military-style breather tube, I scrounged up a plastic tub that the motor would fit into, and filled it with four gallons of automotive engine oil.
![Harley engine soaking in oil harley 45 engine teardown and inspection](http://www.classic-motorcycle-build.com/image-files/xharley-engine-soaking-in-oil.jpg.pagespeed.ic.8AvCORj_b3.jpg)
The motor soaked for two months before being pulled out of the oil, then placed into a flat drain pan. Most of the cleaning was done with cans of brake parts cleaner, compressed air, and shop towels.
![old Harley engine teardown and inspection Harley engine soaking in oil](http://www.classic-motorcycle-build.com/image-files/xmotorcycle-engine-soaking-in-oil.jpg.pagespeed.ic.l3-Gt8Bhrk.jpg)
Oil Pump Removal
On a Harley 45 engine, the generator, oil feed pump and ignition timer need to be removed before the gear cover can be removed. One bolt and three nuts hold the feed pump on.
The gear cover is set onto dowel pins and is secured by ten screw-head bolts.
![Harley 45 remove gear cover harley 45 cam cover removal](http://www.classic-motorcycle-build.com/image-files/xremove-gear-cover-harley-45-flathead.jpg.pagespeed.ic.aiLCu_SG-s.jpg)
A little coaxing with a gasket scraper and light hammer.
![Harley 45 engine teardown Harley WLA engine teardown and inspection](http://www.classic-motorcycle-build.com/image-files/xharley-45-engine-disassembly-47.jpg.pagespeed.ic.OrFiJb-x7x.jpg)
As is evident from the pictures, the motor collected a lot of dirt and debris from sitting outside with no top end.
A two-jaw gear puller helped remove the pinion gear.
![Harley 45 tappet removal engine teardown harley 45 valve tappets](http://www.classic-motorcycle-build.com/image-files/xpinion-gear-24011-37-harley-45-flathead.jpg.pagespeed.ic.3JMs25BeJp.jpg)
The scavenger oil pump is mounted with four studs and nuts. Removal required light tapping with a small hammer and punch.
![Harley 45 engine disassembly harley 45 remove oil pump](http://www.classic-motorcycle-build.com/image-files/remove-oil-pump-harley-45-flathead.jpg)
The breather valve is an integral part of the scavenger pump. The small screen between the breather valve and crankcase port will be cleaned or replaced.
![Harley scavenger oil pump screen Harley WLA engine teardown and inspection](http://www.classic-motorcycle-build.com/image-files/harley-oil-pump-screen-26343-39.jpg)
Harley 45 engine cases are held together with two bolts that thread into the case, and five studs with nuts on either end.
![split engine cases Harley 45 engine harley 45 split engine cases](http://www.classic-motorcycle-build.com/image-files/split-engine-cases-harley-45-flathead.jpg)
The studs were driven out with a flat-ended punch and hammer.
![split engine cases Harley 45 engine harley 45 split engine cases](http://www.classic-motorcycle-build.com/image-files/split-engine-cases-harley-flathead.jpg)
With the help of a gasket scraper and light hammer, the right case separated from the left case.
![splitting the cases Harley 45 engine harley 45 engine cases](http://www.classic-motorcycle-build.com/image-files/harley-45-flywheel-assembly-29.jpg)
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Remove Flywheel Assembly
The flywheel assembly was pressed out of the case in a hydraulic press.
![Harley 45 engine disassembly press flywheel out of engine case](http://www.classic-motorcycle-build.com/image-files/press-flywheel-out-of-engine-case.jpg)
The reason for the frozen flywheel was now apparent.
![Harley engine teardown and inspection harley 45 separate engine cases](http://www.classic-motorcycle-build.com/image-files/harley-45-engine-teardown-49.jpg)
The roller bearings and cages were rock solid from years (perhaps decades) of non-use.
![old Harley engine disassembly Harley 45 roller bearings and cages](http://www.classic-motorcycle-build.com/image-files/harley-45-roller-bearings-and-cages-42.jpg)
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Remove Tappet and Tappet Blocks
Even after the soaking, the valve tappets and blocks wouldn't budge.
![split the cases Harley 45 engine Harley 45 right side engine case](http://www.classic-motorcycle-build.com/image-files/harley-45-right-side-engine-case.jpg)
I decided to stop and put the the right-side engine case back into the container of oil, where it soaked for another two weeks. But even after the second soaking, three of the four valve tappets and blocks wouldn't budge.
![Harley 45 tappet removal engine teardown harley 45 valve tappets](http://www.classic-motorcycle-build.com/image-files/engine-teardown-and-inspection-harley-45-flathead.jpg)
Next, the engine case was placed in an oil drain pan, then sprayed down with penetrant. Every morning, I'd spray them down, and then again in the evening. After a week's time, they still wouldn't move.
![split the cases Harley 45 engine harley 45 right side engine case](http://www.classic-motorcycle-build.com/image-files/harley-45-engine-teardown-42.jpg)
Finally, I heated the valve tappets and blocks with a torch (Map gas), then slowly tapped them out with a hammer and punch.
![valve tappet removal Harley 45 engine harley 45 valve tappets and guides](http://www.classic-motorcycle-build.com/image-files/valve-tappet-removal-harley-45-flathead.jpg)
Once the tappet blocks were out of the case, they were placed in a vice.
![Harley 45 tappet removal harley 45 valve tappets](http://www.classic-motorcycle-build.com/image-files/remove-tappets-harley-45-flathead.jpg)
A tappet removal tool is required to remove tappet from the block.
![Harley 45 tappet removal harley 45 valve tappets](http://www.classic-motorcycle-build.com/image-files/harley-45-tappet-removal-tool-60.jpg)
The tappet removal tool (Harley #11960-38) fits 1938-1973 Harley 45 Flatheads, also fits UL and VL big-twin flatheads.
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Engine Parts Inspection
After the engine was stripped down to left and right cases, visual inspection revealed no cracks, broken edges, or stripped threads.
![Harley 45 engine cases Harley WLA engine cases](http://www.classic-motorcycle-build.com/image-files/harley-wla-engine-cases-45.jpg)
The cam cover cleaned up nicely.
![Harley 45 flathead gear cover harley 45 gear cover](http://www.classic-motorcycle-build.com/image-files/harley-45-gear-cover-53.jpg)
Very often, you'll find Harley gear cover bolts stripped out due to a previous owner using too small a flat-blade screwdriver.
![Harley 45 engine disassembly harley 45 gear cover bolts](http://www.classic-motorcycle-build.com/image-files/harley-45-gear-cover-bolts.jpg)
Most of the bolts on this engine will be re-usable.
After being cleaned up on the wire bench wheel, the cams were found to be too pitted for further use.
![Harley 45 engine disassembly harley 45 cams](http://www.classic-motorcycle-build.com/image-files/harley-45-cams-removal.jpg)
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Related Articles:
Install Harley 45 Cams
Assemble Harley 45 Cylinders
Harley 45 Bottom End Rebuild
Harley-Davidson WLA Military Bike
![DIY Harley engine stand DIY motorcycle engine stand](http://www.classic-motorcycle-build.com/image-files/diy-harley-engine-stand-23.jpg)
Read: DIY Harley Engine Stand
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