Compression test how to?

[BengNY]

Hey everyone,
I need to do a compression test but can't really see a good way to get the gauge in without removing the battery tray. And since its a basic compression meter I need the battery to run the test. Any tips for this one?

Back story: Cam chain tensioner failed about 3 months ago. Replaced it and it runs fine but now makes a horrible metallic ticking noise between 2 and 5krpm. I'd like to check compression to see if a piston kissed a valve and bent it, giving increased clearance and the ticking.

 

[FinalImpact]

A hose with whip would make this possible. Remove the tank and bolts holding battety tray. Thread gauge in. And allow tray to settle.

IMO a leak down test would be more valuable, that said, any bent valve(s) and its not going to idle well if at all. The vacuum would be completely erratic and you'd have other driveability complaints beyond that of ticking.

Use a long wood dowel or screwdriver from your ear to suspect noise area and find the source. It may just need the lash adjusted (valve adjustment via shim).

 

[TownsendsFJR1300]

Plus 1 on the leakdown test. If you have a bent valve, you can pin point down what cylinder is bad and you don't have to crank the engine over. Simply get the cylinder being tested at TDC and lock it up.

If you have a bent/open exhaust valve, you'll hear air coming out of the exhaust. You can further narrow it down to the cylinder after pulling the header.

This is the tool I use which seems to be quite accurate and not terribly expensive. You will need at least a small air compressor to use it..

You'll get an over health check of your engine as well..

Cylinder Leakage Tester Kit | OTC Tools


BTW, the hose in this kit is very flexible and you should be able to do the test without pulling the battery, etc.


You mentioned the engine runs as good as before, no loss of power??

Can you upload an audio/video of the engine running, making the noise, etc..

 

[BengNY]

Thanks for the replies!
Leakdown test will be tricky because I have to find somebody with a compressor.
I took a video of the ticking noise, any feedback would be greatly appreciated:
[video=youtube_share;Cs1RBphELfM]https://youtu.be/Cs1RBphELfM[/video]

 

[FinalImpact]

Use a long wood dowel or screwdriver from your ear to suspect noise area and find the source. It may just need the lash adjusted (valve adjustment via shim).

I am not sure what I'm hearing there but givin the RPM, it sounds like the noise is half the speed or the crank so its pointing at the CAMs but you need to be our ears... Please PIN POINT where the bulk of the sound is coming from. Engine Top, Engine Bottom, or transmission. I would start here! ^^^


Valve lash tapping BEFORE Adjustment! 48 second walk around. Most obvious at beginning and end of track.
MP3 Audio from SoundCloud. FZ6 Valve Lash Tap

Listen to the first few seconds of this. Valve lash was corrected, then a test drive.
MP3 Audio after Valve lash Adj. First Ride.

Random: Blah
Star Trek transporter sound from FZ6

 

[TownsendsFJR1300]

To add to the above post, a cheap stethoscope from Harbor Freight, Sears, etc, might be worth the investment.

Its very hard to tell as the inside of the engines bounces the noise around internally making it worse..

***ALSO, really important, did the new noise start right after the repair? Or was it gradual?



And do you know how many teeth (if it did jump) off the cams were and if so which cam?

 

[BengNY]

Thanks for those links! I'll see if I can correlate those with what I'm hearing (excuse my phone quality video)...

Sound is coming from the top end for sure. I can't tell where or which side since the sound reverberates all over.

***ALSO, really important, did the new noise start right after the repair? Or was it gradual?


And do you know how many teeth (if it did jump) off the cams were and if so which cam?

Started right after the repair. Bike ran like poo when the tensioner failed, either because it was interfering with the crank position sensor or was genuinely off timing.

When I brought it in, my guy said the chain was on the proper teeth of the sprocket. Which is why I was leaning toward the tensioner guides. I could just replace them, but its a good chuck of change and effort if its the cams. If it is the cams I'm assuming bent valve? Seems like the only way to introduce a big valve clearance overnight.

 

[ozgurakman]

sorry about that, you can buy a test kit for $30 from ebay.

 

[TownsendsFJR1300]

Yep, I have to agree with you. If the noise started right after that failure, I'd put money the valves are bent. Hopefully the cams are ok..

You could also pull the valve cover and check the clearances. As you noted, if their (the valves) are indeed bent, you'll have some MAJOR clearances, way out of spec.

The leakage test, with the header off, would certainly verify bent EXHAUST valves as a bunch of air would pass thru the "closed" valves. With the air filter off, the same test, you'd also hear air coming out from the intake. (all tests done at TDC, VALVES CLOSED)


I don't think I'd run it until either pulling the cover and checking clearances, or the leakdown test.. If you bust off a valve while running, that engine is toast. Hopefully the pistons are still usable and not damaged...


Just curious, how many miles on the engine before the CCT failure?

 

[FinalImpact]

That said, any bent valve(s) and its not going to idle well if at all.
The vacuum would be completely erratic and you'd have other driveability complaints beyond that of ticking.

It seems to idle pretty staedy from the sounds of it. Bent intakes really screw up vacuum and it would be popping out the intake... Exhaust will burn and you'd have a serious misfire....
How many miles on since the repair?

 

[BengNY]

How many miles on since the repair?

Probably a few hundred miles since the repair but the ticking noise started right after.

The CCT failed with only 7kmi on the bike!

Looks like I'll have to check some valve clearances. On a related note, I'd appreciate any leads on a low mileage head/valves!

 

[FinalImpact]

JM2C - but at idle all the cylinders are producing power on your vehicle.

If ANY ONE cylinder were off due to lost compression it WILL NOT idle worth a Sh%t. In the case of CAMs being out of time its pretty rare to damage only ONE hole. Yours runs too good to have damage of BENT valve proportion. Well as best I can tell from Audio.

I'm saying yours did not eat valves and you likely just need the valves adjusted to make it stop tapping. Pull the valve cover and measure them. Figure its a days work for most of us. Look in the How too section for the Valve Adjustment Sticky.

 

[TownsendsFJR1300]

Agreed with the above.

Pulling the valve cover, especially with all that noise, you should find something amiss...

 

[Meshuggah]

so what happened at the end? cause I've got a very similar problem and i did the valve clearance. thanks

 

[BengNY]

So Ima resurrect this thread with an update. I apologize for not doing so sooner.

As per the suggestions above, I pulled the valve cover. Valve clearances are perfect. While I was in there I replaced the CCT guides and added a manual tensioner to see if that made a difference.

Still ticks!!! Loud as ever.

So I still have no idea. After verifying the valve clearances I doubt its coming from the valves themselves. The bike runs perfectly so no loss of compression mostly rules out a damaged valve as well.
Using a mechanics stethoscope I think its coming from about where the cam sprockets are but its hard to tell.

For now I'm just riding it and hoping it doesn't explode but any ideas short of replacing the head and valves are welcome!