Engine metallic rattle help

[Revvesupbikers]

I have a metallic noise coming from the front cylinder. CCT's have been changed to manual ones both front and rear.

Any help or guidance would be great.

Thanks

[sirch345]

The question is, were the manual CCT's fitted as suggested in this link:- viewtopic.php?f=31&t=28583

You need to have both cam covers removed so you can measure the up and down movement of the cam chain between the cam sprockets as described in the link above.

If not one or both may need adjusting, as in tightening up a little, too much slack in the cam chain. Hopefully the cam timing hasn't jumped in the process,

Chris.

PS. Welcome aboard

[Revvesupbikers]

Hi,

Thanks for your message.

Yes, this is the guide I followed to each point.

Put it all back together and then started it and it sounded horrendous, but only the front cylinder.

I did have to set the cam chain as it looks like it had jumped previously. What damage would this have caused?

I mean, it does run, but has the loud metallic noise.

He's a video of the sound

[tony.mon]

Hi,

Thanks for your message.

Yes, this is the guide I followed to each point.

Put it all back together and then started it and it sounded horrendous, but only the front cylinder.

I did have to set the cam chain as it looks like it had jumped previously. What damage would this have caused?

I mean, it does run, but has the loud metallic noise.

He's a video of the sound

You have bent the two inlet valves on the front cylinder.
Turn it off and don't start it again until repaired, if a valve breaks you will destroy the piston and possibly the whole engine.

Take off the front head and all will be revealed.

Then order two new inlet valves, a head gasket and, if you don't have them, a valve grinding tool and paste and a valve spring compressor.you will probably also need shims but you can't measure that until it's all back together.

[Revvesupbikers]

Brilliant, thank you

I'll try that

[grumpyfrog]

Question from the uneducated :
What would have caused this, moving the chain over 1 tooth?

[tony.mon]

At least more than 2 teeth out. The valves don't hit the piston on one or two teeth out.
with two teeth out at high revs they can touch, downshifting at higher revs, for example.

Sometimes this is caused by trying to rotate the engine to time the second cylinder without setting the first cylinder's cct properly.
What can also happen is that the chain rests on the point of the teeth on the lower (crank) sprocket rather than sitting at the valley of the teeth.
Then, as you rotate the engine it drops to the valley, but the cct is the much too loose, and the chain can then ride over the teeth as the engine rotates.

The cam stays where it is and the chain jumps three teeth or more, valves hit piston.

Or just getting the timing instructions wrong.
It's easy to rotate to the second cylinder, seeing the crank marks align and pulling the cct out. You need to rotate the the second time the marks align, if you time the rear cylinder first.