Loss of engine revs/power and 'pop'py running

I replaced the points and set the gap at .025. Tested HT from coil again but spark still appeared a bit weak. Tried to run the engine but it kept stalling within seconds of starting. I'd got a new coil at lunch so put that in place and tested for spark again. Still not what I would consider strong blue but seemingly a slight improvement and so reassembled and engine now runs without stalling - much! It does still stall now and then but not often and it will at least now handle the throttle being pressed withut hesitating and dying.

I still think it has other issues but these two seem to have been the most pressing things stopping it from being drivable.

Thanks for everyones help once again!

Have you any sparking at the points? If so, replace the condensor 'cos it's a common cause of weak spark.

Maybe you've got some crap in the carb so here's a little trick to clean it out without having to strip it

Take the air filter hose off the top of the carb then start the engine,rev it to 2-3000rpm from under the bonnet and put your hand over the top of the carb,it'll feel like it's gonna suck your arm off but don't worry it won't,the engine will start to die and kick black smoke out,keep the revs on with your hand still over the carb untill it nearly cuts out and then take your hand off,it will cough,spit and fart and run like a bag of crap for a few secs then clear.(you will have to rev it to keep it going and clear)if it stalls just start it again giving it some revs.Do this a few times and if there's any crap in the jets it'll all be sucked out.

V8jon said:

Maybe you've got some crap in the carb so here's a little trick to clean it out without having to strip it

Take the air filter hose off the top of the carb then start the engine,rev it to 2-3000rpm from under the bonnet and put your hand over the top of the carb,it'll feel like it's gonna suck your arm off but don't worry it won't,the engine will start to die and kick black smoke out,keep the revs on with your hand still over the carb untill it nearly cuts out and then take your hand off,it will cough,spit and fart and run like a bag of crap for a few secs then clear.(you will have to rev it to keep it going and clear)if it stalls just start it again giving it some revs.Do this a few times and if there's any crap in the jets it'll all be sucked out.

Click to expand...

Thanks mate, I loved this tip!!

When I did it, the top of the carb left 'lots' of very wet, very silver stuff all over the palm of my hands. What is this and is it normal? I also noticed that when I removed my hand there was loads of moisture (presumably petrol?) everywhere and as I revved it to get it running again that moisture was spitting everywhere for a second or two. No problem to me but again, is that to be expected or are either of these things symptoms of anything?

Cheers!

Andy.

Yeah that's normal,its petrol that gets sucked back into the top of the carb. Has it made a difference?

I had a problem just like yours once you get it running spray brake cleaner or the like at the carb body and if it tries to die probaly all or some of the gaskets it sits on are shot,so its sucking in to much air so just replace them it cured mine

The major problem has gone since I replaced the ignition coil and replaced the points. However, it still runs a litter 'jerky' when the throttle is off, doesn't always start first time and has limited top end power and so there are obviously still other things which need help. That's why I was glad to try your dizzy trick. I haven't taken it for a run since but will report back if it has helped any of the other symptoms.

Pat - I had the dizzy off 6 months ago and replaced all the manifolds then so would hope they are all good.

Thanks.

V8jon said:

Maybe you've got some crap in the carb so here's a little trick to clean it out without having to strip it

Take the air filter hose off the top of the carb then start the engine,rev it to 2-3000rpm from under the bonnet and put your hand over the top of the carb,it'll feel like it's gonna suck your arm off but don't worry it won't,the engine will start to die and kick black smoke out,keep the revs on with your hand still over the carb untill it nearly cuts out and then take your hand off,it will cough,spit and fart and run like a bag of crap for a few secs then clear.(you will have to rev it to keep it going and clear)if it stalls just start it again giving it some revs.Do this a few times and if there's any crap in the jets it'll all be sucked out.

Click to expand...

was gonna suggest crap in carb from first post.
good advise ^ but you be persistently doing it.
might be worth stripping carb and cleaning out.

with the amount of stuff thats been tinkered with now, you might also be worth starting from scratch with tuning. static timing, carb setting while running then check the running timing with strobe.
there are mobile tuning people that do this, tho never used one myself.

nb- used to run a 32-34dmtl twin choke weber on me first landy, gave same symptoms as yours. the jets for both throttles could be removed in situ on these and when i got blocked jet problems used to remove them and poke the lump of crap out with a jet pricker.
still ended up stripping and cleaning the resovoir tho as bouncing it about off road stirs all the crap up.