British Seagull motor rebuild?

[novocaine]

Chris

if you're playing with it today, pull the HT lead off, clean all the contacts (both ends of the lead and where it attaches to the coil. remove the fly wheel and clean the big metal bits either side of the coil, if you got a multimeter, put it in ohms, put one end on the contact that goes to the HT lead and the other to the body of the engine, you should see 3-5k (so you'll want to put the meter in the right range to show you that thousands) if you haven't got a meter yet, don't worry about it, I'd be surprised if the coils dead. be nice to know if it's a villers or a wipec coil and points system too (again, age dependent).

you got a post in before me.
as above, but once the young apprentice is back.

 

[Chris152]

Thanks novocaine, will wait for the apprentice! And it's wipec, apparently...

 

[novocaine]

I'm guessing (because youth does this better than the rest of us) you've seen this YT channel, but in case you haven't.

https://www.youtube.com/user/barjhealy/videos

lots of very good info on here, most of which we have already covered but still. nice run down of the HT lead and how to strip it for cleaning.

 

[sunnybob]

Novocaine... agreed. I was of course refering to a plug with a covered cap. Thats why I said "earthing the BODY" will do nothing.
If its an open top connector, then that could be shorted to earth.

I have far too much experience on 4 stroke motors, but absolutely zero on 2 strokes (horrible tinny things :shock: ), so if I go quiet you'll know I'm out of my depth.

 

[novocaine]

As you might have guessed Bob, I wrote something then noticed you'd said body, so a quick amendment was made.
I grew up with 2 strokes, my first bike was one (I don't count a c50 as a bike ), the hovercraft had a pair, so did the kart and the dingy had one too, I've spent 2 long replacing pistons, sleeves and heads because I've run them to hot to care to mention and most likely done every dirty trick you can imagine (and some you hopefully can't) to get the pippers running or to eek out a couple more ponies. these little single cylinder 100cc jobbies are so simply that they rarely fail and your unlikely to get out your depth here luckily. now repeat after me, suck squeeze bang blow. or in 2 stroke terms, suck squeeze pipper it, hit it with a hammer, pray to the gods of petrol, kick it, scream at it, start again.

 

[sunnybob]

Back in the 60's I had a friend with an ariel arrow 2 cylinder 200 cc two stroke (I actually passed my test on a borrowed ariel leader after blowing up my bike the week before).
There was a very old joke at the time about a biker riding blind in the mist, saying to his passenger "its either a thick fog or we're following an ariel arrow"
That wasnt a joke. We always insisted he rode at the back. And his tool kit consisted of a plug spanner and 10 assorted plugs.
No ta, I'll stick the 4's. :roll: :roll:

 

[novocaine]

bet he learned to ride with 2 fingers on the clutch lever too, in case it nipped up.

very little beats the smell of Castrol TTS on a cool misty morning, a rather evocative smell normally associated with race meets and 15k red lines on teeny tiny lightweights. actually thats not quite true, the sound of silence than rains over the open paddock at lunch time of said race meet is right up there too :lol: .

 

[sunnybob]

wrong castrol.
A 1963 BSA 500cc dbd gold star, running castrol R in the engine, with a tablespoon of R in the petrol tank.

mmmmmmmmmmmmmmmmmmmm, you can keep yer 2 strokes =D> =D> =D> =D> =D>

 

[Chris152]

Quick update. The new plug made no difference, still no spark. I borrowed a multimeter, tested the cable leading to the plug for continuity, fine; tested the coil as per this vid
https://www.youtube.com/watch?v=7qU8slqE2Jc
fine (I think, though the meter reading kept hopping all over the place, but it came in at between 3.5 and 5 mostly - probably user error). Cleaned the contacts at both ends of the lead. So next we're going to clean everything inside the flywheel and replace the LT wire, re-check all the gaps (I still don't have a feeler gauge but will borrow one), and see where we get to.
We had found a couple of videos by Coastal Works novocaine, but hadn't seen the index page that you linked to - that's brilliant, really clear videos and covering most of what we need, I think.
He's back in school now which is slowing things down, and I'm getting impatient! I guess I can do some of it while he's not here and retrace the steps but feel like I'm cheating...
Ta
C

 

[Eric The Viking]

Be very systematic/methodical and check everything to a known-good state as you go. You seem to have narrowed it to the electrics, now you're finding the component that's broken (and there may be more than one.

You should get a healthy spark, by holding the end of the HT lead (no plug cap nor plug) on the cylinder head or cylinder barrel (any part of the main casting you can reach would probably work). just push it down close to the top with a plastic ruler or similar, so the plug end of the lead is next to the metalwork - the spark should jump across the end of the cable easily. If that works, it implicates the plug cap (get NGK replacement, as I said earlier!), but it's not unknown for new plugs to be faulty, too (rare tho). Plug can simply be continuity-checked from electrode to connector.

