Mickly

I got something similar, trouble was that I couldn’t get my helmet on .. I like a tight helmet but that was a squeeze too far.

I’ll let you know when I’ve finished the Trophy engine rebuild

No problems for me, just watched episode 2 series 3 of Black Sails

Right, I’ve found a place that will skim the head, hone the barrels (& properly clock them) & reseat the valves. I decided to remove the valves myself to have a look at the condition of the seats. obtained a cheap valve spring compressor & oh bugger, because it’s a shim & bucket arrangement it can’t act on the spring coz it’s hidden. So a bit of head scratching & with the help of a modified old spark plug socket .. all 16 out - it got easier as I got the knack, still took 3 hours !! All out, Tagged & bagged. The inlet valve seats look ok, the exhaust seats look a bit crusty, but passed the diesel test? exhaust valve.

Yep

Right, taking @Mr Fro ‘advice I’ve measured all the gaps - I checked that the top ring gap was the same, top middle & bottom down each liner, which they were although they differed across the liners. so it seems that all gaps are within tolerance although towards the top end .... The head scratching continues !!

I think there was a T-shirt that said “ What would Dan do? “

I liked this, Dan Walsh used to write for Bike magazine & combines an easy writing style with bonkers ( maybe true ) adventures.

My pistons don’t look anything as bad as that. The bikes only done 30k so I’m scratching my head about how the compression has dropped, these engines are renowned as being robust, the early Hinckley Triumphs were over engineered to break the link to the bad reputation that the Meridan bikes had developed.

Ah, yes .. the ‘special’ off set cam nut

Good point, I did try to ensure they were square, I’ll measure the distance from the end of the bore to make sure it’s square.

New rings are £45 per piston !! yeah, all the rings were free when the liners came off.

Dunno yet, but the reduced compression was across all cylinders

“Usually” your experience in this matter shows

That’s the conundrum - is 0.05mm above the tolerance enough to make the difference?

Piston number one off looks good? Top ring = 0.35mm tolerance is 0.20 to 0.41 installed in liner Piston Diameter tolerance is 75.96 to 75.98. Actual is 75.98 We might have a winner - the second ring gap is 0.63mm - upper tolerance is 0.56mm is this enough to cause the compression issue?

Found this bit of swarf next to liner 4 !! All 4 liners out - not an easy job ( understatement) some vertical marks, but not much, might have to ask for a second opinion from someone more experienced.

Meant to say it doesn’t vaporise as quickly as petrol .. Doh !!

Did it today, levelled the head up with a spirit level & filled the combustion chambers with diesel - that was 4 hours ago & it hasn’t dropped at all. mused Diesel as it doesn’t vapourise as quickly as diesel

Got number 1 liner out, did it by levering it out with a screwdriver - tiny bits all around the edge, there is a chamfer at the top that is quite shallow & doesn’t present much purchase. And also used a piece of wood to protect the sealing face of the crankcase.

So, the cylinder liners are supposed to just pull out by hand yeah, right!! any ideas on how to get them off without damaging them or the pistons?

Phew, the threads survived the transition as have I.

Managed to lift the engine into my wheelbarrow with some carpet to protect it & a bit of wood to can’t it forward so it wasn’t resting on the gear change shaft & wheeled it up the road So, Neil at NWC sorted the bolts - used a breaker bar 1/2drive Snap-on bit. Wasn’t phased by the 1/4 turn before the bolts cracked, said it’s not unusual for such long bolts to be ‘flexible’ He left the mangled one until last & did a lot of teeth sucking - eventually he cracked it by tightening it up until it cracked & then undid it For a total cost of Zero pounds - what a good guy!! The head looks ok Not too much carbon build up, valves look like they’re seated well. The liners look ok as do the crowns of the pistons There’s no lip or scores in the liners & piston crowns look quite clean.

But the policy wasn’t becoming active until today 17th and I called yesterday the 16th. So there shouldn’t have had to have been a change if the policy didn’t become active till the 17th surely. You’ve been done !!