Author Topic: 1952 A7 valve gear  (Read 1202 times)

Offline duTch

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Re: 1952 A7 valve gear
« Reply #15 on: 18.06. 2018 11:53 »

 
Quote
Quote from: RogerSB on June 10, 2018, 02:18:20

    If oil is going up the pipe check that washers are not covering and blocking the holes.
    (edit) Added a picture to make it clear.


Not covering the holes Roger. Thanks

 Although anji's, if you've drilled the holes out, it may be advantageous.... *dunno*
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 anjimehra

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Re: 1952 A7 valve gear
« Reply #16 on: 20.06. 2018 13:34 »
Anji, not a good idea to enlarge those holes. Their part of a metering system. If too big more oil will go up there instead of the oil tank and could overwhelm the scavenge side of the pump.
These are not actual figures but just an example. Imagine there's 100 ml/minute of oil going in the feed side and the scavenge side can pump 120ml/minute at the same revs (that's why there's bubbles in the return to tank oil). Now say the scavenge pumps 90 to the tank and 10 to the rockers so in reality there's 110ml going in but that's OK as the scavenge can do 120ml. With larger holes say 70 to the tank and 30 to the rockers means there's 130 going in which is 10 more than the pump can handle. In theory the sump will slowly fill and the tank empty. As I said this is just theory but could happen. By increasing the hole from 3/64 to 1/16 will increase the area of the hole by 77% which is a sh!t load.
If the oil line is clear the banjos are clear and the shafts are clear there will be oil up there. With the motor running loosen one of the banjo bolts, oil should emerge. Tighten that one and loosen the other, more oil emerges. Tighten both. Remove tappet covers, start motor, finger over return pipe in tank, should be able to see oil dribbling out the rockers. If not the pump can't give enough pressure to get through the bolt holes. Time to look at the pump. Lap the end plate on a piece of glass with wet & dry (400 grit) till the gear wear marks are gone.
Well that just about wore the print off my one typing finger!
Cheers
Hi Muskie
Have taken a video clip of the sound but the forum is not accepting it I think because of its format. Can I mail or whatsap it to you
Cheers

Online Greybeard

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Re: 1952 A7 valve gear
« Reply #17 on: 20.06. 2018 13:43 »
Have taken a video clip of the sound but the forum is not accepting it I think because of its format. Can I mail or whatsap it to you
If I want the forum to see a video I upload it to YouTube and post a link to it here.

Offline RoyC

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Re: 1952 A7 valve gear
« Reply #18 on: 20.06. 2018 14:06 »
If I want the forum to see a video I upload it to YouTube and post a link to it here.

That's what I do.
My bike is a 1958 A7SS
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Re: 1952 A7 valve gear
« Reply #19 on: 20.06. 2018 19:16 »
G'day Anji.
Yes please mate. I'll then put it on youtube and post the link.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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Offline anjimehra

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Re: 1952 A7 valve gear
« Reply #20 on: 21.06. 2018 11:00 »
G'day Anji.
Yes please mate. I'll then put it on youtube and post the link.
Cheers
[/quote
Need your whatsapp number Mine is +919975292020
Cheers

Offline RogerSB

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Re: 1952 A7 valve gear
« Reply #21 on: 21.06. 2018 12:06 »
I often wondered why the small holes were slightly different, different part numbers, another confused. com sorted cheers

Rocker feed banjo bolts: As far as I know: small for inlet, large for exhaust - but for later Gold Stars only.

I believe there is also a similar bolt with a bigger hole used as a rocker drain bolt on the B series.

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Re: 1952 A7 valve gear
« Reply #22 on: 21.06. 2018 21:19 »
G'day Fellas.
Uploaded a video from Anji. https://youtu.be/7xFTj58ghF8
Anji, can you use a stethoscope to pin point the rattle? Most likely in the valve train but is it front or back of the rockerbox, or lower down at the lifters?
Cheers

PS: 1st time I've put up on youtube! Easier than I thought. Now I'm off twerk.
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Online chaterlea25

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Re: 1952 A7 valve gear
« Reply #23 on: 21.06. 2018 22:12 »
Hi All,
It sounds to me like the "tack, tack, tack" is at engine speed  *ex*

Pistons touching head gasket ??? (has happened  *ex*)

John
1961 Super Rocket
1963 RGS (ongoing)

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Re: 1952 A7 valve gear
« Reply #24 on: 22.06. 2018 08:52 »
G'day John.
You may be right. I was in a rush this morning and only listened to it once.
Anji, what comp pistons and have the barrels been decked (lowers the gasket in relation to the pistons)?
All the gasket kits I've seen down here have head gaskets for the A10 not A7 so it's larger than the A7 bore.  *dunno*
 The other problem of the return oil flow being continuous could be due to the banjo bolt holes being opened up in order to quieten the "tappet rattle".
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: 1952 A7 valve gear
« Reply #25 on: 27.06. 2018 14:13 »
Hi All,
It sounds to me like the "tack, tack, tack" is at engine speed  *ex*

Pistons touching head gasket ??? (has happened  *ex*)

John
Hi John
The gasket is the right size & pistons low compression with flat top ( not domed ).
Thanks, Anji

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Re: 1952 A7 valve gear
« Reply #26 on: 27.06. 2018 21:04 »
G'day Anji.
Have you been able to narrow down where the noise is coming from, top or bottom, drive or timing side? If you slowed the idle down it would be easier to tell if its full or half engine speed.
I notice there's no dynamo. With no dynamo drive sprocket there would be excessive end float of the idler pinion.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline coater87

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Re: 1952 A7 valve gear
« Reply #27 on: 28.06. 2018 10:45 »
 If you had the primary cover off, make sure one of the 3 forward most larger screws is not touching the crank and making that rattle.

 I would just back them out a ways and see if anything changes.

 Lee
Central Wisconsin in the U.S.

Offline anjimehra

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Re: 1952 A7 valve gear
« Reply #28 on: 10.07. 2018 06:34 »
G'day Anji.
Have you been able to narrow down where the noise is coming from, top or bottom, drive or timing side? If you slowed the idle down it would be easier to tell if its full or half engine speed.
I notice there's no dynamo. With no dynamo drive sprocket there would be excessive end float of the idler pinion.
Cheers
Hi Muskie
Thanks for posting & feedback. Sorry for delay in replying as I was out of station. The noise appears to be from the timing side . Have put the dynamo drive sprocket back on but noise persists. There is a little play in the breather hole that fits on the cam gear wheel pin. Could the sound be because of the advance retard springs having lost their tension??
Cheers

Offline JulianS

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Re: 1952 A7 valve gear
« Reply #29 on: 10.07. 2018 09:09 »
Timing side noises may be from wear in idler pinion or idler pinion bushes. Also possible that the crankshaft pinion may not be a tight fit on the shaft and is rocking on the woodruff key.