Noisy open primary

Friscokidd

New Member
I have a 2008 Ron Simms custom with a 125 revtech & 3 inch Ultima open primary when the bike is running in neutral the clutch sounds like the bearing or something inside is going to come apart any suggestions thanks
 

Sven

Well-Known Member
When in N the transmission main shaft spins freely with fixed clutch outer to the crank. The clutch assembly is the middleman between rear wheel and engine. Apply Newton's 3rd law of motion of the paraphrase, 'for every action goes the reaction.' So for every pulse of the one cylinder is the power stroke, then the lax, then the reaction. When the next cylinder fires, it begins the motion again, and the fiber plate tangs in the basket bang in the opposite direction.

Think like turning off the stove and the tea water stops boiling instantly when the stove is turned off. Think of that as boiling power and then subsides. So the basket acts like a bell and can increase the sound level when the clutch tangs bang the forked slot blades (for a better name).

In gear, the tangs are locked to the one side of the baskets fork blades of the clutch outer. When you back off on the throttle, the tangs reverses and bangs the other side of the fork blades. Thus the indents at the clutch outer basket fork blades.

To see if it's more a mechanical noise then a worn bearing going out, is the noise gone under load in gear? Yes? Then it's back to for every clanging the bong slowly, she be the basket to clutch tangs banging the bellows.
 

Mickmorris

Well Known Member
Supporting Member
I have a 2008 Ron Simms custom with a 125 revtech & 3 inch Ultima open primary when the bike is running in neutral the clutch sounds like the bearing or something inside is going to come apart any suggestions thanks
My suggestion would be to take it apart and see what’s going on before it goes to hell on you.
 

mastiffdave

Well-Known Member
When in N the transmission main shaft spins freely with fixed clutch outer to the crank. The clutch assembly is the middleman between rear wheel and engine. Apply Newton's 3rd law of motion of the paraphrase, 'for every action goes the reaction.' So for every pulse of the one cylinder is the power stroke, then the lax, then the reaction. When the next cylinder fires, it begins the motion again, and the fiber plate tangs in the basket bang in the opposite direction.

Think like turning off the stove and the tea water stops boiling instantly when the stove is turned off. Think of that as boiling power and then subsides. So the basket acts like a bell and can increase the sound level when the clutch tangs bang the forked slot blades (for a better name).

In gear, the tangs are locked to the one side of the baskets fork blades of the clutch outer. When you back off on the throttle, the tangs reverses and bangs the other side of the fork blades. Thus the indents at the clutch outer basket fork blades.

To see if it's more a mechanical noise then a worn bearing going out, is the noise gone under load in gear? Yes? Then it's back to for every clanging the bong slowly, she be the basket to clutch tangs banging the bellows.
I believe this is the first time that I have agreed with Sven all the way. i Was always proud that I had the quietest open primary around until that trip to the smokies where the entire bike about fell apart. One day fine the next and as deaf as I am it drove me nuts. . Pulled it apart and found as Sven said the basket to clutch tangs extremely wore. Didn’t affect the workability but the noise was awful. Changed the basket and new disks and now it’s quiet as before. Might also make sure the cutch disks are facing the proper direction. We saw one where a few were installed incorrectly. Also have seen an instance where some disks were mismatched from original set which were wore on the tangs more and that let the original disk wear more quickly and more noise. Anyway as mick said you won’t know till you see what you got.
 

Sven

Well-Known Member
Steel direction is easy. Steels are stamped out so the sheer cut is round on one edge, sharp and flat on the other side. HD had steels with a holding cage that had a ball bearing at the edge as the tang. There was also letters stamped on one side that said "OUT." The next thing I noticed was the cut side of the plate faced the pressure plate.

Segway to the Japanese line and noticed all the cut sides of any model had the cuts facing the pressure plate. Recently rebuilt a CT70 clutch. This had pad material on one side only on the round side. Cut bare side faced a full friction plate, where all 3 plates total all cuts faced the pressure plate. Then I rebuilt a CBX clutch pack, where the pressure plate was the first part to enter the clutch outer. On disassembly, the cut side steels faced the pressure plate.

All those decades in the trenches replacing clutches, never saw a turned around plate facing the wrong direction. So that made me learn that whatever bike I walk up to, I know to make the cut side always face the pressure plate, no matter the design.
 
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