Engine Noise & Blown Head Gasket

[headshrink]

Ever since my last valve adjustment I’ve been chasing down a nasty noise, which to me sounds like tapping. It seems to be synchronized with the speed of the engine. The noise is there both when the engine is cold, and fully warmed. I don’t know if it was there before the valves were adjusted, because when I did the adjustment I also installed a manual CCT, which took care of a very noisy cam chain that MAY have masked the sound.

The sound seems to come from the left side of the engine, primarily toward the rear. It sounds VERY loud in the left carb and carb boot. This is confirmed with a screwdriver to ear. I just got a mechanics stethoscope, but as of this writing, I haven’t confirmed the screwdriver test with the real deal…. I’ll assume it will reveal the same result, but will edit this if I am wrong.

I don’t notice a HUGE difference in performance, BUT after I thought I finally nailed down my jetting and got rid of a phantom surge, it SEEMS to be slowly creeping back. Overall performance seems like it COULD be better, but with the carbed bike it is so different day to day…. AND I really don’t know how long the problem was here before I noticed it, so it is very difficult to compare.

I noticed this winter that my bike didn’t start as well as it used to too. When it was newer, and after needles were shimmed, I only needed to use the choke when it was really cold (for CA). This year it seems I have needed to use the choke until the weather was much warmer (70-80 degrees maybe).

About two weeks ago I caught an exhaust leak, right before a header bolt almost vibrated right off. I immediately fixed it, but could never shake the feeling it may still be leaking somewhere. The sound I am tracking down sounds similar to the sound of the exhaust leak. But since tightening the header down again, I couldn’t feel a pulse with my fingers, or get an earful using a tube. I couldn’t feel anything around the head gasket either.

Due to the location where I thought I was hearing the noise, I was beginning to fear I had a jacked up intake valve on #1. I’m still not convinced that isn’t an issue. I thought maybe I was getting piston slap, possibly from incorrectly timed cams…. I was very careful when I timed the cams, but couldn’t guarantee that nothing slipped. I even opened the valve cover to double-check everything.

I just received my compression tester from Harbor Freight, and did a test…. I got some interesting results (below):

Cylinder #1:
Dry = 165 psi
Wet = 215
Cylinder #2:
Dry = 130
Wet = 170
(Wet tests with ¾ tsp oil)

Something is not right with those numbers 
Some additional observations are noted in the picture below:


As I was putting everything back together I discovered THIS:


The oil leak was from the WET compression test.

So if I am interpreting the symptoms and evidence correctly, I believe I have a blown head gasket. The last picture kind of nailed that one. Is my thinking correct on this?

Based on everything I have said, is there reasonable suspicion that I may also have a bad valve, or something else?

I likely have been driving on a blown gasket for at least a couple months… would it be a horrible thing if I didn’t get to it for another month, but still drove it to work (primary transportation?

I suppose this would also be a good time to replace my clutch too (that is another story, in another thread).

[bob706]

How's your coolant and oil levels?

[headshrink]

Originally Posted by bob706

How's your coolant and oil levels?

Oil level seems fine (hasn't seemed to raise or lower), and coolant level is a touch below the min. line, but is holding steady. I had over-filled it originally, but think I just took out a touch too much.... but who knows. Since it is holding steady, I assume it isn't going anywhere.

[bob706]

To me no loss of oil or coolant would indicate your head gasket is alright. Have you checked the oil strainer lately?

[headshrink]

Originally Posted by bob706

To me no loss of oil or coolant would indicate your head gasket is alright. Have you checked the oil strainer lately?

No, I haven't checked the oil strainer.... what are you thinking I might find?

I would thing you were right about the oil/coolant thing, BUT why would the head gasket all of a sudden leak oil during the wet compression test?

[CThunder-blue]

With your compression numbers, I would say one of your piston rings is shot. When you did the compression test, it pressurized the crank case (thru the bad piston ring) and forced oil thru your head gasket. While the head gasket may not be completely blown, having oil seep from it indicates the head bolts are not torqued correctly and/or the gasket is on it's way to being blown out.

[headshrink]

Oh crap... I have some new information that doesn't sound good.

