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Engine Flush. Opinions please...

Discussion in 'Bling and Appearance' started by green_envy, Apr 4, 2009.

  1. Hello Guys & Gals,

    I'm going to service my Kawasaki ZXR250A over the weekend, and I am unsure whether or not to use some engine flush before adding the fresh oil?

    When I replaced the Camshaft Chain Tensioner several weeks ago I noticed the oil was a little sludgy/dirty.

    The bike has traveled 33,000km approx (if the odometer is being truthful).

  2. You haven't answered the most important question, however.

    How long has it been since the oil was changed last :)?

    If you don't know, yes, I would certainly flush the motor. And replace the filter too....
  3. I wouldn't.

    Change the oil at the appropriate intervals with good oil and you will never need any of the hocus pocus snake oils for flushing.

    If you are really concerned, do a couple of shorter interval oil changes with new filters. If you become too aggressive with attempts to de-gunk a mucky engine, you run the risk of dislodging more rubbish than the filter can tolerate at once. Remember that sludge stuck to cases and other non moving surfaces is NOT being circulated through the top end, bearings and gearbox and therefore doing no damage. If you suddenly dislodge it all at once, it all circulates through the works until caught by the filter. If the filter blocks, oil pressure drops and you cause more damage than if you had done nothing.

    I still laugh when I hear about people flushing engines with kerosene.
  4. This will be the first oil change since I bought the bike. I've added 2,500km to the clock since then. I wouldn't have a clue as to how well the bike was treated before I bought it.
  5. Whoa! I'm glad I've always taken VERY good care of my cars. I'll be sure to do the same with the bike!

    Can you use car engine flush or is there a specially formulated engine flush for bikes?
  6. Yeah any engine oil flush will do there all about the same, but i would rather change the oil more often than flush like Mac said.

    Why do you laugh. Most of the Engine oil Flush is Kero. Besides you should see what they do in the outback, they use diesel.

    Don't think that this is the safe one but a mate that worked in Mumba Gas fields in South Australia. Middle of no where.

    He had an old XU1 torana with a 308. He noticed that it started to develop a sludge problem. So one of the mechanics up there told him no problem i will fix it for you its a common problem here. They dumped the oil, and filled the engine up with Diesel Fuel to the brim of the oil cap, took the plugs out and filled the cylinders with diesel as well to decarb them. And let it sit overnight. In the morning he sucked the diesel out of the cylinders, they cranked it over a few times and then dumped it. Apparently a lot of crap came out and the diesel was black. He then filled up the engine with just normal oil i think he said RX Super which is a multi fleet oil and ATF oil about 25% mix and told him " when you drive it home just don't give it full noise" and then change the oil when you get there or i will change it when you get back here. Now that's about 1700km to Melbourne form there. When he dumped the oil mix at his place i have never seen oil that black. He changed it with RX Super again and it ran and sounded like a dream.

    Anyhow with regular oil changes these things don't happen only when the engine is neglected.

    P.S. Never ever do the above.
  7. Kerosene has about the same lubrication qualities of water. The only thing I'll put in any engine I have is oil. Do what you like...
  8. Just do an oil and filter change with decent 15W 40 (not car oil) and check it again in 2000k. Drop it again if its still sludgy otherwise continue on for another 3000k.
  9. regular oil changes = no need for flushing.. oil cleans your engine.. its a sneaky way for mechanics to make $10 off a $2 product..
    just change it every 600 km with filter for 3 goes. that shoud clean it out
  10. :LOL: Great anecdote!
  11. I've opted for a couple of oil and filter changes at shorter intervals just to be on the safe side.

    Surprisingly, when I serviced the bike yesterday the oil was quite clean. Almost like honey. Not quite sure why the old Camshaft Chain Tensioner had a sludgy build up around it though. :?
  12. What oil are you useing?

    Like Mac and Bell said, just more regular changes with good qulity oil and it will clean things up.

