So, having finally discovered from the previous owner that the sludge trap on the Lightning is clean and the bike was not run after it was cleaned before it got to me, my question is. How long between cleaning intervals? Is it miles or time dependent?

Am I correct in thinking that if I fit an oil filter into the return line then I can forget about ever having to clean out the sludge trap?

That would be my opinion, unless one were to ride thousands and thousands of miles. I'm 63, not planning on repeat cleaning of any of the ones I've done.

Unless an engine blows, but then you'd be in there anyway.

Fit the filter, magnet in sump and forget the sludge trap until the next time the cases need spliting.

Triumph twins have much the same sludge trap.I know of a '70 Bonneville that was still running fine at 180,000 miles.It had regular oil changes,but the bottom end had never been apart.

I have no idea how many more miles it did after he sold it.There were no magic magnets or return-line filters in those days.

I'd like to believe that Peter, but really, 180,000 miles! Dream on! I suppose after ten sets of pistons and about 4 regrinds and a couple of sets of cams and ten sets of followers....and rings... I forgot about ring sets!

I can kinda believe it, I owned a Thunderbolt, which at some point SRM had rebuilt with their end feed crank. It had done 140 thousand miles between 3 owners (I knew the previous 2 owners) It ran really well and was a quick bike (105 was top speed)

It eventually got sold to a dealer, after I had started running iridium plugs in it, it ended up running rough, the day the dealer was coming to buy I took my iridium plugs back out of it and put in some old Champions, Started the bike up for the buyer and it ran perfectly - the plug was duff and a good bike was sold.

In my ownership the oil (and filter) was changed regular.


The only things that actually failed on it was the kickstart quadrant (the cotter pin section was badly worn) and the SRM alloy clutch lifting plate, which SRM replaced with a new one FOC

if your running a filter & modern type oils,the sludge trap should stay clean .the last crank i rebuilt i threw the trap away .regular oil & filter changes & it will be fine.

There were no new cams,because the bottom end was never opened up.Yes,it had different pistons,and for a time it had an 8-valve top-end.The crankcases were never separated.I know the man who owned the bike and did those miles.

That may not be a world record.I think there was one case in the US where a Triumph was running well at 400,000 miles,without the bottom-end ever being opened up.If I can find a link,I'll attach it.

The one case I've seen of a really badly plugged sludge trap was in a bike that had sat idle for many years in an adverse (cold, damp) environment with dirty oil in it. The oil in the trap had turned to the consistency of a wax crayon.

The traps in both of my A65s have stayed clean over many years. I don't run oil filters, but I change oil very often, around 1000 miles or twice a year, whichever comes first.

I had three A10 cranks in a row, sludge traps so full of sludge, that all three of 'em had almost covered the left rod oiling hole.

Disaster averted.

Rickman, do you know anything of the history of those cranks?

Up to the time I bought them, no.

There is a photograph in Roy Bacon's book, BSA Twins and Triples of a 650 plunger Flash that belonged to Nottinghamshire police force. The photograph is captioned "A very well used police Flash which covered 120,000 miles on the original crankshaft". Being a police motorcycle it would have had a hard life, but equally of course it would have been well maintained, and would have had regular oil changes.

I'm with the "fit an oil filter and forget the sludge trap" school.

Lannis

Sorry to read this, Lannis.

Apparently a "class" should be held with a refresher about the power of the centrifugal oil cleaner and the it's sludge collector tube. A paper oil filter can only catch damaging particles above a certain size and only after they pass through the the rod bearings.