When doing an oil change should I use an engine flush type additive?

[Flashjammin]

Basically I'm doing an oil and filter change on the bike and I'd like to know if it's recommend that I do a flush with some sort of engine oil flush additive first (like I would for the car)?
Bike is a gsxr250

[Erelyes]

Save your money

[frogfeaturesFZR]

just change the oil regularly

Save your money

[Rhys]

I have never bothered, just get it good and hot and have the bike level to get most of the oil out

[skippa1]

Who would bother doing that? What do ya think you're going to wash out?

[AllanB]

Nah - I'd not put that in a bike for fear of it fucking the wet clutch. May not but who knows.

If your oil is really overdue and bloody dirty do this: leave existing filter on - drain oil, throw in the cheapest dino motorcycle oil you can find - run the bike for a good spin (needs to get right through the transmission gears so don't just idle it) then drain it and change the oil and filter, then fill with something decent. You have effectively 'flushed' the old oil then.

[avgas]

"Wash" with a diesel oil.
Basically what I do is:
1) Drain old oil, leave in old filter
2) Put diesel oil in
3) Do about 20-30km in the diesel oil (don't thrash the clutch - take it easy, the better the diesel oil the more beans you can give it)
4) Drain diesel oil, remove old filter
5) Fit new filter, fill with new oil

Works a charm every time. Especially if you don't know what previous owner put in the oil tank (motorup etc)

[caspernz]

just change the oil regularly

Yes that's my approach too

[mrchips]

Save your money

+ 1

I've never bothered with any of my cars either. Expensive enough with oil & filter.

[TimeOut]

"Wash" with a diesel oil.
Basically what I do is:
1) Drain old oil, leave in old filter
2) Put diesel oil in
3) Do about 20-30km in the diesel oil (don't thrash the clutch - take it easy, the better the diesel oil the more beans you can give it)
4) Drain diesel oil, remove old filter
5) Fit new filter, fill with new oil

Works a charm every time. Especially if you don't know what previous owner put in the oil tank (motorup etc)

Only problem with that is you never get all the old oil out (up to 300 ml )

So you're mixing the good oil with some inferior oil

[avgas]

Only problem with that is you never get all the old oil out (up to 300 ml )
So you're mixing the good oil with some inferior oil

Actually you math is fail. This is the common wash the glass out math.

300 ml mixed in with 3L. Then removed. So really the old oil residue is actually far less than 300 ml. 300ml is 1/11th of 3.3L so therefore you could assume that 300mL diluted into 3.3L meaning you will have 1/11th of the old oil left in the sump when you do the second drain.
So basically less than 30ml of the old oil is left after the flush. Not 300mL. 300mL remaining is made up of 270mL new Diesel oil and 30mL old oil.

Also diesel additives have detergents - so break down lots of the stuff that is in the inside of the sump. Making it easy to get the nasty stuff out.

(Think of it like pissing in the pond then drinking the pond water - you might have pissed 300ml, but you don't drink 300ml of raw urine do you)

[Kickaha]

So you're mixing the good oil with some inferior oil

Which in real life doesn't matter at all and has been happening since the advent of the motor vehicle

[Flip]

Personally I would not bother ever doing a flush. The only time I would bother is if I was returning a old retired motor to service. If the bike was just due an oil change I don't see any advantage.

As fer as putting diesel oil in a bike goes.........Light Diesel lube oils (mixed fleet lubes) usually have dual C (commercial) and S (service station) API ratings. Usually these diesel motor oils make brillant bike oils because they have a much stronger addative package than SH and later motor oils. However few diesel oils will meet the JASO clutch compatability rating because the addative package is to strong/good.

If you are talking about "Bunker" diesel lube oils. Or lube oils made for boat motors running on bunker fuels (smelly black almost tary shit) I would have to check, however the bike motor would be clean afterwards but I would expect a wet clutch to slip.

I would just change the oil and would not worry about it and save the money when you trade up on a Harley.

[The Reibz]

I just did a full rebuild on a 4L falcon motor. As a prep I drained the oil and then put 5L of kerosene in it. Ran it for 20mins at Idle and reved it even 5mins or so to pump it up into the head. Kero came out the other end competely black and full of shit.

Car had 320,000km on it and the engine was spotless when I opened it after the flush. Im talking sparkling valve retainers, lifters and aloy. I flushed my air compressor like this too.

If I was to do it on a bike though I would be changing the clutch plates at the same time as the kero would probably fuck them.

[pete-blen]

Only problem with that is you never get all the old oil out (up to 300 ml )

So you're mixing the good oil with some inferior oil

...O well if yer that picky ... yer just going to have pull the motor
down and put it though a wash tank....