Head gasket replacement?

[Quimrider]

Has anyone replaced a head gasket? My 2000 after 9800 mi. has developed a small leak. I'm talkin about the gasket between the cylinder head and piston jug. Not the gasket on the cylinder head cover.

[Easy Rider]

Has anyone replaced a head gasket? My 2000 after 9800 mi. has developed a small leak. I'm talkin about the gasket between the cylinder head and piston jug. Not the gasket on the cylinder head cover.

I would certainly have a go at re-torq'ing the bolts first.....if it is a tiny leak.

[theneanderthal]

What kind of leak?

Compression?

Minor oil seepage?

There's probably an upper engine gasket set which has everthing you'll need.

Try,
http://www.sspowersportsclarksville.com/

[Sarris]

I had a little of that (Oil leak or stain) on the right rear of the cylinder just below the head. I had the head re-torqued at 12k just to be sure it wasn't a gasket leak. I got the crud off with bumper sticker remover. I used it on the motor when cold, let it sit 10 minutes, and took it right off with a brush. Cleaned that up w/ soap and water. Voila, no crud no stain.

My pal who teaches a Florida MSF course says almost all their GZ's get it. He told me it's a shipping preservative (some type of cosmoline) that the dealer didn't get all the way off at delivery clean-up


This is what I wrote in the Ride Report thread where Easy Rider stated he stopped to have his bike checked on his trip because he thought he had an oil leak.

FYI


You should read the "Oil Leak" topic below on this page.

:tup:

[Quimrider]

I've had oil leak out of the valve cover. I'm still trying to figure that one out. now I'm getting a puff of smoke accompanied by a "poot" that comes from the front of the engine where the cylinder jug meets the cylinder head when I first start it. I went thru several restarts tracking down where the little puff of smoke was coming from. I'll have to re-torque everything and see if that helps.

[Sarris]

If it's pooting out a puff of smoke between the cylinder head and the cylinder a re-torque ain't gonna help. Sounds like you're needing a head gasket.

You'll have to replace the valve cover gasket when you disassemble it anyways, so you also may want to put a cylinder base gasket on her while your at it if you have ring compressor or have it done at a shop.

Sorry bro. :skull:

[Quimrider]

I guess that's what I get for riding her WOT all the time. I'll keep riding her till the snow flakes start flying here in Ohio. It's not that terribly bad... yet, but I do notice a small loss of power. I guess I'll have to shell out the big bucks for the valve cover gasket goo. You can see in the "oil leak" thread I've tried a couple different liquid gaskets, but none seem to hold very long. And no I checked it's not warped.

[Easy Rider]

You can see in the "oil leak" thread I've tried a couple different liquid gaskets, but none seem to hold very long. And no I checked it's not warped.

I guess I wasn't reading those posts closely enough. There is ZERO hope of sealing a head gasket leak without taking the head off......and if you have the head off you could have put on a new gasket, along with the appropriate sealer.

What is not warped? You can't tell if the head is warped without taking it OFF.

AND for the final bad news: If you NEED to be going 70+ mph most of the time, either you have the wrong bike OR you're just gonna have to resign yourself to a little more maintenance. Any engine that is run WFO all the time requires extra care. :cry:

[Quimrider]

Ok seems to be confusion between two separate issues.

1) The "valve cover" or top half of the cylinder head has only a liquid gasket. That is where I leak oil. The service manual says something about using "Suzuki bond 1210" or something like that. It also says to check to make sure that the cover has not warped. I checked mine it didn't warp. I've tried an aviation liquid gasket maker, and high temp "Copper RTV silicone" Neither of which have lasted more than a week or two before resuming leaking. I guess I'll just have to break down and spend 20 bucks on the Suzuki liquid gasket.

2) Combustion gas leak between the cylinder head and piston jugg. (cylinder head gasket). This is what I started this thread for, to see if anyone else has had to replace a head gasket and get their feed back. Yes I'm aware this involves tearing off the top half of the engine.

Sarris, Thanks for the idea about changing the base gasket while I've got it apart. I didn't think about that, but makes a lot of sense to do that too.

Easy Rider, I'm well aware of this bikes limitations and you're right, I have resigned myself to more maintenance. Correct me if I am wrong, but I thought the redline on this engine is 8,500 RPM. I use the 16t sprocket and I rarely exceed 7000 RPM (65 - 70mph typ.) Maybe I'm just naive to think it "should" be able to cruise at 7000 RPM all day without a hitch. I have it jetted pretty close to stock. The bike will go 75-85 when jetted rich as hell but the loss of 15-20 mpg and having very blue pipes isn't worth it. Aside from that all the other mods, opening up the intake and exhaust really don't do anything other than lower your mileage and/or make the bike noisy.

