Topic: synthetic versus standard

[grcamna2]

I don't want to start 'an oil thread'   
I just have a question;
When using standard oil versus synthetic oil.
I normally run standard 'Dino-oil' usually Rotella 15/40 T4 is my go-to.
I ran some Castrol Actevo 10/40 and have leaks here and there;I've always known that about synthetics:it brings-out the leaks.
I'm considering just stop using any synthetic because of this.
Have any of you done that and still experienced leaks with the standard 'Dino-oil' after running synthetics and then giving-up on it ? I have just now(after 350 miles)noticed the leaks here and there;nothing major.
I'm still running the synthetic presently,I haven't switched-back to Dino yet.
                                                                         thanks,Bill

[BomberMann650]

My fj would deplete itself of even "the best" synthetic oils.  Wether that was through high temperature or aging valve seals, it still sucked.  Running Lucas 10710 now.   

[TwoTired]

Synthetic creeps into places standard oils can't due to smaller molecules.  However, the additive package is really the determining factor.  It should have chemicals that soften the seals, so they seal better.  Not sure this is true of all synthetics, or brands.   Some have claimed that the switch made seals leak, for a while.  But with time, the chemicals that soften seals eventually did their job and it stopped leaking.  However, if the seals have been heated and aged for 40-50 years, they may be beyond softening,  ... or it may take a while.  I know that Honda HP-4 didn't make my 550's leak.  Well, except the oil seals in the head.  But, they weep a little regardless of the oil selection.  It's just not bad enough to take the engine apart just for that.

Cheers,

[grcamna2]

Synthetic creeps into places standard oils can't due to smaller molecules.  However, the additive package is really the determining factor.  It should have chemicals that soften the seals, so they seal better.  Not sure this is true of all synthetics, or brands.   Some have claimed that the switch made seals leak, for a while.  But with time, the chemicals that soften seals eventually did their job and it stopped leaking.  However, if the seals have been heated and aged for 40-50 years, they may be beyond softening,  ... or it may take a while.  I know that Honda HP-4 didn't make my 550's leak.  Well, except the oil seals in the head.  But, they weep a little regardless of the oil selection.  It's just not bad enough to take the engine apart just for that.

Cheers,

Thanks TT 

[HondaMan]

I don't want to start 'an oil thread'   
I just have a question;
When using standard oil versus synthetic oil.
I normally run standard 'Dino-oil' usually Rotella 15/40 T4 is my go-to.
I ran some Castrol Actevo 10/40 and have leaks here and there;I've always known that about synthetics:it brings-out the leaks.
I'm considering just stop using any synthetic because of this.
Have any of you done that and still experienced leaks with the standard 'Dino-oil' after running synthetics and then giving-up on it ? I have just now(after 350 miles)noticed the leaks here and there;nothing major.
                                                                         thanks,Bill

Yes, on my 750. I used the Valvoline synthetic 20w50 bike oil once in 2010 or 2011. In the 12 miles I rode to work, I could not shift gears very easily after the first 8 miles, and by the time I got home (24 miles) it felt like the gearbox was seizing! The gaskets on the clutch and tranny covers were already weeping, too. I changed the oil immediately (to Bel Ray EXL Mineral 20w50) and rode out 3 miles, which "fixed" the tranny again, but it took almost 500 miles before the gaskets quit weeping.

This was in hot, 100-degree Colorado summer days.

[Shtonecb500]

I run regular castrol motor oil, I have never run synthetic in my bike and not had is piss oil on me.

[Trevor from Warragul]

Last year I put expensive Penrite fully synthetic in my CBX.  When the weather got colder, the starter clutch started slipping really badly at every start.  Changed the oil for Penrite mineral, and the problem (mostly) went away.

[jlh3rd]

I have a 75 550F that i tried to run synthetic in back when it was ridden 1994-1998. It began seeping from the head gasket. I went back to standard 10w-40 rotella, and it quit seeping.
   I had similar problems with a 1987 Chevy Monte Carlo SS., unfortunately, as I'm a synthetic supporter.

[grcamna2]

I drained all the Castrol Actevo 10/40 semi-synthetic from my hot engine,as much as would drip out and refilled it with Rotella T4 15/40 and have driven it 75 miles since removing the synthetic oil.The bike is an 81' Honda CB125S with an XR185 engine installed and it has a vertically split crankcase plus I've removed my right side clutch cover and re-used that Vesrah gasket 3 times.I imagine if I replaced all gaskets with fresh ones,it wouldn't have leaked that much.. I normally run the bike on the right lane of I80 @ 65-70 mph which works-out to between 6800-7250 rpm(redline is 9500)or faster to pass some cars:it'll do a solid 90 mph flat-out,but I prefer slower speeds as it's light and gets blown-around.I also ride it around in-town at slower speeds.The oem Honda seals have all been replaced 8000 miles ago and they were lightly 'misting' during the 350 miles running the synthetic 10/40.I was surprised that even my oil filter/strainer-drain plug cover with the large rubber o-ring had been dripping with the synthetic.My oil leaks have cleared-up now by about 90%.This engine holds about 1.25 qts when completely drained.I like the Rotella 15/40 T4 and it'll be what i continue to run.

[74cb750]

Synthetic creeps into places standard oils can't due to smaller molecules.  However, the additive package is really the determining factor.  It should have chemicals that soften the seals, so they seal better.  Not sure this is true of all synthetics, or brands.   Some have claimed that the switch made seals leak, for a while.  But with time, the chemicals that soften seals eventually did their job and it stopped leaking.  However, if the seals have been heated and aged for 40-50 years, they may be beyond softening,  ... or it may take a while.  I know that Honda HP-4 didn't make my 550's leak.  Well, except the oil seals in the head.  But, they weep a little regardless of the oil selection.  It's just not bad enough to take the engine apart just for that.

Cheers,

My former CB550, which I gave to my son, Also leaks at the head even after installing new gaskets. Are  you saying it's not worth bothering about?
michel

[grcamna2]

I have some Lucas full synthetic 10-40 wt which is formulated for wet clutches Jaso MA-2.I've had good results with Lucas synthetic in the past on other bikes.I don't see what it could hurt adding the Lucas synthetic as 20% of the(mix)oil volume with the Rotella T4 15/40 wt.I think it may have just the right additive package with one of the selling features listed as "less noise,fewer leaks".I may just run the Lucas Synthetic outright as these old gaskets in the engine are in need of replacement anyway,give it a try.

edit:To be fair,the gasket that's leaking the most(clutch cover)and the tachometer seal where the cable hooks-up to the spinning tach cable pinion had issues previously and needed replacement.The oil screen/drain which is the same as the 24mm hex-head tappet cover that's on the bottom of this engine with large o-ring was what surprised me.I imagine it takes synthetic oil to 'find' the small leaks and cause them to grow..  I know there are some benefits to running certain synthetic brands.

[TwoTired]

My former CB550, which I gave to my son, Also leaks at the head even after installing new gaskets. Are  you saying it's not worth bothering about?
michel

I have 550s that have been weeping for years.  Just have to wipe it off once a week (if ridden regularly).  But, if it ever gets bad enough to foul clothing, then it is worth doing the repair, IMO.

Hondaman says that recent head gaskets are thicker than originals.  And, he has thicker o rings to help keep them from leaking.

Cheers,