Author Topic: A7 timing side noise  (Read 2637 times)

Online muskrat

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Re: A7 timing side noise
« Reply #15 on: 13.07. 2017 20:44 »
G'day Anji.
I still think it's the backlash in the gears. It only takes a few thou" to get the tick-tock. turning the motor over the cam is pushing one valve open then as it goes over max lift another valve is on it's way down and exerts backward pressure on thr cam and tries to turn it backwards. Then the cam catches up as it starts to push the next valve.
If you take both covers off (leaving the idler in place) and turn the motor over you will see it happening.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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Muskys Plunger A7

Offline anjimehra

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Re: A7 timing side noise
« Reply #16 on: 17.07. 2017 07:08 »
G'day Anji.
I still think it's the backlash in the gears. It only takes a few thou" to get the tick-tock. turning the motor over the cam is pushing one valve open then as it goes over max lift another valve is on it's way down and exerts backward pressure on thr cam and tries to turn it backwards. Then the cam catches up as it starts to push the next valve.
If you take both covers off (leaving the idler in place) and turn the motor over you will see it happening.

Cheers
Hi Muskrat
Thanks. Took off the timing covers, plugs, & turned the engine by hand. Noise. Took the tappets right off, noise still there. Removed the rocker box , no noise. The only backlash is on the mag auto advance gear, but this is fibre & shoudnt be a contributing factor in my opinion. No play in the rockers. Cam bushes new. Backlash on gear train very negligible, almost 0. Cam bushes have been line bored & no radial play. Even changed the auto advance springs. Really not keen to strip the engine again.
Take care, cheers

Offline anjimehra

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Re: A7 timing side noise
« Reply #17 on: 17.07. 2017 07:12 »
  May be a REAL long shot,  but do you have the stock studs on the Primary chain tensioner ? I know is not the side that the sound is,  but no other suggestions are working.
 If  you have non-standard studs in there,  maybe they're too long and banging on the crank Web (or crank web is banging on them) -once per revolution
  *dunno*
Hi Dutch
Studs are original. Sound happens when the valves start opening / closing. Have turned the engine over slowly by hand & seen this happen

Offline anjimehra

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Re: A7 timing side noise
« Reply #18 on: 17.07. 2017 07:13 »
a valve adjuster is not hitting the rocker cover is it? that makes a row.
Negative, Checked that. Thanks

Online Joolstacho

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Re: A7 timing side noise
« Reply #19 on: 17.07. 2017 07:14 »
Anj, has it occurred to you that these things ARE old rattly motors. They were like that when they were new. You seem to have covered most of the bases, maybe you're worried about nothing!

Offline anjimehra

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Re: A7 timing side noise
« Reply #20 on: 17.07. 2017 07:21 »
Anj, has it occurred to you that these things ARE old rattly motors. They were like that when they were new. You seem to have covered most of the bases, maybe you're worried about nothing!
Point taken Joolstacho. Just worried it's that & nothing more serious. Even my Plunger flash is noisy & Ive driven her on long hauls of 1500 kms with no hassles. So maybe you're right

Offline anjimehra

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Re: A7 timing side noise
« Reply #21 on: 17.07. 2017 07:24 »
G'day Anji.
I still think it's the backlash in the gears. It only takes a few thou" to get the tick-tock. turning the motor over the cam is pushing one valve open then as it goes over max lift another valve is on it's way down and exerts backward pressure on thr cam and tries to turn it backwards. Then the cam catches up as it starts to push the next valve.
If you take both covers off (leaving the idler in place) and turn the motor over you will see it happening.
Cheers

Another thought just occurred. Is it possible that the valves could be touching the piston

Online Joolstacho

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Re: A7 timing side noise
« Reply #22 on: 17.07. 2017 08:04 »
Mate, I think if valves were hitting the pistons you'd have more problems than a little noise!
If that were happening you'd soon have a bent valve and loss of compression.
How high have you revved it?

Offline chotus52

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Re: A7 timing side noise
« Reply #23 on: 17.07. 2017 12:24 »
I wouldn't set the tappets at .002. The correct setting is .008 for the inlet & .010 (.012 in the maintenance manual) for the exhaust. You will lose power plus burn an exhaust valve if they're too tight.
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Offline Klaus

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Re: A7 timing side noise
« Reply #24 on: 17.07. 2017 12:33 »
G'day Anji.
I still think it's the backlash in the gears. It only takes a few thou" to get the tick-tock. turning the motor over the cam is pushing one valve open then as it goes over max lift another valve is on it's way down and exerts backward pressure on thr cam and tries to turn it backwards. Then the cam catches up as it starts to push the next valve.
If you take both covers off (leaving the idler in place) and turn the motor over you will see it happening.
Cheers

Another thought just occurred. Is it possible that the valves could be touching the piston


Yes, iff the valvegiude is not in the correct angle and a little bit out offline the valve can touch the outside from the valvepockets at the inlet valve, because it is bigger diameter than exhaust.

By building  up some engines I have learned everything can happen.
Fit new conrods and pistons and by running there was a twittering noise. My first thougt it take a little time to keep oil up to the rockers, they were also new. The noise growing bigger when the engine get worm. I opened the timing side to get the ignition a better set up there was a little alloy flitter swiming in the oil.  Damned....another strip down..
It was the pistonshirt that touched the flywheel by a whisker... *eek*

Take a negative selection, sort out what not can happen.


If you think, everything is under control, you are not fast enought.

Online mugwump

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Re: A7 timing side noise
« Reply #25 on: 17.07. 2017 12:38 »
If the valves or guides are worn the valve head can make a clack sound as it seats.

60'Matchy G12
58 AJS 18s
58 Ariel Huntmaster]

Offline anjimehra

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Re: A7 timing side noise
« Reply #26 on: 18.07. 2017 06:27 »
I wouldn't set the tappets at .002. The correct setting is .008 for the inlet & .010 (.012 in the maintenance manual) for the exhaust. You will lose power plus burn an exhaust valve if they're too tight.
Hi Chohtus, just set them at .002 to eliminate one possibility. Never ran the engine

Offline anjimehra

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Re: A7 timing side noise
« Reply #27 on: 18.07. 2017 06:33 »
Mate, I think if valves were hitting the pistons you'd have more problems than a little noise!
If that were happening you'd soon have a bent valve and loss of compression.
How high have you revved it?
Ran her for a few minutes at fast idle. Just a thought in case the valves were just "kissing" the piston at TDC non compression stroke. Can't otherwise fathom what could be the cause

Offline anjimehra

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Re: A7 timing side noise
« Reply #28 on: 18.07. 2017 06:34 »
If the valves or guides are worn the valve head can make a clack sound as it seats.
New guides & valves

Offline anjimehra

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Re: A7 timing side noise
« Reply #29 on: 20.07. 2017 07:26 »
Hi
Not really in the mood to strip the bike down again for the second time , so considering these are supposed to be noisy motors, should I just go ahead & run the bike ?