I've a Pulsar 150cc bike bought in may 2009, roamed around 70k kms. Problem is it is exhausting white smoke only when it is started, mechanic at a Bajaj showroom says it has come to bore and had to be...
Hi, if the smoke really is white smoke and is only present when you start then it COULD be just water vapour which once exhausted (after warming up) would result in normal exhaust gas colour from then on.
If it is burning white smoke all the time then it could be piston ring failure. As this is a single cylinder engine you would need to find out what the normal compression reading should be and then check your reading with a compression tester. You probably don't have one but most motorcycle garages should be able to test it for you for a reasonably small fee.
From what I can find out online your compression ratio should be 9.4:1 which means your psi reading on the gauge should be around 124 psi - this may be a little lower due to engine wear.
If you can get hold of a compression tester, make sure you have the bike sized fitting on it (same thread size as your spark plug) and then warm up the engine for a few minutes then turn it off and remove the spark plug. Then fit the compression tester into the cylinder head in place of the spark plug.
Turn the engine over using the electric starter if you have one or the kick start if you don't (it wont run without the spark plug but it will turn over) and note the reading on the gauge of the compression tester. If you have a friend with a similar bike then you can check his and compare it with yours.
Regardless of the reading, now remove the tester and then put about a couple of squirts (teaspoon full max) of engine oil into the cylinder head and then repeat the compression test.
If there is a noticeable increase say 20-30 psi then I am afraid its your piston rings or valve guides which are leaking pressure, the oil temporarily sealed the leak and gave a higher reading.
BUT if the pressure is about the same then its probably not your rings and like I said earlier it could be steam caused by water vapour in the engine burning off at start up. If you smell the smoke what does it smell of?
Hope this helps,
Steve B
UK
×