1986 Suzuki DT140 intermittent cooling.

[Andre3]

Does anyone know how to narrow down the number of ways exhaust can get into water jacket?

Head Gasket?
Powerhead Base Gasket?
Exhaust Cover Gasket? --- (Just replaced with new)

Thanks!

[Andre3]

Discovered problem

It was bad Head Gasket. Hooked water hose directly to water tube feeding Powerhead and with good line pressure discovered water leaking from headgasket.