[Easy Rider]

Ok seems to be confusion between two separate issues.

1) The "valve cover" or top half of the cylinder head has only a liquid gasket.

Indeed.
There is no real pressure inside the valve cover. An engine is an engine; whatever works on a car should work on your bike too. Nothing magic about the Zuki product.

Your detailed description of your riding habits is quite different than the previous message:
"I guess that's what I get for riding her WOT all the time. "
Your bike is about 8 years old and sounds like it gets a lot of miles. That may be more of a factor than the speeds you ride......which sounds more like cruising than "WOT".

And finally, when changing out the head gasket, I would recommend NOT digging any deeper than you need to. Removing the jug to do the bottom end gasket just adds an additional level of complexity to the project.......and additional places for things to go wrong.

[Quimrider]

Ok so maybe I exaggerated a bit :) I do about 2/3 highway 1/3 city. 95% of my riding is 45mph + However, unless the wind is at my back 65-70mph is usually WOT with the taller 16t sprocket. Which of course isn't quite as hard on the engine as WOT at 75mph+ with the stock 15t sprocket.

I'm quite perplexed about the leaky valve cover. Maybe the 7ft-lb torque spec in the service manual is wrong? That doesn't seem very tight for a part of the engine that receives quite a bit of vibration. I hope it's not the case but I suppose it's possible my cylinder head is warped. Awe screw it!!! I'll just throw on that big bore kit and be done with it! :lol:

[Easy Rider]

I'm quite perplexed about the leaky valve cover. Maybe the 7ft-lb torque spec in the service manual is wrong?

No, I don't think so.
Are you sure there isn't supposed to be a "real" gasket there? (I could go look at my service manual but no time right now).

For something like that, like the lug nuts on a car with disc brakes, the sequence of tightening is as important as the torque. First all barely finger tight, then all at about 1/4 tight using a "star" pattern, then 3/4, then full.

Also when using sealer only, both surfaces must be squeeky clean (brake cleaner is good) and sufficient cure time must be allowed.......I'm guessing 24 hours.

If all else fails, I think I'd be getting a new cover......on the off chance that yours warps in a funny way when it gets hot.

[patrick_777]

You guys are making me want to tear apart my engine.

[Quimrider]

see details in this thread if you want to read about the oil leak (http://www.gz250bike.com/forum/viewtopic.php?f=7&t=1236&hilit=oil+leak) There isn't a "real" gasket. I was surprised about this and it explained why I couldn't find the part number for a gasket that doesn't exist. The service manual says to use some special Zuki gasket goo. I cleaned it up with gasket remover and then cleaned off the gasket remover with brake cleaner for shiny clean surfaces. The aviation gasket maker I tried only lasted about 3 weeks. The RTV silicone only about 2 weeks. I checked for a warped cover. I hope I'm doing something wrong and don't have a warped cylinder head! At least it's a slow annoying leak and nothing imminently dangerous.

I only finger tightened the screws after applying the RTV silicone and let it cure for 24 hrs before following tightening instructions in the service manual.

[mr. softie]

Funny, but my '99 GZ has paper gaskets under the valve covers. They stay stuck to the engine.

Good luck wrenching on your bike!

[Quimrider]

Funny, but my '99 GZ has paper gaskets under the valve covers. They stay stuck to the engine.

Good luck wrenching on your bike!
We're not talking about the access covers to adjust the valves. We're talking about the "valve cover", the top half of the cylinder head. The part that the rocker arms are attached to.

[mr. softie]

:oops:

[Easy Rider]

We're talking about the "valve cover", the top half of the cylinder head. The part that the rocker arms are attached to.

OK, here's part of the problem: The valve cover is NOT the "top half of the cylinder head".

The valve cover attaches to the cylinder head. The cylinder head does not have 2 parts. :biggrin:

[Quimrider]

:rawk: WOOO HOOO problem solved! There is a nut just below and in between the exhaust pipes. I didn't notice this before, it was loose. I snugged it up and all is good. No more pooting! :lol:

[theneanderthal]

Cool!

Fart fixed by tightening the exhaust is way better the a head gasket. I haven't looked
specifically at the GZ but most bikes have have a bronze or similar gasket in this area.

Might be time to replace it.

