I have an Ariel w'ng which I got last year, it was running well until a couple of weeks ago, (although I haven't ridden it on the road yet) I have been working on it over the winter and starting it up every week or so, all of a sudden it won't rev above tickover, it starts ok but won't rev, the only thing I have done to the engine is to change the oil, it hasn't wet sumpt, has a good spark, I've removed and cleaned the carburettor, float level is correct, plenty of fresh petrol.
When I try to rev it just coughs spits back through the carburettor and if the throttle is left open the engine dies.
I'm not new to British bikes but this has got me stumped so any suggestions will be gratefully received.

email (option): gh@hibbo.eclipse.co.uk

Enough fuel in the tank. Blocked up taps??

Ron

email (option): ronpier@talk21.com

Hi Ron.
There is plenty of fuel I have just fitted a new petrol tap and changed the rubber fuel line for a copper pipe, if I keep the throttle open the engine stops and the plug is wet.

email (option): gh@hibbo.eclipse.co.uk

Sounds like the carb mix is off.......need to check over the carb, slide, etc..

Hi Ferg.
I hadn't touched touch the carburettor when this problem started but I stripped and cleaned the carburettor today and everything was good and in order, nothing overly worn and in good condition.

email (option): gh@hibbo.eclipse.co.uk

The choke IS off? Just sounds like lack of air in the mix. Points OK? After 10 years of learning the hard way about getting a motor to run, I sympathise and I think I have been through every permutation of engine dysfunction. The fact the plug is wet tends to suggest fuel supply is OK, but the symptoms suggest lack of air or fuel. Despite apparent wet plug, are you sure the fuel flow is good? Tap filters and carbs get blocked over the winter recess. Even more likely if you have a Petsealed tank.......ticked that one!

Not a petsealed tank, I've checked and rechecked the fuel supply (new petrol pipe and tap, Nos) choke on or off makes very little difference, and as I say I have started it every week or so over the winter and the problem only started last week.

email (option): gh@hibbo.eclipse.co.uk

I know it sounds silly. But on a number of occasions I have come across guys who don't know which way the choke works. The lever needs to be pulled fully towards you for 'choke off'! The fact that you say that it makes little difference either way, indicates that you might have a problem in this region. Ron

email (option): ronpier@talk21.com

Ron, thanks for your reply however I also have a Bsa b31 with more or less the same carburettor so I I'm familiar with this type of carburettor/choke, I understand how difficult it is to advise without seeing the machine or knowing the level of experience of the owner and I appreciate the help of all those who respond to the request for help.

email (option): gh@hibbo.eclipse.co.uk

Daft idea maybe...Advance / Retard cable broken (do Ariel's have tight wire advance ?)

Is it responding to the pilot air screw ?

Advance/retard cable is ok I've checked it moving in the mag. Pilot screw is not making much difference but does have an effect if screwed completely in or out.
Thanks for your reply

email (option): gh@hibbo.eclipse.co.uk

Weak spark could cause this, as soon as you open the throttle the compression increases and blows the spark out. Get an old plug bend the side electrode out to create a large gap plug onto HT lead and kick bike over and see if the spark will jump the gap.

Gentleman thanks for your replies, I have spent the last two days finding with this Ariel and after stripping the carburettor twice and on the second effort leaving at to soak over night in solvent, and resetting the timing twice, it was still not revving above tickover, however I noticed a small petrol leak from the bottom joint under the float bowl and took of the pipe to fix it (this pipe had been on and off several times) on Reassembling started the bike and it revs ok now, what did I do?, I don't know.
It not running perfectly but it's ok to ride.
It's so annoying I don't know what I did to make it run?

email (option): gh@hibbo.eclipse.co.uk

Dislodged some crap in the fuel line?

Who knows, I had blown it though several times with 100 psi airline.
Who knows.

email (option): gh@hibbo.eclipse.co.uk

Oops I appear to be back to square one the bike is doing exactly what it was doing before, won't rev above tick over, when I open the throttle it struggles coughs stutters and dies.
The plug is showing black soot, very rich, I have again stripped the carburettor, it has the correct main and pilot jets and the needle is in the no 3 notch, checked the timing (1/2" btdc fully advanced,
I'm at a total loss as to what to do next.
Even removed the exhaust to see if less back pressure made a difference.
Help.

email (option): gh@hibbo.eclipse.co.uk

It still sounds like fuel starvation to me? Not enough head in the tank- blockage between float and carb body.

