The good oil

[Box'a'bits]

Thats LC4's for ya, mine was a 2000 model tho, without the hi flow head. And I didn't have any service history when I bought it, so who knows. When the motor was pulled apart, everything else was mint, so it was just one of those things I guess.

I've always changed oils at 3000 kms. Perhaps I baby the bikes too much.

Andy's 640a also did its cam follower bearing at similar kms. I bought the bike at about 20k kms, & service history appeared good. Maybe just a service item at that mileage.

Agree Clint, mine always went black almost straight away too. Funny going back to a Beemer, & having the oil staying reasonably clean by 1,000kms.

[pete376403]

What was the piston and the rings like? Black in the oil is suspended soot particles from blowby. (Not a diesel, is it?)

[warewolf]

Andy's 640a also did its cam follower bearing at similar kms. I bought the bike at about 20k kms, & service history appeared good. Maybe just a service item at that mileage.

Cam bearing vs cam follower bearing... not the same thing. Cam bearing failure is rare. However there was bunch of bikes around the '04-'06 model years that had premature cam follower bearing failure. My bike was/is always serviced by the book and the cam follower bearings started to go before 20,000km. It's obvious because the valve clearances open up and the engine sounds really, really tappety. Ignore these warnings at your peril, 'cos when she goes she takes progressively more- and more expensive- things with it. Earlier model bikes were getting the same problem at the same time, but with typically 50-60,000km on them.

I've always changed oils at 3000 kms. Perhaps I baby the bikes too much.
...
Agree Clint, mine always went black almost straight away too. Funny going back to a Beemer, & having the oil staying reasonably clean by 1,000kms.

Modern bikes running on synthetic oils have good power and good lubrication. They need to be loaded up regularly to get good combustion pressure to seat & seal the rings. Otherwise you get glazed bores and blow-by on an engine that ain't never gonna wear out because the oil is stopping the rings doing their job (this is one reason some bikes use a "running in" oil that is a dino-oil before switching to synth at an early change). Having learnt this lesson I've made a point of loading up my 640 regularly - oil still looks pretty mint at 5000km, uses 100-200mL of oil in that time.

I've heard that sometimes its difficult to get all the oil out of the engine (not 640 specifically) so you end up with some old black oil contaminating the new oil - and it doesn't take much to look bad. My DR-Z250 did this - 10km after the oil change, basically as soon as the engine was fully warmed up, it was dark again. But this discolouration in itself while not ideal is not catastrophic either. The new oil is still going to do a good job.

Surely black stuff could also be clutch material? When a mate (doncha love 'em) fried my DR-Z250 clutch, the oil was a totally cooked black-as-knight stink-fest.

[Waihou Thumper]

The KTM 625sxc had an oil change over the past weekend. I starter it up and the oil turned black, very dark....I then emptied the crank, filled her up again with new oil and now it looks nice and toffee coloured...The bike has only done 7700Km
The main reason for this was because assemling it back, I noticed the gasket was stuffed. The last owner had re-used it and I don't know how many times? I got a new gasket but left oil in the bike, it leaked a little bit and topping it up I sort of put a tad too much in...
So, I thought in my wisdom to start over and go from scratch without doing the frame oil part....
All good now, nice clean oil and the correct quantity..

[yafeetup]

The KTM 625sxc had an oil change over the past weekend. I starter it up and the oil turned black, very dark....I then emptied the crank, filled her up again with new oil and now it looks nice and toffee coloured...The bike has only done 7700Km
The main reason for this was because assemling it back, I noticed the gasket was stuffed. The last owner had re-used it and I don't know how many times? I got a new gasket but left oil in the bike, it leaked a little bit and topping it up I sort of put a tad too much in...
So, I thought in my wisdom to start over and go from scratch without doing the frame oil part....
All good now, nice clean oil and the correct quantity..

dont think it would be an issue but I would air bleed the frame again, you know take out bolt start up until oil comes out, just to be safe

[Quasievil]

Modern bikes running on synthetic oils have good power and good lubrication. They need to be loaded up regularly to get good combustion pressure to seat & seal the rings. Otherwise you get glazed bores and blow-by on an engine that ain't never gonna wear out because the oil is stopping the rings doing their job (this is one reason some bikes use a "running in" oil that is a dino-oil before switching to synth at an early change).

Im not sure how you come to this conclusion, I dont agree at all

[NordieBoy]

What a load of crap dude

Really?
Apart from the ring loading being most important during the break in period, what's wrong with those wordy things?

[Quasievil]

Really?
Apart from the ring loading being most important during the break in period, what's wrong with those wordy things?

Damn you Nordie, I re worded my post as it was a bit well, much.

What engine isn't loaded up regularly, having a "regular loading" doesn't modify the oils performance or attributes, it may offer variance to the oil temperature, which a synthetic can handle better than another oil type.
the most grueling part of the engines routine is start up, this is where synthetics offer definite advantages over semis and minerals.
Out of any oil Synthetics enable the rings to perform better than other tyes of oil, also they offer the rest of the engine significant benefits (a good synthetic anyway)

[Padmei]

Good to see you've still got a bit of KLR in ya Quasi

[dino3310]

Good to see you've still got a bit of KLR in ya Quasi

are you a Bisexual Quasi

[Quasievil]

Good to see you've still got a bit of KLR in ya Quasi

yeah I got to stop and rewrite PC style, no wonder my rep is shit lol

are you a Bisexual Quasi

No, but good on you for asking but sorry mate not keen.

[wysper]

Quasi has being helping me via pm. Without confusing the living crap out of me.

Looks like I might give a fully synthetic a whirl and see how I get on.
Price scares me a bit, but an engine rebuild price would scare me more

[NordieBoy]

I haunt really noticed any difference running din/synth.

The 3rd gear whine gets a little louder near the end but that's about it.
Change every 3 months and no problems so far...

[wysper]

I haunt really noticed any difference running din/synth.

The 3rd gear whine gets a little louder near the end but that's about it.
Change every 3 months and no problems so far...

Damn you Nordie - just as I thought I had made a decision

[Quasievil]

I haunt really noticed any difference running din/synth.

The 3rd gear whine gets a little louder near the end but that's about it.
Change every 3 months and no problems so far...

Think of it like this

(god here I go)

think of the two surfaces in your engine, if there was no oll they would basically fuse and blow up right, so what ya do is seperate the two surfaces with an oil...........of course!
okay
so think of two oils one a mineral or semi syn basestock and the other a full synthetic

now

one oil has molecules made up of (lets me imaginative for the purposes of illustrating the point ok) variable sizes marbles, a beach ball a rugby ball and a few tennis balls (use your imagination now) and a few cricket bats and tennis rackets.

this is mineral

now think of

a nice perfectly matching row of exactly the same sized marbles

this is synthetic

ok

now think of those two surfaces held apart by an oil , now answer this question

which is more efficient ??

the second one the even sized marbles right..............this is Synthetic.

and the bennifits?

less friction, more power, less fuel used, better start up lubrication..........the list goes on.

Now what do you want to use in your engine?

synthetic or Mineral/semi

I use synthetic, all my road bikes and my KTM motard, all mint ,never an engine issue even with hard racing.

Synthetics FTW