Does anyone know the diff between 3LN3 and 3LN6 pistons (p/n 3ln-11631 has suffixes -01 and -02)? I can't measure any, and having no idea how to get the gudgeon pin clips out, would like to leave the 3LN3 bottom end when I drop the LN6 head on.
Nice article on EngineBuilderMag about bearings, clearances and honing. https://www.enginebuildermag.com/20..._campaign=Tight+Tolerances+and+Building+Power
That's a great article. In case anyone is wondering, they show a picture of two guys and mention one of them is Greg Anderson. The below pic points out which one he is. You can use the following link to appreciate what Greg knows about engines. Greg has won 3 Pro stock championships as a crew chief and 5 as a driver. Good post Blair. https://www.nhra.com/drivers/greg-anderson/871
Hey @maelstrom What would you advise for running-in new rings, if you also need to (likely) balance carbies? Following new rings and valve clearances, I'm assuming the carburettors need to be balanced again, or would there not be enough load during balancing to really affect the rings? If it runs, just send it and balance after, or balance to get them perfect first? Also, the original link around mineral/synthetic oil doesn't work anymore, so do we think synthetic is Ok for running in (say a ZXR250C), or should mineral or semi-synthetic be a better choice? Or a dedicated 'break-in' or 'running-in' oil? (Penrite 10-Tenths for example) Cheers! Dano
Hi Dano, After new rings, I would not try to synch the carbs or set the mixture screws until I had completed the "running in" steps I mentioned at the beginning of this article. Your pilot mixture screw settings will change if compression changes. More compression means you need to lean them (turn in). As you adjust them you are also changing engine speed so you have to check the synch again etc etc. If it is taking too long then quit, let it cool down and try again. Finally, I am not wading into the running in oil debate.
Ok so, if the bike will not run due to incorrect syncing, then can we run the bike enough to try and sync quickly, but only for short bursts so to stop the engine getting too warm? Am I correct in saying that the running-in (good) or glazing (bad) both require the engine to be hot to occur? I had a feeling this might be the response for the oil debate haha!
Gee, how bad can it be? If you have overhauled the carbs and changed everything then just do a bench synch.
With a pin, needle or a very small drill bit you can bench sync them, then put all idle air screws to the same number of turns out - that should get you into the ballpark to be able to run it in properly.