Hey guys.

Question: Does anybody know about using diesel to flush out an engine? I'm thinking of emptying the oil, adding diesel to the engine where the oil goes, and turning the engine over a few times. Not actually running the bike with the diesel in the engine, just turning it over a few times to disperse the diesel, then empty it out. Maybe repeating the procedure a few times and getting all the crap out in the process.

Has anybody ever tried this, or can anybody recommend a better or other method of flushing the engine? I'd like to try this, so I guess I'm asking if it could harm the engine, or have any other adverse effects.

Reason/history: My piston cracked in Bolivia and, being in Bolivia and unable to buy a replacement, I had the piston welded. Over time the weld started to break apart a little, resulting in little metel slivers throughout the engine. With new oil the bike ran fine, but eventually after about 2.000 km I would start to loose compression, with the bike stalling out and sometimes not starting again until I changed the oil. After I changed it I wouldn't have any problem, and she ran great...for the first 2.000 km or so.

Eventually in Buenos Aires, about 10.000 km later, I replaced the piston and assumed that the problem would go away since they should have flushed the engine out when they changed the piston. It didn't. Every 1.000 km she starts to loose compression and die on me until I change the oil. Hence I'm looking for a way to flush all the crap out.

I would love any input you guys could give me.

Currently in Bariloche, Argentina.

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www.motoadventures.org Photo Journal of My Alaska to Argentina trip.
www.casakiwi.net My Moto Hostel in Medellin, Colombia...with a garage of course.

Along with the new piston .. they did put in new rings?! The thing you describe sound like the rings are not sealing correctly .. maybe the bore is worn too far?


When you change the engine oil - you do change the oil filter? And does the old oil contain particles .. what colour is it?

I've used diesel engine oil to clean out motors .. it has more detergent than 'normal' oil. Put in the diesel engine oil, run the motor for a day to a week and then change the oil again (along with the filter). Warning .. this may effect your wet clutch.. so take care.

I'd also take extreme care if you use fuel .. that may not be nice to your clutch either?

One other thing to watch for .. if some particles are moved into an oil way and get stuck there .. then the other end of the oil way will be starved of oil .. mucho problem. If the engine is 'bad' then striping and cleaning is the only way. If the oil that comes out is reasonably good then flushing using fresh oil should be ok. Depends on how the motor has been serviced. Think you should be ok to flush (apart from the potential clutch problem).

Good luck what ever happens.

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Regards Frank Warner
motorcycles BMW R80 G/S 1981, BMW K11LT 1993, BMW K75 G/S

I don't think diesel will do a damn bit of good , quite the reverse in fact .
You obviously have a serious engine defect that will only be revealed by a strip down of the engine .
The "loss of compression " is baffling and that it should be regained by new oil is also a mystery .What are the compression readings ?
A rebore and a valve job may need to be done - not the end of the world by any means .

The term detergent for oil is a misnomer as it implies a cleaning action ,this is not the case , dispersant is a better term as it describes the action better .Products of combustion and wear are held in suspension in the oil for elimination by the filter or ,if the particles are too small, by changing the oil .
Nearly all modern oils have a high level of dispersant .

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Blessed are the cracked, for they let in the light. - Spike Milligan
"When you come to a fork in the road ,take it ! When you come to a spoon in the road ,take that also ."

Thanks for your responses guys.

Here's a little clarification and resonse to your questions:

The "compression" that I was loosing after the piston-weld wasn't actually just a compression loss, but the bike was actually stalling out completely. It was a complete loss of compression all at once, resulting in the bike running fine one minute, and then dying the next. I'm sure that it's due to the metal particles, as they do appear in the oil filter. And yes, I change the filter regularly.

This was all occuring before I changed the piston. Right after the engine would die, it would take a bit to start it again, but when it started it ran fine, then after a while would die again and keep doing the same thing until I changed the oil. After putting in new oil, meaning it was more viscous, the piston would work smoothly, until the viscosity deteriorated (after 1.000 to 2.000 km) and it would start stalling out again, as the particles get stuck more easily.

When I changed the piston we put in a larger piston and rebored the cylinder. Yes, the new piston came with new rings, which are the correct size. The problem before and after the piston change and cylinder rebore is exactly the same. The valves have also been adjusted recently, so that's not the problem.

It seems to me that what the engine needs is a good flush-out with something in order to get the particles out. I'm sure this "flush" is occuring slowly with the oil changes, but it's frustrating to stall out and have to do the oil change in the middle of nowhere. And the particles can't be good for the engine so I'd like to get them out of there asap without having to open the engine up.

As far as using diesel engine oil for a flush, I think I would be concerned about the wet clush damage issue, and I agree that it probably wouldn't solve the problem any more than regular oil would.

I'm wondering if diesel fuel, since it's also petroleum product, will damage the wet cluch or anything else. Keep in mind that I wouldn't actually be running the engine with the diesel fuel in the engine, just turning it over a few times and emptying it out.

Thanks again.

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www.motoadventures.org Photo Journal of My Alaska to Argentina trip.
www.casakiwi.net My Moto Hostel in Medellin, Colombia...with a garage of course.

I didn't find what model of Kawa.
Does this bike have a decomp lever/valve?

Errrr

So the assumption is it is compression .. but why do you think it is compression?

When the bike is not running - have you checked for spark? If there is no spark then it is not compression .. could be particales in the generator/pick up area causing problems .. so fulshing cures it .. all conjecture without measurement.

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Regards Frank Warner
motorcycles BMW R80 G/S 1981, BMW K11LT 1993, BMW K75 G/S

Geez Paul, you think just cause you're the boss you think you can go off riding to Argentina? You were right, Argentine Spanish is the hardest in Latin America to understand.