You can test the points with a bulb and small battery wired across them to make a battery-bulb-switch circuit - bulb on = points closed, bulb off = points open (when the spark should happen, just at the point in the rotation that the bulb goes off, approximately).

I'd also get a new condenser (AKA capacitor or suppressor) before stripping it though, as getting the timing right afterwards is fussy enough without doing it twice. Why? It's unlikely, but if the condenser has failed (to now be short circuit), it will short the points so there can be no spark at the crucial moment. Condensers are pretty cheap, or should be, and the exact value matters far less than having the right mounting lug or whatever on it.

 

[Chris152]

Thanks Eric. We tried the lead direct to the block but there was no spark, the lead continuity is fine and the coil seems to be ok, so we're going to clean contacts within the magneto asap. Hopefully that'll have it sorted, we'll see!

 

[novocaine]

You are doing well Chris, keep digging. I'm getting worried that it might be the flywheel that's the issue, lost it's magnetism over the years. might be worth waving a compass over it to see if it dances around.

Eric, there isn't a condenser on the points, it's all to low of a voltage to charge a capacitor or make it worth while for protecting the points.

 

[Eric The Viking]

That sounds like a Very Nice Engine to work on then!

 

[Chris152]

Eric, there isn't a condenser on the points, it's all to low of a voltage to charge a capacitor or make it worth while for protecting the points.

Glad to hear that - I spent a little while finding out what a capacitor is, and then couldn't find any reference to it on the Seagull!
We don't have a compass in the house - the boy uses his phone as a compass when we need one (I've no idea...), but I just held a file to the flywheel and it sticks well to one part of the wheel, so hopefully all good there.

 

[novocaine]

meh, 2 stroke, what you gonna do. if you think about it, as a single cylinder engine thats only running at a few k rpm (it's screaming at 2k) there really isn't much stress on the points (in comparison to a 2 or 4 cylinder engine where they are possibly firing twice every revolution and much high revs) they last forever.

they are quiet amusing little things to play with, so simply that if you can get a spark and fuel they will, unlike something a bit more modern that needs life support to work.

Chris, that's good news, how about sticking the drill on it again and testing for a spark while it's spinning? if it's got the original cap on it still (which I think it has) you can wingle out the end of the HT lead and do it without the spark plug if you feel the need. did you swap the LT wire to a new one yet? if not, do that now. then as you've already said, clean all the contacts and the big chunks of iron and give it another go.

 

[Eric The Viking]

After making a twit of myself* over the non-existent condenser, I hesitate to comment further, but...

... in the past, I've found crimped fittings that are mechanically strong but that don't actually connect through the fitting to the wire itself, because the crimp was made badly. It's possible that the LT side was indeed originally made badly and has been iffy for years (only one or two strands actually connecting), but has now failed.

Remaking the wires is probably a very good idea. The better those connections are, the stronger the spark will be on the HT side.

E.
*happens often.

 

[novocaine]

not made a twit yet Eric, if you haven't played with something this small you simply don't know stuff like that, every day is a learning day after all. Me, I'm used to playing with small things, especially things that need a lot of tugs to get going and only stop if you run them out of fuel.

 

[Chris152]

WE'VE GOT A SPARK!

We re-cleaned the points, cleaned where the LT cable meets the coil (we couldn't replace it as it's soldered onto the points and have no iron), cleaned the contacts around the coil (though I don't think they actually contact anything?) and re-cleaned the connection between the HT lead and the plug - I don't think we did that properly first time. The sort of thing most of you'd have done in the first 10 mins I guess, but we got there!

OK, so now we move onto the fuel supply? It won't be today as he's gone out now - but I could get on with cleaning the inside of the petrol tank. It's alloy - do I just swill it out with some fuel?

Thank you!

 

[novocaine]

Excellent.

Swill out the tank. Fuel will be fine.

Change that fuel pipe then stick the scary end in water and see if it starts. If it doesnt then the carb can come off and be striped and cleaned. We can go in to that when we need to.

Reckon if fuel flows it will start. Follow the starting procedure.

 

[Chris152]

The boy's been away with his mother lots lately so work on this has been slow. BUT, we had a crack at the fuel system today (inset day in school):
https://vimeo.com/292332004
The oil mix was a bit hit and miss (the 2 stroke mixer bottle I bought this morning didn't have 10:1 marked on it, so we ended up putting 9cm depth petrol to 1cm oil in a jam jar). Lots of smoke which may be due to the mix, general dirt or maybe that's just the way it runs (I remember a trail of smoke wherever we went in the mirror with that motor!).
Brilliant though, so happy with getting it going at last - that's over 40 years since it last ran!