Finding Top Dead Center

[Filmcamera]

I am planning on doing a leak down test to see how my rings etc are.  To do this I need to put each piston in turn at TDC - is there any clever way of knowing where that is with the valve cover on or do I need to remove the valve cover to be sure of getting each piston at TDC.  Also if I can do it with the cover on do I have to turn the engine over by putting it in gear and rotating the rear wheel when the bike is on the center stand?

[The Mighty Gryphon]

Pull the spark plugs. 

Turn the rear wheel in 5th to get near TDC. 

Put a dowel in the spark plug hole until it gently touches the piston face and sticks out of the hole in line with the cylinder bore. 

Rock the rear wheel feeling for the dowel to register the top. 

Remove the dowel and install the leak down apparatus.

[Filmcamera]

Great, thanks TMG I will do exactly that, wish me luck on the results of the test... I will post later when done

[Filmcamera]

Well the results are in and as kinda expected they are not great.


Here are photos of each cylinder


Cylinder 1





Cylinder 2





Cylinder 3





Cylinder 4





Spark plugs cylinders 1-4 left to right





There was a loud hissing when cylinder two was connected and it seemed to be coming from cylinder 3 - the cheat sheet that came with the tester says that means the head gasket is gone.


There was a much quieter hiss from cylinder 1 that I could not easily trace.

[Laitch]

Well the results are in and as kinda expected they are not great.

I'm uncertain why those results shouldn't be considered good if not great.

[Filmcamera]

Sadly I think you are looking at the wrong end of the pointer.


Cylinder 1 shows 70% leak and is in the red , cylinder 2 85% leak and is way in the red and 3 and 4 about 60% leak.  The best of the lot is on the very bottom edge of the moderate leak (yellow) area

[Filmcamera]

Laitch can you please do me a favour and accept that I am reading the gauge correctly. I really do not feel like getting everything out and setting it up again and filming it just so show you the direction the pointer rotates.

[The Mighty Gryphon]

I am pretty sure the pointer is correct with the long end at the reading.  If not the needle would hang up at the zero-stop pin.   

[Laitch]

I'm uncertain why those results shouldn't be considered good if not great.

. . . can you please do me a favour and accept that I am reading the gauge correctly. .

You and TMG have healed my vision. I'll honor your request. It must be comforting to have that Triumph. :giggles

[Filmcamera]

The Triumph is amazing, super fast, super agile and just a blast to ride.  However the seat makes the OEM brick seat feel like a pillow and anything over 80 mph is hell after a few minutes because of the wind blast.  Also - well I suppose it is a little soulless. It just works, you know? No character flaws, no little sounds to make your anxiety level rise.


 I still ride and enjoy the brick often, it is just now it can be semi retired and be used when I need to be able to carry some stuff or go on a ride with the wife or a kid or just feel like a gentle not hypersonic ride.


[size=78%]  [/size][/size]Given the readings of the leak down test my next step is going to be to adjust all the valves into spec and try it again.  Since that means 16 x $34.79 on Max for each valve follower plus CR tax plus shipping for a total of around $700 or so I need to save some pennies first.  After that the next thing would be probably be the oil rings.  Either way I 100% intend to keep the bike and keep it running right so any insight as how to properly interpret the leak down test results would be great.[size=78%]

[Laitch]

Given the readings of the leak down test my next step is going to be to adjust all the valves into spec and try it again.  Since that means 16 x $34.79 on Max for each valve follower plus CR tax plus shipping for a total of around $700 or so I need to save some pennies first.

I wonder if you could buy and have shipped to CR the shims indicated by stokester in this post, or buy them locally if there are Yama or Kawa dealers locally down there.

[Filmcamera]

The 16v does not use shims like the 8v bricks, you have to change the whole bucket - or cam follower as BMW calls it.

[Laitch]

The 16v does not use shims like the 8v bricks, you have to change the whole bucket - or cam follower as BMW calls it.

Right.

With leaks like those, does the moto run like a cross between something from the Scooter Store and a mosquito fogger with the temperature of a wok during the midday lunch hour?

Regardless, I'm taking shutting down the phone ringers and computer to take the rest of the day off for introspection.

[Filmcamera]

[size=0px]With leaks like those, does the moto run like a cross between something from the Scooter Store and a mosquito fogger with the temperature of a wok during the midday lunch hour?[/size]

More or less, that is a little harsh but when two up and climbing one of Costa Rica's endless mountains the temp does spike and get very close to the red and the fan runs non stop.


Having never ridden another K I am not 100% sure how hard it should pull but it is no Ferrari that is for sure.  My guess would be a 6 second 0-60 or there abouts.  Having said that once at speed she cruises comfortably at 80 - 90 mph with no trouble.  I have had it up to 125 mph but that was a struggle.


One of the reasons I got the Triumph was that I was feeling that when on group rides I was having to push the bike harder than I really liked to keep up when the riding got more spirited.

[daveson]

Have you ever torqued the head bolts?  If they're loose it might be an easy fix.

[Filmcamera]

Good idea, I have never touched them since I got the bike, worth a try for sure.