[Quimrider]

:bang: I spoke too soon It's back to poooting again. I didn't see if the nut was loose again. It's not on the exhaust it looks like its on a stud in the cylinder head that goes thru a hole on the front of the cylinder jug. :cry:

[Easy Rider]

:bang: I spoke too soon It's back to poooting again. I didn't see if the nut was loose again. It's not on the exhaust it looks like its on a stud in the cylinder head that goes thru a hole on the front of the cylinder jug. :cry:

I'm not close to my service manual.....or to my bike :cry: ....but on most that is the cam chain tensioner adjustment. There is a specific proceedure for adjusting it. If that is what it IS and it keeps coming loose......it could cause SERIOUS trouble.

OTOH, maybe in the process of tightening that, you bumped the pipes and they are just now settling back to their previoius position. If you do mess with the exhaust manifold bolts, be VERY careful; they tend to rust and are easy to break.

[Quimrider]

The cam chain tensioner is on the back left side of the cylinder jug. at first glance it just appears to be a stud in the cylinder head that secures thru a hole and with a nut to the cylinder jug. My car is out of commission right now so I'm not going to do anything with it for a while. :biggrin: I get to enjoy the lovely cool Ohio liquid sunshine on my way home from work today. <that was sarcasm in case you missed it>

[Easy Rider]

at first glance it just appears to be a stud in the cylinder head that secures thru a hole and with a nut to the cylinder jug.

Curious. They generally don't just drill extra holes so they can plug them with a bolt. It must have a function......or a potential function.

Maybe Alan, with all his vast mechanical experience, can tell us what it is! :skeptical: :biggrin:

[alanmcorcoran]

Be glad to help:

If you don't know what it is, don't mess with it!

I know I'm in the minority here, but I prefer to spend my motorcycle time riding it rather than effing with it. I know I am gonna be screwed when I'm out in the middle of nowhere and get a flat or the flitzer-jammer pops out of the crustpump. I'll be sure to let you all know when that goes down so I can take my lumps. Hopefully I'll be in cell range and can have the wife come get me.

For those keeping track, so far I've:

1) Put gas in it.
2) Checked the air pressure.
3) Put air in it (more than once!)
4) Assembled 3/4ths of a windshield. Disassembled and re-packed same.
5) Located (and used!) the reserve switch.
6) Reset the trip odometer to zero.
7) Set the choke on (and back off!)
8) Tightened the nuts on the mirrors.
9) Looked at the brake fluid porthole. (Yep, there's fluid in there alright!)

Tonight maybe I will look into how to check the oil level. That one seems kind of important.

For the record, I had the head off my Peugeot moped back in the day and, although I can't say I knew exactly what I was doing, I cleaned up the cylinder, changed the spark plug, etc.

Plus, how many of you guys can do this?




http://www.postimage.org/gx1HcBhA.jpg (http://www.postimage.org/image.php?v=gx1HcBhA)

[Moedad]

Plus, how many of you guys can do this?

Saaay, nice dove-tail!

[Quimrider]

DOH! there seems to be some misunderstanding about what I'm talking about. I'll take a picture when I find my camera. There is a stud and nut that helps to physically hold the cylinderhead to the cylinder jug together. The combustion gases that are leaking are doing so where the cylinderhead meets the cylinder jug which is where the head gasket is located. It is not leaking from a bolt or stud, granted both the stud i am talking about and said leak are close in proximity. It appears to be a minor issue at the moment. I'll tear down the engine and fix it later this winter.

[Easy Rider]

DOH! there seems to be some misunderstanding about what I'm talking about.

Well, yea, that's kind of what tends to happen when you say "I tightened a bolt and the problem went away!!" :roll:

Sounds like you have a good handle on the problem now. No real need for pics.

[Badbob]

Plus, how many of you guys can do this?
http://www.postimage.org/gx1HcBhA.jpg (http://www.postimage.org/image.php?v=gx1HcBhA)

I can but I'm not what I would call real good at it.

I've never seen dove tails in plywood before.

[alanmcorcoran]

Probably will get a whistle blown here by the "off-topic" police, but I cheated a little with a router jig. I think it's 5/16" ply - I made 4 of these drawers for a media niche to hold CD's. Then they invented the ipod. It's also deep enough to hold DVD's. If this was a wood working site I'd post a few more pix, but I think I'm already pushing it. Suffice to say, it's some of the best results I've ever gotten with wood and power tools. I glued 'em, but there was really no need. Things went together like a puzzle and once assembled, could not be taken apart.

[Quimrider]

Thought I'd post an update to let you guys know how things turned out. I had my local shop fix it. Turns out I must have slightly overheated the cylinder head as it had slightly warped contributing to the head gasket leak. $330 later they had machined the head flat and replaced all the gaskets from the cylinder up. She purrs nicely again.

