First ride on an AJS (and oil leak)

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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AJS_Chris
Posts: 28
Joined: Thu Mar 16, 2017 7:45 am
Location: Wiltshire

First ride on an AJS (and oil leak)

Post by AJS_Chris »

Morning all,
I managed to get out for a ride on Saturday on the 1951 Model 18 I bought at auction at the beginning of March, what can I say.....

. it starts
. it stops
. it goes round corners
. it waterproofs my right boot

so almost perfect!

This is my first AJS but not my first British bike, it is however my first British bike with manual advance / retard. I think I followed the instructions correctly, full advance then back two fifths for (easy) starting, as I rode away I gradually increased the advance to full. I left the bike on full advance until I came to a standstill then I put if back to two fifths, I'm not sure whether I'm doing this bit right so please put me straight if I'm at fault! I was a little worried about manual advance / retard but the feeling when it wasn't quite right was as though I'd left the choke on, the engine started to run cleanly when the setting was (what I think) was correct. I couldn't detect any pinking but I may have been listening for the wrong thing. Sadly, having just re-read the the previous paragraph I sound like a numpty.

Anyway, back to the auto waterproofing. As good as it is (right up there with the Scott oiler), I would prefer to disable this feature. The majority of oil appears to be coming from around part 000651, the bush for the inlet cam. I can't work out from the parts list and maintenance manual whether this is just a press fit into the cover and relies on the fit for oil sealing, I may be looking in the wrong place for the information? At two shillings and tenpence it would seem to be sensible to replace it if the oil leak will be cured, which of course leads onto the next question, can the bush be replaced in situ or does the cover have to come off to be able to do it?

Summer is almost here!

Regards to all,

Chris.
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1608
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Joined: Mon Oct 05, 2009 1:00 am
Location: ESSEX UK

Re: First ride on an AJS (and oil leak)

Post by 1608 »

The cover needs to come off to do the job. The new one should be fitted same as the old core plugs fitted to engine blocks. Heat the timing cover and apply a little sealant to the cap before tapping it in. Some times end float can be excessive on the i/l cam shaft and is usually overcome with shims ( not ideal as the shims can wear quickly) before fitting the new one determine what, if any end float is apparent and tap the cap in to suit.
With regard to the manual A/R, leave the timing fully advanced when riding and when stopped at lights or junctions etc. Only need to retard timing if pinking is heard or when starting the bike.
Slight edit to the above, the depth of the bush in the timing cover will determine the end float of the cam spidle so the bush may need tapping in slightly and shim placed btn bush and cap if necessary. Hope that makes sense. I have fitted shims in the past, as suggested by the manual to overcome end float ( light tapping noise ) but found the shims wore too quickly. Correct method is to shift the bush to suit ( as with the cam bushes on twins). Starting to ramble on a bit now. Good luck.
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