76 cb750 engine noise question

[southernsnake428]

I just bought a 76 cb750 that has what appears to be cam chain noise,I have adjusted it according to Clymers manual, except that I didn't worry about being 15 degrees after TDC.I did achieve TDC by holding my finger over the #1 spark plug hole and finding both rockers loose.Engine runs good,does not smoke,has good power.I've been told not to let it bother me,just ride it.Is that true?Whats making the noise?Is it a serious problem & how difficult is it to fix?Bike supposedly has 27,000 miles,Thanks for any help guys.Chris

[mikey440]

 Hey there, does the noise get quiet when you pull the clutch lever in,
 if it does then it is probably the clutch basket and clutch plates rattling around a bit, my 82 750k does it also, noise goes away also on increased rpm,s, some say to syncronize carbs,helps because of uneven firing of cylinders so gets a little out of balance, but i believe
the clutch basket is the culprit, alot of guys call it the death rattle and they just live with it,
 ive heard some pretty raspy soundin 750,s on idle, sounds like a bunch of walnuts in a barrel
goin down a hill, so try running your bike on idle and pull in the clutch and see if it gets quieter,,hope so,,,good luck,,mike

[brcree]

  I have a 76 cb750 myself....and the cam chain sounded really bad until I changed over to Amsoil. I would try the clutch lever just to make sure. As for carb sync......do it.....mine were all way out and I could never get it to idle or run smooth. It runs like a new one now! Make sure your valves are ajd., carbs are clean ( I put a in line fuel filter) in just in case. I will be putting in new dyna coils next week. Hope this helps.

[southernsnake428]

Thanks,guys,I am new to cb's and the forum,thanks for having me.I did notice if I let the clutch drag with it in gear and hold the brake, it took a lot of the noise out

[Re-run]

Son, what you are riding is an air cooled bike. You will notice odd sounds that would be absent in a water cooled engine. There will always be some goofy sounds. Some people even claim to hear the noise from the points but I think it is just exhaust fumes getting to them.

Part of a tune up regime is a carb sync. You can use either vacuum gauges, mercury gauges or what is called a morgan carb sync. Many people talk highly of the morgan and it IS good but you can do just as good of a job with the others. The morgan is just easier. Expect to spend 50-100 bucks for one of these at least. I know it sounds expensive but a shop may charge you that much to do that job and it may need to be done every couple of years. Actually, anytime the slides are removed, the bike MAY require one. So the tool is cheap when you compare it to 1 or 2 shop visits.

Also, the cam chain can be adjusted while static or running. I have a 78 and the cam chain set up is identical and the Honda SHOP MANUAL says to do it while running. HOWEVER, the tension unit can get gummed up and not move. Remove the unit and clean it out good. there is a fair amount of spring tension so be careful you dont shoot yourself in the eye with it or shoot it across the garage!