G9 pressure release valve

[Robs G9]

Hi
I wonder if you can help...
I'm trying to help my father-in-law locate a part for his Matchless G9. I haven't got a part number, but do have a picture of what he needs (link below, hope that works...)
I believe it's a pressure release valve that is located on the end of the crankshaft (from what I can see), also believe it may be particular to one year only.
He's been searching for the part for nearly 2 years and I haven't been able to get much info out of him to help! (I've got Ariels myself, so haven't got much idea on the Matchless!)
Thanks for reading!
Gary
https://1drv.ms/u/s!AsyCjJOFtBbyiMQ2hDSoBUTI80WgRg

[clive]

if you think it might be one year only perhaps best to tell us the year. The club stocks the assembly for 52-56 bikes but only sells to club members.

[Robs G9]

Hi Clive
Thanks for the reply- I've been trying to get him to join the club! (I'm in Ariel owners & spares/ support is great & thought it would be the same here)
The bike is 55 but now has 51 bottom end (this all started from a seizure & broken crankshaft). He pulled the engine from the bike & then bought a bottom end on eBay, hoping he could build it up from that, but it's never that simple!
He doesn't like asking for help, so I've tried to gather the info and have a look myself as he's ground to a halt on it. We were at an autojumble yesterday & he showed me the image I linked to so we could have a look for one!
As far as I can gather this is the only part he now needs.
If I know he could definitely get the part from club spares I'd join myself or subscribe for him so he can get it done & back on the road while he can still ride it
Thanks for your help

[Duncan]

Hi Gary, is this what you are seeking?: https://www.amoc-parts.com//store/comer ... duct=21220

Its best to fit new complete units for some reason as worn units can let too much oil past.

[Robs G9]

Hi Duncan
Thank you so much!
I think that could be it- looks very similar to the drawing I have seen.
Am I right to think that is club member spares?
Thanks, Gary

[ajsph]

the 51 crank case has another release valve, the valve is driven from the inlet cam, not from the crank end.
Poul

[Robs G9]

Thanks Poul, good info- the picture he's shown me may be for wrong year, from what I've read that valve is 52-56 & I'm sure the crankcases, crank etc are 51

[Duncan]

Apologies your update wasn't visible when I posted and I referred to the link image, this is the inlet driven breather: https://www.amoc-parts.com//store/comer ... duct=24131
I would suggest working through the bits you have first to confirm the bottom end is correct for year, a parts list is available here: http://archives.jampot.dk/book/Spares_l ... _twins.pdf
Page 11 shows the breather 014248, as Poul states it is fitted to the inlet camshaft and not the crankshaft.
Page 16 shows the crankshaft bolt 011775: https://www.amoc-parts.com//store/comer ... duct=21011

[Robs G9]

Thanks Duncan for your update
That's really helpful- I think that my FiL maybe confused what he needs. Seems to me he probably had (on original bottom end) the crankshaft relief & he needs the camshaft one.
Thanks again- need to get a proper look at the engine

[clive]

Is it possible he already has the 51 relief valve fitted to his crankcase? If it's missing he would have a hole in his crankcase behind the barrels and about level with the primary chaincase.