Another use for Diesel Fuel?

[Nessism]

If you have a roller crank you won't see any problems there. The only area that I would worry about (for a short run/flush would be the cams...a long way from the pump, many areas for the diesel to leak past on it's way the the cams, and no replaceable bearings if something does score.

Two cycles run just fine at a 40:1 mix and I've run them for 8 hours at a crack on more than 50:1 and have never seen a problem. Granted they have reed valves and no cams, but the rest of the "up and down" junk is the same...

I agree that the roller crank is an advantage over plain bearings if oil content is low, not the other way around.

I think the main problem with flushing the crankcase is that 1) there will be residual solvent in the engine after flushing, and 2) the sludge that loosens up may migrate into places where it can do damage. Not worth the risk in my opinion.

[ned37]

the only four stroke engines i have rebuilt that ever had any sludge in them to speak of were car engines. i have never seen any crud in a bike engine that would warrant a flush. only time i ever flush a bike engine is to remove metal swarf.

[Spyder]

DON'T DO THIS ! ! ! !
You could be risking major problems, such as CLUTCH, OIL PRESSURE, SEALS, and EMBARRASSMENT.

Sludge occurs in car engines when you don't change the oil for ever. The viscosity of the oil breaks down and no longer lubricates. Then begins to burn, the byproduct of burnt oil is sludge.

I can't see this being a common thing in a bike. the rings would gum up and lose compression. Change your oil regularly and stop thinking so hard.
No such thing as bottled "Run Perfect".

[twistedwankel]

No experience with a crank case full of diesel and personally I wouldn't try it.
long ago we use to mix 1 quart of no.1 fuel oil with 4 quarts of engine oil in our cars to thin out the oil in very cold weather, in order to allow the engines to crank easier at low temps. it never hurt the engines we did it on.
I imagine a small amount would help clean a engine.

In the late 50's my dad's respected mechanic/buddy told him to put one quart kerosene in place of one quart oil to avoid having to change to "winter" oil every season up north. Back then there was no multigrade only 30W or 20W season to season. Also note that there were a number of non-detergent oils too and paraphyne wax was a common additive to non pennsylvania crude. Oil was cheap tho'. So go figure the logic? Oh yeah cars were cheap used too!!

That said: One day after this "cost saving method", the old chevy 6 developed a serious rod knock. Obviously it was a bad idea for continuous use under actual driving conditions. Those old babbet bearings were easily wiped (melted) but also fairly easy to replace or scrape and reuse. Not like today's engines that are marvels of engineering and metalurgical science.

With todays fantastic lubricants and an ounce of sense in changing the life blood of the engine and transmission - in a bike's case. Why would anyone try to cut corners to save a buck? How far can you walk?

If the engine/trans is so messed up to require magical flushes I guess it doesn't matter as it's not reliable anyhow and you need a complete rebuild involving a thorough cleaning piece by piece.

1. I do know that certain products are able to swell neoprene so can temporarily slow/stop a drippy seal prior to tradein.

2. I do know that certain products contain ketones/solvents (that evaporate) are temporarily effective in dissolving sludge out of a sticky hydraulic lifter before tradein.

3. I do know that a couple ounces of SeaFoam in a bike's crankcase at warm idle for a short period can improve worn/old clutch performance and make the oil dirtier than you've ever imagined only one time after 28 years and 34K miles. So far I haven't had any reason to do it again or tradein the bike either so maybe that is okay as a last resort prior to new clutch springs or spacers?

[fast pom]

Dont even think of doing this at best you will contaminate the clutch plates . There is a huge differance in a motorcycle engine to some old clunker of a car. The best thing to do is drop the sump off clean / clean the filter on the oil pick up job done,

[cbxchris]

Yamaha actually had a out a engine flush a few years back. It works.