Aren`t you happy with the bike.Why does everyone assume that anything that goes wrong with machinery is the worst case senario and a heart transplant is the only answer.This type of thinking leads to an empty wallet,but the dealers are laughing.
I explained before about the smoke,but nobody except 120fly agreed or even understood.I asked under what conditions it was blowing smoke? What colour? How long has it been sitting ? and any other relevant information pertaining to the concern.Then we can diagnose,then we can fault find,then we can advise.Please don`t go and spend money when you don`t have to.
#1. If it was a bent valve,you would have compression loss,most times serious.In a single cylinder,won`t run.A V8 Ford will chug along because it has 7 other pots.Most times causing serious engine damage,valve through piston,valve guide chews out,head chews out,valve wrecks head and piston by squashing against the combustion chamber (head),if it bends at the top or stem it does all kinds of nasty things to your cam and rockers and head and cam chain and the list goes on.
I did not follow that diagnosis.Alternatively if the valves are sticking there would be a compression loss also.Both of these would not allow the bike to run and are not in relation to the smoking habit this bike has.
If it is as I presumed,that the bike probably sits for a week or longer in a cold shed,blue smoke on start up when cold with full choke.Goes away quickly after choke is off and warm enough to run whilst not cold start assisted.It`s normal.
You come back from riding,turn the bike off and put it away.The oil sits on the valve stem seals which lie in a recess like a bathtub.The rubber stem seals cool down,become cold and lose their suppleness and get harder.The only other stopper is a cylindrical spring coil that applies pressure like an elastic band,these too can be effected when cold and the spring steel becomes cold and a bit more stiff.
Also the carbs on these bikes have a narrow choke or mixture area to create a higher intake velocity over the main jet creating a more efficient capillary bleed through the main jet.That`s why the jets are smaller to compensate,because the fuel draw is greater and the optimum air/fuel ratio is 14.5:1,so they downsize.If you put a cork in the inlet for example the choke is full on and blocks up the narrow passage.The air pressure will try to equalise,High pressure to low pressure.So the 1/2 a teaspoon of oil that bled under the stem seals gets drawn down through the guides and into the combustion chamber,it also is unfortunate that these nearly flat laying cylinders have their inlet pointing up.Fuel vapours that carry on up into the valve chamber from the float bowl and help the oil dilute and bleed through the stem seal as it sits does not help either.The inlet stem seal is the one that bleeds,helped by it`s engine design and configuaration,the drawing of air through attempting equalisation of pressure and the thinning of the oil that has bled through and the fact it doesn`t get ridden often enough.
Don`t panic if this happens.There are ways around it,as 120 fly said time for an oil change.Put some decent grade oil in it,it can look expensive,but thank god you only need about a litre,so you are getting top quality oil and it works out cheaper than filling an R1 or a 6 cylinder car.I pay $18 a litre for my oil.Buy a conditioner additive to mix and keep the rubber seals soft and they will seal better and the rest of the seals in the engine will thank you for it and they will all last longer.Run the bike out of the excess fuel in the bowl.Turn the tap off and let it cut out,but be carefull not to do it while the bike is overly hot,sometimes leave it for 10 and come back and do it before you store it.This will stop any build up of petrol vapour assisting the process.
Finally,if you really get annoyed or it bothers you,you can allways replace the seals.But you will be doing it frequently and it will become expensive.Although not as much as replacing the engine every couple of months.
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