250 S compression

[josephthediviner]

The subject of engine compression came up lately between my self and my scooter mechanic

   The kymco manual states that engine compression should be 15 +-2 KG/ cm2  which works out to 213 psi which seems diesel high.   What has everyone found to be ballpark good?   

   Upon hearing this my mech responded that he should call Kymco and see about getting some new engines since the new scooters were out of spec.  LOL..

SPECIFICATIONS
ENGINE
Throttle grip free play : 2～6mm
Spark plug : NGK: DPR7EA9
Spark plug gap : 0.7mm
Valve clearance : IN: 0.1mm EX: 0.1mm
Idle speed : 1700±100rpm/1600±100rpm(people s 250)
Engine oil capacity: Cylinder compression : 15±2kg/cm²
At disassembly : 1.1 liter Ignition timing : repeatedly
At change : 0.9 liter Coolant type : water cooling
Gear oil capacity :
At disassembly : 0.20 liter
At change : 0.18 liter
TIRE
1 Rider 2 Riders
Front 1.75kg/cm² 1.75kg/cm²
Rear 2.0kg/cm² 2.0kg/cm²

I wonder what unit of measure it should have been?  another met in!

[mrbios]

I tested mine but I had to make an adapter for my compression tester so I'm not sure if it is an accurate reading.  I only measured around 140 psi.

2005 GV 250.

[TLRam1]

140 PSI sounds more likely.

[josephthediviner]

after the rebuild the engine has about 165psi after 4 revs cold.  I will give it another few thousand miles and retest hot and repost to the forum   thanks    Jim.

[mrbios]

after the rebuild the engine has about 165psi after 4 revs cold.  I will give it another few thousand miles and retest hot and repost to the forum   thanks    Jim.

Thanks for the update.  As you probably know the motor is supposed to be fully warmed up meaning you could see 180psi? +  Those are good numbers.