I posted about my first cam change and got some good questions about adjusting pushrods.

https://www.hdforums.com/m_2825599/tm.htm

I thought I would start a seperate post.

I'll take a shot at explaining it.
My terminology might not be correct, but I think you'll get the point.

And, I will not be offended if someone corrects me or adds to this explanation.

When the lifters are completely pumped up and unloaded, they are at 0.200".
For example, without pushrods installed, the lifters would expandout to the 0.200".
This is obviously an internal hydraulic measurement, not the actual length of the lifter.
The idea is to adjust the pushrods out until the lifters are compressedto 0.100"
Therefore, adjusted to the midpoint of their travel.

Here’s how I did that:

Put the bike in 5th or 6th gear. This makes the rear wheel easier to spin.

Put the bike on a lift.

Take out both spark plugs.

Open all four pushrod covers and push them as far up as possible. I used two paper clips connected with a rubber band. Bend the paper clips, hook one under the pushrod cover, and hook the other end on a fin or something. This is a neat trick to keep them out of way while you’re adjusting.

Verify that you are on the compression stroke of the front cylinder by pacing your finger over the front spark plug hole and have someone rotate the rear wheel until you get a rush of air out of the spark plug hole. This step might not be necessary, but this way I knew I was on the compression stroke with both valves closed.

Now move to the right side of the bike and touch both front pushrods.

While touching the pushrods or the tops of the lifters if you are installing new rods, have someone rotate the rear wheel until you feel the rods both move down and stay down while you are still rotating the rear wheel. Trail and error will quickly find that area where both front cylinder rods and lifters stay down. You should be very close to one end of that range based on being on the compression stroke. Very roughly, they will stay down about 25% of the tire rotation.

I took a piece of chalk and marked the rear wheel even with the fender to represent the endpoints of this low lifter/pushrod zone.

I then rotated the rear wheel to the middle of the two chalk marks. This should place you in the middle of the un-loped part of the front cam. For adjustment purposes, you do not want the cam lopes to induce lifter compression. That’s why you position to the un-lobed part of the cam.

[font="times new roman"][size=3]Now, cut the rods out with a bolt cutter if you are replacing them or adjust the rods until they are loose. This will allow the lifters to expand to the 0.200” mentioned earlier. I really don’t know h

 

http://http://www.bigboyzheadporting.com/showthread.php?t=131

 

After you adjusted them and they bled down, was it easy to spin the rods or hard?
Thanks
eric

 

Rahall, you did a nice job of explaining everything. Your theories are correct. The hydraulic lifters are supposed to run midway between fully compressed and fully expanded so if 0.200 is total travel 0.100 is half way. The only thing I could add to this is that the un-lobed part of the cam is called " base circle" but please dont take that as criticism its just the technical term. Thanks for the good post..........BG

 

They were snug, but you could spin them with a little effort.

 

This is good info!... I'm about to install HQ EZs in my 07 twin cam, and since I had to remove the lifters because I couldn't hold them up with anything when changing my cams, this adjustment procedure makes a lot of sense considering the compression required against the lifter by the pushrod at 0.100"

 

Should you adjust them hot or cold??

 

cold.

 

Be sure you tighten the locknuts on the pushrods. I had one come loose. Bike don't run well on one cylinder.

 

Check out the article about adjusting pushrods in August issue of American Rider magazine.