Oil flush concentrate .

I had a tl1000s motor which had sat for about 3 years . I got it running and then drained the oil which came out very black.
Ive never done this before but I put in some cheap oil and a small bottle of nulon Oil ENGINE FLUSH .
After running the motor for about 7mins I drained the new oil . This was also very black after only 7 mins of running .
Makes you wonder how much crap is left in your motor after an oil change . The Nulon seemed to work well in getting hidden sludge removed .

Probably lots of nooks and crannies for stuff to hide in . You never really completely drain all the dirty oil out when you do an oil change anyway , so there would still be some crap left in the motor in that . I suppose the more often the oil is changed , the cleaner the inside of the motor would be . Good to know the nulon works especially in a motor thats been sitting around for a while .

High detergent oils (like those in diesels) tend to keep the inside of your engine much cleaner

yeah, it does make you wonder...

the car I currently own, have had it for 10yrs, bought it 54 000km`s on it, and from that purchase date, change the oil every 5000km`s.

At 150 000km`s it started getting really bad hydraulic lifter noises, which had me very concerned.

As it turns out, I was running the wrong weight oil, a 10-40, instead of a 10-30. After seeking advise of the issue, from a particular expert in the brand of car I own, he asked this question, of what weight oil I was using. I assumed 10-40 was kosher.  Did I really think in the big picture, this was going to matter, and also not realizing I was using the wrong weight oil...nahhh, but it did, as the oil galleries so I found out, are very small in the head chambers, in the brand of car I own, and it started gunging up the galleries, causing major hydraulic knocking.

So I promptly put a hydraulic lifter cleaner through it, and then the correct weight oil, and its now got 275 000km`s, and hasn`t misted a beat since.

So lots of factors to think about, when it comes to oils and services on an engine.

Chook wrote:High detergent oils (like those in diesels) tend to keep the inside of your engine much cleaner

That is the advice that I received from a plant mechanic mate. 
The diesel oils have no friction modifiers and so can be used in bikes with wet clutches.  
The high detergent content helps keep the workings clean & I imagine that it would aid in cleaning out existing deposits.  

There is something to be said for not skimping on the quality of your oil.  
When I pulled the side casings and rocker covers off my SV, to dial the cams and do clutch work, I was amazed at how sparkling clean my motors insides were. I have run full synthetic since I got her with 17k on the clock. 
The longer and more stable chemical chains that make up synthetic oils don't break down as readily as dinosaur oil, providing better protection and allowing less deposits to form. 

Cleaning away the deposits after they are formed would be another science altogether.  
Knowing Gus' attention to detail, I have no doubt that his motor will be sparkling clean before long. 

I knew an old bloke who used to drain his oil and refill it with diesel! He'd then run it briefly and then dump the diesel out. Swore by it for every oil change.

Personally i doubt you'd get all the diesel out and therefore you would end up diluting the new oil.