In the picture above of the oil leak.... I noticed two little holes, or ports. Thinking it MAY be a water drain for the spark plugs (it is on the side of the engine on the pre-gen), I stuck a probe in it. Sure enough, it really is a hole, and the probe came out with oil and anti-seize lubricant on it. The pattern of the leak also looks like it very possibly may have come from the ports, and not the head gasket! Assuming this is the case, I am back to catastrophizing that I have a FUBAR engine.... Any thoughts?

[bob706]

Originally Posted by headshrink

No, I haven't checked the oil strainer.... what are you thinking I might find?

Just thinking if something internal took a dump it might end up in the strainer.

[headshrink]

Originally Posted by CThunder-blue

With your compression numbers, I would say one of your piston rings is shot. When you did the compression test, it pressurized the crank case (thru the bad piston ring) and forced oil thru your head gasket. While the head gasket may not be completely blown, having oil seep from it indicates the head bolts are not torqued correctly and/or the gasket is on it's way to being blown out.

I typed over you.... your theory is rings? Does the wet test rule out valves?

[kkim]

Originally Posted by headshrink

In the picture above of the oil leak.... I noticed two little holes, or ports. Thinking it MAY be a water drain for the spark plugs (it is on the side of the engine on the pre-gen), I stuck a probe in it. Sure enough, it really is a hole, and the probe came out with oil and anti-seize lubricant on it. The pattern of the leak also looks like it very possibly may have come from the ports, and not the head gasket! Assuming this is the case, I am back to catastrophizing that I have a FUBAR engine.... Any thoughts?

that's actually good news. If that's the oil source, that means oil is seeping into the spark plug towers somehow. could be something as simple as leaking gaskets around those towers in the valve cover gasket.

as far as your compression numbers, are you sure you have the valve timing correct for both cylinders? maybe the valves are never closing at the same time resulting in low compression numbers?

[rockNroll]

Originally Posted by headshrink

Ever since my last valve adjustment I’ve been chasing down a nasty noise,

Go back and do it again... carefully. There are many open directions here and you should start with making sure the valves are they way they need to be. Be sure there isn't a broken spring. Make sure your timing is correct. Etc.

[CThunder-blue]

Originally Posted by headshrink

I typed over you.... your theory is rings? Does the wet test rule out valves?

Are you sure that's oil and not gas? I'm reading the service manual and it states:

Compression range: 139-213 psi

Cylinder compression is lower than usable range:

• Gas leakage around cylinder head - Replace damaged gasket and check cylinder head warp
• Bad condition of valve seating- Repair if necessary
• Incorrect valve clearance- Adjust valve clearance
• Incorrect piston/cylinder clearance- Replace piston and/or cylinder
• Piston seizure- Inspect the cylinder and replace/repair the cylinder and/or piston as necessary
• Bad condition of piston ring and/or piston ring grooves- Replace the piston and/or the piston rings

Is it possible what you're seeing is unburned fuel coming out of those holes? I wonder what those holes are for. You might want to pm RacerX. He's the only guy I know who routinely tears and and rebuilds these engines.

[rockNroll]

Originally Posted by CThunder-blue

I wonder what those holes are for.

Drains

[DaBlue1]

Originally Posted by rockNroll

Drains

+1
http://www.ninjette.org/forums/showp...9&postcount=27

[headshrink]

Originally Posted by CThunder-blue

Is it possible what you're seeing is unburned fuel coming out of those holes?

Yes, positive.

Originally Posted by rockNroll

Go back and do it again... carefully. There are many open directions here and you should start with making sure the valves are they way they need to be. Be sure there isn't a broken spring. Make sure your timing is correct. Etc.

I will.... but I was VERY careful the first time, and then did it again for good measure.

Originally Posted by kkim

that's actually good news. If that's the oil source, that means oil is seeping into the spark plug towers somehow. could be something as simple as leaking gaskets around those towers in the valve cover gasket.

as far as your compression numbers, are you sure you have the valve timing correct for both cylinders? maybe the valves are never closing at the same time resulting in low compression numbers?

I think it is more likely oil from the towers that was in there from when I originally injected it, rather than being forced through..... I used a small oral syringe, so I did get some on the walls. I also used brand seals for the spark plugs when I did the valves.

I would be surprised if I got the timing wrong.... but theoretically it is always possible.

[kkim]

Originally Posted by headshrink

I think it is more likely oil from the towers that was in there from when I originally injected it, rather than being forced through..... I used a small oral syringe, so I did get some on the walls.

eh? you wanna explain that?

