The End Of The Road or a new beginning . . . . . .

[varnerju]

Originally Posted by Javaman

Thinking this through, surely the inlet valves should always stay clean, even if not seating fully as they are continually washed with fuel.
Perhaps I was misled by Varneju’s post when he was investigating his cracked pistons and he showed two “inlet” valves, one of which had significant carbon build up on its rear face. I don’t see how this is possible. Perhaps it was a typo and he meant “exhaust” valve?

It was certainly the inlet valves that were mucked up. Real easy to get a view of through the air box. Must have terrible gas here in the states. Your photos look nice and clean, so sadly probably not a simple valve seal problem.

[Javaman]

Originally Posted by Paul2bikes

You haven't said if that new starter is an o/e or a/m? That would appear to be your problem until proven otherwise. Your engine turns over easy enough by hand, but not by starter. That says it's the starter's fault, not the engines.

The early pre-Sport Tigers were prone to sprag failures and around 2011/12, Triumph redesigned the entire assembly and also changed the starter. This design was carried over to the Sport so that the later pre-sports and Sports have the same starter/Sprag assembly which is different from the early 1050 Tigers.
Triumph made available an upgrade kit for the early Tigers which included the entire sprag assembly, idler gears, new crankcase covers and starter motor for around £600.
This is what I fitted to my bike - all brand new and all genuine Triumph OEM parts - this aspect of my bike is now basically Tiger Sport!!
The compression figures I achieved are all PSI. They were measured with a cold engine  (I had no choice) but with the throttle held open.
I suspect this problem has existed for some time as reading through other threads, cracked pistons can be present for quite some time before manifesting as an issue.
It is clearly not yet certain that my loss of compression is not due to some other cause, such as valves not seating fully and/or the remote possibility the camchain has jumped - there is one thread where this happened and resulted in the same symptoms I am getting.
Never say never but as of now, I am pretty confident there is nothing wrong with my starter motor. If push comes to shove I can always look at testing with my Speed Triple RS 1050 starter but it is different again and also another brand - It may well not fit anyway.
For now, my focus is on the problem I know I have rather than problems I might have.
In respect of the former, I know I have very little compression on all three cylinders - much much less than when I repeated the same tests on my Speed Triple.

[Paul2bikes]

Originally Posted by Javaman

I know I have very little compression on all three cylinders - much much less than when I repeated the same tests on my Speed Triple.

This doesn't make any sense.....to me. With so much less resistance, your starter is struggling to spin the engine. What could possibly cause that, other than a weak starter?

[Javaman]

Originally Posted by Paul2bikes

This doesn't make any sense.....to me. With so much less resistance, your starter is struggling to spin the engine. What could possibly cause that, other than a weak starter?

Exactly . . . . I’ve been querying the very same contradiction.
The first few attempts at starting using the bike’s own ignition suffered from crankus interruptus before the starter got going in any meaningful way . . .  2-3 seconds tops. This could have been due to duff pressure sensor readings which will happen with cracked pistons but led me initially to suspect a flat battery.
When I cranked the bike with external wiring the cranking speed still felt laboured but at least it didn’t get cut by the ECU. I made a video of that test  - I will post it when I get back after the weekend and you can pass judgement and let me know what you think but as for slow cranking with cracked pistons. . . . . .
I am wondering if blowby into the crankcase effectively increases cranking resistance and thus slows down the starter?
All my thoughts thus far are suppositions and educated guesswork.
All I do know absolutely for sure is that I have extremely low compression on each of three pistons - this is the one known, undebatable fact and will need investigating and there’s only one way to find out the cause.
If my starter motor is faulty too, then I have more than one issue going on. I will worry about that if and when I find out why I have naff all compression 😢

[Paul2bikes]

I would do the same compression test, in the same way, with the same equipment, on your speed triple, to prove or disprove the test equipment.

[Javaman]

Now back from weekend away and will be spending some time this week working on the bike. Have never gone much beyond routine servicing and so unsure how long this is going to take or where
I will end up but fingers crossed.
Meanwhile, the link below demonstrates what I was meaning by a "laboured crank".  When starting via the bike's ignition, I am getting crankus interruptus within a few seconds but the link below demonstrates the cranking speed with the fully charged battery connected direct to the starter motor with 16mm external cables . . . standard cables are 10mm and so my cables offer significantly less resistance. Although "laboured", the engine hasn't now run for a month or more and so lack of oil in the bores etc will doubtless contribute to some extent. Regardless, the cranking speed is well down on my Speed Triple 1050 RS.
I made this video when I was investigating the starter motor as at the outset, I suspected it was the starter which was my problem. 
After checking the compression, it became clear that errh . . . .  I don't have any!!   
My focus has now moved on . . . . valve timing, valve clearances and valve seating - if all appears OK, I will be looking to remove the liners but doubtless asking advice along the way.
Watch this space

[Sidewinder]

If you get to the i"'m taking it to bits" stage make sure you whip the cam cover off first to check the camshaft timings etc.

[sax_000]

Check the starter solenoid behind the battery.  Give it a good clean or replace it, they don't cost much (you don't have to buy OEM, I got one off Aliexpress).

[Freddy]

Starter solenoid won't be the problem as leads have been connected direct to starter.

Volts above 11v while cranking indicate low resistance / compression within engine.  The slow cranking is therefore very curious. 

Check valve clearances and report back.  Cam timing fault is an extremely remote possibility as the chain has to be very very loose for it to jump a tooth or 3.

Piston damage seems evident due to crankus interruptus. 

[Javaman]

Originally Posted by sax_000

Check the starter solenoid behind the battery.  Give it a good clean or replace it, they don't cost much (you don't have to buy OEM, I got one off Aliexpress).

I actually have a brand new OEM spare solenoid and that was one of the first things I tried whilst initially working on the assumption the issue was within the starter train itself. It made no difference but thanks for lending the thought.
I will be working on the bike this morning.
Plan will be to remove the cam cover and check the clearances - never say never but they should be OK as they were all within tolerance  8K miles ago. Then I will check the valve timing. Again, I'm expecting it to be OK but there was a post on here a few years back where the camchain had skipped and the timing ended up 180 degrees out but without any collision between valves and pistons - bizarre how this could have happened and must be a chance in a million but has got to be worth looking.  If both the above are OK, I will need to look at the pistons and will do so with engine out. With this in mind, it will be a coolant drain, engine oil/filter drain and remove etc etc - might even remove the starter, sprag and clutch etc, simply to make the lump as light as possible before removing. I'm dreading it but at the same time, idly curious!!!
Will take pictures and post when I get chance but my work ethic is more "sloth on [SPAM]" than "Ussain Bolt on Speed" and so don't assume I've disappeared into the bondu if I go AWOL for a few days . . . . .I WILL RETURN!!