With that $330 lesson in mind, I guess it really isn't a good idea to ride WOT for extended periods of time.

[alanmcorcoran]

Thanks for the update Quim. That happens to be how I ride the GZ. Do you think that's really what caused it? I thought as long as you don't redline, it's okay.

[Water Warrior 2]

At wide open throttle you are asking the bike to make maximum power all the time. Maximum power equals maximum heat generated regardless of RPM.

[Quimrider]

Thanks for the update Quim. That happens to be how I ride the GZ. Do you think that's really what caused it? I thought as long as you don't redline, it's okay.

The damage was probably cause by a combination of things. I ride WOT with a 16T front sprocket averaging just under 7000 rpm. There also was a fairly large carbon build up on the top of the piston. The head mechanic I talked to (whom I got the impression he knew what he was talking about) asked if I had ridden on the freeway a lot and if I used the low grade gas. He said something about the alcohol blended with the cheap gas was bad for the engine. I'm not sure why a small amount of alcohol would be bad for the engine. Other than throwing the air - fuel ratio being different for alcohol, I thought alcohol burns cooler and would be better for the engine?

About a year ago I experimented using various amounts of alcohol and gasoline (blending E-85 with gas at various ratios) for $hits and giggles. I was curious what would happen. I quickly learned that without major carb adjustments alcohol made it run like $hit!

I also fiddled around trying to tune the carb for a K&N filter and to compensate for the holes drilled in my exhaust. For a couple tanks of gas I was extremely rich. I attribute the excess carbon on the piston to this. I found the intake noise annoying and there really wasn't much of a noticeable difference. I could make it really rich and gain ~5mph top end and sacrafice 15-20mpg. This wasn't wort it to me so I went back the stock filter with the diverter removed and Plugged 3 of the 4 holes drilled in the exhaust. I don't know if it's true or not, but I read somewhere that without the restriction in the exhaust, the momentum of the exhaust gases will pull some of the incoming air/gas mixture into the exhaust pipe during the brief moment the intake and exhaust valves are open at the same time. This air/gas would then burn in the exhaust pipe overheating it and causing the chrome to blue.

I rode 2 up on a 120 mi trip 1/3 to 1/2 of which was WOT. Another time I was in a hurry to get home and rode 163 mi all WOT.

I think the damage to my engine was mainly due to the two trips that I took with the alcohol and carb tuning as contributing factors. I also have over revved the engine a couple times down shifting which couldn't have helped. The mechanic said that riding on the freeway was ok, but that I should back off the throttle every now and then to let the engine cool. He also suggested mid grade or higher gas since it resists pinging/detonation in a hot engine better.

I'm toying with the idea of adding a cylinder head temp sensor monitoring the temps for a while and then trying to figure out how to add an oil cooler to see if that helps cool the engine. I'm also going to adjust my riding habits so that I'm not as hard on the engine.

[alanmcorcoran]

Thanks for the background Quim. The Strat asks on the 91 octane on the tank, and I've obliged except for one tank when I forgot. Previous threads on here have not felt that higher octane is of benefit to the GZ, but those discussions were focused on power, not heat, so perhaps that could be revisited. I'm not sure we even have an ethanol option out here...

I solved my freeway/power/climbing issues by buying another bike. So far, that seems to be the option that provides the most trouble free solution. The GZ is still a great option for getting around town and relaxed (no high speed, steep hills) touring.

[Easy Rider]

The mechanic said that riding on the freeway was ok, but that I should back off the throttle every now and then to let the engine cool. He also suggested mid grade or higher gas since it resists pinging/detonation in a hot engine better.


I'm sorry but that "mechanic" is a total putz.

You would KNOW it if your engine was knocking or pinging; if not, higher octane is a waste of money.

It is not the position of the throtle that is important but how fast the engine is turning.......so, with a 16T front, it is highly doubtful that whatever you did in 5th gear would hurt the engine any......unless you lug it or go screaming down the side of a mountain at 95 mph.

So the question then is: How did you ride it in the lower gears ?? If you were in the habit of winding it out as far as it would go, then that might be a factor. The other experiments that you tried might be factors too. Sometimes, however, heads just warp and sometimes they are not perfect when new and the gasket just finally gives out.

I think you are just wasting your time trying to pinpoint the cause and would be much happier just riding a tiny bit easier getting up to 70. You haven't done anything to the front of the bike that would cut down on the air flow across the engine, have you ??

One final thought: It is good to give the engine a short "cool down" period before shutting off. That is, don't go racing home at WOT, whip it into the driveway and shut it off; instead reduce your speed a bit for those last few miles before reaching your destination. Not working the engine as hard while still moving at a good clip will cool it down some.

