Sumping

[silverarrow]

Dear Ian sumping is when oil seeps into the sump of a bike when it left standing for a length of time and a crancase full of oil does not help the flywheels to go round.

it is not a problem with AJS&M singles, it's more of a twin thing as they have different oilpump arrangements. It does affect the later 60's singles though.

best cure is to ride it every day or at the very least once a week. I have also seen an ingenious tap fitted in line which was automatically switched on when you kick started the bike. Regards,

Les Smith

[Charles.]

If you oil pump is worn and your bike is left to stand for some time, the oil in the oil tank can drain down into the sump. The bike will smoke on start up or you may have to drain the crankcase to spin the engine atall. Depending on where the engine breather stopped, the oil can even syphon out all over the floor. Your bike could be liable to this but if it is not causing you a problem just carry on as normal. I use Bri-Tie anti-sumping valves, so far without problem but these are definitely not approved of by the Club and problems have been reported using valves of this type. If your bike is coil ignition which, I think from the year it will be(?) then you would be safer to fit a solenoid operated tap if you need to take action. Geo

[morris]

That "sumping"... Hello Ian! It seems to me more or less as a self-imagination trauma among us, friends of the twins of the AJS-Matchless maschines. As you already obvius is told, oil from the tank seeps down (bloody gravity...)to crankcase if the bike is left for a "longer" time. You can take your decision in one of two ways, depends on how disturbed you are. 1)Ignore it! -what I recomend. 2)Repair the worn things in oilsystem who cause the phenomen. The 1-way you can take if oillevel in tank sink a inch, I say it is normal over a night, built in. The 2-way has to be your way if more oil disappear. In that case, you have some detail in the system, out of order. Most probable, run out in the oilpump itself. Well? And a question, you please can launch over to the "antisumping-experts": How can oil in the bottom cause blue smoke then you start up? I can not realise that. The explosin is on the top of the piston, not below. But I can imaginage oil on the head to go thru worn valveguides, and cause blue smoke. In the end, a little warning:Antisumping walves has in my opinion ocurred more brakedowns than the twistgrip! Please think about that. Regards from sunny Sweden/Tord 10850.

[Jordan Princic.]

Any details of the auto-on valve?