Author Topic: 1952 Plunger Flash  (Read 3059 times)

Offline anjimehra

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1952 Plunger Flash
« on: 05.01. 2011 12:31 »
Hi
Back again after a gap of 2 months.The bikes been on the road for about 3 months now & has logged on about 300 kms. Everything appears to be fine, except for noisy valve gear.The bike runs silent for the first 5 mts & then this distinct rattle from the valve gear.
Have tried increasing the oil flow to the rockers by blocking the return hole in the tank but not much joy.
The cam bushes are OK & the followers are old.The rocker shafts & rockers are also old, but did not show much play when tested by hand before assembly.
Any suggestions
Anji

Offline terryk

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Re: 1952 Plunger Flash
« Reply #1 on: 05.01. 2011 13:20 »
Take off the oil feed to rockers and while the bike is running get an oil can or plastic bottle oiler etc and squirt oil under pressure into the rockers shaft holes. If the noise goes away you know you need more oil there.
If the oil return to tank is a good pressure make sure the oil line to rockers and the rocker shafts are not blocked.
Sometimes old oil pumps dont have enough pressure on the return side to feed enough to the rockers. Maybe need a new pump?
Try the oil to rockers thing for a starter if the noise is still there with plenty of oil check tappets and on it goes.
These bikes are a bit noisy in the tappets anyway is there another bike near you to compare tappet noise.
Terry
1950-53 A10 rigid/plungers, 1958-61 A10 super rockets, 1947-50 A7 longstrokes, 1949 Star twin,
1951-54 A7 plungers, 1940s M21, WDM20s,
1948-50s B33s rigid/plunger/swingarm, 1948-50s b31s rigid/plunger/swingarm

Offline LJ.

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Re: 1952 Plunger Flash
« Reply #2 on: 05.01. 2011 13:34 »
Anji... What a lovely looking restoration that is! congratulations... Now all you need to do is take a nice long ride to run it in and get us a photo of the bike just in front of the Taj Mahal. That would be super! Cheers. LJ.
Ride Safely Lads! LJ.
**********************
1940 BSA M20 500cc Girder/Rigid- (SOLD)
1947 BSA M21 600cc Girder/Rigid-Green
1949 BSA A7   500cc Girder/Plunger Star Twin-(SOLD)
1953 BSA B33  500cc Teles/Plunger-Maroon
1961 BSA A10  650cc Golden Flash-Blue
1961 BSA A10  650cc Golden Flash-Red

Online bsa-bill

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Re: 1952 Plunger Flash
« Reply #3 on: 05.01. 2011 13:44 »
Hi Terry

Nice work

Just a suggestion

Sounds like maybe tappets after warm up?
what gap are you running on them, I would try closing them a bit,  some bikes ( Triumph I think) used to have no clearance on tappets when the bike was cold, they were set so they just turned then as everything reached running temp the clearance was right.
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

Offline RichardL

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Re: 1952 Plunger Flash
« Reply #4 on: 05.01. 2011 17:18 »
Anji,

Good to hear from you again. Almost a guarantee that you would win Best Picture 2011 with the bike in front of the Taj Mahal, or one of the other exotic locations (from the viewpoint of the American midwest)  to which you tour. Yes, it is a fantistic looking bike, but what exactly did you not like about the pre-resoration version?

Regarding the valve noise, it occurs to me that if it were simply oil starvation, the noise would occur right at startup, having already been starved at the previous shutdown. It would be interesting and important to pinpoint the origin of the noise. Have you tried a noise probe between the engine and your ear? I use a long 3/8" ratchet extension with the male end closing my ear by pressing against the tab of cartilage that you would press if you were closing them with your fingers. The other end is then touched to vaious points on the engine. The ability to discern noise localization this way is amazing versus just pointing your nose in the general direction.

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 a10gf

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Re: 1952 Plunger Flash
« Reply #5 on: 05.01. 2011 21:41 »
Nice to see you on the forum, happy new yesr, and nice to see the bike, what a good work ! As mentioned, why not try taking a picture of the (great) bike in a great surrounding, and enter it into the best picture contest ?
e

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Offline muskrat

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Re: 1952 Plunger Flash
« Reply #6 on: 06.01. 2011 07:47 »
G'day Anji,
              gee that's a great looking bike.
 I think you will find the tappet clearances close up when hot so don't go any smaller than what is recommended for your model.
 Might be a sticky exhaust valve that grows a little when hot, just enough to give a tappet noise.
 Just another thought.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline A10Boy

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Re: 1952 Plunger Flash
« Reply #7 on: 06.01. 2011 11:40 »
If it only happens when the engine warms up it could be a loose valve guide. Tight when cold but when the head heats up and expands it goes loose and rattles around.