When you say you have "stripped the carb" Have you actually removed the jet block?

When you look into the carb from the flange end, there is a tiny little drilling. This needs to be poked clear with some thin wire after the jet block is removed and the corresponding drilling in the jet block should be cleared also.

Is your needle fixed into the slide properly? I've seen them drop off into the needle jet.

Is your bike timed on the up ramp and not the down ramp of the cam plate?.....I've seen that a few times also.

Ron

email (option): ronpier@talk21.com

Ron thanks for the reply, I have not removed the jet block, the only thing I haven't though I've blown it out with 100psi air jet, however I will take it out tomorrow.
The needle is in the correct position and fixed securely in the clip.
The tank is half full and the fuel flow is good right through the float chamber.
I've checked the timing several times but I will check it again and make sure it's on the up ramp.
I'm puzzled because the plug is indicating rich and it starts ok.

Graham.

email (option): gh@hibbo.eclipse.co.uk

It's pretty much impossible to clean these carbs without removing the jet block. The small drillings run off in odd directions.

If you haven't done it before, be careful. The blocks are easily damaged. The best technique in my opinion is to drop the carb in a pan of boiling water, whip it out and tap it upside down on to a piece of dowel held in the vice...or old hammer handle etc. It should tap out easily.

Have you checked to make sure that the magneto gear is sitting properly on its taper and not slipping back and forth while seeming to be tight ?

Iv'e had the jet block out today, used a hot air gun to heat the body and taped it out with an ally tube, (thanks for the tip Rick) anyway the jet block has been thoroughly cleaned and all the drillings cleared.
Made no difference
I have timed it again, but now it won't start at all it must be me, I'm obviously doing something wrong but its not the first time I've timed a bike and I've never had this trouble.
Another day tomorrow

email (option): gh@hibbo.eclipse.co.uk

Well it certainly won't hurt to try a new plug.....or two. If you have the correct mag it's tight wire advance and the correct handlebar lever will require that you push it away from you for full advance.

If you get nowhere with it on your own, you could always push it up the road to Ian Hatten. Ron

email (option): ronpier@talk21.com

Ron. I would be to embarrassed to ask Ian at this stage, in any case he's on holiday,
I do have the correct handlebar setup and yes I'm setting it up full advance 1/2" btdc on compression, as I say I don't understand what I'm doing wrong because I've done it all before

email (option): gh@hibbo.eclipse.co.uk

Ok I now know the problem is with the magneto, I've changed the magneto for another but not the correct type.
What I need to know now is considering that the original magneto had a really good pull on the magnets and a really strong spark when turned by hand, what component is breaking down under load, and if I have to get it completely rebuilt who would do it quickly?

email (option): gh@hibbo.eclipse.co.uk

Hello,

Getting a magneto rewound and refreshed is often a lengthy business because most of the good restorers have a backlog especially in the Spring. From their point of view a backlog is good because it means they're never waiting around for business. That's not so good from our viewpoint. You might be better off buying a good condition/refurbished mag.

There's one on ebay right now:
http://www.ebay.com/itm/391426954285?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Restorers include FTW magnetos who offer a 2 year warrantee. They do good work.

Failing that go to theodole.nl -- he has all kinds of magnetos.

I have a spare magneto on my spare motor, but I've never run it, so it may end up being the same as yours.

Now - as regards your magneto, it sounds as if you might have a bent armature at the points end, or something that causes the points to wobble. Check that the points plate is fastened correctly.

All best wishes,

Allan

email (option): allanmatchless@yahoo.com

Alan thanks for your reply
Graham

email (option): gh@hibbo.eclipse.co.uk

Alan you were spot on the armature was bent, now rebuilt with a new old stock parts and all is well running like a dream.
Thanks all for your input.
Regards
Graham

email (option): gh@hibbo.eclipse.co.uk