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Drive Sprocket Wobbles??

breakbeatz69

breakbeatz69

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So I was just going through some stuff on this engine on my 1981 cb750C and I noticed that the front drive sprocket can be wobbled back and forth a little when the sprocket bolt is completely torqued down. Is that normal on these bikes? It’s like the washer in between the two plastic pieces that get mounted to the sprocket just kind of floats between the steel sprocket and the plastic pieces (are the plastic pieces a chain guide or something???) which makes it impossible to tighten the sprocket so it doesn’t wobble. I don’t get it unless it’s supposed to float like that and have some play? Help please. Here’s the pieces I’m working with….
IMG_6227.jpeg
 
That's normal, that's the way it was designed, like you said, IT FLOATS. DO NOT REMOVE THE SEAL BEHIND THE FRONT SPROCKET. That is not a normal seal, the case will have to be split to replace that seal.

Edit .....notice the Oring placement.
 
Last edited:
mrtwowheel said:
That's normal, that's the way it was designed, like you said, IT FLOATS. DO NOT REMOVE THE SEAL BEHIND THE FRONT SPROCKET. That is not a normal seal, the case will have to be split to replace that seal.

Edit .....notice the Oring placement.
Click to expand...
Ok, I thought there had to be a logical explanation for it and the only thing I could come up with was that’s how it’s designed. It’s a strange design, I’ve never had a front sprocket like that but thanks a ton for jumping so quickly to tell me not to worry. 🤘
And yeah, the oring seems to go behind the sprocket and onto the bolt.

As far as that seal goes, they ALWAYS leak on the xs650’s but to my surprise, mine on this bike isn’t leaking a drop so I’m good there. Will definitely leave that alone. Thanks again man. 👍
 
Hey while I got you here, clutches steel and fiber discs, do you guys soak them in oil overnight before installing the new ones?
 
There’s an oil pump on these bikes so you might not need to soak them. In the xs650’s we soaked em overnight so they were wet when you first hit the clutch because there is no oil pump.
 
I might dip them in a tray of 10w40 right before they go in. Wipe them down a bit so there isn’t oil over the place.
I’ve put them in dry, pulled the clutch in and rocked the bike back and forward a bit after refilling the oil.
Or hit the start with clutch disengaged 2 or three times to get some oil between the plates.

Biggest thing is they go back in the same order they came out.
 
Well they’re in dry now. I’ll just make sure to let them get soaked naturally by either the pump, sloshing the bike side to side, and disengaging the clutch and hitting the starter a few times to get some oil up there. I knew my better judgment said to soak ‘em’. At least there’s an oil pump with passages that go to the plates.

On a different note, anyone know or have a diagram of the clutch cover bolts and where the long ones go vs the short ones? The fucking locator pins were stuck and when the cover finally let loose the bolts all went flying.
 
Hold on to the cover with your one hand with the holes vertical and drop the bolts in the holes. They should all stick out the bottom the same amount. Move them around until you have them all sticking out the bottom the same amount and then you will know which bolt goes in which hole.
 
Oh and as far as my compression problems, I took the pistons off, ultrasonic cleaned them, I re-honed the cylinder bores yesterday and got a real nice 45 degrees angle cross hatch. Ring gaps on the new rings are all in spec still and I install them on the pistons and taped them at their 120 degree gap points (oil rings at least 20mm away from the spacer gap), and they’re ready to go back on the rods. Once I build the engine back up to the valves with the cams in, I’m gonna go through and check my shim gaps.
 
Loose Chain said:
Hold on to the cover with your one hand with the holes vertical and drop the bolts in the holes. They should all stick out the bottom the same amount. Move them around until you have them all sticking out the bottom the same amount and then you will know which bolt goes in which hole.
Click to expand...
Nice, yeah that’s what I was gonna do if no one had a diagram or something. Thanks man.
 
You guys use copper coat type spray a gasket on your paper gaskets for extra insurance where ever oil is gonna be sloshing around?
 

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