Cylinder head

Begonnen von † Will, 04 April 2016, 17:55:15

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† Will

Hello community.
I am working on Lottie and need to examine the valves to investigate a loss of compression in the cylinder.
I have removed the 4 bolts and rocker gear but I can not remove the cylinder head from the cylinder. I have tried gentle force with a lever and a rubber hammer but it still does not move.
What should I do next please?
R25/3 + R65LS. The R27 has found a new home.
I was not lost, my GPS just found a different way back.

† Will


R25/3 + R65LS. The R27 has found a new home.
I was not lost, my GPS just found a different way back.

Taz

Hello Will.

Don't worry, that is normal behaviour for a cylinder head.

It will require some firm taps from the side to the carb base to loosen the head, best witb length of 2 by 2 wood ..alternating sides..once it can be turned like a pivot on the cylinder it can be lifted off....

Don't use a  Birmingham adjuster on the cooling fins, these are easily bent and tend to break at readjusting...

Happy  :schrauber:, Taz

Ich hab noch nie einen Sarkasmus vorgetäuscht


auf Tour:

Zipfelreise (2019)
Cymru "Radnor Revivals" (2016)
Alba "Isle of Skye" (2013)
Austria Großglocknerhochalpenstrasse (2012)
Alba "Spittal of Glenshee" (2011)

Rütz

What i try first in this case and in most cases it works:

- reasamble rocker and bolts. Don't tighten the bolts but leave them two turns loose.
- if compression is low, squirt a small amount oil through the plug-hole.
- refit the plug.
-> do some "spirited" kicks on the kicker.
I never dared to be radical when young.
For fear it would make me conservative when old. (Robert Frost)

4Taktix

#3
Hi Will,
if the carb is already off, you can wrap a broomstick or suitable steeltube with a rag and plug that into the intake port, then lift while grasping the frametube.
Just like big pliers, know what I mean ?
Take the push rods out before. Side to side may also work. Take care of your fingers, if the head releases suddenly.
But Rütz's method sound very interesting and plausible, will try that next time, if my way does not work.
I suppose you already tried out, if the piston is worn out ?
Simple check: plug a compression-tester in, open the throttle and kick several times, read indicator.
Then remove it and fill in let's say a tablespoon of motoroil through the plughole and repeat the above.
If the reading is clearly better now, your piston/cylinder/rings are definitely worn out.
If not, proceed with the valves as intended.
Good luck.
Cheers,
Sascha
Think outside the box !

† Will

Hello again,
Thank you for all your replies, I was finally able to remove the head with your help.

Lottie had lost all compression and would not start. The spark was OK but the plug was dry so no mixture in cylinder ?
Looking at the pictures I took this morning I think the exhaust was sticking open as the sealing area of the valve is dull.
I also know that oil was leaking past the cylinder head gasket and leaving a carbon deposit on the outside of the crankcase after a long run.

Top of the piston




The cylinder bore appears to be OK.







Valve seatings



Exhaust valve



:)



Top of cylinder head











Many thanks again for all your help.:blumen: :schrauber: :bike:
R25/3 + R65LS. The R27 has found a new home.
I was not lost, my GPS just found a different way back.

† Will

After I removed the cylinder head I cleaned most of the deposits off and I had the parts vapour blasted at my local car workshop.
I found that the valve springs were weak and too short so now I have new ones.
The pictures show the results before I assemble all the parts and rebuild my favourite machine.

The vapour blasted cylinder head.



The valve covers.



The valve chambers.



My spare R25/3 crankcase

R25/3 + R65LS. The R27 has found a new home.
I was not lost, my GPS just found a different way back.

thoro

Quite more than a difference, well done, congratulations.  :applaus:
All my best,
Thomas

Herculestom

Hi Will,

looks good, man.

Hope you won't re-use the old valves and valve guides. Your outlet valve looks pretty worn. I would definitely not use it again. Don't know about the intake valve. I can only recommend to do all this this now as the head is off and more or less disassembled.

The other thing I noted is your seal surfaces. You should plane both of them, head-cover and cylinder side.

Enjoy it
Tom

umuntu ngumuntu ngabantu

bwprice100

They have done a good job cleaning the casting Will.

Brian

www.eBolt.co.uk www.TooolroomChucks.co.uk


rolf

NOT plane!! measure ist.....and then...eventually plane ist.
Everybody planed the Head at once...I've had heads on my workbench which has a compression rate of over 11! because of too often planed.

Herculestom

Rolf,

absolutely, I agree. Planing not in the sense to remove tons of material. One day this would certainly have an impact on the compression ratio. More in a sense to smoothen the surface and to remove the dent on the right hand side.

regards
Tom
umuntu ngumuntu ngabantu

† Will

The cylinder head has been reassembled ready to fit to the machine. The dent in the sealing surface has been filled in and made smooth.
The compression chamber was filled with petrol to test the valve sealing and was OK. No leaks after 4 hours!

I bought new valve springs and made a spring compressor from scrap steel in my workshop. The compressor can be operated with one hand or if two hands are needed the handle can be tied down.

Yesterday I was working on my boxer and today working in the garden while we have some sunshine. There is not enough time for everything that has to done when you are retired! :)

The spring compressor from scrap steel.




The compressor in position.

R25/3 + R65LS. The R27 has found a new home.
I was not lost, my GPS just found a different way back.

Herculestom

Hi Will,

cool tool!!!  :applaus: Costs nothing, but works. Again and again I must realize that oldtimer fans are the masters of improvisation.

All the best
Tom
umuntu ngumuntu ngabantu

OldsCool!

Ich bin auf dem Dorf aufgewachsen. Ich wurde nicht erzogen, ich habe ÜBERLEBT!

† Will

Thank you my friends for your kind comments. :)
R25/3 + R65LS. The R27 has found a new home.
I was not lost, my GPS just found a different way back.

bwprice100

.
I like Bill. :)

Brian

cledrera

Me too,
but Sir Bill please.  ;D
Du bist im Recht; nun sieh zu, wie du da wieder heraus kommst. (v. Chamisso)
Lieber Einzylinder als zwei Fallschirme (v. mir)

bwprice100

.
This is my very poor effort. :)

Brian

Karl

Nice idea - both of them! :)

I'd love to have a *LIKE*-button here ;)
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