Flushing Crankcase. What's better and how long?

[DasUberKraut]

First off, let me state that I did search first and didn't seem to find an answer. If I missed the thread that answered this, I apologize.

I want to flush my crank case on my 125m. What is better diesel fuel or fresh gas? Also, how long should I run the trike for flushing?
Just let it idle or rev it up?

One last question. Am I correct in thinking the oil system on the 125m covers the main engine, trans, and sub trans? Or is the sub trans separately maintained?

Thanks in advance. Again I apologize for any ignorance on my part.

[Motorious]

I've never heard of flushing a crankcase with fuel, but I have used Seafoam to clear a lot of carbon (bike had been ridden rich for years) out of the crankcase of my '97 FZR600 sportbike and had good results.

I had some concerns that the Seafoam might damage the clutch, but those fears turned out to be unfounded. I poured a few ounces into the crankcase, and drove it around normally for about 100 miles before changing the oil; repeated the process 1 more time for good measure and afterwards the oil stayed much cleaner, and the shifting actually seemed smoother.

[dougspcs]

You might try 2 quick oil changes..if the oil is really bad then change it, run it 5 minutes then change it again.

The 125 only needs 1 quart per oil change..cheapest flush you'll find!! Just did it on the 185 I bought, perfectly clean now.

Running fuel in the crankcase even for a short period is retarded. You strip all the lubrication from your bearings and rings!!

[DasUberKraut]

An old timer told me this is a good idea when you aquire a machine because you never know what oil the previous owner was using and how often he changed it. Cheap oil contains parafin wax that will build up over time and restrict flow in small passages. He just never specified how long one should flush for.

Doug - I understand you think it's retarded. The way I see it, as long as the motor doesn't get overly hot and you add fresh oil promptly after flushing and run it again to relube everything, drain that to remove any remnants of fuel and then replace again with fresh oil, everything should be fine and unharmed.

[ceaserthethird]

Seafoam - is your best choice.

Works really well !

[tri again]

First off, let me state that I did search first and didn't seem to find an answer. If I missed the thread that answered this, I apologize.

I want to flush my crank case on my 125m. What is better diesel fuel or fresh gas? Also, how long should I run the trike for flushing?
Just let it idle or rev it up?

One last question. Am I correct in thinking the oil system on the 125m covers the main engine, trans, and sub trans? Or is the sub trans separately maintained?

Thanks in advance. Again I apologize for any ignorance on my part.

Nope, no silly questions, and if there are, it's better than a ruined engine.

Engine advice is as prevalent as the cures for gophers.
Some are for entertainment only.
Some say run ATF in an engine.
Break loose a bunch of crud and plug oil passages Worse.
Backflush an automatic transmission with some fancy machine, no fuss no muss and
it
may never work right again. So much for preventative maintenance.

I think there are tons of cans of stuff that will promise almost anything in the engine cocktail aisle.

I've taken to just dumping oil out the dipstick hole.
Takes less than a minute, no tools needed and costs, what, like 2$?

Maybe there's nothing to worry about.
If you ARE concerned with internal crud accumulations, I posted for Honest answer
on who really has ever cleaned their internal centrifugal filters on these things.
(that's where heavier crud spins out like in a washing machine)

If I was real concerned, I'd look there first, and change the oil with the tip over lawnmower
technique a few times with cheap 10-40 and then treat it to some of the correct stuff.
Seafoam has been around for decades but I just don't know enough about this stuff
to recommend anything other that whats in the (free) manuals on here, and lots of fast, cheap and tooless oilchanges.

[The Goat]

We used Half ATF and Half oil at the shop when someone swamped a bike. If it was swamped really bad and they milked their oil to paste. We'd fill with diesel, wait. Drain. Fill again, wait. Drain. And then do ATF and oil swaps. To me that's what supertech is good for. Fill the bike, idle in place, drain. Repeat.

I've seen people take a water house into a valve cover and pull the drain plug and fill plug. Left running for a long time, it flushes dirt and mud out, and then you use ATF and oil to get the water out. I'd never do it though.

[dougspcs]

An old timer told me this is a good idea when you aquire a machine because you never know what oil the previous owner was using and how often he changed it. Cheap oil contains parafin wax that will build up over time and restrict flow in small passages. He just never specified how long one should flush for.

Doug - I understand you think it's retarded. The way I see it, as long as the motor doesn't get overly hot and you add fresh oil promptly after flushing and run it again to relube everything, drain that to remove any remnants of fuel and then replace again with fresh oil, everything should be fine and unharmed.

Your 'oldtimer' friend is talking about oil they produced around the turn of the century..and engines built around the same time.

Your engine survived 25 years without burning it's rings out by maintaining a layer of oil in the cylinder a few microns thick..this is the one thing keeping a tight seal yet at the same time not allowing destructive metal to metal contact to take place.

Running fuel in your crankcase no matter how briefly would remove that thin layer and starve your rings of lubrication if only for a short time, damage will result..This is completely unnecessary!!

