cb500t smoking exhaust and good compression

[markmatt]

So to further introduce myself, i come to you fine fellows with what my woes are at the moment. To make a really long and embarrasing story short my bike was running well and then because of some forseeable circomstances, it wasnt! what i was left with after the fact was a burning right cylinder. Now iv posted this in honda twin before and gotten many many many responces but i figured id give you guys a go and see if anyone has other ideas.

some background info to give you a better idea

-the compression tested 155(L) 150(R)
-right cylinder is burning a LOT of oil. like i said in my introduction thread, burning enough oil to trick you into thinking its a 2 stroke.
-**bonus information, when we did the valve adjustment the exhaust valve lock nut was fused with the actual adjuster. didn't break it free but adjusted it by rotating the lock bolt and the adjuster together.

so my question. what is making it burn oil. 50% say rings 50% say valve seals. Does anyone here think it could be from the stuck valve adjuster possibly coming loose and letting the valve sit open too much dripping oil into the cylinder?

side note, and this could be completely irrelevant, when i look into the cylinder via the spark plug hole, when the intake valve is open, its relatively clean and shiny. when the exhaust is open its coated in oil. not carbon but oil. even on the seat of the valve.

 

[VonYinzer]

Assuming rings are good... The lower compression number on the right cylinder would imply a valve issue. The fact that your adjuster is NOT functioning correctly (fix the small issues first...) adds to that notion. Do you have any reason to believe there's an issue with the piston rings other than the oil burning?

 

[xb33bsa]

it could be a broken oil control ring and or a worn out exhaust guide/bad seal
it has nothing to do with the adjuster you can be confident of that
time to tear it down :'(
be sure and check the stem to guide clearance as per the factory service manual,on all valves
this will tell you if you need new guides

 

[VonYinzer]

it could be a broken oil control ring and or a worn out exhaust guide/bad seal
it has nothing to do with the adjuster you can be confident of that
time to tear it down :'(
be sure and check the stem to guide clearance as per the factory service manual,on all valves
this will tell you if you need new guides

Agreed on the adjuster... It's not the cause of the issue, as much as another sign that something isn't right there. The adjusting nut should never have fully seized on like that.

 

[markmatt]

Agreed on the adjuster... It's not the cause of the issue, as much as another sign that something isn't right there. The adjusting nut should never have fully seized on like that.

Well it clearly had been exposed to some moisture. there was that green colored kind of corrosion all around it. I am going to take another wack at dissecting that. yea generally what you guys are saying is what everyone else has said. by exhaust guide do you mean valve guide(exhaust side)?

Yea i will most likly be tearing it down this winter. I am in the process of making that happen. my goal was either sell it before first snow hits, or fix the top end if the snow comes. the bad part is that parts are hard to come by for the 500t even though they are similar to the 450. rings for instance are expensive as all hell. I dont have any reason to believe its rings that are wrong other then the burning oil and the compression numbers. i was told that in spec is 160-180 compression. However when i had done the compression test i did it cold so i figure that could account for another 10 psi. the shop i hang at is in the process of getting or setting up a leakdown test so that will be a definitive answer right?

 

[xb33bsa]

the adjuster nut no bigee , it just got rusty
if the motor has good cams and followers its worth redoing

 

[markmatt]

it does. as far as i know. and i actually just started breaking down a parts engine that has good innards as well just in case.