1973 Commando issues

Steve Highfield · Apr 20, 2025

Good Afternoon guys
I have a question on my 1973 Commando.
Over the winter I did the top end..
After a few starts and tuning I noticed oil traveling up the front cylinder bolts.. So I took it apart and found one of the machined stud holes broken through into the pushrod tunnel.. Easy fix.. Seal the threads.
When I took the head off I found oil on top of the cylinders. Friggin wet Sumping... rings did not bed in and glazed the cylinder walls. I noticed my top end oiler tube with a constant drip of oil.. It drained out of there all night until the oil tank was empty.. Too excessive eh?
I'm looking on the Andover site this morning putting together a parts list for reassembly.
Question 1. Are Andovers rings good quality? Dealers in Canada list atleast 4 different types of rings.. I think I put Hastings in it this winter..
Question 2. I see Andover sells the MK3 timing coverer the 750/850. I've read that is supposed to be the best fix for wet sumping.
I don't want to start a whole wet Sumping thread. I just want to fix it once and not have to worry about it..
Is the cover replacement a good upgrade? Anything else need to be done for the conversion?

kommando · Apr 20, 2025

Send your cover and oil pump to AMR for the check valve to be added to the cover and the oil pump to have internal seals. Your pump sounds like it needs a recondition by removing the clearances. ask AMR if they will add that to the job, if not then you can DIY with a piece of plate glass and emery paper.

drp · Apr 20, 2025

I had mine done, it did significantly reduce the wet sumping but did not eliminate it completely. What also has helped is the reed valve breather kit now sold by NYC Norton. I bought mine used but it was one of Jim Comstock's. With the CNW estart I can leave the ignition off, crank the starter and partially clear the crankcase, The breather kit did reduce the leaks too.

Tornado · Apr 20, 2025

Not sure I understand. The top end oil pipe was dripping? How is that wet sump related, it should be above the oil tank "altitude" and thus gravity cannot be forcing oil up and out there. Perhaps you just saw residual oil in pipe escaping with head off?

I use a manual oil tap with ign circuit interrupt micro switch to eliminate wet sumping on my 74 850. Made it myself for about $15 from local hardware store tap and microswitch.

marshg246 · Apr 20, 2025

Steve Highfield said:
Good Afternoon guys
I have a question on my 1973 Commando.
Over the winter I did the top end..
After a few starts and tuning I noticed oil traveling up the front cylinder bolts.. So I took it apart and found one of the machined stud holes broken through into the pushrod tunnel.. Easy fix.. Seal the threads.
When I took the head off I found oil on top of the cylinders. Friggin wet Sumping... rings did not bed in and glazed the cylinder walls. I noticed my top end oiler tube with a constant drip of oil.. It drained out of there all night until the oil tank was empty.. Too excessive eh?
I'm looking on the Andover site this morning putting together a parts list for reassembly.
Question 1. Are Andovers rings good quality? Dealers in Canada list atleast 4 different types of rings.. I think I put Hastings in it this winter..
Question 2. I see Andover sells the MK3 timing coverer the 750/850. I've read that is supposed to be the best fix for wet sumping.
I don't want to start a whole wet Sumping thread. I just want to fix it once and not have to worry about it..
Is the cover replacement a good upgrade? Anything else need to be done for the conversion?

Oil on top of the cylinders has nothing to do with wet sumping. That sounds much more like Hastings rings installed upside down. Also possible that the intake area drain into the timing chest is blocked and the head was full of oil when you removed it.

Don't understand about "top end oiler tube" if you mean the rocker feed, there is no open end and even if there were, it's well above the oil in the tank unless the tank is VERY overfilled.

The AMR timing cover upgrade or the MKIII timing cover are both good and *usually* stops (or really slows down) wet sumping. If you have a reed valve breather, then wet sumping is not much of an issue; even without one it's not a really big deal but does make starting hard.

If you have a reed valve breather that is stuck closed or no breather, then oil can be pushed out in many places.

Steve Highfield · Apr 20, 2025

Thanks for the answers guys.. Yes it was the rocker feed pipe.. When disconnected from the head and hanging off to the side below the oil tank it dripped oil all night..
Any recommendations or ring I should use?

1973 Commando issues

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