I am with Lone Rider, in thinking the compression release is the problem. Assuming you are on your KLR, they have a device that holds one exhaust valve open slightly at cranking speed, centrifugal force moves some weights that deactivates it once the engine fires. If that is sticky, it could cause loss of compression. It's easy to get at under the cam cover. That is the only mechanical thng I can think of that could come and go like that. I can't imagine why changing the oil would ave anything to do with it, though.

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Andy Tiegs
https://new.horizonsunlimited.com/ts...lsouth-america

Ahhrrrrr - the mechanium can be jamed up with old particles .. the new oil freees it up enought to work for a while .. same thing happens on old bmw K bikes - they had a slipper clutch for the starter motor .. they increased the oil flow through the area on 'newer' models (post 1986?) and never had the same problem .. or did they do a different clutch? Whatever.

If it is easy to get at - put some rags around it to catch what comes out and blow it out with compressed air .. if it is dirdy gunk then I'd replace the rags with clean ones - and spray it with WD40 .. wait a minute and blow with air.. repeat untill you don't get any more gunk. Then operate engine for a day - flush oil. operate for a week and re check for gunk in the release.

__________________
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Regards Frank Warner
motorcycles BMW R80 G/S 1981, BMW K11LT 1993, BMW K75 G/S

Hi Paul!

I did flush my KLR engine before with diesel

My bike went to swim for a while in a river in the amazone and the engine was filled with brown/sandy water.

I flushed the engine with diesel: Double the amount of oil you usually put in your bike. Don't forget to remove the spark plug! And hit the start button. Repeat a couple of time. Put your bike on the floor on both side.

It happened when my bike had 50 000km. And 30 000km later my KLR still run and do wheelee.

Patrick

I had a tiger cub back in 1961. It kept dying on me on long runs. Seizing up. Let it cool and it would run again. turned out to be faulty oil pump. But eventually the engine had to be rebuilt. Ran faultlessly for two years after that and then I traded it in for a new speed twin.

Did the bike ever start after stalling, ie, without you changing the oil, if so, how soon did it start again and was the ignition switched off during that time? And does this stalling occur unpredictably, or after being ridden hard for some time?

I had similar syptoms on a bike many years ago (too many to be honest) and it turned out to a blocked vent in the filler cap. Fuel level drops and creates a partial vacumn starving the bike of fuel very quickly.
Hope this helps.

Cheers, Richard.

Andy! Hey, somebody's got to live the dream! Anyway, that's what employees are for! It's all about being a good delegator.

PatrickOT - Very interesting about the flush. I'm glad to hear that somebody has done it before. One (or two) side question(s): how did you get the bike back to civilization in order to do the flush? Or do you always travel with 5 liters of diesel fuel and 2.5 liters of oil just in case you tip over in a river crossing?

Thanks tons for your input guys. Well, MollyD, the hammer didn't work so I'm going to try something else.

Just a few side notes. It's a 2002 KLR650. The piston cracked between the first and second rings and was welded and machined down as good as possible. The problem began about 8.000 km later - just about enough time for the weld to start breaking apart. Every oil change the oil filter has lots of silver and black particles. The oil gets really really dirty more quickly than it should. I was using Castrol GP 20/50 mineral oil. (Just switched to Castrol semi-synthetic, which should give me a better range before having to change the oil again.)

About 1.500 km after each oil change, and the bike running perfectly with tons of power, it just dies. From one moment to the next it looses all of it's power and dies, literally. From running at 100km/hr, to the engine dying, but it's still in 5th gear, so it slowly slows down to a stop. I usually try to use the momentum that it has and release the clutch to push-start it, to no avail. Once we come to a complete stop, I try starting it for a few minutes without any luck. I turn the key off every once in a while and let it sit, then resume with the start button. Eventually it will fire and run perfectly for a few kilometers (sometimes until 10 or 20km), and then die again in the exact same way. After 3 or 4 of these episodes it won't fire again until I change the oil and clean the filter - then it starts up like she was new and runs perfectly for about another 1.500 km or so.

So to recap: the problem started after a piston weld. Now she runs perfect after every oil change, until the oil looses something of it's viscosity, then the problem returns. I change the oil and the problem goes away, temporarily.

For me, the problem is definately oil/particle related. I'm going to try to diesel fuel flush that PatrickOT used, and see what happens. If that doesn't work, I'll try some of the other suggestions.

It's pretty late here and I've got another long ride tomorrow, so I'm going to hit the hay right now.

Don't worry guys, I'll get back to you to let you all know how it all turns out. What I try, and what (hopefully!) fixes the problem.

__________________
www.motoadventures.org Photo Journal of My Alaska to Argentina trip.
www.casakiwi.net My Moto Hostel in Medellin, Colombia...with a garage of course.

Hi Paul!

My bike was in a small motorboat and it flip over because of the stupid driver. The boat engine broke at the same time. Another boat passed at the end of the day but it was too late to go back to civilization. They suggested me to leave my bike and all my gears by the river and we would go sleep in a small village in the jungle not too far.

I did not agree with that! I wanted to stay with my bike! So they left me there and I slept alone by the river in the amazone jungle. What an amazing night it was to hear all those noises from the jungle and hearing the water moving like if animals were fighting all night. The next morning I woke with a new friend at 300m from my tent: A crocodile was waiting for me. But the people who left me the day before came back to bring me to civilization.

Patrick

No Crocks there! Just Leopard Seals!

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Patrick passed Dec 2018. RIP Patrick!