Excessive smoke and mis fire from LH cylinder

[Richard B]

Problem with my Arrow. Excessive smoke, oil and mis fire from LH cylinder. I don’t think it’s a carburettor issue as it would affect both cylinders. I have checked timing using the 6v bulb technique and 9/64 rod as per maintenance manual. I have also checked the rings bore and gaskets are intact. Any ideas please?

[will_curry]

What state is the oil seal in the left-hand crankcase door in?

[nevhunter]

A likely cause. Depending on the gearbox oil you'll pick it by the smell. Nev

[Richard B]

Thanks for the responses. But the seals are all new, replaced as part of an engine rebuild. As for gearbox oil, can the oil leak into the LH crankcase?

[ian williams]

hi Richard ;
check if engine runs ok when the points cover is off , if it is ok then you may have a problem with one of the condensers shorting to the points cover .
the original condensers would have had a bit of tough card like material fitted on the stud which then folded over top of the nuts and stud so it insulated the top of the condenser studs from touching the points cover plate when it was put back on .

i think draganfly did make a thin ring which you could buy to go inside the points cover but not sure if its still made .

the card material is used in electric motor rewinds , i get it from a company next door to where i work .

the other thing you need to look into is the battery condition and charging rate , these bikes do have tendency to boil the battery by overcharging them with the basic bridge rectifier not having any regulation , so you end up with anything between 6-9v when running engine .

when i encounter such a battery problem on my leader it usually means the battery is dry and almost had it , i will find i get the misfire when i put lights and indicators on and it could go away when they are off , but by the time it is noticed its gone low on elctrolyte in battery it can be too late .

i think the AO services A REG 6 regulator rectifier is whats needed if you want to make sure the alternator charging output is regulated .

i think you might find some crankcases may have screw plugs in bottom of them , check yours to see , and make sure theres no leaks .

bike will smoke a fair bit upon starting it and for a bit so best to get it running and then a good ride to dry it all out in the cylinders and exhaust etc .

plugs, i think many use B6ES ngk type , i use champion n5 or something from ngk .

check your plug gap too , only sometimes its overlooked .

regards , ian

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[JohnnyBeckett]

hi this maybe a draft question but have tried draining the sump i had one that had a lot of old two stroke oil left in the bottom of the engine

[Richard B]

I looked for a sump drain but couldn’t find one.

[will_curry]

As far as I'm aware none of the Leader/Arrow engines had sump drains.

[nevhunter]

How much oil is getting on each plug?. Compare them. .. Nev