Engine Flush

[Flyingw]

A guy brought me his 85 350X today because his clutch didnt disengage when the handle was pulled in. I pulled the clutch apart and found the plates fused together. The bottom of the case has a fine brown silt buildup in the bottom of the case. I believe this to be clutch plate material but when I get the motor back together, I want to flush the motor out. I am thinking of putting a solvent of some sort in to the motor (warm and oil drained) and flush the solvent through the motor using my drill to turn the motor for several minutes. Drain and refill with cheapo oil. Run the motor. Drain and fill with good oil.

What can I use to flush the motor out and not damage the motor?

[Just-Tri-It]

May want to stay away from the solvent and just run a couple motor flushes through it with good oil and new filters. Don't want all that stuff breaking loose at one time but gradually. Most motorcycle owners usually stay away from the solvents.

[Yamaha_Rules69]

I am not too keen on flushing a 4 stroke, this topic has been brought up before. The best thing to do is as mentioned above, do several oil changes back to back. I would use the cheapest automotive oil I could find, and when you think its clean, put in the good stuff. I have heard of other guys using gas, deisel, and kerosene, but it just dosent seem like a good idea to me, that stuff was never meant to be in there. --- Jon

[atc007]

What I've done for 27 years now is gas. Put the drain plug in,put in 3/4 gallon of gas or so,stand on the pegs and rock back and forth. Don't start it. All the clutch grit and dirty slime comes right out. Drain,do again with gas.,most all of the years of deposits are laying in the bottom.Then put in fresh oil,run the tar out of it and drain,new filter. New engine. No machine left my shop without a flush,,didn't matter if it was a service or a rebuild of any kind. Gas does NOT eat bearings,seals etc,,ALL wives tales. I have done this to countless 100's of engines,and they all ran like a fine swiss watch for decades. You are heading straight down the right road Jim,,one that most are afraid of,but makes a HUGE difference in the performance/life on an engine.

[Dirtcrasher]

ATF works good.

I have even filled them with gas and or diesel :lol:

[Flyingw]

The basic fundamental sound reasonable. Like I said, I have no intention of starting it, just rotating the motor to circulate the fluid through the entire oil system. I really dont want to leave the sludge in the motor and if I can flush the majority of it out I think would be good.

The guy just bought this thing for 1400.00 and its in great shape for its age. It has typical wear and corrosion on some fasteners but its been garage kept all of its life. The paint on the frame is in awsome shape but the frenders have been replaced. All I'm doing is giving it some TLC and replacing some wear parts.

[fabiodriven]

Yup, gas or diesel will work fine.

[RapidRick]

YEP, ditto with fabiodriven

[dougspcs]

Not to dispute the years of experience that has already chimed in on this topic, but my personal feeling is to flush the engine with the only thing intended by the manufacturer to go into the crankcase...oil.

If I buy a machine that has really dirty oil I'll do a change then run to temperature and change it again. Take it for a days ride and change it once more..

Everyone has their opinion, but just realize that's what it is...opinion.

Soak up all this knowledge and pick the one that you are most comfortable with!

[Flyingw]

Sounds good. I'll use some diesel as its less flammable than gasoline and a little safer.

[Flyingw]

Normally Doug I would completely agee with you but this sludge is stuck good. Flushing with straight oil won't get out. The inside of the clutch basket is coated with this debris and even parts solvent is having trouble loosening it up so I think a more aggressive solvent is needed.

[dougspcs]

That is a bltch...then as a backup I'd probably agree with DC..

The ATF has a lot of detergent, maybe that will break it up..perhaps a commercial engine flush!

I'd be careful not to get it too stirred up or all that crap could start travelling around and find its way into fine oil passages and cause starvation..

[Flyingw]

This debris is very fine. I believe once loose, it should flow through the oil system just fine and eventually end up in the bottom of the motor where it will be carried out by the diesel.

[fabiodriven]

Just out of curiosity, was the clutch replaced? If there's that much clutch debris in there, the clutch must have been thrashed at one time, no?

[Flyingw]

The clutch that was in it went in to the trash. Some of the stationary plates were fused to the rotating plates. The fiber on the stationary plates had decomposed and started shedding this debris. I'll clean up the clutch basket and put in a fresh clutch and it should be ok. This thing apparently had been sitting for a while.

[RubberSalt]

diesel is my favorite.

If bad enough, ill pull a clutch cover and use a power washer. Avoid rubber seals. Dumping all the water out, quickly fill dump diesel in there to prevent rust.

[Scootertrash]

What I do is when I have that right side cover off, I'll take some diesel or mineral spirits and put it in one of those little 10.00 Home Depot hand sprayers and rinse as much of the crap out as possible before I put it back together. I've also bolted the cover back on using 4 or 5 bolts without the gasket, dump in the solvent, slosh it around by rocking the trike all over, then remove the drain plug. Do this a time or two, then hit it with the hand sprayer method, put it back together, then do what FlyingW is talking about with the drill as a final rinse. This way the majority of the sludge and crap comes out without running it thru the system to avoid the possiblity of plugging a passage like Doug was talking about.

YMMV

[fire1]

I have always used kerosene.

[Flyingw]

Dont misunderstand the degree of contamination in the motor. Its not a whole lot of debris and its very fine but stuck real well. I'll flush it with either kerosene or diesel and whatever doesnt come out will remain until the motor is disassembled for an overhaul.