Author Topic: Rotten clatter!  (Read 609 times)

Offline UncleD

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Rotten clatter!
« on: 11.02. 2019 08:30 »
1958 Super Rocket.  At around 55mph I get a rattle that seems to be coming from the top of the motor.  It seems to diminish at 60mph so feels like it is within this vibration /harmonic range.   

I have checked tank and engine mounts and other possibilities for loose external fittings.

I rechecked the tappets and found what looked like fine metal fragments on the top of the right inlet valve stem .  The valve clearances were all a little tight but not overly so; I rectified these with little improvement in the rattle  (perhaps some or perhaps my imagination).  The noise does not seem isolated to the right side of the bike but it's a bit hard to tell at 55mph.

Not burning or using oil.  Compression is good.  Starts and runs fine.

I do have badly unbalanced points gaps (outside reasonable tolerances) and am getting a richer reading from the right cylinder plug (not overly so but not as lean as the left cylinder)...no pinking.

Could the points gap be causing a timing problem that is causing the valve noise / damage?

I am getting an experienced friend to help me with the magneto but am wondering if the rattle and points issues could be connected?

Northern Territory, Australia

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Re: Rotten clatter!
« Reply #1 on: 11.02. 2019 09:52 »
G'day D

I had a similar vibration at that speed and it turned out to be the tank. Do you have the strap fitted to tie the tank halves together?
I think my tank is an Indian made one and the gap in the centre is slightly wider so I had to make a longer strap - also, even with the rubber buffers fitted, the tank still rattled at that speed. The solution was to snug it round the frame with some foam pipe insulation taped in place which fixed the problem.

Jim
1959 A10 SR
1938 Wolseley 14/60
1955 Ferguson TEF20 tractor
1965 Ferguson 135 tractor
1952 Matchless G80 rigid
1960 BMW R60

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Offline UncleD

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Re: Rotten clatter!
« Reply #2 on: 11.02. 2019 10:07 »
Thanks Jim,
Yes I have the tank strap in place and some thick rubber tubing on the frame.

Of note is that although the sound of the rattle seems to be in the head, the vibrations can be felt in the tank, handlebars etc .  Probably notice this more now that I have replaced a broken head-steady bracket.

Northern Territory, Australia

Offline berger

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Re: Rotten clatter!
« Reply #3 on: 11.02. 2019 14:01 »
mine had a really bad clatter that made me think the rockers were starved of oil and they were because I had put the pipes  on the wrong way *problem* *bash* , this was also added to with piston slap but this is a story that I covered some time ago. my next clattering came last summer on a hot day and I convinced myself the rockers were being starved so I checked and this wasn't the case *good3*, the bike has a rubber mounted honda tank and has carpet underlay wrapped around the frame. as I sat uprightish [ clip-ons fitted] it was terrible but as I leaned out to listen to the rockers it was ok. *bright idea* so I took the tank off and replaced the old mounting rubbers and underlay, this cured my rattle . I am not saying this is your problem but tank mounting is a thought *dunno2*

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Re: Rotten clatter!
« Reply #4 on: 11.02. 2019 15:06 »

 I hear more rattles when I'm low on fuel..... *eek*

 
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......... because I had put the pipes  on the wrong way *problem* *bash* , ........

   Which way is not the wrong way ?    *conf2*
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Offline berger

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Re: Rotten clatter!
« Reply #5 on: 11.02. 2019 17:26 »
"which way is not the wrong way"---- well its putting the feed from the tank to the feed on the crankcase and not putting it to the return *bash*

Online bsa-bill

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Re: Rotten clatter!
« Reply #6 on: 11.02. 2019 17:54 »
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well its putting the feed from the tank to the feed on the crankcase and not putting it to the return

Whooaaa don't do any lottery or buy raffle tickets as you've used up all your luck for a decade or two
Thats if I read you correct "feed from the tank" might better be described as "return to the tank"
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Online RichardL

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Re: Rotten clatter!
« Reply #7 on: 11.02. 2019 19:48 »
I had a (maybe) similar rattle. The noise would be substantially reduced when I clamped my knees hard against the tank. Turned out to be the nut on the top head-steady bolt was contacting the tank. I've ground down the bolt length and nut thickness and all seems fine.

Richard L
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Re: Rotten clatter!
« Reply #8 on: 11.02. 2019 20:49 »

 
Quote
"which way is not the wrong way"---- well its putting the feed from the tank to the feed on the crankcase and not putting it to the return *bash*

 Ooooh- a 'down there' issue... You tried to suck the oil *out* from the  return & rocker feed to supply the (air) pump..... *eek*  so, *bash* ...though maybe the oil tank had enough head to self-syphon some to the rockers (nah- only if overfilled)
     
 
Quote
Thats if I read you correct "feed from the tank" might better be described as "return to the tank"

 back to topic....

 
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Offline UncleD

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Re: Rotten clatter!
« Reply #9 on: 11.02. 2019 20:54 »
Righto, as much as I think my tank is solid, I'm going to have a good look at this again. 90% of problems have the simplest causes.

But just to appease my negativity bias...
If in fact there were some fine metal splinters at the tappet of the right inlet valve (my eyes are not the best), what might cause this?  If it were just poor adjustment I would expect loud tappet noise all the time.  Could it be a problem with the valve spring?  What other indicators would be present if this were the case?

Northern Territory, Australia

Online RichardL

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Re: Rotten clatter!
« Reply #10 on: 11.02. 2019 21:52 »
With regard to the metal fragments, maybe take the adjuster all the way out and look at its tip to be sure the metal hasn't broken away at that point. That would probably cause some clatter. Also, it's not impossible to have simultaneous problems to add to the confusion.

Richard L.
Plan on signing up for the world-wide 2017 DISTINGUISHED GENTLEMAN'S RIDE on September 30, 2018. Watch website at https://www.gentlemansride.com for details.

Offline UncleD

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Re: Rotten clatter!
« Reply #11 on: 12.02. 2019 08:42 »
... it's not impossible to have simultaneous problems to add to the confusion.

Richard L.

Ain't that the truth!

Northern Territory, Australia

Online bsa-bill

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Re: Rotten clatter!
« Reply #12 on: 12.02. 2019 10:13 »
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back to topic....

apologies - note to self, don't assume your on topic with a reply
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

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Re: Rotten clatter!
« Reply #13 on: 12.02. 2019 17:19 »

 
Quote
Quote

    back to topic....


apologies - note to self, don't assume your on topic with a reply

  Bill-  I wasn't having a shot at you, just nipping it in the bud before it had a chance to go awry..... *beer*
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Online bsa-bill

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Re: Rotten clatter!
« Reply #14 on: 12.02. 2019 17:38 »
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  Bill-  I wasn't having a shot at you, just nipping it in the bud before it had a chance to go awry

no problem Dutch, I dodge in and out the house when weather allows and don't always take as much notice as I should
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco