Topic: In need of some help!

[dwain61]

Hey Guys
My friend recently recieved a 1975 CB750F from his in-laws.  It had been parked in a barn for many years and they just wanted to get rid of it so they gave it to him for free!!  It is in pretty good cosmetic shape and has about 21xxx miles on it.  Well I have some experience with bikes so I have been helping him get this thing roadworthy again and have run into two problems. 
    The first is that the master cylinder for the front brake is not pumping brake fluid.  I have attempted to take it apart to see if it needs a rebuild kit but there is a nasty little snap ring in there that I cant seem to find the right snap ring tool to get it out of there.  Any suggestions?
       The second more major problem is that when the engine is running it refuses to climb above 4000 rpm and I am hearing some nasty chatter coming from what sounds to me like the bottom end.  It almost sounds to me like a bad bearing on the crank.  Is there anything else that would make this kind of chatter?  Primary chain?  Cam chain?  Any advice on where to start looking would be very helpful.
Thanks Guys   DJ

[Bob Wessner]

I had good luck with these from Sears for removing the circlip. If it is badly rusted, might want to soak it a bit in liquid wrench or the equivalent first.

You named most of the probable noise makers. Might want to try adjusting the cam chain tensioner first to eliminate one possible cause.

[dwain61]

Thanks for the help Bob.  I'll have to get down to sears today and see if those will work.  I'll also take a look at the tension on the cam chain an hope that it is my noise maker.  Does the primary chain have a tensioner?  Other possibilities for noise? 

[Bob Wessner]

Was the noise present with the clutch in, or out? If only while the clutch is in, it could be the carbs are out of synch and the clutch basket makes a rattling sound. Syncing the carbs usually helps, though I have never been able to completely eliminate it on my K0, but maybe I'm just not that good at the syincing business.

[dwain61]

If I remember correctly it didnt matter if the clutch was in or out.   Same nasty chatter either way.  I am just really hoping that it is not a bearing because this bike is in too good of shape to part out.  Thanks for the heads up on those pliers too Bob.  I got the ring out without too much trouble. 

[rklystron]

I had a very similar noise problem when I finally got my 750 K0 up and running for the 1st time in 23 years. The problem I found that was making a noise like you described. It turned out to be a bad slow speed jet for my #3. As it turns out #3 was dead and the rest of the engine was taking #3's load. The other 3 cylinders sounded great and it wasn't until I started to choke all the carbs individually that I found 3 was bad. Fixed the slow jet on 3. Rattle gone. You may want to check and see if all your cylinders are firing. I thought mine was lower end as well.