Exhaust valve seat again G11CS

Information relating to the Matchless G11 or AJS Model 30 600cc twin
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Re: Exhaust valve seat again G11CS

Postby SPRIDDLER » Sat Dec 06, 2014 2:21 pm

Samuel wrote:Rather than inflict one bodge to fix the effects of another............


Nah, stick with what you're good at, Clive.
:rofl:
I poke badgers with spoons.

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Re: Exhaust valve seat again G11CS

Postby ajsph » Sat Dec 06, 2014 5:33 pm

Hi Clive
The shape on the low and high Pistons are the same, but the distance from the top edge to the first Ring Groove is on the 7.5 Piston 4mm, and on the 8.5 Piston it is 5.3mm, sorry about the metric. On my G11CS the timing is 3/8mm before top , it has the 8.5 pistons mounted, and runs very smooth.
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Poul Hansen
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Re: Exhaust valve seat again G11CS

Postby Malleon » Sun Dec 07, 2014 2:09 pm

ajsph wrote:Hi Clive
The shape on the low and high Pistons are the same, but the distance from the top edge to the first Ring Groove is on the 7.5 Piston 4mm, and on the 8.5 Piston it is 5.3mm, sorry about the metric. On my G11CS the timing is 3/8mm before top , it has the 8.5 pistons mounted, and runs very smooth.
Best regards
Poul Hansen
Denmark


3/8 mm, Poul, or 3/8 inch ??

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Re: Exhaust valve seat again G11CS

Postby ajsph » Sun Dec 07, 2014 6:55 pm

3/8 inch
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Re: Exhaust valve seat again G11CS

Postby clive » Sun Dec 07, 2014 7:37 pm

All very helpful thanks, (even Spriddlers confidence in my bodgery!). I am currently building a 500 single from bits which will be pure bodgery and have threatened an article or two on the progress. Meanwhile on the twin I will certainly check out the distance from the top ring to the edge thanks for that Poul. Good point Les about the tappet adjustment as I am currently close to full adjustment. I feel a deep thinking period coming on, especially since I am currently hobbling around having taken a tumble off a H...a whilst green laning today, unfortunately I parted company from said bike but my foot and ankle did not as stuck against the side of the track. Huge swelling currently being treated with medicinal whisky. :beer:
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Re: Exhaust valve seat again G11CS

Postby G15 Roy » Sun Dec 07, 2014 7:56 pm

image.jpg
Was this you just before the fall.
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Re: Exhaust valve seat again G11CS

Postby clive » Sun Dec 07, 2014 10:41 pm

I didn't realise you had it on camera Roy. Actually i am threatened with a youtube version, if it was recorded I will post the link!
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Re: Exhaust valve seat again G11CS

Postby Les P H » Mon Dec 08, 2014 8:48 am

Hi Clive. I was checking out valve seat replacement and it's not as expensive as you think...take a look at the SRM price list. I would not hesitate in sending my heads off and get them done. This would end all the thinking and worry and you'll have a good engine again without any fuss or bother...hardest thing will be finding the right size cardboard box and taking it down to the post office....ignore the cost....you CAN afford it....ATB....Les
http://www.srmclassicbikes.com/engine-a ... -head-work

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Re: Exhaust valve seat again G11CS

Postby Samuel » Mon Dec 08, 2014 1:16 pm

I think you should be tempted by this Clive. They even have a collection service!
http://www.srmclassicbikes.com/arrange-collection
cheers
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Re: Exhaust valve seat again G11CS

Postby Rob Harknett » Mon Dec 08, 2014 3:58 pm

If a gasket sample is available, to make another gasket or compression plate. With a scanner/printer print a copy, stick it on the alloy or gasket material with paper gum glue, to get shape and hole positions correct, soak off paper copy when made. Also, would valve end caps give additional tappet adjustment? If new valve seats are to be fitted, the head could be made suitable for non leaded fuel.

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