[headshrink]

Originally Posted by kkim

eh? you wanna explain that?

Yes... I used the syringe to shoot oil down into the cylinders for the wet test. Some of the oil got on the wall of the tower, rather than directly down the hole.

[kkim]

ah, okay... ever heard of vinyl tubing to use as an extension on the syringe?

[headshrink]

Originally Posted by kkim

ah, okay... ever heard of vinyl tubing to use as an extension on the syringe?

Now that is just to brilliant and obvious! I actually didn't have tubbing small enough, but damn.... I could have used my kids' bendy-straws!!! Oh well - live and learn.

[kkim]

Originally Posted by headshrink

Now that is just to brilliant and obvious! I actually didn't have tubbing small enough, but damn.... I could have used my kids' bendy-straws!!! Oh well - live and learn.

then you'ld be fishing the straw out of the top end.

true story... I was using a shortened pencil down a spark plug hole to find TDC on a dirt bike years ago. well, I cranked the kickstarter a bit too much and the piston dropped to the bottom of the stroke and the pencil disappeared into the spark plug hole!!

How was I to know the pencil was shorter than the stroke? I ended up having top remove the head get that pencil out.

[headshrink]

Going to be gone this weekend, but when I return I'll re-time the cam, and visually inspect, as we discussed. Although I hope it works, I am really sceptical that is will. If that is the case, am I shopping for a new engine on ebay?

[bdavison]

You said you did a valve job recently.

Many times, when you pull the valve cover off, the little o-ring seals that go around the spark plug ports come off with the cover.

Its a good idea to peel them off the cover, and replace onto the head before re-installing the valve cover so they stay in place.

Im thinking when you reinstalled the valve cover, you either pinched, or displaced one of the o-ring seals. This would explain your leak, and perhaps the valve noise that is coming from that side.

[headshrink]

Originally Posted by bdavison

You said you did a valve job recently.

Many times, when you pull the valve cover off, the little o-ring seals that go around the spark plug ports come off with the cover.

Its a good idea to peel them off the cover, and replace onto the head before re-installing the valve cover so they stay in place.

Im thinking when you reinstalled the valve cover, you either pinched, or displaced one of the o-ring seals. This would explain your leak, and perhaps the valve noise that is coming from that side.

Possible.... I did install new ones, but like you said, it may have been pinched. I'm still suspecting something expensive, but will re-check all, as I'm often wrong about these things.

[headshrink]

Update: I'm back, and got up early this morning to beat the heat and dig down to the cams. I won't put it back together until later tonight, or tomorrow morning, so I force myself to go slow and methodical. So here is what I found.... nothing obvious.

I put the engine at 2T, and checked the cam position. It all LOOKS right to me.

In the interest of being thorough, here is a pic of 2T. Look accurate enough?


Here is a pic from the SM of how I timed the cams and chain (forgot to take my own picture before I took it apart). I photoshoped the white and blue marks that are on my cams, as well as highlighted the relevant pins on the chain.


I'm not sure why all the other DIYs have the white dots facing each other, but I stick with the method in the SM. Either way should work, to my knowledge, since they are both at 2T (just at different strokes).

The gaskets on the spark plug towers looked in-place and intact, with no damage.

While I was at it, I checked my valve clearances again.... all were good.

The only thing that wasn't by the book was that I am using a manual CCT. I suspect I may be getting a wee bit of wear on the cam gears now that the [loose] OEM CCT didn't seem to have an issue with, but could be I just never noticed it. I keep it as loose I can without the chain rattling.

I can't think of a reason I would be having problem, but I am. Will report after getting it all back together again.... Worried I have major damage to the valve (noise), and rings/cylinder walls, but I suppose I should wait until it is back together before officially worrying.

[headshrink]

Update:

I got it all back together. Cams are timed “by the book,” valve clearances are WNL, manual CCT was carefully adjusted. Of course the sound is still there.

I did the compression tests again, and believe they are more accurate than the first, because I used a tube this time (thanks Kelly for the tip) to get the oil INSIDE the cylinder for the wet test.

Compression results are listed in the image below (original and second attempt).


