Primary noise - first time tear down
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Joined: Aug 2017
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From: Uppsala, Sweden
Primary noise - first time tear down
Hi!
I've got a bad noise coming from the primary and I'm planing on tearing into it and troubleshoot for the first time and would like to hear what I should keep an eye open for.
The bike's a 1992 FXSTC with 30 k miles.
When it gets warm, I get a noise (first thought it was the belt squeaking) when I accelerate in any gear. A high pitch grind/squeak.
There's no noise when cruising, in neutral or clutch disengaged.
When decelerating, I get a grinding noise and a repeating clunk. Also get a clunk when engaging the clutch.
I've got a small inner primary seal leak and there were some metal shavings on the plug.
Clutch and primary chain are adjusted and there's new oil in it. No problem shifting.
I would appreciate all input I could get on how to proceed.
I've got a bad noise coming from the primary and I'm planing on tearing into it and troubleshoot for the first time and would like to hear what I should keep an eye open for.
The bike's a 1992 FXSTC with 30 k miles.
When it gets warm, I get a noise (first thought it was the belt squeaking) when I accelerate in any gear. A high pitch grind/squeak.
There's no noise when cruising, in neutral or clutch disengaged.
When decelerating, I get a grinding noise and a repeating clunk. Also get a clunk when engaging the clutch.
I've got a small inner primary seal leak and there were some metal shavings on the plug.
Clutch and primary chain are adjusted and there's new oil in it. No problem shifting.
I would appreciate all input I could get on how to proceed.
Grand HDF Member
Joined: Apr 2007
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From: Brighton, MI
With regards to the oil leak, smell it. If it a sulfur smell then it is differential (trans) fluid. If it smells like plain old oil, then it is primary fluid. That will help us narrow down what might be going on. Any pics of the metal shavings on the drain plug? YD
Road Warrior
Joined: Dec 2012
Posts: 1,539
Likes: 692
From: magnolia tx
Id look at the clutch hub bearing, "inner primary bearing most likely", race has walked out into the primary bearing, and if original clutch set up, your year were not the best clutch assemblies, with the boom boom
grenade plate, starter jackshaft vibrating slightly forward and catching on the clutch shell gear and primary chain adjustment
Last edited by mike131; Jul 9, 2020 at 07:58 PM.
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From: Uppsala, Sweden
Assumed it was from the primary, since the trans side was clean, from what I could tell.
The bike also had some oil at the base of both cylinders, but I haven't seen any new oil there either.
(It struck me now that it could have come from the air filter. I now have routed the vent hose to underneath the bike.)
My guess is that they're really small leaks and that oil has accumulated over time.
The bike was very neglected and both oil plugs (trans and prim) were stripped. Motor oil was pitch-black. But no metal in the oil filter.
Sorry, no pics of the shavings on the drain plug. They were like small splinters.
Last edited by JensWest; Jul 10, 2020 at 04:58 PM.
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Joined: Aug 2017
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From: Uppsala, Sweden
Yes. There was "glitter" in the oil, but the amount of "glitter" didn't feel out of the ordinary considering that it probably was a while since the oil last was changed.
Road Warrior
Joined: Apr 2016
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From: Long Island
Take a look at your front pulley behind the inner primary cover being loose.I chased a noise which resulted in just that. But like others saying it may just be that inner bearing.
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Road Warrior
Joined: Dec 2012
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From: magnolia tx
That could definitely be true
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Grand HDF Member
Joined: Apr 2007
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From: Brighton, MI
The oil around the cylinder base is fairly common. The stock cylinder base gasket is paper and can "shrink" from lack of use. Then when it gets used, the oil makes it swell and seal up after a few uses. Mine did this every spring with the stock gasket. It was taking longer to seal up each spring, till I decided to replace the gaskets. Fairly common problem with evo's and the reason why you need to let the cylinders get good and warm before putting a load on them. The cylinders actually "grow" in length as they heat up. Don't flog it till the cylinders get good and warm.
Double check that it is not your trans vent tube that was puking a little oil. It will be a sulphur smell. It can dribble oil from being over filled. However the noise you mention is concerning.
Good advice about checking the front pulley. Try to get a wooden stick (somewhat sturdy like a broom handle cut at a 45 degree angle) and loosen the rear wheel so no tension on the belt, then get the cut end in there and try to move (pry with out going ape crazy on it) the front pulley around to see if it has wobble or play. If so, get the tools out.
Other than that, thinking inner primary bearing or clutch bearing but hard to tell without taking it apart. Some metal on the magnet is normal because of the chain and the teeth on the compensator/clutch. YD
Double check that it is not your trans vent tube that was puking a little oil. It will be a sulphur smell. It can dribble oil from being over filled. However the noise you mention is concerning.
Good advice about checking the front pulley. Try to get a wooden stick (somewhat sturdy like a broom handle cut at a 45 degree angle) and loosen the rear wheel so no tension on the belt, then get the cut end in there and try to move (pry with out going ape crazy on it) the front pulley around to see if it has wobble or play. If so, get the tools out.
Other than that, thinking inner primary bearing or clutch bearing but hard to tell without taking it apart. Some metal on the magnet is normal because of the chain and the teeth on the compensator/clutch. YD
Road Warrior
Joined: Dec 2012
Posts: 1,539
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From: magnolia tx
Have you pulled the outer primary off yet? if original clutch set up and your going to take the clutch apart you need a special spring compressor to get the snap ring off, some people make one but they are cheep enough to buy