kevincurtis Posted March 13, 2012 Report Posted March 13, 2012 Hey guys, I've been trying to figure out an issue i had with my shee since my last disassembly, I had taken a trip with my bud a few months ago and ran into some tranny problems so i had to split the case, and during that what i found when i took the head off was one piston in very rough shape. looked to be like very bad detonation, but where im confused is my compression was only about 110, and im running pump gas 91 octane (so i believe) i live in New Brunswick, Canada, and i am at sea level. The highest point of elevation in my town is (102 ft). Could this be a timing issue ? I'm running the Dyna-tek CDI ignition, just recently installed the dyna-tek coil shortly before dissasembly And i did have the 200 watt ricky stator but that had failed on me one night and i had drove home with it back firing quite heavily, for a few kms to get home at a low rpm and speed and i replaced that with the OEM stator because i seem to here nothing good about ricky stator here on hq, im at a state of wonder, never dealt with detonation before any info would greatly be appreciated.. I'lll add a attachment picture of the piston below. I'll be re-assembling my shee come this spring, i have a .40 vitos forged super stock piston kit to go along with my 4mm / long rod crank that i previously ran. And i have a pro-design cool head with 21cc domes and also 22cc,, would appreciate any info on wich dome size i should use with the elevation and octane i've providided, just at a jam or mind fuck you could call it, i want to do it right and have the correct knoweldge and avoid that from happening again HQ is the place to do just so Quote
Ieat4strokes Posted March 13, 2012 Report Posted March 13, 2012 The 21cc domes at your elevation should net u around 140 ish. That's what I netted at 100-300ft elevation on my old motor on a fresh build. Which your octane and +4 timing should be fine bro. Need to do a compression check with the 21cc in so we can know better Quote
Larry's Shee Posted March 14, 2012 Report Posted March 14, 2012 Did you do leak down before tearing it apart? Was coolant level good? Did all these issues start at same time? Trans and back fire? Which piston was it? Sure the rod on that side is good? One other area of concern. Are you sure the Vito's SS pistons are compatible with the long rod crank? Quote
EvilBanshee Posted March 14, 2012 Report Posted March 14, 2012 Could be a leak, could be poor fuel. YOu have plenty of octane for your elevation and compression. How old is the engine? Have you checked your squish? Quote
WINDYCITYJOHN400 Posted March 14, 2012 Report Posted March 14, 2012 Did you do leak down before tearing it apart? Was coolant level good? Did all these issues start at same time? Trans and back fire? Which piston was it? Sure the rod on that side is good? One other area of concern. Are you sure the Vito's SS pistons are compatible with the long rod crank? Good point there. I'm a fan of the SS pistons for basic power gains on a budget. But I don't think they make them for the long rod motor. With the long rod motor you run a blaster piston that has a different pin height. I'm pretty sure you would have to run a spacer plate with your combo........ Quote
kevincurtis Posted March 14, 2012 Author Report Posted March 14, 2012 Did you do leak down before tearing it apart? Was coolant level good? Did all these issues start at same time? Trans and back fire? Which piston was it? Sure the rod on that side is good? One other area of concern. Are you sure the Vito's SS pistons are compatible with the long rod crank? I never leaked any coolant, and my oil level was good when i checked, the issues never started at the same time my stator went bad and was back firing a few months prior than my tranny inncident, one of the gears seased on the shaft making me not able to go out of neutral, it was a long drive so i think maybe i ran low on oil.., it was the magneto side piston, i inspected the rod and seems fine to me, but i did have a bad outer crank bearing on the magneto side, all the balls fell out when i took it out, i bought a replacement bearing from vito's, and i did have trouble with magnetos breaking ?? 2 actually. they cracked in the middle, but the second time i think it was due two a improperly installed key.. could my crank not be trued correctly ? hope i dont have crank issues.. i plan on using it again. Quote
kevincurtis Posted March 14, 2012 Author Report Posted March 14, 2012 Could be a leak, could be poor fuel. YOu have plenty of octane for your elevation and compression. How old is the engine? Have you checked your squish? my engine is about 5 years old but it sat in a barn for that period, the crank was new, i bought it off a buddy and he had scuffed a piston with the 404/421, and parked it right after for all that time. and i bought it off him and rebuilt it with .20 over jugs, ran great all summer until towards the end,, started cutting out on topend with the dyna-tek igniton, i put my stock cdi on and the cut out at higher revs went away, so i thought it was the dyna so i bought a new one and it did the same thing, than i advanced my time manually with my adjustable stator plate and it did the same thing, so i put my stock cdi with timing at zero and ran it like that till my disassebly,, what would cause this ? Quote
kevincurtis Posted March 14, 2012 Author Report Posted March 14, 2012 Good point there. I'm a fan of the SS pistons for basic power gains on a budget. But I don't think they make them for the long rod motor. With the long rod motor you run a blaster piston that has a different pin height. I'm pretty sure you would have to run a spacer plate with your combo........ ya i have a spacer plate for my combo, so ill have no issue with pin height Quote
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