engine done?

[cleankat96]

So i started to ride the kat and had the shop tune it up, ran like a dream! Long story short i pulled into my driveway and it died, wouldnt start for 3 hours(let it sit after cranking until flooded) and when it did there was a noticable missfire and smoke blowing out of left pipe. Got it back to the shop and they took it back free of charge and found two fouled plugs and did a comp check and said that all four cylinders were between 115/116 psi. My question is is this just wear -22000 miles-1996 600 kat- or is it simple like a head gasket? I have no idea how all four would be low and almost even at the same time.

[TheSteve]

Whatd the tuneup consist of? Maybe they screwed up the valve adjustment and set them too tight, preventing the engine from building compression.

[md86]

And which 2 plugs ? Could be a clue .....

[cleankat96]

cylinders 1 and 2- and by tuned i meant the af mixture and synch but they also recleaned the carbs because i failed emissions so they made it pass

[The CyberPoet]

116 means either the valves are really off, or it's been deprived of good oil during engine use (wheelies starving it, going way too long between oil changes, running without enough oil, or flooding carbs washing gasoline into the oil).

I hope for your sake, the valves are just way off.

Cheers
=-= The CyberPoet

[cleankat96]

116 means either the valves are really off, or it's been deprived of good oil during engine use (wheelies starving it, going way too long between oil changes, running without enough oil, or flooding carbs washing gasoline into the oil).

I hope for your sake, the valves are just way off.

Cheers
=-= The CyberPoet

i hope so too theyre doing a leakdown test tomorrow to see if they can finally pinpoint this thing

[The CyberPoet]

i hope so too theyre doing a leakdown test tomorrow to see if they can finally pinpoint this thing

Valve adjustment needs to made before the leak-down test for the leak-down to be valid in terms of measuring the wear at the cylinder walls.

Cheers
=-= The CyberPoet

[diavolo]

And they need to be adjusted with the engine STONE COLD

[ATOMonkey]

Do compression test results very between throttle open and throttle closed with CV carbs? Makes a big difference with EFI or normal carbs.

[The CyberPoet]

Do compression test results very between throttle open and throttle closed with CV carbs? Makes a big difference with EFI or normal carbs.

As I understand it, real peak compression should always be measured with both sets of valves closed and the engine being turned by hand, so I'm not sure how it would make much difference WOT vs. no throttle would make

I could see how it might make a difference if you measure while using the starter to turn the engine over or if the engine were running under it's own power...

Cheers
=-= The CyberPoet

[ATOMonkey]

Ah yes, we always did it with the starter, WOT.

Cranking a car engine over by hand typically gave some pretty worthless compression numbers. They'd be all over the map.

Using the starter, the readings were much more consistent.

Even then, I've always used compression tests as a way to see if all the cylinders are running evenly, not so much as a monitor for overall engine health.

It's interesting to learn the differences between large engines and small engines as I get more familure with MC stuff.

[The CyberPoet]

I went back and checked the service manual -- you're right, it's done with the carbs at WOT and running on the starter (98+ Suzuki Kat 600 factory service manual, page 2-23).



Cheers
=-= The CyberPoet

[cleankat96]

ok i have a small update- i called the shop today-yes its still in the shop- and they did the leak down test and said it "passed" and they cant find any leaks so my service advisor friend said he would give me a call tomorrow when he has a better chance to talk with the tech- supposedly they put new plugs in and it idles and runs great, i was thinking could they have not held the throttle at wot when they compression checked it? would it throw off the numbers that much? a mechanic friend said it could and thats why it showed all four equal at 115 psi-thoughts?

[md86]

A leakdown test is different than a standard compression test , so .... Holding the throttle WOT during a leakdown does nothing , as far as I know .

[cleankat96]

No i meant holding the throttle wot during the standard compression test- i dont know if they did or not- the leakdown came back fine- so my question is if the throttle was not at wot during the standard compression test could it in fact throw off the readings by a lot and show a low number and make false readings across the board?- thanks for the response