Modern oils contain detergents to remove the sludgy buildup your oldster is talking about..flushing twice with engine oil will give you the results you want with zero risk of damage.

ATF perhaps as 'the goat' suggested..at least it to is a form of lubricant and the detergents are even higher in it than oil. Not sure I'm with him on the water idea though..that's nutz!

Don't put fuel in your crankcase!!!!!

And we all ignored your other question..yes the oil in the crankcase lubes the whole thing. Transmission, wetclutches, crankcase, top-end..everything that receives internal lubrication.

[atc007]

I "flush" every engine I service,,,with gas.. I however,,DO NOT run it. Hot drain the oil,,if possible overnight,,I start the machine for 1-2 seconds AFTER the main oil s out. Drain,,replace the drain plug loosely. Put the gas in,,rock the bike vigourously. Drain. It will eat all the clutch grit and garbage out. IF you're hellbent on running it,,And I,,understand that!! I would do the diesel/ATf,,you need an oil in there of some sort. 100% Agree with Goat and all he said. I would strongly argue that todays detergent oil will not TOUCH the amount of grit in a 125M oil screen or clutch housing.. But I have been known to be wrong,,hour after hour!! I also Love the IDEA of Seafoam,,have Not used it,,but all reports seem to be good ones. You are certainly on the right track to getting a nice fresh engine there. Side note,,After 25 + years doing this.. A LOT of 185S,200's,,all except the 200X.. AFTER I change the oil,,they smoke like crop dusters?? Ran fine pre oil change,,after?? Unuseable! The fresher oil should ring seal Better? Anyhow,,do not be surprised when it happens on the 200"s. I flush all my engines that aren't new. Just me

[dougspcs]

007, that explains the smoking on my 185. I just got it fresh from a 5 year sit in some guys shed...he said it ran great and didn't smoke when parked.

Don't know the 185/200s well since the only one I owned in the past I pedalled out of here pretty quick.

Double changed the oil, nice and fresh..but smoking to beat hell. I can't take it out for a spin because I live in town. I will have to trailer it out of town to run it a bit.

So there is hope he wasn't pulling my chain..makes me feel better.

[bentthumbtriker]

i got told by a mechanic that he once cleaned an old black motor out with 1/2 diesel and 1/2 oil by putting it in taking it for a spin around the block and dumping it.
he reconed it worked but dunno if id try it. id rather by some cheap oil an changing it a couple of times then put some quality oil in.

[El Camexican]

I've been told to run high deteregent diesel oil (not fuel) in a dirty engine, and don't just flush with it, use it like regular oil. Running straight gas, or diesel fuel through the engine??? Wow! If your engine was that dirty I guess you could pull the plug, put diesel in and spin the engine without starting it. Then drain it, put oil in and spin it again without running it to get the diesel off the bearing surfaces and lubricate them. I suspect those store bought car engine flush fluids are mainly diesel, or kerosene, but you are only putting a 20% mix in when you add it and you don't load the engine, just idle. When I was 16 I spun a 425 Olds with pure gas in the crankcase. Soon after it was smoking pretty bad on start up and now that I know a little more about how engines work I'd never do it again. Any thoughts on the possibility of a engine with a crank case full of gas and running blowing up?

[fabiodriven]

I think if nothing else you should know not to run your engine with diesel fuel or gas in it. That is an absolutely retarded idea and it will cause premature wear in your engine in a best case scenario. Awful, awful advice.

[TennesseeATC]

I agree with fabio, Whatever you do dont start it up and let it run. Disconnect the spark plug wire and spin the motor a little. I had always heard of Diesel or Kerosene, NEVER straight gas. Good luck and let us know what you end up doing and how it works for you!!

[DasUberKraut]

Thanks everyone for all the info.

I wasn't talking about turn of the century oil having parafin in it. I was talking about today's CHEAP dollar store oil that too many people use.
I always use Seafoam in my vehicles and other small engines, but I've never used it for flushing purposes.
Also, I should state that I am getting rediculous ammounts of smoke all of a sudden. I know this machine sat for a long time without the crank case cover on it.
They did however leave oil in the motor if that makes sense. They didn't leave it in gear and roll it to completely empty the engine. I did that before I filled up.
For the life of me I cannot find the centrifugal filter on my 125m. I do have the shop manual and it only mentions it once with no description of how to service it.
I ran if fine for a few hours without it smoking. Now all of a sudden thick white smoke at startup that gets thinner when it warms up but it still smokes. I did read on another thread about making sure to turn the petcock off after use. I need to get better at that but in all my experience with motors thick white smoke is always a valve, ring or oil related problem. Currently using Valvoline Motorcycle 10W-40 that I had left over after I sold my cycles. Maybe I just need to take it out for a good romp? It'll have to wait until I have wheels again. Currently they are all disassembled waiting for sandblasting and powdercoat. Can't find O-rings anywhere without having to pay rediculous shipping costs. Local dealer is an idiot and won't talk to you unless your machine was bought at his store.