Motorcycle Repair: Clutch slip 1970 Honda cb 350, honda cb 350, wet clutch

Question
QUESTION: Hi Rich,
I've got a problem. The clutch on my old 1970 Honda CB 350 now slips when I'm kind of going up hills or trying to speed up. This happens through all the gears.
First I thought it was because of the oil I was using (20W50 rather than the 10W40 the manual recommends) but now I think the clutch slips because of the way I've been parking it.  You see, the problem is that I have to share my garage with a friend (who drives a car) and there's not much space left over. For that reason, sometimes the bike has been lent up against the wall for a week or so with the clutch semi-engaged (the clutch leaver being forced in about an inch because there's no space and its the only to leave the bike in there).
So, if this is the problem, what can I do to get excess oil out of the clutch plates?
Also, do you agree that a full mineral based 20W50 oil is too thick for my 1970 Honda cb 350? Should i really be using 10W40 mineral based oil?
I hope you can help me with this problem - I really love my old bike and it's really sad that it's now playing up on me.

Thanks for any help
Scott

ANSWER: Scott, it's possible the fact that the clutch is constantly compressed the springs have relaxed and can't apply the right load on the clutch.  The clutch is flooded with oil all the time so it's designed as a wet clutch.

I don't think the oil you are using makes a difference unless it's a synthetic.  I've had trouble with synthetic oils causing my wife's clutch to slip the first time I tried using it.  

It's possible the clutch is worn out just needs to be replaced.

Regards
Rich

---------- FOLLOW-UP ----------

QUESTION: Hi Rich,

Thanks for the follow up.  It’s interesting you should say that leaving the clutch semi engaged might not be the problem, as after doing a little bit of research it occurred to me that I might have what’s commonly called a ‘glazed clutch’.  What I was planning to do was to pull the clutch out (it’s not a very difficult operation I believe?), remove any excess oil around the plates and do a basic oil change (I’m going back to 10W40).  On this point, the oil capacity on my bike is 2L I believe.  How much oil should I really be putting in? 2L or a little bit less/little bit more?

Finally, if it does turn out that the clutch is kaktus, does that mean that I just need to buy a complete new set of clutch plates? Or a complete clutch assembly??

Hope you can answer my (probably obvious) questions
Scott.


Answer
There's a dipstick has a high and low mark and anywhere in between there is good.  If the clutch is worn out, you just need to replace the friction disks.  Provided the metal plates aren't all blue and warped.  If they are warped you will need to replace both friction and metal plates.

Regards
Rich