Beautiful resoration BTW, it looks lovely.

Regards

Andy

1960 A10 - Black Golden Flash
Plus
1974 Kawasaki Z1a
Yam XJR 1300

Online bsa-bill

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Re: 1952 Plunger Flash
« Reply #8 on: 06.01. 2011 14:42 »
Terry sorry if I sent you a bum steer there, now I always thought tappet clearance grew as the engine got up to temp hence the setting to just have the pushrod turn when cold.
Now your all telling me this is wrong and I do respect your knowledge on here - well you live and learn, although I'm not 100% convinced as of now - more research needed  *computer*
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

Offline MG

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Re: 1952 Plunger Flash
« Reply #9 on: 06.01. 2011 14:53 »
The valve stems expand with temperature, so clearance can only become smaller (assuming that the barrels and push rods expand for about the same amount).

Anji, very nice bike, great work indeed.
1955 A7 Shooting Star
1956 A10 Golden Flash
1961 Matchless G12 CSR

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Online chaterlea25

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Re: 1952 Plunger Flash
« Reply #10 on: 06.01. 2011 18:27 »
HI All,
My  ?0.02 worth
MG, the valves are only a couple if inches long and I would think that because of their smaller length compared to the cylinder / head and pushrods, the clearance increases when hot (I know the ex valve will be the hottest item in the engine!!)
My reasoning is backed up by observing that (as others have mentioned ) some engines are set with zero clearance cold
Also modern Harleys engines have allowances made for the expansion lengthways of the head and cylinder
Special "stretchy" head bolts are used, also hydraulic tappets to take up the bigger gap when hot!

Regards
John O R
1961 Super Rocket
1963 RGS (ongoing)

Offline beezalex

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Re: 1952 Plunger Flash
« Reply #11 on: 06.01. 2011 18:44 »
Judging whether or not the clearance opens or closes when hot depends on the bike.  Comparing an iron head A10 with other models to justify a supposition about this is pointless.  The temperatures in the engine are not uniform, so you can't just draw conclusions based on that.  What DOES matter is measurement and conclusions.  The one data point I have is that at the extreme, the exhaust valve clearances close up on an Iron head A10.  When pushed hard (and I mean 100+ mph), my somewhat tuned motor would open up the exhaust clearances and fire into the pipes.  Larger exhaust clearances cured this.

Now, Anji, first of all, what a great looking bike.  And they are a joy to ride, aren't they?  About the noisy valve gear, some of this may be relative.  Be sure to check oil delivery to the top end and your clearances, but it is normal IME for the valve gear to get a bit noisier as the motor warms up.  This is because the oil gets much thinner.  Just how much noisier is hard to say, but all you can do is check and make sure everything is all right and then just go.

Cheers
Alex

Too many BSA's


Offline muskrat

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Re: 1952 Plunger Flash
« Reply #12 on: 06.01. 2011 19:21 »
G'day all,
            my experience with valve clearances on the cafe (alloy head ) was when pushed hard (always) and set at std specs, the ex valves would be propped open. Larger clearances cured this.
 The only zero clearance bikes I know of are ones with hydraulic lifters eg Hardly Drivable.
 Andy could be on the mark with a loose guide. There was a post not long ago with that being the final wash up.
 Time to get the old stethoscope out.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline a101960

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Re: 1952 Plunger Flash
« Reply #13 on: 06.01. 2011 19:47 »
I would tend to agree with A10Boy
Quote
If it only happens when the engine warms up it could be a loose valve guide. Tight when cold but when the head heats up and expands it goes loose and rattles around.
Anji, your description of this rattle is exactly the same as the symptom that I had, when I had a loose valve guide. If you remove the head the guide will appear to be nice and tight. Heat the head up and you will find a loose guide. You will also find evidence of oil burning on the piston crown.

I spent quite a bit of time adjusting, and readjusting the tappets before removing the head and finding the problem. The tappet clearances were always correct, and there was no blue smoke visible at the exhaust. You have the classic loose guide indicator. Once the engine has warmed up the tappet noise becomes audible due to the guide being loose.

John

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Re: 1952 Plunger Flash
« Reply #14 on: 06.01. 2011 20:04 »
Well I've goggled my way through lots of pages and come to the conclusion that there is no definitive answer to whether tappets close or open, the best reasoning is as has already been stated here is cast head will close the gaps alloy heads will increase them, so to determine for sure measure cold, go for a run don asbestos gloves and check while hot -mmmm

However while in Goolge I found an article of interest, I've mailed elswhere
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