oil in exhaust pipes-rings

TODDSTER wrote:

MFolks, bountyhunter,Patton & Beat poet. Comp. test on my kz650 D1A sr with motor at op. temp. are as follows
#1-135 lbs
#2-140 lbs
#3-140 lbs
#4-150 lbs
#1 plug was fuzzy sooty blk. What do yall think. :huh: Didn't get to the wet comp. test yet, maybe later today or tonite. 15 lbs of seperation=10% ??? Let me know what your thoughts about this might be. Thanks TODDster

Those readings are well within service limits for a 750 twin, don't have an FSM for the 650.

CoreyClough wrote:

Why a cold, not a hot compression test, both dry then wet with throttle wide open? What would the cold show that the hot wouldn't?

Metal expands as it heats up, so the rings will seal better as they get hot. It's always good to get the worst case number and then see how much it improves going to hot.

TODDSTER wrote:

She smokes when I start her up.

That will usually be valve seals. They can also degrade compression because the oil that flows down past the valve into the combustion chamber gunks up the valve seat..... ask me how I learned that....:laugh:


TODDSTER wrote:

Not sure what clear tube test is.

It's how to check the actual fuel level in the carburetor float bowls.

TODDSTER wrote:

... thinking valve burnt or no seat or not closing completly....

Thinking valves are indeed seating/sealing okay. Because a leaking valve would significantly reduce compression inside the cylinder.

Valve clearances (gaps) might or might not be a little too tight and need adjusting. But should at least be measured (the easy part).

Am thinking the only issue with this relatively low mileage engine is the minor problem of leaking valve seals which is causing exhaust smoke during the first few miles of riding, and an easy-to-fix cam chain tensioner. :laugh:

Good Luck with whatever is decided!

Patton your theory sounds more sound than corey IMO. I'll do a cold compression test, that should give me a true starting point. I did notice the smell of gas coming from the crank case other day. some one had asked me if i checked,:blush: frankly I couln't remember if I did so I must not have or it just started:huh: Maybe at 50 i'm losing or lost more of my mind than i realized. I guess i'll cheeck out carberation & go from there. to much fuel = gas in crank. i'll ck points again then timing. sound righ,back to beginning. cold comp.test,carbs level,poinsts,timing ?? Is that about the order & the ckeck list to figure this out? Bounty hunter, what type comp. test did you do to find that out, cold or hot? Piston tops look real nasty through plug openings. Wet in #1 & lots of cabon build-up in #1 #2 & a litle in #3 & same in #4 as In #,s 1&2 Thanks guys;)

TODDSTER wrote:

Bounty hunter, what type comp. test did you do to find that out, cold or hot? Piston tops look real nasty through plug openings. Wet in #1 & lots of cabon build-up in #1 #2 & a litle in #3 & same in #4 as In #,s 1&2 Thanks guys;)

Compression testing won't detect a worn out valve seal. If you see burned-on oil gunk around the valve seat and on the top of the piston, the oil is coming down from the valve past the seal. The only sure way to know is take the head off.

Thanks bounty hunter, thats what i'll do first to check things out. What all parts am I looking at obtaining for a complete top end rebuild? gaskets,pistons,rings, oil seals, valve seals,valve seats?,valve springs, tensioner chain parts. I've never done a top end ,not sure of a parts list. Any help would be appreciated. Thanks again!

TODDSTER wrote:

Thanks bounty hunter, thats what i'll do first to check things out. What all parts am I looking at obtaining for a complete top end rebuild? gaskets,pistons,rings, oil seals, valve seals,valve seats?,valve springs, tensioner chain parts. I've never done a top end ,not sure of a parts list. Any help would be appreciated. Thanks again!

Until proven wrong, I'd assume the valve springs, cam chain and tensioners are reusable.

I just did one on mine, going from memory:

Top end gasket set (valve seals if they are not included)

pistons/rings/wrist pins (very pricey)

Valve shims

Machine shop to bore cylinders and do head work

Maybe valve guides if yours are worn, but don't buy them until the machinist checks them (they are expensive)

Valves if any of them are too far gone to reuse.

NOTE: measure cylinder wall wear before buying pistons and rings. You may not need new ones. The cost of the pistons/rings/bore job are going to be the main $$$ if you need them.

Thanks for the come-back. Also need some special tools to measure piston bore,valve springs,micrometer,metric feelers etc. I'll pull top end in a wk or 2,may be able to get a couple more short rides in before the weather turns to crap or the motor,whichever comes first. I will keep you & everyone else who gave me advice & pointers updated on my progress. I know this won't be my last question or post. Man am I ever bumbed. Oh well I still got my sanity & thats sayin somethig Later

on a note,, stock rings for the 650s are damn near impossible to get, I got a set on fleabay and expensive.
you may want to budget new pistons and boring out the cyls in your project

HEY diagnosis for oil in exhaust pipe is a snap...

leak down test -- special tool.
compression test hot engine dry AND wet.
remove exhaust pipe and locate wet cylinder do a visual on the valve stem.
the readings need to be interrupted correctly.

either way the head comes off.
now is a good time to consider
1.valve face/seat resurfacing
2. new valve springs
3.valve guide to valve stem clearance
4. new valve seals
5.piston rings
6. piston size-bigger??
7.cylinder size- out of round?? barrel shape? Taper?
8.ALL parts are readily available and easy to obtain.

one more thing!!

if your oil is saturated with gasoline no seal will keep it out of the exhaust!!!

change the oil and filter and run this machine.

verify the fuel tap positively stops fuel from flowing when the machine is not being used.

you might save your self some work