Topic: CB750 K6 Clunk into first, Clutch drags

[rtbmrgl]

Hello,
'76 CB750K
Bottom line,-
Bad cluck going into first, when started in gear clutch in I fell a surge(clutch sticks)
Full throttle high rpm in higher gears slight slip.

A new set of fiber plates, straight cut on the way. I have Barnett springs, they are heavier, will they be really stiff. This a commuter bike.

here are pic, does everything look normal.
stock springs-


One of the metal plates was upside down as to the others ones.


The top disc has wider tabs and angled slots



barnett springs, will the clutch be really stiff with these


All the plates I removed are 3.5mm


the are three holes in each area of the pressure plate



these were in the bike when i bought it


Nonfat Greek yogurt with flax seed, breakfast, wife making me cut back on carb intake.

[martin99]

First thoughts reading your description is that your clutch needs adjustment, but as you're giving it a work over there's a couple of things to think about.

When the new plates arrive, soak them overnight in clean engine oil - don't be tempted to fit them after a couple of hours. Also, your clutch basket is showing familiar wear. Use a fine file to dress out those notches that have been made by the plates as much as you can.

There's a few threads on here re. Hondaman's clutch mods, including drilling holes and changing the o rings on the pump. Now seems a good time to do it. Perhaps a PO has already done it?

I would imagine heavier springs will mean a little more effort is required at the lever.

Oh and that yoghurt looks disgusting. Use it to lube the clutch cable and just tell the wife you ate it

[rtbmrgl]

First thoughts reading your description is that your clutch needs adjustment, but as you're giving it a work over there's a couple of things to think about.

When the new plates arrive, soak them overnight in clean engine oil - don't be tempted to fit them after a couple of hours. Also, your clutch basket is showing familiar wear. Use a fine file to dress out those notches that have been made by the plates as much as you can.

There's a few threads on here re. Hondaman's clutch mods, including drilling holes and changing the o rings on the pump. Now seems a good time to do it. Perhaps a PO has already done it?

I would imagine heavier springs will mean a little more effort is required at the lever.

Oh and that yoghurt looks disgusting. Use it to lube the clutch cable and just tell the wife you ate it

Thanks oldskoolnuts for quick reply,
Important items first, the yogurt, it taste way better than it looks and if it gets me one more ride its all right with me.

I found the thread for the clutch mods
http://forums.sohc4.net/index.php?topic=78643.0
I already did the counter shaft o-ring but not the mod to the oil pump so I will be taking it out and replacing the o-rings.
And yes on soaking the plates.

[PeWe]

Dragging clutch might be the oil.  I had that this year, never during the 80's. Changed oil.
Slip can be oil too. Use of car oil can cause this, friction modifiers that reduce friction like moly....

[rtbmrgl]

Dragging clutch might be the oil.  I had that this year, never during the 80's. Changed oil.
Slip can be oil too. Use of car oil can cause this, friction modifiers that reduce friction like moly....

thanks for info, Ive been using Rotella non syn 15w40 CJ-4 on this bike and my CB500 and vstrom, the clutches have been perfect.
oldskoolnuts mentioned the wear notches on the hub and drum, Ill be smoothing them out. 
When I got the bike a years ago the angled plates were installed, I swapped them out for the straight plates the guy gave me with the bike. The straight plates had been on the bike, I measured the thickness and 3.5m so put them in.  I had no idea what oil he uses so maybe they were saturated with the energy conserving oil.

[flybox1]

Got HondaMans book?  do the clutch basket oiling hole mods.
Clean your metal plates.  kerosene and a soft (brass) brush would be good.
Ensure your oil has low or no detergents and high levels of zinc

Im using BelRay 4T Mineral MC 20w50 + Rislone 4405 additive
http://barsproducts.com/catalog/view/245-3x-concentrated-engine-oil-supplement-with-zinc-treatment-4405
My rear wheel no longer spins at mach 5 when on the center stand 

IIWM id also stack all the cork plates so the cutouts are in the same direction.
Might just be my ocd.  Maybe the clan can chime in if there are benefits to a specific direction.

[rtbmrgl]

Got HondaMans book?  do the clutch basket oiling hole mods.
Clean your metal plates.  kerosene and a soft (brass) brush would be good.
Ensure your oil has low or no detergents and high levels of zinc

Im using BelRay 4T Mineral MC 20w50 + Rislone 4405 additive
http://barsproducts.com/catalog/view/245-3x-concentrated-engine-oil-supplement-with-zinc-treatment-4405
My rear wheel no longer spins at mach 5 when on the center stand 

IIWM id also stack all the cork plates so the cutouts are in the same direction.
Might just be my ocd.  Maybe the clan can chime in if there are benefits to a specific direction.

Like your idea on the brass brush for cleaning the plates, also I didn't mention the plates are not warped.
Yes I have Hondaman book, I love i. I have noticed a lot are using 20w-50, not sure if its to heavy for winter, great for the summers. I ride in winter to work, although where I live is not as cold as back east, there are morning times when its in the 30's F and coming hm in the 40's

[rtbmrgl]

An update, did a few mods on the clutch, new oil pump o-rings, new friction discs, de-glazed steel plates.
Clutch doesn't drag anymore and no bad clunking going into first, very smooth between gears, so everything good and back on the road.
Im using Rotella T 15w-40 and stock springs.
I did have an "ahh crap" moment. I was putting in Barnett springs and the pressure plate broke, there much stiffer and Im sure I wasn't tighten it even. So I went back to the stock springs.

[martin99]

You're not the first, and certainly won't be the last to brake a pressure plate. I'm so paranoid about them now it takes forever, doing 1/4 turn at a time. Glad to see you got it sorted.

[rtbmrgl]

You're not the first, and certainly won't be the last to brake a pressure plate. I'm so paranoid about them now it takes forever, doing 1/4 turn at a time. Glad to see you got it sorted.

Thanks,
i believe i read that 20w 50 is a better choice for oil, come spring ill be trying that.

[PeWe]

Yes, the springs are not the problem, its how each bolt is turned. It takes time to tighten them to avoid the alu stuff to bend and crack. I should use the Barnett springs. I use similar springs from an old heavy duty clutch kit but new fiber plates.
Dragging clutch when cold, OK when warm is most likely the oil. Maybe the neutral is hard to find when warm too?

[rtbmrgl]

Yes, the springs are not the problem, its how each bolt is turned. It takes time to tighten them to avoid the alu stuff to bend and crack. I should use the Barnett springs. I use similar springs from an old heavy duty clutch kit but new fiber plates.
Dragging clutch when cold, OK when warm is most likely the oil. Maybe the neutral is hard to find when warm too?

Thanks for reply.
Actually neutral is easy to find, would put into neutral when i was still rolling. . It clucked going back into 1st when light changed.
Its way better now. When time for oil change Ill put in 20w-50

[Duke McDukiedook]

I would only recommend using 20w-50 if you have temperatures consistently above 70F.
Otherwise that can be kinda thick for cooler temperatures and cold startups.