    Bell right on the money thats its just another way to get ripped off. But you will be supprised how many people do it. Most delerships when they service your car will do it but thats just so that they charge you more.
  13. Why not? Sounds like a mighty fine idea! Except I'd be a bit iffy putting ATF in the motor, bloody thin stuff, like water, or running it 1800 ks on a diesel/atf/fleet oil mix

    As for crud, the best example I have ever seen was a Model T fire engine, in the states (I forget where), that had been sitting as a display for lord knows how many years - it still had it's original oil, and the crud was about 1/8" thick on the surface of the oil!
  14. OMG. The search button works.

    So any car oil flush will work.. I can see some sludge stuck on my k7 gsxr750 oil level window and it just does my head in.

    I'm planning to buy it,pour it in before I have the 36,000km (36,800 now) service. Can anyone recommend one?
    Since I'm get oil and filter replaced I wont have to worry about the crud blocking the flow so much.
  15. Motul make one for bikes but it looks and smells like the one used for cars (albeit 200mls rather than 300mls).

    'Cause I'm a curious fellow, I have run an experiment where I drained the oil as per usual, removed a small portion and poured the rest back into the engine. I then added 250mls engine cleaner, ran the engine on idle for the recommended period and drained it again. This was at 100,000kms on a VFR800 that sees mostly freeway riding (700kms/week). The oil after using the cleaner was absolutely pitch black, where as the oil prior to cleaning was dark brown/ blackish. Oil used is Motul 5100.

    I used a cleaner again at 200,000kms and again the oil came out much darker than usual. Obviously additional residues are being removed. Whether they are important in the ultimate scheme of things, who knows.

    I'm also yet to hear any of the prophecies of doom being realised. You are only adding 250mls to almost 4L of oil.

    While the base solvent is kerosene (like WD40 and a huge range of commercial products), a quick sniff tells you there are a number of other components as well.

    Also synthetic oils have more polar components and thus solvent effect so there should be less build up with them or any oil with high detergent content such as the diesel oils popular with a sector of this forum.

  16. I have to pull you up on a few things here.
    EVERY engine oiling system has a filter bypass. If a filter clogs, oil pressure will bypass the filter element and continue to lubricate the engine.
    Engine flushes do work, and work well. I've flushed a few engines with a kerosene mixture and they're all still fine, although I've never seen a motorcycle engine that needed flushing.
    Light slime building up on the sides of casings is perfectly normal and no cause for concern.
    Proper sludge is thick and a lot like soft tar, and very thick.
    The correct way to flush an engine with kerosene is one part Kerosene to four parts oil and do not do anything more than idle the engine for 15 minutes. Then let it sit overnight and drain.
    Change oil and filter, run for about a week, then oil and filter change again.
    It's perfectly safe and has been done for many years.
    Sludge is not dislodged by flushing, it is dissolved. Any large chunks (god help you if you own an engine that bad, I've never seen it) just settle into the sump, which is what a sump is designed to do. That's why you can find chunks of metal draining out with your oil if you have engine damage, the sump collects it using gravity and the slowing of oil flow, much like panning for gold.
    There is a coarse metal screen on the oil pump pickup to prevent damage to the oil pump, so even that is not a concern.

    Regards, Andrew.
    • Like Like x 1
  17. Thanks for that Andrew. That all makes perfect sense to me.

  18. i agree with you up until this bit.

    the metal screen will not protect the oil pump in every case. i have a ruined oil pump sitting on my desk that is scored and damaged after it sucked up bearing material and bits of engine when a big end failed (in a spectacular fashion might i add). the metal screen only stopped the large chunks, but the finer bits went thru the screen, and thru the oil pump!
  19. I'm hoping my magnetic sump plug will catch any small debris. After a major disintegration like yours, I'm guessing a dead oil pump is the least of your worries :cry:

  20. It took me 4 oil changes to clean out my engine after i got my bike.
    Thats after the shop i bought it from told me that they had changed it for me (among their lies).
    I highly recommend you clean your oil screen too, but make sure you have a new gasket ready for it, some are easy to break.

    Edit: schleppin.. er... spelling