Engine Oil Flush - Wet Clutch

[Kris78]

So I have a bucket of Penrite Engine Oil flush:
https://www.penriteoil.com.au/products/engine-flush

I asked here if this stuff was appropriate for a wet clutch running in the same oil as the engine, and got a sort of indirect, 'yes, it is fine'....:
https://www.penriteoil.com.au/forum...wet clutch lubricated by engine oil/post/3387

Can anyone tell me more about what is in these engine oil flush treatments, and whether there is any wisdom in using it (at all) and whether it would be okay in a wet clutch application with lubrication via the engine oil?

Thanks!

 

[wpod]

I would first have to ask does the engine need flushing?

 

[Kris78]

I would first have to ask does the engine need flushing?

Without splitting the whole engine apart, the real answer is, it's hard to tell. It's now a 10 year old bike, and as far as I know, the oil that's in at has sat unused and unchanged for about the last three years or so. I figure flushing it would be erring on the side of caution, particularly since I'm not sure what oil was used during the last replacement.

 

[Oro_O]

As much as a fan I am of flushing oil where appropriate, this doesn't sound like that case.

Just because it sat isn't a compelling reason. Modern oils are not going to spontaneously decompose. Compelling reasons for a flush are things like running an OCI far, far too long, using an oil too long high in VIIs, high-mileage engines with known sensitivity to lube issues, etc.

That said, there's nothing in a conventional flush that should damage clutch plates in the slightest if you aren't loading them at the time. But it really isn't necessary here it sounds.

 

[wpod]

Just run a short oil change with the oil you are going to use.

 

[Kris78]

Righto, thanks guys.

 

[RDMgr]

Rather than an engine flush why not try one or two short intervals using a JASO MA/MA2 synthetic oil that contains ester? The ester should help flush out old oil and solubilize sludge. It won't do much for varnish.

 

[Ride_Red]

If you are worried that the old oil is 'bad', change it before you start it.
Pull the plug and drain the old oil. Change the oil filter. Fill with new oil.
Ride it around for 500 miles and change it again if you want, or not. I'm guessing that the oil will still be pretty clean and fresh.
I sometimes go two years on an oil change if my miles are low. The inside of my engine (where I can see) is still spotless.

 

[BusyLittleShop]

Mileage not additives are the observed cause of clutch slippage...

The holy trinity of science is 1)Reason 2)Observation 3)Experience...
employing those tools we observe that the primary cause clutch slip
are high mileage... mileage is the constant among all of the clutches
that begin to slip... oil choice whether JASO approved or not is not a
constant... High mileage is the constant where all clutches begin to
loose grip due to normal glazing and contaminates that build up over use...

 

[DGXR]

Personally I would never use an engine flush in a shared sump motorcycle. I would use it only as a last resort, just before splitting the cases to properly address the problem. Short oil change intervals is a much better approach. Run it with the new oil and get it good and hot a few times and then change it out. Of course a new filter too.

 

[Alain2]

The glazed over clutch in my 1977 Yamaha RD400 slipped when I would hit 3rd gear even with the best oil available. I filed the friction discs( dirty job), they still measured within specs and fixed the problem.

 

[RDMgr]

But the original question was not about a glazed clutch. It was about flushing old oil and potential oil residues from a common compartment. This is safely done with a JASO MA/MA2 oil with ester. The ester increases solvency to remove old oil and sludge. It won't touch varnish or glazing.

 

[BusyLittleShop]

The glazed over clutch in my 1977 Yamaha RD400 slipped when I would hit 3rd gear even with the best oil available. I filed the friction discs( dirty job), they still measured within specs and fixed the problem.

True... de-glazing clutch plates use to be part of every savvy rider's
maintenance plan and for some reason that all change during
the 90s... why fix what you can buy new is the what you hear
now a days... but if we invest in some good old sweat equity we
can fix our clutch bite good as new...

Inspect the friction plates for glazing... make sure you have plenty
of material to work with... your shop manual states clutch thickness
in thousands of an inch or mm...

First removed the contaminants with Acetone... pick a hard surface to lay
over a 600 grit black dry emery paper... rotate the clutch plate in a
circle... you're just busting the glaze... don't get carried away
remove too much material... You should end up with a friction plate
looks dull like a new one as opposed to a shinny glazed one... recheck
thickness...

Next check the pressure plates for bluing caused by localized heat...
make sure they are not warped... consult the manual for a thickness
range... now removed the contaminants with Acetone and wire wheeled
them to erased the blue and also to generally scuff up the surface...
you should end up with a dull surface free of Blue marks...

 

[BusyLittleShop]

But the original question was not about a glazed clutch. It was about flushing old oil and potential oil residues from a common compartment. This is safely done with a JASO MA/MA2 oil with ester. The ester increases solvency to remove old oil and sludge. It won't touch varnish or glazing.

True on both counts... however I wanted to highlight that mileage not chemicals are the observed truth of clutch slip...
RDMgr you are distinctly qualified to speak for the industry... Do you know of any chemical or additive that will defeat a new wet clutch???

 

[Kris78]

But the original question was not about a glazed clutch. It was about flushing old oil and potential oil residues from a common compartment. This is safely done with a JASO MA/MA2 oil with ester. The ester increases solvency to remove old oil and sludge. It won't touch varnish or glazing.

Thanks very much, I'll go with this as the oil I've bought is an ester based one anyway. Out of interest, would the percentage of ester particularly matter, does it need to be above a certain percentage concentration by weight or volume?

Helpful info from everyone else too, thanks. Clutch is currently not an issue, but I'll take a look at the plates during the next oil drain, as it's going to need to be reliable for a trip I'm preparing this bike for.