I’m wondering if the low [dry] compression explains why my bike doesn’t start as nicely as it once did. With the cams timed, and variation in dry vs wet compression in both cylinders, my DX is bad rings, maybe scored cylinders too.

The noise is definitely loudest in the left carburetor, whether this is resonating from an intake valve, or something inside the carb itself, I don’t know. I wonder if the slide is rattling around…. I have read they can go bad (slide portion, not tear in diagram), but don’t know what would happen. I was able to do a decent job capturing the sound in the following video. The best part is at the very end, when I finally got a good connection between the camera’s mic and stethoscope. The probe is placed on the carb.

Link to original page on YouTube.

Ideas???

EDIT:
I just remade the video, and included a second video revving the engine (don't know why I didn't think of that before).
Here are the newer, improved videos: http://www.ninjette.org/forums/showp...7&postcount=46

[DaBlue1]

Originally Posted by headshrink

Update:

...Ideas???

Try a heavier weight oil. I run 20w-50 no problem. Engine is smooth like butter.
http://www.newninja.com/forums/f97/t...tml#post152575

[headshrink]

Originally Posted by DaBlue1

Try a heavier weight oil. I run 20w-50 no problem. Engines is smooth like butter.
http://www.newninja.com/forums/f97/t...tml#post152575

I supose it wouldn't hurt to try, but that thread was referring to ticking associated with the CCT..... since mine is manually adjusted, I have already ruled that out as the cause. In adjusting it, you can hear how the CCT affects engine noise.

[DaBlue1]

You may be on to something when you mentioned the slides. From what I've read they do make some noise and can wear out. The ticking sound can also be amplified by open exhaust but for the most part seems normal.
Even though we have Keihin carbs this info about slide rattle from Mikuni may help a little since they work similar. http://www.mikuni.com/c-faq.html
Also some info from Factory Pro. http://www.factorypro.com/tech/needle_jet_wear.html

Hope that helps.

[headshrink]

I just switched the slides (R to L, L to R) to see if I could get the noise to change sides too..... I believe it did, BUT the L didn't loose it's death rattle completely. I then used a cannibalized slide from an old crab to see if it made a difference..... I didn't notice any, but I think I forgot to switch the original slides to their original sides, because the R is still really noisy (remember it was originally the L side that was loud).

I'm thinking it wouldn't hurt to order new Needle jets, but that would cost ~$100 through the standard on-line parts suppliers (not to mention new slides if they are needed). Anyone know of a better source for the needle jets?

I wasn't finding anything on ebay.... well there was one really newish looking carb, but they want $55 for shipping! I was thinking about reporting that to ebay for violation of TOS.....

One more thing. I listened really hard in the stethoscope while I reved the engine, and at a point it seems like the death rattle MAY stop. I think this supports the slide theory, based on the above linked article.

[almost40]

Originally Posted by kkim

then you'ld be fishing the straw out of the top end.

true story... I was using a shortened pencil down a spark plug hole to find TDC on a dirt bike years ago. well, I cranked the kickstarter a bit too much and the piston dropped to the bottom of the stroke and the pencil disappeared into the spark plug hole!!

How was I to know the pencil was shorter than the stroke? I ended up having top remove the head get that pencil out.

Done something very similar.

[headshrink]

For some reason the vehicle filter on ebay was filtering out MOST of the results....
I just found a CLEAN '09 Carb on ebay with only 1.3K miles for $150, & $16 shipping (I hope the previous owner is OK).
It is now on it's way to my house

So here is the question now.... if I put my old jet kit in the new carb, with all the same settings as before, should I expect it to be dialed in the same, or will vary from carb to carb (like with the engine).

[kkim]

Originally Posted by headshrink

So here is the question now.... if I put my old jet kit in the new carb, with all the same settings as before, should I expect it to be dialed in the same, or will vary from carb to carb (like with the engine).

should be close, if not perfect.

[headshrink]

*sigh*
I'm currently dialing in the new(ish) carb, and at this point believe I still hear the noise that I was thinking was "slide rattle." On top of that, I had the opportunity to do a couple runs at WOT all the way to the limiter. Since I wasn't in my garage, the engine/exhaust noise wasn't reflected back at me, and I could still hear the noise gremlin. My understanding of slide rattle is that when the throttle is opened to a point, the suction is great enough to hold the slide against one side of the guide, and won't rattle. So I may have wasted my $$.

