Author Topic: Another noise question -A7SS  (Read 4816 times)

Online muskrat

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Re: Another noise question -A7SS
« Reply #15 on: 06.04. 2016 20:46 »
That's another good point Greybeard. I remember my plunger tank did the same.
Cheers
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Offline BSA500

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Re: Another noise question -A7SS
« Reply #16 on: 07.04. 2016 21:59 »
http://i11.photobucket.com/albums/a170/bsa500/DSC04987_zpsjy4t8l7i.jpg

New nut and timing disc to hopefully sort the bike out  *smile*

adm edit: removed photobucket link, added as attachment

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Re: Another noise question -A7SS
« Reply #17 on: 07.04. 2016 22:26 »
Very nice. Makes timing so much more accurate and easy to see if there's a difference between the L & R. Aim for 32-35 deg BTDC full advance. 32 for low (91-) octane and 35 for high (98+) octane fuel.
Cheers
'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: Another noise question -A7SS
« Reply #18 on: 08.04. 2016 08:37 »
Stupid question time.The kit did not come with instructions, is the timing tool a stop for tdc?. If so I assume it must be tighten fully to be accurate, or do you shove a thin wire to indicate tdc through the hole in it ??

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Re: Another noise question -A7SS
« Reply #19 on: 08.04. 2016 09:39 »

 
Quote
..... is the timing tool a stop for tdc?.

 One would presume so, but may depend on the piston crown height, and the thickness of the head gasket or other things i haven't thought of.....after I lost the important part of the depth gauge, I've used a length of stainless filler rod vertical down the hole with marks on it that I align with an arbitrary mark on the rocker oil feed pipe- until I half-made a degree wheel *smile*
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
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Offline BSA500

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Re: Another noise question -A7SS
« Reply #20 on: 08.04. 2016 10:57 »
I contacted SRM and they have sent me a copy of the instructions. Its quite invloved. Later I could post them here if anyone needs them??

Offline BSA_54A10

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Re: Another noise question -A7SS
« Reply #21 on: 08.04. 2016 11:22 »
The piston stop is for finding TDC.
It is not a TDC stop.
You fit, rotate foreward till the piston hits the stop and mark the disc
You then do the same backwards.
The difference between the 2 marks is TDC.

So called TDC indicators are very inaccurate as +/-  7 deg is about .010"
+/- 5 deg is about .003"
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Online bsa-bill

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Re: Another noise question -A7SS
« Reply #22 on: 08.04. 2016 12:30 »
Quote
So called TDC indicators are very inaccurate as +/-  7 deg is about .010" +/- 5 deg is about .003"

Yes,  to realise how far they can be out use a dial gauge (can be got for around £20 UK) and have lots of use around a shed, it's the quite amazing time the TDC tool remains still "on right up" while the pistons still moves each way, doesn't happen with a dial gauge.

That said these old girls are quite forgiving in timing dept
All the best - Bill
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Online Greybeard

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Re: Another noise question -A7SS
« Reply #23 on: 08.04. 2016 14:24 »
The piston stop is for finding TDC.
It is not a TDC stop.
You fit, rotate foreward till the piston hits the stop and mark the disc
You then do the same backwards.
The difference between the 2 marks is TDC.

So called TDC indicators are very inaccurate as +/-  7 deg is about .010"
+/- 5 deg is about .003"

Sorry to be nit picking but finding TDC using the above method should be accurate as the angle, (of the dangle) is the same both sides of TDC. Finding accurate BTDC position using a rod aligned with the plug hole onto the piston crown is not going to be accurate. That BSA tip looked as though the rod was held vertically in the plug hole. Surely that should be ok?

Online RichardL

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Re: Another noise question -A7SS
« Reply #24 on: 08.04. 2016 14:43 »
A little thing to check is the that the fuel tank is really solidly attached. I had a very strange and scary noise soon after I put my old girl back on the road. I think someone here suggested checking the tank attachments. Seems the petrol tank can resonate with vibration. I gave the attachments a good nip up and the noise went away.

I was hesitant to mention this until I saw the posts from GB and Muskrat as reinforcement, but I had a similar RPM-specific noise that I tracked to my tank (by pushing my knee hard against it while riding). A bit embarrased here that I can't recall if it was due to a loose center bolt or the tail of the tank in physical contact with the frame, or both. I do know that reseating the tank and a good tightening fixed the problem.

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Re: Another noise question -A7SS
« Reply #25 on: 08.04. 2016 15:19 »
Quote
A little thing to check is the that the fuel tank is really solidly attached. I had a very strange and scary noise soon after I put my old girl back on the road. I think someone here suggested checking the tank attachments. Seems the petrol tank can resonate with vibration. I gave the attachments a good nip up and the noise went away.

 I get a bit of noise when I'm low on fuel *eek*
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 metalflake11

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Re: Another noise question -A7SS
« Reply #26 on: 08.04. 2016 16:10 »
 I get a bit of noise when I'm low on fuel. *eek*

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Online Greybeard

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Re: Another noise question -A7SS
« Reply #27 on: 08.04. 2016 16:22 »
I get a bit of noise when I'm low on fuel *eek*
Wind?

Offline BSA500

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Re: Another noise question -A7SS
« Reply #28 on: 08.04. 2016 20:43 »
Well update tried the SRM nut and before and after extra sideplay in the crank  *sad2* *sad2* *sad2*. Rough measurement said 6 thou but I could 'see' movement so it could be more. Again no shim break up. If this proves nothing else, with the crank  cush nut correctly torqued excessive clearance cannot be removed with that nut  *sad2*.
Why this happened again, well the strip down might help I hope and fix it for all time.  Another thing for another topic/post checked the clutch/crank sprocket alignment and the clutch sits 'behind' the engine sprocket by 1/4 inch  *conf*

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Re: Another noise question -A7SS
« Reply #29 on: 08.04. 2016 22:32 »
Primary misalignment would be the 1st thing to rectify. That would put thrust on the crank towards the timing side. That would wear the thrust face of the bush and create more end float.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7