Engine compression 250 hawk

Dewey · 01-17-2021, 06:01 PM

Hi all. I'm Having issue with engine spitting and sputtering. Discovered that the carburetor was not fastened down snugly . My bad I should have checked that during assembly. Nevertheless I tightened it hoping that would solve the problem but it didn't so I ended up checking the compression getting around 60psi. So I decided to remove the head and clean up the valves and reset them they were pretty fouled up. After doing all this and adjusting the valves I am still only getting 70 psi on a compression test is this normal for this particular engine? What else could be wrong? Cylinder looked good. Checked fuel filter, good.

TxTaoRider · 01-17-2021, 07:23 PM

Are you checking compression with a good charged battery and the throttle fully open?

Megadan · 01-17-2021, 08:48 PM

Quote:

Originally Posted by TxTaoRider

Are you checking compression with a good charged battery and the throttle fully open?

This, x 2. You have to either remove the carb or have the throttle fully open when doing a proper compression test. If the throttle is closed, there is less air getting into the cylinder, and thus a lower pressure due to the decreased volume.

TheChairman · 01-17-2021, 11:09 PM

Did you also check valve clearance after the head came off?

Is it fuel washed?

You said you had the problem after assembly. Is this bike brand new? New rings will always leak until they are broken in.

Pour a teaspoon of motor oil into the cylinder, kick it once or twice and then recheck.

01-17-2021, 06:01 PM	#1
Dewey Join Date: Jan 2021 Posts: 1	Engine compression 250 hawk Hi all. I'm Having issue with engine spitting and sputtering. Discovered that the carburetor was not fastened down snugly . My bad I should have checked that during assembly. Nevertheless I tightened it hoping that would solve the problem but it didn't so I ended up checking the compression getting around 60psi. So I decided to remove the head and clean up the valves and reset them they were pretty fouled up. After doing all this and adjusting the valves I am still only getting 70 psi on a compression test is this normal for this particular engine? What else could be wrong? Cylinder looked good. Checked fuel filter, good.
	0

01-17-2021, 07:23 PM	#2
TxTaoRider Join Date: Oct 2020 Location: Flower Mound Texas Posts: 904	Are you checking compression with a good charged battery and the throttle fully open? __________________ 2021 Tao Tbr7 - "Lucille" Mods so far- Brozz swingarm, 21" front rim (Bridgestone Tw302 rear/Dunlop D606 front tires), Digital gauge cluster, pz30b pumper carb, after market hand guards, aftermarket brake and clutch levers, round fold away mirrors, Fly handlebars shortened slightly, 13t front sprocket 2009 Q-link Legacy 250 1982 Suzuki GS1100ES - "Jolene"
	3

01-17-2021, 11:09 PM	#4
TheChairman Join Date: May 2020 Location: Philadelphia Posts: 115	Did you also check valve clearance after the head came off? Is it fuel washed? You said you had the problem after assembly. Is this bike brand new? New rings will always leak until they are broken in. Pour a teaspoon of motor oil into the cylinder, kick it once or twice and then recheck.
	1