Valve Problem?

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Apr 19, 2010 | 08:55 AM

48FLpan

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Joined: Mar 2009

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Valve Problem?

48 panhead solid lifters. Had noisy valves. Adjusted valves, found rear intake had 1/8 inch play. Got them right, second and third check. Rode to work and back (30 mi) next day. Ran great, not noisy at all. Rode to work again. On way home after work noticed rear cylinder gotten noisy again. Next day cheacked and rear intake 1/8 play again. Distinct "clinck" sound when motor rotated to rear intake fully raised position. I know its not good - broke or bent rocker or dropped valve? I know its hard to diagnose with hearing it. Any ideas?

Apr 19, 2010 | 01:02 PM

48pan

Tourer

Joined: Mar 2009

Posts: 260

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From: Fort Worth, Texas

Just a thought have you checked your pushrods for straightness. Put the pushrod on a piece of glass and roll it. Should tell you if there is a bend to it. If you had a stuck or bent valve you'd have some backfiring going on. You can take the pushrods out and blow some air in the cyl and see if it leaks out anywhere. Do you get the noise with the pushrods adjusted correctly? 1/8 in. clearance is quite a bit, could explain the noise when the valves seat. Haven't had much experience with bent or broken rocker arms but I would think that would be a continuous and would open/close exhaust too soon or late causing timing problems. Just a thought. Good luck and keep us posted.

Apr 19, 2010 | 03:29 PM

48FLpan

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Nice bike 48pan. Mine is not restored to original, has some updates. Thanks for the reply.

Guy that listened to it to is pretty sure that the noise is the valve-spring. Thinks the rocker is slipping off pushrod when raised. Will know for sure in a day or two.

I know I should have checked pushrods, but didn't have any around and wanted to ride. Never enough time.

Apr 21, 2010 | 08:53 AM

sqdealgeorge

Road Warrior

Joined: Dec 2007

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From: Eagle River WI

Check the roller on the lifter assembly (roller rides on the cam ) Maybe the roller bearings are failing ? or have failed

Apr 21, 2010 | 03:57 PM

Kuda

Novice

Joined: Jan 2010

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From: Baltimore, MD

Definately check the lifter. If the rod's not bent then the lifter's probably going south. Don't wait 'till it grenades and pukes metal through your motor, pull it and check it...

-Kuda
'49 panchop

Apr 22, 2010 | 11:17 AM

greenbikemike

3rd Gear

Joined: Sep 2008

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From: minnesota

Quote:

Originally Posted by sqdealgeorge

Check the roller on the lifter assembly (roller rides on the cam ) Maybe the roller bearings are failing ? or have failed

+ 1 on the roller

Apr 30, 2010 | 04:54 PM

48FLpan

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You're Right!

The needle bearings came out of the roller on the rear intake lifter. Luckily they did not get jammed in any of the gears under the cam cover. New lifters and I am good to go.