Cracked head?

If it is a crack or porosity problem you could spray some carb cleaner on it as the bike is running. If the RPM goes up you have your answer. Or you can use ATF and if it starts to smoke you again have your answer. I would use carb cleaner only because it is cleaner.

Actually before i pulled the carbs and was diagnosing it while running, the engine would die instantly when carb cleaner was sprayed.

Bowtoy70 said:

Actually before i pulled the carbs and was diagnosing it while running, the engine would die instantly when carb cleaner was sprayed.

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Of course it depends on the composition of the carb cleaner. If it happened to be an older can of carb cleaner containing a chlorinated solvent, which is non-combustible, the idle speed would either decrease or the engine would die. Since halogenated solvents have been largely regulated out of carb cleaners and most spray cleaners nowadays, carb cleaners tend to be pure hydrocarbons that are combustible and cause idle speed to increase.

The propellant employed in a spray can is another factor that could alter the test result. If the propellant is CO2 this too can cause idle to fade, especially when employed with halogenated solvents as described above. Propane, dimethyl ether and isobutane are commonly employed flammable propellants and will cause idle speed to increase if there is a leak.

For a completely unambiguous test, try your test with starting fluid (employs flammable propellants and diethyl ether) which should cause idle speed to increase if there is a leak.

Another factor for the situation. Yes try a new can of spray.

WZ507 said:

Bowtoy70 said:

Actually before i pulled the carbs and was diagnosing it while running, the engine would die instantly when carb cleaner was sprayed.

Click to expand...

Of course it depends on the composition of the carb cleaner. If it happened to be an older can of carb cleaner containing a chlorinated solvent, which is non-combustible, the idle speed would either decrease or the engine would die. Since halogenated solvents have been largely regulated out of carb cleaners and most spray cleaners nowadays, carb cleaners tend to be pure hydrocarbons that are combustible and cause idle speed to increase. For a completely unambiguous test, try your test with an ether-based starting fluid which should cause idle speed to increase if there is a leak.

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+1 on ether.

I hadn't thought about either That will do the trick, just use it in a well ventilated place.

N0rt0nelectr@ said:

I hadn't thought about either That will do the trick, just use it in a well ventilated place.

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relatively small fireballs, lol