1981 gs 450e (startout $50)

[Guest]

Is it sealing correctly in the spark plug hole? Is the pressure release button working ok on the gauge? If that's stuck in then the gauge won't maintain the pressure reading. Definitely sounds like a gauge issue to me...

 

[MisterCinders]

Your cam timing could be off, opening the valves too early and botching the compression.

 

[surviverguy]

Not 100% sure but I think the throttle wide open is to allow air to get sucked into the chamber to be compressed, whereas the throttle being closed will stop that happening.

In theory that would mean no carbs is fine... hopefully someone chips in who knows a little more than I though...

No carbs are needed for compression test. "throttle" will be wide open with no carbs...

 

[surviverguy]

yea thats what i was figureing... i just did the test and it sounded like it wanted to start the back tire would spin a litlte... i barly got any compression the the needle would fluxuate but not go over 30psi..anyone kno what would cause this.. im thinkin maybe its the gauge cuse the needle should staty at the highest point right cuse min would just go back to zero on its own

You've got two problems. The bike needs to be in neutral. With the bike on the centerstand the rear wheel should spin freely by hand. If using a side stand the bike should be able to be rolled around (when not on the side stand of course).
The compression gauge shouldn't return to zero. That's a problem with the pressure release valve on the hose near the gauge of the compression tester. The release valve is like a tire stem valve.
Be sure all (4) of your spark plugs are out of the engine.
With the gauge attached to a cylinder, when the engine spins the needle will bounce up on the compression stroke. A proper functioning gauge will keep the needle at the max pressure.
I usualy let it hit compression 4 times and that's my reading.
The battery needs to be healthy and fully charged. Using a battery charger at the same time is a good idea.
Keep a piece of paper and pen handy. Write down the reading of each cylinder when the readings are taken. Don't rely on your memory.
I hope this helps!

 

[lorello]

the battery maybe its brand new after i put the acid in it i waited half an hour like it said hooked it up to my dads charger ... like five minutes later my volt meter was reading 12.88 volts i ddidnt get why it would be charged so quick but i figured if it wasnt id kno when i hooked it up to the bike.. every thing seen to be working the selinod would click and the starter would go sounded like the bike wanted to start (obviously its not gonna) and i did it a lota times so im guessing the battery was charged good

 

[surviverguy]

The small motorcycle batteries should only be charged at 2amp (low) setting. The battery maybe completely charged with the new acid in there. I'd still keep a 2amp charge on it during testing. The engine isn't locked up- that's a good thing. The engine should spin fast since there's no compression. When I'm getting an engine to run again which hasn't in a long time- I always pour some oil in the spark plug holes and spin it. About a tablespoon is enough. The oil helps lubricate the cylinder walls and the rings. Oil might shoot back out of the holes when spinning with no plugs in there. That's a good thing if it happens. You could test the compression gauge on another working engine- a lawn mower, weedeater, or a car....

 

[lorello]

yea im gonna get my dads charger tomrow and try it with it on.. and it i figure seeing the tire was spining the first time that would mean that the motor still in working condition right...poured a little oil in like you said but what do u mean when u say spin it?

 

[surviverguy]

yea im gonna get my dads charger tomrow and try it with it on.. and it i figure seeing the tire was spining the first time that would mean that the motor still in working condition right...poured a little oil in like you said but what do u mean when u say spin it?

What I mean when I say spin it is energize the starter solenoid so that the starter spins the engine...spin it="crank" the engine using the electric starter.

 

[lorello]

alright thats what i thought but wasnt sure if u ment manualy ill give it another go tomrow try the gage on my lawn mower

 

[surviverguy]

also when spinning the engine- monitor the starter temperature. Don't let the starter get too hot. Let it cool off as needed if it gets hot. Hot=hot to touch using your hand.

 

[lorello]

sorry about the delay havnt had money to put into my bike but just got a new job so should be able to get the carbs and air box soon.. im planing on trying to get a tank at the same time as the carbs n stuff save on some shipping. i wanted to know how interchangeable the tanks are between models or the mesurments id need to know to get an aftermarket one.