How much compression does a ktm 65 have from the factory?

Answer 1

Not an easy question to answer. Compression readings are greatly impacted by your gauge, altitude, air density etc.

I have seen many places where the compression on a KTM 65 should be at least 135PSI. I live at 7,000 feet, I purchased a cheap Harbor Freight compression gauge. I tested compression on 2 new KTM 65s and 2 Cobra 50s. The KTMs read between 88 and 95 PSI, the Cobras read between 60 and 65 psi. All the bikes run great and have plenty of power.

I know my gauge reads low, I also had to use an adapter to fit the gauge on the cylinder head. From what I understand the adaptor also adversely impacts readings.

I think the best bet calls for measuring compression when the engine is new, record the PSI, date temperature, elevation and gauge used as a benchmark. Check the compression again at intervals, when compression drops by more than 10% from the benchmark consider a rebuild. When compression drops by more than 20% rebuild is imminent.