Adjusting Pushrods - Harley Davidson Forums

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Adjusting Pushrods

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Old 08-16-2005, 04:55 PM
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Default Adjusting Pushrods

Different pushrods require different adjustments

One reason you are getting different explanations is that there is more than one right way. The second reason is that Harley mechanics and wannabe wrenches alike are always trying to reinvent the wheel. This is one of the many idiosyncrasies that define the contradictory nature of the Harley rider in Harleydom. "There must be a better way", they reason. Well……sometimes there is and sometimes there isn't. When there isn't a better way they are not deterred in their quest. On they go, using half truths and rationalizations to fuel their rebellious needs. Take oil for example. Airplanes must use the very best products. Right? Right! Therefore the oil they use must be better than what the automotive industry has developed for land based vehicles. Right? Wrong! A top automotive/motorcycle oil, (which are the same but we won't go into that scam of scams now), is unsuitable and even potentially downright dangerous in an airplane. And yes, you got it, an airplane oil is especially unsuitable for your Harley. Enough of that, Magic, let's explore some of the right ways to adjust pushrods. You didn't mention the year and model of your bike which is ok with me since I can ramble on even more than normal.

Types of Pushrod/lifter setups

Some Panheads used a solid lifter with a hydraulic pushrod. I haven't seen one of these setups, which is still functional anyways, for many years now. We won't go into these ones since 99% of Harley riders will never see these anyway. Early Big Twins and all Ironhead Sportsters used a solid lifter assembly with an adjuster built in. These were combined with fixed length pushrods. Shovels use a hydraulic lifter with an adjustable pushrod. Evo Big Twins and XL's and Twin Cam 88's use a non-adjustable system with fixed length, location color coded pushrods and automotive type non-adjustable hydraulic lifter/tappets. The aftermarket expands on all these types. They provide very necessary adjustable pushrods to replace the fixed length Evo and Twin Cam 88 ones. Another example is the Colony spring loaded solid lifter kits for the Shovels. There are little springs that supposedly take up play when the engine heats up and expands. Many riders like these kits since they allow for a little sloppier, (I didn't say correct), adjustment. The same riders dislike the S&S solids since an eighth turn preciseness is required for quiet but very effective operation.

Always do these steps:

Rule 1

The engine must be COLD during adjustment….not hot, not warm, not cool…it must be cold. Why? The metal expands when the engine is hot. The barrels, heads and rockers grow taller when hot and contract when cold. If a pushrod/lifter is adjusted when the engine is hot, the valve may be forced open as the engine cools and contracts. A valve that is opened at the wrong time will cause a loss of compression at the very least. At most the extended valve will hit the ascending piston and bend necessitating a rebuild. This can also happen if the lifters are adjusted on a high spot of the cam lobe. More on this in a bit. The Pros can tweak a lifter adjustment while the engine is hot. They listen to the tappet noise when the engine is running and determine which of the four is making the noise. They can tell by the noise on how much to turn down or up the adjustment. Leave these smooth moves to the Aces as they are also capable of rebuilding your top end if they screw up.

Rule 2

Take nothing for granted in mechanics If unfamiliar with the lifter setup that is about to be adjusted always read THAT SPECIFIC manufacturers instructions. Sound stupid? Not really when you consider that the threads per inch on the adjusters vary from manufacturer to manufacturer. One source may say turn the adjuster down 5 full turns. Well 3 full turns is more when there is less threads per inch and it is less when there is more threads per inch.

Rule 3

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adjust, adjusting, adjustingpushrods, adjustment, cam, davidson, evo, harley, lifter, lifters, panhead, pushrod, pushrods, solid, twin

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