Pushrod adjustment

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May 22, 2023 | 03:18 PM

#41

paud

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Joined: Oct 2009

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From: Las Vegas

Quote:

Originally Posted by Max Headflow

You sure it's TDC compression?

For the most recent adjustment, yes. I had the cam cover off. I have not gone back in to check it though. With the cam cover ON, I remove 2 spark plugs, put the bike in 6th gear, and rotate the rear wheel. I watch the pushrods move, etc.

May 22, 2023 | 04:00 PM

#42

Max Headflow

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From: poway

Quote:

Originally Posted by paud

So the back pushrods were moving when you bumped the front to TDC?

May 22, 2023 | 05:12 PM

#43

paud

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From: Las Vegas

essentially. TDCC, both rods are down, piston is moving up, and air rushing from spark plug hole. With a straw, or thin stick in spk plug hole, observe piston position...

May 22, 2023 | 05:48 PM

#44

djl

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From: san antonio

Sounds like Paud knows how to find TDC on the compression stroke. I would just start over and adjust both push rods but increase preload past his 2.8 turns; 3.5 to 4 turns dependng on 32 or 24 TPI. Maybe the exhuast lifter just takes longer to bleed down??

Last edited by djl; May 22, 2023 at 06:04 PM.

May 22, 2023 | 06:13 PM

#45

paud

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From: Las Vegas

Quote:

Originally Posted by djl

Thanks. S&S wants my SE pushrods to move 3 complete turns. That means compressing the S&S tappets to .125 of an inch. Harley wants their tappets to compress .100 of an inch. To me this all boils down to oil pressure and spring strength in the tappets...thats my guess. I have heard that the more compression on the tappet, the less noise in the top end. ANYway, if one Correctly adjust the pushrods and then after a few hundred miles checks the adjustment and finds when both tappets of the same cylinder are on the bottom lobe and ONE push rod can turn with your hands and the other can NOT....then what next is the question.

May 24, 2023 | 08:35 AM

#46

djl

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From: san antonio

Does "bottom lobe" mean cam base circle? Is it an assumption that both lifters are on the base circle or visual confirmation? This can be tricky; a lifter can look like on the base circle but actually be on the beginning of a ramp. Both lifters must be squarely on the base circle.

Assuming both lifters are squarely on the base circle and both pushrods are adjusted the same, the situation Paud discribes is, mechanically, unlikely. Perhaps one lifter isn't bleeding down or bleeds down slower than the other. Given more time, can the OP spin the other pushrod? Maybe try this with another lifter and see what happens.

May 24, 2023 | 09:29 AM

#47

Max Headflow

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From: poway

So if when the pushrod was originally installed, it spun freely. After riding it didn't. Pushrods really don't grow, neither do lifters. Since the pushrod is tight on TDC compression, I'd pull the pull it and check the ends. Maybe not enough lube on the end when installed and it seized in the rocker arm cup? Possibly the oiling hole in the pushrud is plugged to had some crap in it..

May 24, 2023 | 02:17 PM

#48

paud

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From: Las Vegas

Sorry for not being clear in some places. I find I forget proper terms for things so we can all understand them. Djl, yes, I mean cam base circle. When I check again, if I can not spin one pushrod, I will wait a bit longer. I will check for possible oil blockage in pushrods, and look for any abnormality in the ends of the rods. Having said all of that, I am still trying to find how increasing the lifter pre-load affects things.