feliks Posted January 13, 2014 Posted January 13, 2014 Whether tis nobler to get new rings and a new hone, or whether tis good enough to use piston rings and cylinders that were just done in September? Should I get a hone job, and new rings, or should I just install these as is? They're out of my parts engine, the guy who sold it to me said they were just done in September...and I trust his word, so I'm thinking I save myself $200 in new rings and just use these! What do you think? Discuss. Untitled by feliks.ca, on Flickr Untitled by feliks.ca, on Flickr Untitled by feliks.ca, on Flickr Untitled by feliks.ca, on Flickr Untitled by feliks.ca, on Flickr Untitled by feliks.ca, on Flickr Untitled by feliks.ca, on Flickr Untitled by feliks.ca, on Flickr Untitled by feliks.ca, on Flickr
Moderator DirtyDT Posted January 13, 2014 Moderator Posted January 13, 2014 Hard to tell from the pictures but it does look like you can see some old honing marks. I wouldnt hone unless i had all the equipment to hand.
slice Posted January 13, 2014 Posted January 13, 2014 They look ok Feliks, as above hard to tell but is there a LARGE lip at the top of the barrels or just a small lip? Are the pistons upsized? cos that might give you some idea about what has been done over the years to the engine. You could try the old fashioned "wiggle" test, just shove the pistons in the barrels and see how much wiggle room there is and if it slops about then you need to hone it or even rebore, but as I said they look ok in the photos, no major scoring, there's some, but nothing huge and there is always some scoring just from normal use. Best to leave it alone really if it all seems tight and your happy with the fit. Might be an idea to run it with some upper cylinder lubricant (REDEX) when you first fill it with fuel just to give it a bit of help. Best of luck with it tho.
Moderator DirtyDT Posted January 13, 2014 Moderator Posted January 13, 2014 I would be careful with redex. It clears any residue film and can lead to rings letting oil past them making the engine smoky.
Moderator Cynic Posted January 13, 2014 Moderator Posted January 13, 2014 All the specs are out there, just get busy with the measure. The pistons are marked and good engines dont generate that much carbon build up. Hell 2strokes dont cake like that. If someone stripped and honed it in sept any concientus mech or diy man would have cleaned the piston crowns. Measure twice spend once....
Moderator drewpy Posted January 13, 2014 Moderator Posted January 13, 2014 can i see pocked holes on the bores or is that a dirty lens? I can't see any honing meself, best way is to measure and check gaps
feliks Posted January 13, 2014 Author Posted January 13, 2014 Thanks for the input gentlemen! Checked end gaps on the rings and they're all well within spec - much closer than my old engine was - the ring gap was right at the limit on that engine, this one is well within the limit. I was leaning towards using this set, just wanted some reassurance that it wasn't a horrible idea.
feliks Posted January 13, 2014 Author Posted January 13, 2014 They look ok Feliks, as above hard to tell but is there a LARGE lip at the top of the barrels or just a small lip? Are the pistons upsized? cos that might give you some idea about what has been done over the years to the engine. You could try the old fashioned "wiggle" test, just shove the pistons in the barrels and see how much wiggle room there is and if it slops about then you need to hone it or even rebore, but as I said they look ok in the photos, no major scoring, there's some, but nothing huge and there is always some scoring just from normal use. Best to leave it alone really if it all seems tight and your happy with the fit. Might be an idea to run it with some upper cylinder lubricant (REDEX) when you first fill it with fuel just to give it a bit of help. Best of luck with it tho. What's large and what's small? It's about half a 5mm lip at the top which shows carbon buildup (where the rings don't slide I assume?)
slice Posted January 13, 2014 Posted January 13, 2014 That is pretty small really, not something I think you need to worry about, like most things mechanical you need a bit of space for the thing to actually work without binding up, your right the rings only go so far up the barrel so there will always be a lip of some kind on a used engine. As Drewpy says there are a few marks on the actual barrel in some of your photos, might be an idea to just check that there is no damage before you rebuild it and bung it in the bike frame. Other than that it looks like a good one.
georgen Posted January 13, 2014 Posted January 13, 2014 I am pretty sure those bores have not being honed within the last 5 months, honing de-polishes and puts very small and very fine cross hatching marks in the bores to allow the new rings to wear into the shape of the bore and have a true contact point as there never completely true, I also agree with earlier comment about the amount of carbon and in that short time would not have that lip buildup at top of bores. If as you say rings end gap is well within spec I would be tempted to run a hone tool through those bores to clean them up, you can buy them off ebay cheap enough.
feliks Posted January 13, 2014 Author Posted January 13, 2014 Would honing it be beneficial at all or would it just remove cosmetic crud up top that won't affect detonation? I've heard excess carbon can heat up and cause pre-ignition but it's not bad enough for that... What do you think?? Need a better pic of it to decide? Appreciate all the input!!
Moderator drewpy Posted January 13, 2014 Moderator Posted January 13, 2014 honing keeps the oil in the bores for longer, thus it increases reliability. it also "cuts" the rings into the bore increasing compression as georgen says
feliks Posted January 13, 2014 Author Posted January 13, 2014 But if I'm not replacing rings, and reusing the same pistons and rings that match the cylinders....is it still necessary? I know I would want to if I was replacing rings...
Moderator drewpy Posted January 14, 2014 Moderator Posted January 14, 2014 you didn't say if those holes we saw were lens shite or bore shite
dt502001 Posted January 15, 2014 Posted January 15, 2014 Got to agree with the Drewps ( hold on here aren't you supposed to be building something? Drew How you type with working hands ) Compare your fresh hone up to this newer 1...up and down scratches will = oil burner
Moderator drewpy Posted January 15, 2014 Moderator Posted January 15, 2014 that something is more or less done I need light to fit the engine and electrics as its at home
feliks Posted January 15, 2014 Author Posted January 15, 2014 you didn't say if those holes we saw were lens shite or bore shite Not holes...but at the bottom of the cylinder you can see the hone marks from the last time they were done... may give them a light dusting in there anyway just to be sure I've got the imperfections out of the cylinder walls! Ok thanks for the advice guys.
Recommended Posts