[tom1000]

I haven't begun looking for the cause of the noise yet. Thought I'd throw this out to see what kind of ideas there might be.
Shovel motor, 1977, Hydraulic lifters, Making valve noise only under a load. It won't do it if I just rev the motor. I don't have a tach on the bike, but I guesstimate the RPM when the tapping starts is around 2800 to 3000 RPM.
Oil pressure is OK 30 lbs or more @ that RPM.
The bike had been sitting for about 3 months, ran fine before that.

 

[ftwflh1]

doing it under a load sounds like piston slap or rod bearings.Check lifters and cam though before jumping into engine internals

 

[dsvracer]

I would start with an oil change. Drain the oil into a big flat pan so you swirl the oil around and look into it. Are there any colors in the oil ?? like a silver color or a goldish tint ?? The siver colors usually mean a connecting rod and the goldish colors could mean wrist pin bushings or the thrust washers on the connecting rods are being chewed up by the rods having to much play in them. Whether it is a rod or a wrist pin bushing you should find and fix the problem before you continue riding the bike. It will get worse and eventually cause some serious damage. If you have questions I can be reached at [email protected]

 

[frisco-rigid]

I just wanna approach this from a diff direction..

You say you haven't begun looking for the cause of the noise yet But,,, you call it Valve noise,,, why,,, cuz you're pretty sure it's coming from the Rocker boxes or for some other reason..??
A Mechanics Stethescope is a real good investment (5 bucks +-),,, remembering that noises in these Devil Machines travel and migrate like crabs at a flop house..

Both Ftw and D-racer sound like real smart fellows but I would question this----- since it ran just fine before it sat for three months how could it develop Piston-slap or bad bearings, bushings etc etc while setting like a lump..

If this was my prob, like Ftw sugg'd,, first thing I'd inspect is the Lifters and lifter filter screen..
With motor cold, remove the push-rod tubes and re-adjust the Hydraulic lifters according to your Manual..
If it does Not cease then remove the lifters, dis-assemble, clean & inspect looking close at the wheels..
I've had wheels go bad, they sound like mal-adjusted lifters,, they also destroy the Cam lobes--------- However the question remains,,, why would Anything go bad after just 3 months setting..??

And just one more thing..
Accelerating in the wrong gear causes All sorts a nasty noises and conditions..
What gear are you in when you attempt to accelerate.?
At 2800-3000 R's in 4th gear, an easy accel is Ok,,,, But if you're trying to Jam-it, I would sugg dropping a gear..

 

[frisco-rigid]

Hi Tom

Lil probs like this tend to gnaw at me overnight and I realized I Forgot to include this while talking about the Rpm part..

I am guessing that you are in 4th gear when this noise occurs and, since the noise occurs only under a load in a comparatively low Rpm, it is poss you're hearing the Rattle of Detonation and it can sound very much like upper-end noise..

Loading up at or around "lugging" (for the wrong gear) Rpm's enables and encourages Detonation..
Now,, if you're used to loading-up at around that Rpm Before the sickle sat for 3 months and it Did Not make that noise then, it is poss that during the "rest" one or both manifold O-rings "dried up", possibly old to begin with, and is now allowing an air Intake Leak which will Lean out your A/F mix and again,,, enable and encourage Detonation under load Especially in Low R's..
You might consider spraying around the manifold to check for a leak..

There does Not need to be an intake leak or really any other prob for Detonation to occur,, simply loading-up in Low Rpm ranges can cause it,, and of course,, tooo much Ign advance tooo fast but I don't think that is affecting this prob..

have a ball---------

 

[tom1000]

Found it

Thanks everyone for all the suggestions.
I did start with an oil change, just to be sure. Then I took the bike for a ride again to see if maybe that helped. Nope, no change. No matter what gear the bike was in when the RPM went up the rattle started again and I would lower the RPM's.
I finally rode it home and in the driveway revved it up. Still nothing under no load. Finally I revved it a lot and I heard the rattling.........coming from the shock absorber on the springer front end. It was missing the top rubber mounting grommet.
Relieved, My little "valve" rattle was just the shock.
Thanks again
t

 

[ftwflh1]

Cool you lucked out on that one:clap: