New piston/rings dry break-in or not?

7 replies to this topic
  • nwbikerider

Posted April 20, 2012 - 11:38 PM


I've searched the break-in threads and most are like oil threads. Slow and easy, fast and hard, one heat cycle, or three... take your pick. But I couldn't find anything on whether to break-in the rings dry, or coat the piston and cylinder with oil. Manual is vague and says "oil on pin and piston.." but I've also read about dry starting it, letting the hatch seat the rings, and the oil will spread to the rings and cylinder wall within a few seconds of startup. The rest of the top end is fairly typical, moly lube on the valve stems and cams, oil on the buckets. What are the thoughts of you who have tried both?

  • RiderX

Posted April 21, 2012 - 06:10 AM


I have always coated the piston, cylinder and rings with oil and have had no problems with the rings seating. I've never tried it dry though.

  • highmarker

Posted April 21, 2012 - 06:41 AM


dry, in contrast to slobbering wet. not dry dry, I like the gaskets and gasket surfaces to be dry dry, But the bore and rings I wipe down with a little light oil (twostroke oil) on a rag, just lightly though don't want drips contaminating the gasket surface,

In order for the ring motion to function properly in their groove they have to be able to move, I've never been comfortable with them dry dry on start up.

cam prelube type stuff isn't needed imo, these motors have such light valve springs, oil is fine, DONT use moly that is designed as an antiseize, it's abrasive.

  • grayracer513

Posted April 21, 2012 - 08:52 AM


This is one of those endless debates, with credible people supporting both sides of the argument.

dry, in contrast to slobbering wet. not dry dry,

This is where I come down. I will not assemble any part of an engine without pre-lubing it, and that includes the piston and rings. I don't dunk them in a bucket of oil, though, either. I rub a film of my usual engine oil onto the contact surfaces and assemble them. I haven't had an engine that I built that used a detectable amount of oil, or failed to seat the rings in so long that I honestly can't recall it ever having happened.

When you think about it, the engine might run for 2 or 3 or even 5 seconds before oil gets to the cylinder. Why would you expose any part of it to that? My method works for me, and I can prove it. I'm not going to change.

Engine oil is fine for the cams as well.

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  • StoneRacer

Posted April 21, 2012 - 08:58 AM


From JE Pistons , JE recommends a light coat of assembly oil (marvel mystery oil or similar) on the pistons' skirt , rings, and cylinder walls for initial installation and start up. No synthietic oil until rings have seated. Be sure to thoroughly lubricate wrist pins and piston pin bores with an assembly oil .

  • grayracer513

Posted April 21, 2012 - 09:02 AM


No synthietic oil until rings have seated.

Sorry, more BS. I've used nothing but my everyday synthetics in every engine I've built for more than 25 years without one single problem. There is no logical reason not to use them. An exception to that may be friction modified API ECII oils, but you shouldn't be using those in a motorcycle anyway.

  • Octanee

Posted April 21, 2012 - 05:01 PM


i find it so funny that they try to give some bs about synthetic, trying to say its another oil, or like "once you go synthetic you cant go back" i've heard that alot, then you find semi synthetic mixes all over, they do mix.. and in truth are not so different on a lubrication scale just synthetic lasts longer
the oil is, well oil.... but synthetic is better in the sense its man made, it dont break down as easy as mineral oil does, it lasts longer and keeps its viscocity much better, all around synthetic takes alot more abuse then mineral will

always pre-lube the parts, as said they dont get oil right away and will be dry for a while, and as far as rings seating... 0 issues here between 6 dirtbikes, 4 snowmobiles, and rebuilds total probably 16-18, (preventative maintenance of course)

Edited by Octanee, April 21, 2012 - 05:03 PM.

  • highmarker

Posted April 21, 2012 - 07:44 PM


most of the "don't break it on synthetic" came early on in marketing the syn. The statement was marketing gimmick to implie t the consumer "the oil is SO good that new motors won't break in on it. It somehow implied that your motor would last forever.

The documented problem that were real had to do with the base oil, mainly isolated PAO IF there was blowby before the rings seated, would leave a tenacious glaze that was not only hard to remove, but could cause poor or slow ring seating. It had nothing to do with the oil being slippery or superior in lubrication as inplied by the marketeers.

Since syn oils do not disclose base oil formulation, and aren't labeled, The safe generic advice was to avoid them during break in.

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