Ive not had a chance to strip the engine any further,
but to answer some of the comments.
The engine was rebuilt towards the end of last year, a circlip had escaped and gouged the bore. At this point i found the big ends worn and the cam was marked as well as the followers.
I decided to rebuild myself, (this is not my first bike engine build) the rebore and crank grinding was out sourced.
I cleaned the cases thoroughly using good old elbow grease both internal and external. they were dried and put to one side.
It was at this point i ordered a 4s cam from norvil
The superblends and shells came in a bottom end rebuild kit from RGM whom also supplied new followers.
I picked up the crank and barrels from my engineer.
the sludge trap was cleaned by myself. and the crank re-asembled with new bolts
Oil pump was stripped and cleaned then rebuilt as per the book.
The new followers were fitted to the barrel and the camshaft trial fitted to ensure even contact on the faces.
The Rods were fitted to the crank using engine build lube and torqued to book spec.
Everything was spinning freely.
the crank was put in the case along with the cam (using the supplied lube) with a light smear of sealant on the joints. bolts were tightened up and once again the assembly was checked to make sure it span freely.
Timing set and chain on and tensioned
accralite pistons fitted with NOS accralite rings (I had an issue with the new rings on my triumph)
Barrel on then cylinder head.
ready to go back in the bike.
the oil tank was removed and cleaned out as well as the pipes.
engine back in
bike was run in as per norvils cam instructions.
oil was returning at tank
Had some issues with the boyer so replaced with a trispark, (running better but still not quite right)
so bought a pair of premiers.
had some isolastic issues so wasn't used much.
changed oil after a couple of hundred miles with a new filter over the winter
Oil is Castrol XL40
nothing out of the ordinary in the oil.
Re-torqued the head and barrel.
start of the summer
fitted a PCV valve as per recommendations on the forum.
Ran for a bit more still trying to iron out the tuning issues, no leaks and no smoke.
was running fantastic, went out on the Sunday running spot on.
Got to St Andrews, traffic was a bit heavier so some filtering didn't have me waiting about.
stopped by the beach, (on the road) and caught up with some mates.
started up and headed out to Anstruther, made it around 6 miles before it went bang.
Im still a bit gutted and it hasn't quite sunk in yet.
Grandpaul is right in saying that its been a bit of a "problem child" its certainly been a rather expensive journey so far.
I understand what has been said about airlocks in the system and the possibility of incorrect big end clearance, and i hope to pull the engine and strip it down this weekend.
ive not got a lot of pictures from the rebuild but here a a couple
Thanks for the reply's its helping me to figure this out, not that i can do much now, just got to decide if its worth fixing.