[Water Warrior 2]

The mechanic said that riding on the freeway was ok, but that I should back off the throttle every now and then to let the engine cool. He also suggested mid grade or higher gas since it resists pinging/detonation in a hot engine better.


I'm sorry but that "mechanic" is a total putz.

You would KNOW it if your engine was knocking or pinging; if not, higher octane is a waste of money.

It is not the position of the throtle that is important but how fast the engine is turning.......so, with a 16T front, it is highly doubtful that whatever you did in 5th gear would hurt the engine any......unless you lug it or go screaming down the side of a mountain at 95 mph.

So the question then is: How did you ride it in the lower gears ?? If you were in the habit of winding it out as far as it would go, then that might be a factor. The other experiments that you tried might be factors too. Sometimes, however, heads just warp and sometimes they are not perfect when new and the gasket just finally gives out.

I think you are just wasting your time trying to pinpoint the cause and would be much happier just riding a tiny bit easier getting up to 70. You haven't done anything to the front of the bike that would cut down on the air flow across the engine, have you ??

One final thought: It is good to give the engine a short "cool down" period before shutting off. That is, don't go racing home at WOT, whip it into the driveway and shut it off; instead reduce your speed a bit for those last few miles before reaching your destination. Not working the engine as hard while still moving at a good clip will cool it down some.

The cool down idea is well worth it. Just ask any trucker about shutting off a real hot engine. Big $ signs ring up sooner than later.
As for higher octane I will agree to disagree with Easy. Higher octane gas is slower burning and more controlled which lowers detonation and pinging in engines. It is primarily used in higher compression engines which need more controls but it may help a lower compression engine is some cases.

[Water Warrior 2]

The mechanic said that riding on the freeway was ok, but that I should back off the throttle every now and then to let the engine cool. He also suggested mid grade or higher gas since it resists pinging/detonation in a hot engine better.


I'm sorry but that "mechanic" is a total putz.

You would KNOW it if your engine was knocking or pinging; if not, higher octane is a waste of money.

It is not the position of the throtle that is important but how fast the engine is turning.......so, with a 16T front, it is highly doubtful that whatever you did in 5th gear would hurt the engine any......unless you lug it or go screaming down the side of a mountain at 95 mph.

So the question then is: How did you ride it in the lower gears ?? If you were in the habit of winding it out as far as it would go, then that might be a factor. The other experiments that you tried might be factors too. Sometimes, however, heads just warp and sometimes they are not perfect when new and the gasket just finally gives out.

I think you are just wasting your time trying to pinpoint the cause and would be much happier just riding a tiny bit easier getting up to 70. You haven't done anything to the front of the bike that would cut down on the air flow across the engine, have you ??

One final thought: It is good to give the engine a short "cool down" period before shutting off. That is, don't go racing home at WOT, whip it into the driveway and shut it off; instead reduce your speed a bit for those last few miles before reaching your destination. Not working the engine as hard while still moving at a good clip will cool it down some.

The cool down idea is well worth it. Just ask any trucker about shutting off a real hot engine. Big $ signs ring up sooner than later.
As for higher octane I will agree to disagree with Easy. Higher octane gas is slower burning and more controlled which lowers detonation and pinging in engines. It is primarily used in higher compression engines which need more controls but it may help a lower compression engine is some cases.

[Easy Rider]

Higher octane gas is slower burning and more controlled which lowers detonation and pinging in engines.

That is true but you can't get it any lower than ZERO! :poke2: :biggrin:

I think everybody should try a couple of tankfulls of mid-grade gas. Premium is just foolish in a low compression engine but some people swear that the GZ and other similar bikes run better on 89. Maybe so, maybe not, but the cost difference is minimal and even if it IS all just in your head, feeling good about what you are doing is priceless. :tup:

[dan_]

So what about race fuel in the GZ? We sell 110 octane where I work. Crotch rockets and Harleys use it all the time. I'd consider putting a little in with my tank of 89 to clean the carb but i'd figure it would explode if i put in a full tank of 110.

[Easy Rider]

I'd consider putting a little in with my tank of 89 to clean the carb but i'd figure it would explode if i put in a full tank of 110.

"Octane" does NOT clean carbs.
It would, no doubt, run like crap.
Then you might have another "funny" story to tell us !! :biggrin:

Want REALLY high octane fuel? I think JP4 jet fuel has an octane rating of something like 140; it's pretty close to kerosene.

[Water Warrior 2]

Dan, just invest your money in a proper product meant to clean out deposits in fuel systems.