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What would you do now
Posted: Sat Oct 05, 2013 9:26 am
Author: zman
Some of you may had read my previous post about the bike smoking.
Well its still not sorted after 2 months.
Carbs all clean & working.Electrics all sorted & working .
Plug in No1 is black & sticky.When bike is left on side stand you get a big plume of smoke for a short while then ok.With a new plug in it fires & runs great for about 2 miles then start missing.
I changed the the valve seals & had guides checked with one in No1 being replaced.I was told other one was fine.
So im thinking the other one may not of been fine & should have been replaced.Or may be the heads is cracked & thats where the oils getting into the cylinder.
Posted: Sat Oct 05, 2013 9:46 am
Author: timyoungman
bummer....
Cracked head is a possible. Valve stem seal is a possible.
This may sound stupid but maybe you should make 100% sure you've not got too much oil in the motor first and then...keep calm and carry on !!
Best of luck...
Posted: Sat Oct 05, 2013 9:57 am
Author: z1bman
have you physically inspected the rings/pistons/ bore ? it is no good relying on the compression test. you need to get the bore measured by a engineer check the piston to cylinder clearance / thickness of the rings + check the ring end gap by inserting the rings in to the bore + measure the end gap
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Posted: Sat Oct 05, 2013 12:21 pm
Author: zman
with big plumes of smoke on startup after being left overnight,must indicate that oil is coming down from the head?
is that correct?
Posted: Sat Oct 05, 2013 1:27 pm
Author: z1bman
warm up the engine +remove the spark plugs + turn the engine over until the valves are on their maximum lift + see if there is any oil on the back of the valves. are the valves guides a solid fit in the head? i have known the exhaust valves to let oil between the guide + the head . has it got the large O rings at the bottom of the liners as these prevent oil getting between the the liner + the casting of the cylinder + leaking into the cylinder head. do you leave it on the side stand if so you might have a leaking carb?
Posted: Sat Oct 05, 2013 2:00 pm
Author: Pigford
z1bman wrote:has it got the large O rings at the bottom of the liners as these prevent oil getting between the the liner + the casting of the cylinder + leaking into the cylinder head?
The O-rings are often left off as general opinion is they shouldn't be needed... but if they are its probably a bonus.
Cracked head... or dodgy liner/fit/barrel sounds highly possible.
Is it defo BLUE or WHITE smoke & not BLACK?