Grinding Sound when decelerating

[Bon]

During cruising and acceleration my 1965, 305 Dream, transmission works great and sounds great. However, when decelerating, the transmission exhibits a distinct change in sound. It's best described as a grinding rather than a higher pitch whine. "Grind" is a strong word but it is a low pitch metalic sound. Seems to be the same in all gears. I've been thinking that it might be bearings because if it was gear wear then it would likely be a different sound depending upon the gear I am in . This bike only has 6,000 miles on it so it has been sitting a lot to say the least. Again, my guess is bad bearings but which? Soon I'm going to take off the right side cover and chain guard to inspect the counter shaft sprocket and chain for wear so that I don't overlook anything there. How about it guys, does your transmission sound different in deceleration?

[kustommusic]

Bon, That is a tough one! I think I would call Ed Moore and introduce myself. He is a real good guy and Very knowedgable. And he probably spells better than me[email][/email]emo@ktc.com Good Luck! Steve Greer<br /><br />

[FLYHAVEN2001]

One of my CA77 engines makes a different whining or a different noise too when slowing down , otherwise is a great running engine???

[Bon]

Yes, otherwise is a great engine, decent clutch and shifts fine.

[LOUD MOUSE]

My best guess is that the kick shaft is warn at the 21 tooth counter shaft where the 12 small roller bearings are. If the shaft is warn all the gears on it will not align correctly to the gears on the main shaft. ...........................

[mikescottt]

My 64 dream has the same bad gear noise on all down shifts. I wonder if its normal? Hope someone replys with the answer. It seems to be a very common problem.

[DavidK]

My best guess is that the kick shaft is warn at the 21 tooth counter shaft where the 12 small roller bearings are. If the shaft is warn all the gears on it will not align correctly to the gears on the main shaft. ...........................

This is a very common fault on all bikes with the same transmission design as the CB72. The kickstart shaft starts to break up at it's surface and steel starts to migrate.
The tiny roller bearings eventually become damaged and the whole lot becomes a mess.
the only solution is to replace the shaft, bearings and probably the counter shaft ( it comes in 21 24 and 26 teeth).

All of this goes on inside the gearbox without any signs until the real damage has occured.
I have seen some damage on at least 50 per cent of the transmissions I have stripped. It's very similar to the main bearing on the right (generator) end of the crankshaft, where Honda run a steel shaft direct on the rollers of a bearing. I suspect the depth of hardening is quite thin as its very common to find damage.
I would always recommend checking both these bearings on any old engine.