Had an issue with a fresh x30 running standard HW27 sticking after break in. After talking to Greg Wright who is very very familiar with karting 2 strokes he was wondering why the recommended settings are a more open HIGH needle than LOW. Recommended starting settings from IAME are (depending on which manual you follow…) about 1 Turn on the LOW needle, 1 Turn and 3/5 one the HIGH needle. I ran something close to these settings fine for a year, then had a stick after breaking in with slightly more conservative (ie richer) settings.
However, most of the time with Leopards, KT100s, and other 2 strokes, the common setting is a more open LOW needle than HIGH. Is there something inherently different about the HW27 that does not allow this sort of configuration?
Mind you, I’m not sure the stick was caused by needle settings as there are a myriad of other factors… I’ve ruled out almost everything but an air leak or perhaps an obstruction in the carb, so I’ve cleaned it and added sealant to reed cage gaskets. During stick water temp was 125f, carb had fresh rebuild, 11psi popoff, fulcrum arm level, elf 909 at 7oz per gallon on 93 octane pump gas, piston to bore clearance of 0.052", reeds in good shape, no detonation noted on piston or head afterwards. I do not have an EGT and currently looking for a 2t gauge so I can have it.
I don’t have an engine builder, but Greg Wright at Rapid Racing does the cylinder bore/piston fit for me, and he’s thinking these settings are weird and recommending a much richer LOW and thus leaner HIGH.
Please educate me. Thanks!