Firing on 1 Cylinder/ Oil leak

[Aaron_jay]

Hi all, recently purchased and 1988 R80 that hadn’t run in 6 years. Had the Carbs rebuilt and setup + new sparks and was running fine for a few days.

However, this morning I started it up and only run on 1 cylinder, left side not firing.

In addition, some oil has started to weep from the left exhaust header where it exits the cylinder. Image attached.

The battery has also been draining and needs a recharge after about 10 rides around town. Maybe relevant because the battery is close to dead when I started it up this morning and needed a little charge before turning over.

Any help or advice/ first things to check would be appreciated.

Forgive the naiveness! New rider/ owner of airheads.

[jackonz]

As both cylinders spark at the same time I would be looking at the spark plug to start with as I suspect it is oiled up looking at the oil from the exhaust.

As for that oil it could very well be worn valve guides but cannot be certain, when you had it running was there blue smoke at all from the exhausts, was the bike parked on the side stand after you last had it running?

[Rob Frankham]

A look at the plugs is probably the first thing to do. I wouldn't be at all surprised if the left plug were to be seriously fouled and that is what is stopping the left engine from firing. The oil leaking from the header isn't good, that's a lot of oil... apart from anything else, it implies that there is and exhaust leak at that point... but it also suggests that there is a lot of oil being passed though the left cylinder. This, in turn, implies one of a number of issues some of which are quite serious.

Do you know why the bike was laid up in the first place?

My instinct is to say that you need to do at least a top end strip down to investigate where that oil is coming from. I would also suggest that you need to avoid running the engine until you have done that.

Rob

[Aaron_jay]

Thanks both. The spark plugs are brand new, fitted maybe 20 miles ago. Yes the bike is parked on its side stand, when I first started it up it did smoke from the left exhaust bit more than usual.

The bike was laid up as the previous owner had an accident (on another bike) and never rode again.

I’m going to take it in and get the top end stripped as suggested and go from there. It’s on 75k miles and with such a long period of downtime it might be time for a rebuild I guess.

[SteveD]

Welcome Aaron...
Hopefully a look at the heads will show something simple, easy and cheap.

Two habits to form with these bikes.
1. always turn your fuel tap off when parked.
2. use the centre stand for any long stop. Occasional embarrassing smoke from the left pipe isn't unheard of.

There's more of course but you can do these today.