PISTON RING HELP

[chapapadap]

So im pretty sure my piston rings went bad due to a broken reed. Never found the broken part and now it has low compression, no power, and smokes more than normal. I took the top end off and everything looked good. The only thing questionable were the rings. They seemed hard to move in the piston like they were gunked up or something. I ordered new rings but realized i have a used piston with rings still on it. Should i wait until the new rings get here or throw the used rings in to see if that fixes my problem? Any suggestions?

 

[Awk08]

So im pretty sure my piston rings went bad due to a broken reed. Never found the broken part

nope.....broken reeds will not cause any damage at all.
it's either laying in the layer of oil in the bottom end, or got chewed up and spit out the exhaust.


rings are piston manufactuer specific and cannot be mixed-matched
compression test will tell you if it needs rings.
if that other piston measures correct for your measured bore size, you could run it, it has to match exactly w/ correct clearence. do not just throw it in there and hope for the best, that usually = the worst.

 

[chapapadap]

Im getting around 70psi on compression test. Also it was run with a broken reed for a couple hours.

 

[Awk08]

Im getting around 70psi on compression test. Also it was run with a broken reed for a couple hours.

broken reed only allows more fuel/air mix, if it was jetted correctly = no damage

 

[chapapadap]

broken reed only allows more fuel/air mix, if it was jetted correctly = no damage

yes but a friend rode it for a couple hours with a broken reed and with it revving out. Would that burn up the rings? Seems like they should have been moving in the piston more freely. Felt like the rings had crap in them.

 

[Awk08]

yes but a friend rode it for a couple hours with a broken reed and with it revving out. Would that burn up the rings? Seems like they should have been moving in the piston more freely. Felt like the rings had crap in them.

what premix oil are you running ?
i've had that happen to a few month old top end, using a certain oil i'm not getting into a discussion about.
lets just say it stays home if it doesn't have maxima super m in it


i've also seen and experienced multiple broken reeds (never on v-forces) and each time the bike would maybe start but not run.
i suspect and airleak was the cause of the "revving out" not the broken reed

 

[chapapadap]

what premix oil are you running ?
i've had that happen to a few month old top end, using a certain oil i'm not getting into a discussion about.
lets just say it stays home if it doesn't have maxima super m in it

Just valvoline 2 stroke oil. Was using yamalube before.

 

[Awk08]

Just valvoline 2 stroke oil. Was using yamalube before.

that should be fine, and both of those compatible

 

[speedyslyder]

are you sure your using that comp tester the right way right.I dont got much advice for you only from my experience you should hold throttle wide open kick it as hard as you can for at least 3-5 times or whener it stops rising in compression,also i think ive heard that if the hose is to long it will give an innacurate reading,i have to take off my gas tank to use mine.Is there a rubber washer on the threaded part were you screw it on??.check

 

[chapapadap]

are you sure your using that comp tester the right way right.I dont got much advice for you only from my experience you should hold throttle wide open kick it as hard as you can for at least 3-5 times or whener it stops rising in compression,also i think ive heard that if the hose is to long it will give an innacurate reading,i have to take off my gas tank to use mine.Is there a rubber washer on the threaded part were you screw it on??.check

Its actually a comp tester from Harbor Freight and ive had a couple people tell me that they wont measure compression right in a kick start motor. Its weird because i get 70psi no matter if i have throttle open or not. Also yes it has a long rubber hose about 2 ft long coming out of the spark plug. The damn kit even stated that it was meant for motorcycle or atv though.

 

[chapapadap]

Im going to test my other running bikes with it tonight when i get home and see what it says. If its not my rings im at a complete loss after this.

 

[speedyslyder]

30$ at auto parts store.What spark plug you running?Check your cylinder,cylinder head for hair line fractors,Also that brownish crap your talking about on your head gasket is not going to fly either your head is warped the gasket is bad or you did not torque it right.
))

 

[chapapadap]

Stock plug. Just bought 2 new spares also. all of that has been checked. I think it was from the a sh*tty head gasket.

 

[Larry's Shee]

Highly suggest "lapping" the head before re-assembly

 

[Herpderplol]

How many times did you kick it over when you tested it? a good 5-7 i would do

 

[chapapadap]

How many times did you kick it over when you tested it? a good 5-7 i would do

Yea about 7. Im getting false readings with this tester. All my bikes are reading the same so i think i have good compression.

 

[speedyslyder]

woodruff key

 

[chapapadap]

View attachment 8891 woodruff key

Problem is my flywheel tool is in my buddys trailer and hes out of town. Nothing is going my way lol

 

[Blaaster]

Head gaskets are seldom sh*tty, unless you put an old one on.

The head must be flat and the nuts must be tensioned at 20 ft lbs dry, no Loctite or oil/grease, it fools the wrench.