Engine Knocking Noise between Clutch and Gearbox- Video Link

Hey guys,
Wondering if you can give me some guidance. I've been able to get my 71 running over the past week after a bit of going through.

There is a pretty regular knocking noise that i believe is coming from between the clutch plates and the gear box, not sure what it is or how best i can address.

I've attached a video i posted on youtube:

http://www.youtube.com/watch?v=5uudlYPoERA

Any help you guy can provide would be greatly appreciated.

thanks
Paul

Re: Engine Knocking Noise between Clutch and Gearbox- Video

Yeah, that's the banjo valve whacking against the fratostat...... it's a terminal problem. It pretty much reduces it to a parts bike, I'll pick it up and give you $500 for it..... Just let me know when it's convenient....

(Sorry, no help here, sounded like an exhaust leak to me. Sage advice should be soon in coming.... Good luck)

Rod R
[ p.s. Serious about the $500 : ) ]

Re: Engine Knocking Noise between Clutch and Gearbox- Video

LOL Paul, we have all played this game, some for decades, the final answer always comes from the one tearing it all down and should always still being suspicious if only finding one obvious thing - preventing tearing all the way down again.

I've had crank or clutch nuts come off and sound like that till they jumped up to badly damage stuff. Could be chain clash slack or clutch center bearing gone sour.
After primary and clutch removed let us know the findings. Forum loves dirty pictures and video.

Re: Engine Knocking Noise between Clutch and Gearbox- Video

Check that the left header pipe is not hitting the underside of the primary case.

Mick

Re: Engine Knocking Noise between Clutch and Gearbox- Video

Im going to say countershaft sprocket nut lock washer. Phil

Re: Engine Knocking Noise between Clutch and Gearbox- Video

Kinda hard to tell by the video - but could be your primary chain slapping against the case, or fouling against the side of the case if the clutch basket is spaced too far inboard (or if the primary cover is spaced too far outboard.

Re: Engine Knocking Noise between Clutch and Gearbox- Video

Sounds like a chain slap to me or perhaps a tappet set very wrong, far from a definative answer, the audio is not so good.

Use a screw driver up to your ear and try to find where the noise is coming from ( or stethoscope if you've got one ).

Suggest putting the bike:

in gear,

out of gear,

clutch in,

clutch out,

rear brake on, with bike in gear and a little tension on the clutch.

Pull the primary cover off, look for metal grindings,

On the centre stand,

On the side stand,

Does it make the noise at higher RPM ?

When you work out when the noise is and is not heard, some here will then have a better chance of helping ( are you sure your tappets are set right ?, pull the plugs and spin the engine with the covers off and check there is not an unexpected error ).

Do not run the bike too much as it may be something not so trivial.........

Re: Engine Knocking Noise between Clutch and Gearbox- Video

paul_b said:

Hey guys,
Wondering if you can give me some guidance. I've been able to get my 71 running over the past week after a bit of going through.

There is a pretty regular knocking noise that i believe is coming from between the clutch plates and the gear box, not sure what it is or how best i can address.

I've attached a video i posted on youtube:

http://www.youtube.com/watch?v=5uudlYPoERA

Any help you guy can provide would be greatly appreciated.

thanks
Paul

Click to expand...

Hi Paul I would remove primary chain case completely (including clutch basket) its not a long job. When someon identifies the noise it will probably require a strip down anyway.( Unless its primary chain slap ),

Good luck

Re: Engine Knocking Noise between Clutch and Gearbox- Video

I would agree with the chain slap, easy to check, just pull the primary cover.

Re: Engine Knocking Noise between Clutch and Gearbox- Video

Don't rule out your alternator rotor loosening on it's center bore section.

Clamp the center in a vice with a washer on each side, then attempt to wiggle/rotate it with a large pair of channel-locks pliers.

Any looseness = replace.

Re: Engine Knocking Noise between Clutch and Gearbox- Video

I've had chain slack striking primary case and it has more definitive chain dragging across pipe sound of links passing, not the loose random strikes sound in video.
Altn rotor striking stator has more dulled rubbing sound not hi pitch tinkle.
This sounds similar to the light tinkles I heard as a rod bolt broke and made
a couple of rounds before seizure. We could go down the parts list in manual guessing but won't know what to buy next till its opened and checked.
Ugh often if one thing has gone wrong to sound that bad then what else along with it not yet noticed.

Could be in transmission sleeve gear bushes so worn the clutch basket wobble is striking inner case. If chain ever got too tight when too hot a series of wrongs in drive train may show up one after another if not fixed in one go. damhik.

Re: Engine Knocking Noise between Clutch and Gearbox- Video

Hey Paul, Did you ever find what your knocking noise was? Phil Paul, Dont make me PM you :mrgreen: