Starting a Commando after 20 years

I have a 1974 Mk IIA Interstate that has been sitting idle for 20 years. I bought it new in the UK (actually Wales) and the last time it ran was in 1995. At that time it was only running on the right side cylinder. I won't bore you with why I haven't started it since then, but I have time now so decided to get it going. I checked this forum for advice on how to prep it (you guys are a fantastic source of technical info - thanks!), and spent some time getting it ready. Changed the fluids of course, stripped the carbs, new battery and plugs. The main jet on the left cylinder was blocked and that probably explains why the left cylinder wasn't firing. It was stored in an unheated garage, and the winters here in Vancouver, Canada are pretty wet so since it had been sitting so long without being kicked over regularly I was worried that it might be seized. When I parked it I may have squirted some oil in the cylinders, but I don't remember for sure. I saw an episode of "Chasing Classic Cars" where Wayne used "Mystery Oil" to loosen up a seized engine on one of his cars, so I got a bottle and dumped some in both cylinders. I wasn't paying attention to how much I put in, but I thought that if a little is good a lot must be better. Probably put at least three quarters of a cup in each cylinder as well as the inlet valves and let it sit for a few days. With both plugs out I hand-cranked the kick start and a stream of Mystery Oil shot out of the left cylinder, across the garage and onto my easy chair (I sit in it for thinking - not good at that on my feet). Not seized then. Cleaned and gapped the points, and adjusted the timing statically (It was way out, probably also contributing to the single cylinder running). Rinsed out the gas tank a few times with new fuel to clean out the worst of the crud (I at least had the foresight to drain the tank and the carbs 20 years ago, and sprayed oil inside the tank as well). That's the background.

Today I decided to try and start the bike. Tickled the carbs, choked it and gave it a kick - nothing. Took the choke off and gave it another kick, and surprise of surprises, it started! I didn't rev it too high, just a little above idle (tach not working - yet) and was just standing there marvelling at this amazing piece of British engineering, listening to the sound as all the memories came flooding back. Then the distinct smell of Marvel Mystery Oil brought me back to reality. I peered over to the left side of the bike and there was a growing puddle of reddish oil just under the joint between the head pipe and the muffler (I have the noise control model, with bean can silencers). I checked the oil return and it was pumping nicely. The exhaust smoke from both mufflers was more of a greyish color, not black, but was heavier from the left side. I shut the engine down and took the mufflers off. I stuffed a rag on a flexible rod down the head pipes and the left side pipe had a quite a bit of Mystery oil in it, while the right side pipe didn't have any. I sopped up as much of the oil as I could, put the mufflers back on and started it again. The left side joint spit out a little more oil, not bad, but the greyish exhaust smoke seemed to be heavier from the left side than the right.

Now my question. I'm itching to take the bike for a ride but don't want to do any damage. Any ideas why there would be Mystery oil in the left side exhuast pipe but not the right side? Do I have a piston ring problem? I am the original owner, and the engine has never been opened up since new. There is probably something like 40K miles on the bike, maybe more (speedo was smashed by a vandal), and it might be time to do so. Thoughts?

klnick said:

Now my question. I'm itching to take the bike for a ride but don't want to do any damage. Any ideas why there would be Mystery oil in the left side exhuast pipe but not the right side? Do I have a piston ring problem?

Click to expand...

Good question - that oil business doesn't sound good.
Until you figure why oil is coming out one side, and none on the other !, a ride might do more harm than good.

My thought would be to do a compression test - quick-n-dirty way of seeing if piston ring problems are serious.
(Kick warm engine over, with throttle wide open and ignition off, and compression gauge should report same approx psi each side).
If not, time for a looksee inside.

I stripped down an 850 that had been standing only 2 years, and one set of rings were firmly wedged solid in their piston.
No telling what had happened before it was parked though, so may not apply to your bike.

its possible that when you turned the motor over and ejected oil onto your seat [ was it from the r/h cyl ] the l/h exhaust valve was open. The valve hole being bigger than the spark plug hole could have allowed more of the oil down the l/h exhaust. Doesn't sound like a problem to me.
Its also possible the l/h piston held more of the oil [ if it was slightly seized in the ring area, this could account for the more smoke from the l/h side. ]
I suggest you ride the bike to clear the oil from the exhausts [ unless you can hear horrible noises. ]
If after riding, you don't hear any extra noises than it could be ok.
If you want to be fanatical about it though, then strip and clean the engine, an d while you are at it, do the gearbox bearing mods as well. [ however if you take that approach you wont be able to enjoy the thrill of riding it ]

Common sense prevails.

Dereck

Yes, maybe the seat copped all the oil on that side....

Yep just sounds like you still have great ring sealing and pushed out out open exhaust vavle thank goodness! Rev the poor thing up to cam break in til nice and warm, re tune idle screw and idle speed, check brake fluid and function and set 2 lb lower front air than rear and make up for some missing time. Might carry fuse and electrical scab up kit and tape for a while. I say about 1000 miles to shake out the grimlins.

Run it 20 miles, report back

If it's firing on both cylinders, ride it around. As long as nothing seems amiss, you're not doing any harm and you might do it some good freeing things up.

OK, thanks for the advice, much appreciated. Gives me a little comfort that I can take it for a ride without doing some major damage. I've already got the brakes working, air in the tires (front is still the original!), horn, lights, signals and so on. Haven't started any of the aesthetics (still some cobwebs on the spokes) but I'll get it licensed, go for a spin and let you know how it went (assuming I still know how to ride it after 20 years).
Cheers, Nick

Not sure if this was mentioned, but make sure you see oil being returned to the oil tank (via the pump) before you ride it any distance.
These bikes can run surprisingly long time on zero oil pressure.
Also, did you replace the oil filter? These can deteriorate by sitting in oil for that long.
Also did you drain the sump? If not it's going to take some time for the pump to scavenge the oil from the sump.
Other than that I'd probably ride it gently and let the excess oil burn off. Stay close to home and shut it off at the slightest hint of odd noise or engine gas/oil leak.

Hey Mark;

Yes, before trying to start it I drained the sump and added new oil, new filter, and also checked the oil return. The clean oil was pumping nicely back to the tank.

I'll take it out for a "gentle" ride and let you know how it went. Thanks for your feedback.

cheers, Nick

be careful going fast on old tires. Tool around locally at moderate speeds and see how she handles and how everything holds up to lighter use before you take her out and do 100mph runs up the hiway..... :wink:

Tires definitely make a Commando work right and old tires are problematic not d/t less traction so much but are more stiff springy so can onset THE Hinge at seeming sane corner rates so do not judge your isolastics isolation nor handling quality till both tires renewed then it all makes such good sense.

You are on the right track . Sounds like you have done everything according to the book. I say you just have oil in the pipes. Run er for all she is worth. Good old Brit iron can take a rest and keep on ticking.

+1 on the tires. Other to check that everything is working and to get an ear to ear grin on your face stop and put new rubber on it.

My other bikes gave me speed and acceleration thrills but none has put the big smile on like my Commando.

Most fun tedious thing is dialing in equal good idle side to side so I often hole my hand on the puff balls and diddle till they feel the same. I find best timeing by tiny adv till hints of back fire starts then retard till none. Each tire and rider combo has a sweat spot balance of rear to front pressures and when right for me the steering becomes the easiest which takes some palying to sense and this also seems to delay hinging form holding long accelerating turn loads. Its hard to resist listening to nice slow idle but its the worse state to run it so be somewhat disiplined to save cam lifters and chamber coking.

Hi Guys;

Just a quick update. I have put about 100 miles on the bike over the last few days and it looks like the "Mystery oil in the exhaust pipe" has sorted itself out. I think I understand why it ended up in the left side exhaust, but still not sure why it didn't show up in the right side pipe. Still some things to do (sync the carbs, tune the timing, some gear box adjustments, petcocks leak fuel, still got the 25+ yr old tires, front is original so its 40 yrs old, and so on), but it starts, it runs and I've got that ear-to-ear grin on my face when I'm on the road. Even the Harley riders around here are giving me the thumbs up and "nice ride!" comments. My feet must have gotten bigger over those 20 years, because a few times I found the toe of my left shoe resting on the rear brake pedal, with a corresponding loss of performance. (I'm 6ft 5in and 260 lb, with foot size to match).

Appreciate the comments and advice from everyone, and I will be sure to solicit your expertise if I have any other issues or questions.

Cheers, and enjoy the ride! Nick

Gotta love a good resurrection story!

This is a good one.

If it has a side stand and has been sitting on it long that could be your issue.