tortron Posted November 3, 2020 Author Share Posted November 3, 2020 a new engine has all the gears and bearings wearing in yes you dont repeat the whole process for new rings and pistons. no one does an additional 1000km break in process Quote Link to comment Share on other sites More sharing options...
Guypie Posted November 3, 2020 Share Posted November 3, 2020 A wise man named @Geophy once told me the break in process for a new lifan 125 is a 4th gear burnout. Pretty sure the man is a mechanical genius. 4 Quote Link to comment Share on other sites More sharing options...
Raizer Posted November 3, 2020 Share Posted November 3, 2020 Just now, Guypie said: A wise man named @Geophy once told me the break in process for a new lifan 125 is a 4th gear burnout. Pretty sure the man is a mechanical genius. Yeah you have to do that, it's the only way to get enough oil flow to wash out the large amount of swarf they come packed with for shipping. 7 Quote Link to comment Share on other sites More sharing options...
SOHC Posted November 3, 2020 Share Posted November 3, 2020 54 minutes ago, tortron said: a new engine has all the gears and bearings wearing in yes you dont repeat the whole process for new rings and pistons. no one does an additional 1000km break in process No but piston and rings still need to bed in over 150 kms or so, just keep doing what your doing it seems to be working well for you Quote Link to comment Share on other sites More sharing options...
tortron Posted November 3, 2020 Author Share Posted November 3, 2020 piston manufactures dont agree http://blog.wiseco.com/proper-engine-break-in-after-a-rebuild but they are in the business of selling pistons 2 Quote Link to comment Share on other sites More sharing options...
tortron Posted November 3, 2020 Author Share Posted November 3, 2020 anyways, i ran the piston over a stone, dingleballed the cylinderactually measured the cylinder and piston by digging out my dusty bore gaugesand its now slighlty over the minimum clearance, so its self clearanced nicely (gn125 clearance being 0.03-0.051 to 0.12 max dr200 being 0.04-0.05 to 0.12 max) i measure 0.055 going to chuck it back in and go do some 11000rpm shifts 3 Quote Link to comment Share on other sites More sharing options...
SOHC Posted November 3, 2020 Share Posted November 3, 2020 24 minutes ago, tortron said: piston manufactures dont agree http://blog.wiseco.com/proper-engine-break-in-after-a-rebuild but they are in the business of selling pistons I cannot see anywhere where it says hold the engine on the maximum RPM it can possabley do 1 Quote Link to comment Share on other sites More sharing options...
tortron Posted November 3, 2020 Author Share Posted November 3, 2020 Even the owners manual says don't exceed 10000 rpm When did I exceed 10000 rpm Itl be doing 115+ in 5th to do that It says drive as normal 1 Quote Link to comment Share on other sites More sharing options...
flyingbrick Posted November 3, 2020 Share Posted November 3, 2020 Yeah there's two trains of thought, one is the old school slow break in method, the other is GIVE IT Heaps so that the rings wear in properly before the cross hatching has gone. Most people who know anything now seem to go with the GIVE IT Heaps method. Anyway, richen it up a bit to keep things cooler maybe? 1 Quote Link to comment Share on other sites More sharing options...
tortron Posted November 3, 2020 Author Share Posted November 3, 2020 12.5 is rich enough id say Quote Link to comment Share on other sites More sharing options...
Raizer Posted November 3, 2020 Share Posted November 3, 2020 Couple idle heat cycles, retourqe head, send it. /I easy for a bit if I've got a new clutch to bed in. Quote Link to comment Share on other sites More sharing options...
tortron Posted November 3, 2020 Author Share Posted November 3, 2020 Whats the break in procedure for a used piston and several used rings from different engines? lerl 1 Quote Link to comment Share on other sites More sharing options...
Popular Post GuyWithAviators Posted November 3, 2020 Popular Post Share Posted November 3, 2020 8 minutes ago, tortron said: Whats the break in procedure for a used piston and several used rings from different engines? lerl You don’t want any air flow for this scenario so park it against the shed wall, put into 3rd gear and rip it lil Jonny until the exhaust glows red. rings are now bed in 10 Quote Link to comment Share on other sites More sharing options...
SOHC Posted November 3, 2020 Share Posted November 3, 2020 Some pistons need measuring at the bottom of the skirt and some just below the bottom ring for piston to bore clearance. If it was was me I wouldn’t rev that little bike so hard at all Quote Link to comment Share on other sites More sharing options...
tortron Posted November 3, 2020 Author Share Posted November 3, 2020 how much jandle do you think dr125s get small engines are 100% about having lots of revs 2 Quote Link to comment Share on other sites More sharing options...
Tumeke Posted November 3, 2020 Share Posted November 3, 2020 Unscientific un-closed road tests suggest you need a Lifan 125. Seems about even match with a GN250 until 80km/h with my current jetting setup. 1 Quote Link to comment Share on other sites More sharing options...
SOHC Posted November 3, 2020 Share Posted November 3, 2020 I just remember those cbr250 and fzr250 gsxr250 would sometime be totaly fucked after under 20,000 kms. When I was doing my apprenticeship my job was to put the 1st 5 kms on the new bikes and I was threatened with death if I blew them up 1 Quote Link to comment Share on other sites More sharing options...
tortron Posted November 3, 2020 Author Share Posted November 3, 2020 and a gn doesnt typically even make 20000km 1 1 Quote Link to comment Share on other sites More sharing options...
Guypie Posted November 4, 2020 Share Posted November 4, 2020 1 hour ago, SOHC said: I just remember those cbr250 and fzr250 gsxr250 would sometime be totaly fucked after under 20,000 kms. When I was doing my apprenticeship my job was to put the 1st 5 kms on the new bikes and I was threatened with death if I blew them up Its not about rpm so much as piston speed. 4age @8000rpm -616,000mm/min GN125 @11000rpm -536,800mm/min CBR250 @18000rpm -608,400mm/min the slowest revving engine of those 3 has the highest piston speed. Also spends the lease amount of time doing that speed in all fairness. Bearings and whatnot are a different story but I really don't think the revs are going to hurt the gn Quote Link to comment Share on other sites More sharing options...
tortron Posted November 4, 2020 Author Share Posted November 4, 2020 tou gotta put conrod length in there too but forget all that and look at the engine being in dirt bikes, the redline being 10000rpm doing 10000rpm is fine, itl do it all day long. Infact i have several times as a 125 and its the piston and bore is fine 1 Quote Link to comment Share on other sites More sharing options...
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