[daveson]

Its a long shot, but something that I think should be done anyway.  Its one of the things I like about bricks, the easy access to the cams, and to the head.

[Laitch]

Given the readings of the leak down test my next step is going to be to adjust all the valves into spec and try it again.

I believe the next step should be a compression test. Done correctly it could suggest the likelihood of burnt valves, faulty rings, leaking valve seals or head gasket leakage between cylinders. If any of those conditions are indicated, you'll need to remove the head so might as well save adjusting the valve clearances for reassembly. Where do you hear leakage for each cylinder—in the crankcase, in the throttle bodies, from the exhaust pipe? Have you tested for exhaust gas bubbles in the coolant yet? Is the engine consuming oil excessively? Is the engine difficult to start and idle?

Your November posts indicated exhaust valves within spec clearance. two intake valves at minimum clearance and one intake valve 2mm tight. The leakdown test seems to show drastic problems but that doesn't seem to square with being able to ride two-up in tropical mountains without the overheat indicator being triggered because the fan and coolant couldn't control temperature. What is the water:coolant ratio in the radiator—60:40, 50:50, or is waterless coolant being used?

The temperature is "spiking" but not overheating. What is the typical elevation and seasonal temperature on the mountain roads you've ridden?

[bocutter Ed]

Is there a possibility you measured at the wrong TDC?

[Filmcamera]

I believe the next step should be a compression test. Done correctly it could suggest the likelihood of burnt valves, faulty rings, leaking valve seals or head gasket leakage between cylinders.

The last time I did a compression test it was a fairly consistent 120-125 across all four cylinders but I will do one again for sure.

Where do you hear leakage for each cylinder—in the crankcase, in the throttle bodies, from the exhaust pipe?

From cylinders 3 and 4 there is no audible leak that I can hear, cylinder 2 it seems to escape through cylinder 3 and cylinder 1 I am not sure, maybe the throttle bodies

Have you tested for exhaust gas bubbles in the coolant yet?

No not yet, how do I do that test?

Is the engine consuming oil excessively?

Yes, it always has, on a 100 mile ride the oil level will go from bang in the middle to not visible in the oil sight glass, 4 - 6 ounces.

Is the engine difficult to start and idle?

Not at all, it fires right up on pretty much the first crank and idles smoothly

What is the water:coolant ratio in the radiator—60:40, 50:50,

100% coolant as recommended by the brand I am using

What is the typical elevation and seasonal temperature on the mountain roads you've ridden?

I live at about 3300 feet above sea level and on a typical ride I might go as high as 5000 feet above sea level but also down to 0 if we head to the beach.  Temperatures range from 80 to 95 fahrenheit on the whole.

[Filmcamera]

Is there a possibility you measured at the wrong TDC?

Yes, I had considered that.  What I did was put the bike in 5th and move the rear wheel to turn the engine over.  It seems to move in noticeable steps, it is not like I can edge the pistons gently up and down. I feel a lot of resistance at the rear wheel then it gives and the engine moves a bit ad then again etc. In those two positions I seem to have either 1 and 4 at the top or 2 and 3. There is little or no fine adjustment to be made, does that seem about right?

[Laitch]

TDC for a leakdown test is found by TMG's dowel method with the camshaft cover removed. When the dowel reaches the top of its stroke, you must observe both the intake valves and the exhaust valves of the cylinder being tested in their closed positions without their buckets being depressed by their cam lobes.

[Laitch]

From cylinders 3 and 4 there is no audible leak that I can hear, cylinder 2 it seems to escape through cylinder 3 and cylinder 1 I am not sure, maybe the throttle bodies

No not yet, how do I do that test?

At what points of the engine's system are you listening? Guessing shouldn't be part of this procedure. Listen through a stethoscope or a tube adapted to the purpose to get better hearing of what's occurring within the intake manifolds; otherwise, try listening with the air cleaner or the entire plenum removed.

The exhaust gas test can be tried using the method shown in the video link I provided, or the fuel tank removed and the coolant topped up so it can be seen in the radiator with its filler cap removed. There is also a sensor to be purchased that could be placed in the radiator for combustion gas detection, but one of the previous two methods should work.

[billday]

What I did was put the bike in 5th and move the rear wheel to turn the engine over.  It seems to move in noticeable steps, it is not like I can edge the pistons gently up and down.

Speaking from memory, so this may be off, but I believe there are flats on one or both cams that enable you to turn the engine over with a 19mm box wrench. Should be more precise than shoving the rear wheel.

[bocutter Ed]

Yes, I had considered that.  What I did was put the bike in 5th and move the rear wheel to turn the engine over.  It seems to move in noticeable steps, it is not like I can edge the pistons gently up and down. I feel a lot of resistance at the rear wheel then it gives and the engine moves a bit ad then again etc. In those two positions I seem to have either 1 and 4 at the top or 2 and 3. There is little or no fine adjustment to be made, does that seem about right?

As per Laitch, and as I was inferring, you need to know you're doing the test at the TDC between Squish & Bang, not the TDC between Blow & Suck. The valve cover should be off.