An interesting article on the compensating sprocket.





Can you tell me what’s causing this noise ?

The caller was inquiring about the cost of a bottom end rebuild on his Evo.

"How do you know it needs rebuilding?" I asked.

"She’s hammering away in there." He replied. "My drag pipes don’t even cover up the knocking."

Already, I knew from experience that it was a loose or worn compensating sprocket assembly.

I told the caller that I had good news for him or at least better news than he was expecting.

Over the years, I can’t think of a noise that’s raised more blood pressure than the dreaded bottom end knock, but the long and short of it is that in most cases, the culprit is something else entirely.

Truth is, a lot of mechanics can’t even detect this noise, especially in its early stages.

But being typical Harley riders, they immediately bypass all the simple, easy-to-fix inexpensive solutions and proceed to the most complicated, hard to get at and most costly-to-fix solutions.

Your first question should be "Can you tell me what’s causing this noise?", not "How much to do my bottom end? "Well, if you can hear your bottom end over the staccato of drag pipes, that sound would almost have to be the shattering of engine cases bouncing off the pavement as a broken connecting rod did its Grim Reaper" routine.

On the streets, I’ve only seen that scenario a few times in the last decade.

So, why don’t we examine what’s really causing this heart-palpitating noise?

Outside of a collapsed hydraulic lifter, nothing else can cause this much internal noise.

The lifter noise will come from the right side of the engine so it is easy to isolate or eliminate the problem. That leaves only one area to check, and that is the primary system, which is on the left side and connects the motor to the transmission delivering power back via the clutch to the rear wheel.

Now, the noises emanating form the primary are serious and require immediate attention, but they do not cost anywhere near that of bottom end work.

Check the simple and inexpensive solutions first

If you’re lucky, your primary chain could be too loose, and all that’s happening is that it’s constantly slapping against the inside of the primary case. That would take 15 minutes to repair. You may want to change the fluid since aluminum filings from the casing will not be attracted to the drain plug magnet. A loose or stretched chain can be whipsawing on and off the front sprocket, which also would make lots of noise and a jerking sensation, especially in high gear. That may simply be a loose chain but more likely it would be an unevenly worn one with tight and loose spots and/or worn out hooked sprocket.

Too tight a chain (or a worn one with tight spots) will cause a whine as opposed to a slapping or knocking and might cause the clutch to drag. this condition lessens the life of all components parts, including bearings.

No lubrication causes all kinds of havoc and noise and is evidenced by an orange rusty color evenly dispensed throughout the primary,. The chain must be inspected for a broken or missing (disintegrated) roller that can emit a grinding noise.

A constant grinding sound can be caused by a misaligned chain as it tries to re-cut teeth to accommodate its path more easily. I don’t even want to get into all the damage all those fine cuttings will initiate.

Also, a new chain should be broken in and checked after 500 miles. Consider changing oil as the break-in period generates lots of filings.

Loose nuts on the primary adjuster will allow it to flop up and down. After these chain-related problems are checked, examine the compensating sprocket assembly.

Compensating Sprockets

Big Twins since 1955 and Sportsters from 1957 to the mid-70s used four basic types of engine-to-transmission power shock absorption devices. The pulsing

 

want to read the rest of this article,we cant find the rest of it

 

http://dumbassbiker.com/product_11.h...ng%20Sprockets

 

any suggestions for a whine on decel from primary area.pull clutch in and goes away..checked and adjusted belt and chain on 95 roadking

 

Hey Mac, Mine started doing the decel whine when cold (whine went away after 10-20 miles)

I changed the primary fluid and the whining noise disappeared almost completely.

Syn 3 will allow more noise than some other primary or trans fluids.

But I like running the same oil in all three holes.

 

Just got back from the local HD dealer. Went in for a tire change, and after about 1/2 hour he came out and said .... " bad news, your compensating sprocket is shot, actually one of the worst I have seen" Then tells me it is about $1000 fix, "give or take". Which probably means closer to $1400.
That's one expensive tire change!!!!.
Needless to say I rode it home, and will check on other options.

UPDATE!!
I have a buddy that used to be a HD mechanic. So I took the bike to him. We opened it up...........ABSOLUTELY NOTHING WRONG!! Not even 1 little metal flake in the primary aprox 50,000 miles on it and all the gears look like new. Everything torqued to specs.
OH YA! and "the worst he has ever seen", with out ever even taking off the derby cover to check!!
From now on I will ride from BC. down to Spokane to have anything done.

Treat people fair and you might have a customer for life