TOPIC:

I have carried out a compression test with the engine cold and the results are as follows.

1/ 100 psi
2/ 87 psi
3/ 100 psi
4/ 110 psi
5/ 80 psi
6/ 97 psi

Now taking into account the bike has only done 19,000 miles and when I replaced the nylon cam chain gear the pistons looked as if they were virtually new, I did not take the barrels off so I did not look at the rings. I have put a syringe of diesel down each pot to see if that will free any stuck rings, if I have no joy I will pull the head and barrels off and check the rings and measure the bores.
The leak down testing kit is due tomorrow so I will try that as well before I start to strip the engine.

Before blaming the rings, are the valve clearances in spec?

Low mileage means it spent a lot of time sitting in its life, time can be hard on any engine. Stuck rings can work loose with a good soaking in penetrating oil and some run time, but sometimes they don't and you have to tear into the engine.

Well the soaking in diesel did not work too well so it looks like a strip down.
2 cylinders increased a little but not the ones that needed too, 3 went up to 105 psi and 4 went up to 115 psi.
I received the leakdown test kit today do you think it would be worth trying this or do I just go for the tear down?

Absolutely do the leak down test. it will tell you everything. If you hear air pissing through the carbs, you've got a tight or leaking (carbon up valve) if you hear hissing out the exhaust, you've got a tight and or burnt valve. If you hear hissing out the crankcase vent, or oil fill cap, you're rings are passing. If you see bubbles in the rad, you've got a burnt or leaking head gasket. if you hear air leaking out an adjacent cylinder plug hole you've got a burnt head gasket or leaking at least. And you could find multiple results for some or all of the cylinders.
Sure you can do a tear down and do your inspection but then you have to check every individual item "looking" for the obvious culprits. That's the way we did it 40 years ago. There's nothing wrong with doing it "the old fashioned way" but it you have the tools , why wouldn't you do the test. If nothing else it will prove to you that the test is way more accurate than teardown and inspect. Besides, it's a new fundamental technicians approach to diagnoses and if you're going to tear it down anyway why wouldn't you learn the new aspect of the trade.

After you're all done with your rebuild, you should do a leak down test and record a baseline leak down rate, then after break in do another one to prove to yourself that in fact you are broke in and then that leak rate becomes your baseline for future testing to determine when to do the next tear down. THAT"S predictive maintenance and that's where you should be driving your maintenance program.

Kawboy is right on... do the test. You have uneven compression but don't know why, you need to find out what the issue is so you can determine what needs to be repaired. If the problem is confined to the head, you will have a much more simple and less expensive repair. Or if there are signs of multiple issues in the leak down test you can plan accordingly.

Well I have carried out the test and can confirm that I have air coming from the oil filler case, however the readings were all around 20% loss. Did not make a lot of sense to me as 2 and 5 are only showing 80 - 87 psi on a compression test.
These will now have to wait anyway has my Dyna box started hissing and then a nice plume of smoke came flowing out - all the damage was around the output connector that sends the signal to the coil 2 - 5.
So now I will have to buy the German ignition kit and start again. Still not giving up though.
I do not suppose anyone has the blue Dyna ignition box for sale?