diagnosis...negative

[finmac]

My bike is more than ready for an overhaul, its held up damn well so far. I'll be taking the carbs off this winter, and the valve cover for shims. I needed to know if its worthwhile dropping the whole engine out to replace the seals on the head and maybe the piston rings? As of late, the bike has been revving ok, just without the power, much more obvious flats spots, and hasnt had the pull it once did. I'm thinking it might be a compression problem? Thoughts?


Fin

*any suggestions on what kind and spec of torque wrench I should have for GS jobs?

[rob1bike]

I would suggest a compression test before you tear it open, however I don't know the values. Just a thought, good luck!

[Chuck]

Doing valve shims is a bit irksome in the frame, but I mean it took me 4 hours to do the first time I ever did it in my life.  It will probably take you longer than that to take the engine out and put it back in, so if valve shims are all you're doing, leave the engine in.

+1 Check the compression.  You might just have carb issues.

Miles??

[FearedGS500]

yea .. i'd leave it in .. unless you really want to pull it .. but if your gonna pull the motor out take the heads of might aswell do it big and get it cleaned and bored/resleaved  and go up a size or to .. get a little more out of it .. if its the first time doing it .. taking the tank of and the cover looking at it and then putting it back togeather should not take you but about 2 hours at most for your fist time ....

[finmac]

Ok, so leave it in. Maybe try the carbs first to see if that does it... Testing the compression- would need some sorta screw in digital pressure tester for the sparky hole? The bike has had at least 4-5k kms on it since any carb adjustment or cleaning. Total kms on the bike, over 16000. Cleaning and boring thats definately a shop job, though I might have a dude who will do it. Ive read that its almost as easy as dropping in larger pistons? 72mm? jetting larger and K&N? I got the sense from Kerrys vid that the valves can be irksome though entirely doable with patience. Getting the right shim sizes will probably be harder. Thanks for the feedback


Fin

[Egaeus]

This thread confused me. 

Is your head gasket leaking oil?  If not, then why are you contemplating replacing it?

Is the compression below spec?  If so, then have you tested to see whether it's the rings or the valves?  If not, then why are you wanting to replace the piston rings?

I think you might just be jumping to conclusions.

[GeeP]

16,000 km?  That's not even 10,000 miles!

Unless it's been operating without oil, is making loud noises, or shows signs of lubricant contamination there is no reason to overhaul it.  Clean and tune the carbs, then do a valve adjustment!

The GS engine should not require any major work until at least 130,000 km.

[finmac]

Its difficult to say whether or not there is a clear leak, but the engine is generally oily. Riders in the lower states might not have quite the same maintenance schedule as those riding in winter conditions, where the road salt does nasty things. For example, my exhaust headers are showing signs of rust.

Egaeus do you have any suggestions to test the compression to spec? I tried putting my mouth over the sparkplug hole and hitting the starter, but the taste of gasoline quickly got to me...

Im thinking maybe less of an "overhaul" and more of easy access to clean the engine, CHECK the gaskets, change up the shims. Thisd give me a chance to adjust the throttle cabling, which has been the cause of my die-at-idle problem I think. I might consider redoing the coating on the headers at this time.

If Im jumping to conclusions, its definately given me something to look forward to when cruddy weather sets in.


Fin

[css4608]

On your oil leak I would wash your bike then ride a little bit to see where the oil is coming from,  follow the trail. If you took the motor out and cleaned it would be much harder to find the leak without seeing it leak.

I hope the bit about the mouth over the spark plug was a joke. You can put your thumb over the hole for a quick compresin check but that is more to see if you have compression not to check for bad rings. You need a compression gage; they are cheep and if you don't want to purchase one AutoZone rents them for free, at least in the US. Just make sure the gage has the same threads as your sparkplug some have different.

On the rusting headers, mine are starting to rust and have never seen any salt, snow etc. actually the brackets holding the pegs on are starting to rust as well.

[rob1bike]

Wtf? You put your mouth over the open head an cranked it? You've got to be kidding!
You can check it buy putting your mouth over the exhaust pipe an have some one crank it. If it breaks a eardrum your compression is good, should test it @ 6500rpms.
























That was a bad joke, don't do that ...ever!

[ashman]

Its not that hard to change shims out, by no means do you need to remove the engine.

-ash

[tussey]

Wtf? You put your mouth over the open head an cranked it? You've got to be kidding!
You can check it buy putting your mouth over the exhaust pipe an have some one crank it. If it breaks a eardrum your compression is good, should test it @ 6500rpms.



lmao, I got my friend to try that, he can no longer hear 




















That was a bad joke, don't do that ...ever!

[MarkusN]

For example, my exhaust headers are showing signs of rust.

Are you kidding? A GS without rust on the headers ain't no GS.

Seriously, don't sweat it. With 16'000 km a carb and shim job is all she needs. I wouldn't even consider measuring compression at that mileage, uless you had serious engine trouble.