I'm thinking that unless something else pops up, or symptoms worsen, I'll just except it and ride it the way it is..... but my compression results do have me somewhat concerned. Although it isn't by a lot, one cylinder was a little below spec (139-213= spec.). How concerned should I be about that?

[Momaru]

Huh. Very sorry to hear this continues to be an issue. Any chance it's the classic Kawi-click?
Hate to suggest it, but perhaps it's time to visit a good shop? Talk through all the steps you've done, see if they have any bright ideas?

Wondering if our pro racer/mechanics (Racer X, etc) have any ideas. I'm fresh out.

Personally I'm curious/bothered by your compression numbers as well, especially the pretty drastic difference between cylinders. Only thing that comes to mind is perhaps your cylinder rings are too well aligned (letting oil by via the gaps that shouldn't line up between rings). Admittedly my knowledge and experience breaks down at this level, despite having disassembled the engine to bare pistons.

[Racer x]

wow A genuine mystery. How did you tension the manual CCT? Try changing the tension a little to see if the sound changes? I don't like the 130 number.My guess is valves because I have seen trouble with them seating. But I have also seen rings stuck from carbon so it is one of those things you have to take it apart to fix.

[headshrink]

Originally Posted by Racer x

wow A genuine mystery. How did you tension the manual CCT? Try changing the tension a little to see if the sound changes? I don't like the 130 number.My guess is valves because I have seen trouble with them seating. But I have also seen rings stuck from carbon so it is one of those things you have to take it apart to fix.

I tensioned the CCT by ear by I tightening it to the loosest point where the CC slap was eliminated, and stopped there. Youtube videos showed people finding that spot, then going 1/4 turn tighter, but I found 1/4 turn can be HUGE once you hit that spot, and I definitely think that would be too tight. I played with it a bit, and can hear a slight whine when the CCT is obviously too tight, but I can't remember if that 1/4 turn put it in that spot or not. IIRC, the CCT manufacturer suggests the opposite.... they say once you find the spot, back it off 1/4 turn. But that doesn't make a lot of sense to me, and sounded just like the crappy OEM CCT. The engine noise I am after is definitely a different noise than the CC slap. In fact, I didn't realize the noise was even there until I fixed the CCT related noise.

This is my first experience getting this hard-core with an engine, but my gut has said valves (and rings after compression tests) all along, but have been hoping to eliminate that and find something easier.

Assuming I end up attempting to repair valves (or other work deep in the engine) myself, will I need any expensive specialized tools, or is it relatively straight forward? I also assume that going to the dealer will cost at least as much as a new-ish ebay engine, which I assume leaves me with DIY... correct me if I'm wrong. There are also no dealer service departments in my area that have a good reputation, so I really don't trust them. One tried to tell me I needed to replace my normally worn rotors at 5.5K miles! Another thought is, do I even NEED to fix it?

[Racer x]

This is a very easy engine to work on but witthout some stuff you will have to find a machine shop to do things like clean up the valves. The pistons are easy to replace. But the crank is a different story all together. How many miles do you have?
As far as needing to fix it.If the worst that can happen is you need a engine then don't worry about it.If you pull the sump screen and don't find copper specs then you are good.

[headshrink]

Originally Posted by Racer x

This is a very easy engine to work on but witthout some stuff you will have to find a machine shop to do things like clean up the valves. The pistons are easy to replace. But the crank is a different story all together. How many miles do you have?
As far as needing to fix it.If the worst that can happen is you need a engine then don't worry about it.If you pull the sump screen and don't find copper specs then you are good.

Almost 25K miles.

Copper in the screen was regarding the valves, right?

[Racer x]

No copper is from the bearings on the crank and rods.If you find that it is over. 25k is a lot of miles .did you get it new?engines are 600 plus shipping all day on e bay.

[headshrink]

Originally Posted by Racer x

No copper is from the bearings on the crank and rods.If you find that it is over. 25k is a lot of miles .did you get it new?engines are 600 plus shipping all day on e bay.

New Bearings aren't feasable/economical?
Yes, I did get it new.... but if I knew then that 25k is considered high milage, I would have never gotten one, since it was to replace my car (that is only 3 years of use - less actually). Of course that was before I fell in love... I was hoping that being a stickler on maintainance would keep it running like a car.