so after a complete top end rebuild (SE pistons and rings at .010, honed jugs, and headwork) ....all work was done by Don at Dewey's Heads

this isn't a thread bashing him, by the way...this is something I did

anyway, 2k after rebuild bike starts smoking white heavily on start up.... diminishes a bit after complete warm up, but still noticeable in proper light...clearly burning oil

so i tore it down...easy enough.....and i find that the jugs on both cylinders are seriously scored... pistons are the same way, in all same spots (front and rear of both pistons)

here's a pic of the pistons for an idea...not best pics...but trust me, they're scored

anyone got any thoughts?

 

so its a fresh bore and pistons? were the rings gaped for the cylinder? you have blowby past the rings and piston, looks like the rings are way over gaped, if the bore is out of round, if it is way over honed or if you have bad rings, it would do that too. it simulates a worn out engine.

the center ring in the third picture looks broken at the end. if it was put together with out gaping the rings, that will score up the cylinder, and break the rings.that will in turn tear up he pistons. only fix is an oversize bore and new pistons.unless the cylinder scoring isn't that bad and can be honed out..

if your sure everything was bored and assembled rite, the engine ran with out oil.. better make sure the oil pump is lined up and working rite, and the passages are clean...

the head work has nothing to do with this, so you can rule that out.

 

the way it looks to me is a possible issue with cyl wall prep and possibly dy assembly or not enough lube.How did you get the 10 thos out???If you just honed it you probably arent square and have a out of round and taper issue.I have done machine work for years and still cant get cyl fitment down like I want in smaller overbore sizes with the equipment I had.One thing is a lot of people bore th cyls out to final size then just put in a crosshatch with a hone.that leaves the actual boring marks and wipes stuff out





might of gotten a little lean to------------------

 

yah i figured the headwork had nothing to do with it, J1mmy

so it is a fresh bore and pistons... and indeed rings were gapped... I sent everything to Deweys and he took care of it all....even double checked when I got everything back

center ring isn't broken, just a lousy picture

and oil sump lined up?...how do you mean?.... i checked all passages, btw... everything is clear

also, was thinking.... i've taken engine down three times, before.... first time was to change cylinder base gaskets, everything was fine

second time was to change head gaskets to cometics, everything was fine

third time was to put in the hayden 'oil fix' jets....now, i'm wondering if that did it because when i put the jugs back on the case they were a very tight fit against those oil passage jets....had to tap jugs with a rubber mallet to get them down...and even then they weren't flush... depended on the head bolt torque to bring things down

so i'm thinking, maybe i was getting false torque readings and the jugs weren't sitting as flush against the case as they ought to have been and so went on a bit crooked? .... maybe that would do it?

 

yuck-------------------thats the rest of the story lol

 

After only 2,000 miles the scoring/wearing on the pistons seems to wrap quite a way around. You would expect it to be more localized to center of the piston perpendicular to the wrist pin.

I'd be suspecting the piston to wall clearance was a little too tight. Do you know what that clearance was? And what was the recommended clearance for your pistons?

 

...that's the first thing that came to mind...but before i installed the hayden jets, the jugs had no scoring on them at all... i always felt for it when i took heads off

can't remember numbers when i checked for ring gap clearance, but it was definitely within spec

i don't know....the only thing that comes to mind when i work backwards thinking about it all is that the jugs had to have gone on ****-eyed regardless of torque readings

i mean, is that possible? ....am i overthinking?

 

one of the things I see occasionally is they will fit the bore for the hyperetic(sp) and its to tight for forged.I usually fit my stuff sloppy loose and have more frequent builds on account of it.Piston to wall clearances have gotten way tighter over the years requiring a way better cyl wall prep with a finer crosshatch slicker wall.



did you crimp your little brass oil jets when you put the jugs on?the horrible mismatch sometimes isnt to kind to them and I dont use them anymore due to that.Aftermarket case have them but they are steel and I have never had a issue with them




as far as the jugs going on **** eyed its possible if the cases arent true

 

looks alittle like my TC pistons year before last. I purchased a set of Screamin Eagle Forged Hi-Comp pistons on ebay, in a box, with a ring set. The ring set puzzled me at first because there was no writing for ring orientation. This wasn't my first rodeo so I noticed the bevel on the compression rings and installed per a previous set. The rings never seated, the smoking got worse to the point of umping oil on a poker run. Tore it down and jsut happened to notice the rings as I was pulling them off the smoked pistons, they were like lead, dead soft and twisted like a pretzel. Can't confirm but, I believe the seller i purchased the piston set through had replaced the original rings with some low quality cheap set.

 

well, i rechecked piston to wall clearance and im coming up with around .001, which appears to be in spec with what the manual is telling me at .00055 to 00165

i'm guessing the SE pistons are same as stock because they're no specs on the SE installation sheet....only end gap and side clearance for rings