Author Topic: Intermittent tapping  (Read 353 times)

Offline BSA500

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Intermittent tapping
« on: 07.01. 2019 18:29 »
Prob along the same lines as Greybeard but I have a tapping when riding notvalve clearance could be followers?. But now I get a delayed tap out of nowhere just like a valve shutting out of sequence etc.
 The bottom end has new shells/bearings/small ends I know I need to pip the top off but what should I check/look for oh maybe loose guides how do they present thanks Andy

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Re: Intermittent tapping
« Reply #1 on: 07.01. 2019 19:38 »
G'day BSA500.
A loose guide will give a tapping sound when the valve spring keeper touches it (pushing it back down). Not heard when cold or even warm but will when hot a and worse the hotter it gets. Tell tale sign is if inlet smoke or exhaust oil in the pipe.
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'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
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Offline BSA500

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Re: Intermittent tapping
« Reply #2 on: 07.01. 2019 19:57 »
She has been burning a little oil for a while even after a rebore. Lots of smoke after being parked on the side stand for a couple of months, Might suggest drive side guide needs attention.

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Re: Intermittent tapping
« Reply #3 on: 08.01. 2019 05:12 »
G'day BSA500.
Is it iron or alloy head? More prone on an alloy head with cast iron/steel guides.
Smoke after park up might be wet sumping. Also rings may not have bed in properly. A soft run in can do that.
Drain the sump before next start up. Listen for the rattle and observe the exhaust smoke. If the rattle starts after she has warmed up and the smoky exhaust happens about the same time I' say yes it's a guide.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline BSA500

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Re: Intermittent tapping
« Reply #4 on: 08.01. 2019 07:22 »
It's an alloy headed A7. I checked the oil levels and no wet sumping and the rebore was a couple of years ago. I think the  oil burning has be gradualbut now increased along with some rattles etc

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Re: Intermittent tapping
« Reply #5 on: 08.01. 2019 08:40 »
G'day Andy.
OK. Bronze or CI? Is the rattle there on start up? Or how long after start up on a fast idle? Is it just one side? Can you hear it at idle when hot or do you have to rev it. Use a stethoscope (screwdriver) to pin point the rattle.
The only way to test is to take the head off, take the valve out and from the inside give it a clout with a piece of broom handle. Or stick it in the BBQ to 150C for 30 minutes and see if it moves with just thumb pressure.
Oversize guides are available +0.002" and 0.004".
Could you post a video on youtube?
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline BSA500

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Re: Intermittent tapping
« Reply #6 on: 08.01. 2019 12:35 »
i will pop the head off sometime during winter and have a play. I have an ongoing project with a car build so I shall fit it in where I can. Of course need it ready for summer  *smile*

Online Greybeard

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Re: Intermittent tapping
« Reply #7 on: 08.01. 2019 13:32 »
i will pop the head off sometime during winter and have a play.
A, you'll go blind and B, the bike will not be ready for the summer.

Offline BSA500

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Re: Intermittent tapping
« Reply #8 on: 08.01. 2019 19:42 »
Oh thee of little faith. But  yeah you're right won't be ready for summer prob find a whole host of issues. Should at least be sorted on the bottom end I spent most of last summer on that *smile*

Offline BSARGS650

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Re: Intermittent tapping
« Reply #9 on: 08.01. 2019 20:07 »
Mmmm...Good luck with your findings/project.  Unrelated to your problem, many years ago on my newly re-built RGS, I had a tapping noise when riding which drove me mad for some time.  Tried all sorts, stethoscope, screwdriver bunged up my ear, checking all fasteners.  Rode it around the block and the noise stopped - yippee!  Out for a real ride, the noise back again.  Eventually, it only happened when I rode the machine with my Belstaff waxed jacket on.  The culprit was one of the lower brass press fasteners vibrating against the Lyta alloy tank due to the position created with the clip-ons......

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Re: Intermittent tapping
« Reply #10 on: 09.01. 2019 08:26 »
Good one BSARGS650.
I had a vibe that blurred my vision, but only when I wore my glasses *ex* Loose lens  *bash*
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
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Offline BSA500

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Re: Intermittent tapping
« Reply #11 on: 10.01. 2019 13:16 »
Well I wont strip it down until I have the spare time so if I fancy a ride I can. The funny thing is the noises are most noticeable with the crash helmet on and closed(filters out the road/wind and assorted rattles). Forgot it has the brass guides.