mike0chek Posted August 30, 2015 Report Posted August 30, 2015 so you can see my mods below, what is a safe amount of timiing to run with my setup running on 93oct? i have a slight hesitation really early in the first few gears and i know the drag ported cyls are not very strong down low but could a few more degrees timing help fix that? or if +4 timing the max i should go on 93oct? Quote
sleeper06 Posted August 31, 2015 Report Posted August 31, 2015 Depending on dome configuration and set up I wouldn't even run +4 , I've seen them detonate at @+4 , backed it down to +1 and it was fine. IMO work it out with needle selection and jetting or use better fuel pump fuel sucks Quote
sleeper06 Posted August 31, 2015 Report Posted August 31, 2015 What's your uccr& static compression , is it ported Quote
mike0chek Posted August 31, 2015 Author Report Posted August 31, 2015 drag ported, +3 timing, i dont think the fuel is the problem, its a very slight hesitation. im running a drag engine for trail use so it will be hard to fond the happy medium. what are you pump fuel guys running for timing? Quote
sleeper06 Posted August 31, 2015 Report Posted August 31, 2015 I don't think it's your timing, if your trying to get rid of a hesitation with timing I think your in dangerous waters on pump fuel . Do you know your done characteristics, compression? What pipes and carbs are you using? I've built many Cubs and even a few on pump and never had an issue even tho i would never recommend pump fuel on a cub. I've never ran more than +2 on the plate I think you'll gain more from needle selection Quote
mike0chek Posted August 31, 2015 Author Report Posted August 31, 2015 comp is 145 both sides which is the compression i had the day i built the motor, been a few years since the top end has been apart so cant remember dome cc's. kevin helped me pick domes at the time and he knew i was always going to run pump. Quote
mike0chek Posted August 31, 2015 Author Report Posted August 31, 2015 sb shearer inframes, 35mm carbs with oversized bowls. i can live with the very small hesitation. bottom line i guess is i want to know is running more timing than i am now dangeous on pump fuel? years ago i ran a shee with just bolt on mods nothing internal with +5 timing on pump and the motor ran great for two summers until it lost compression so installed a 4mil Quote
sleeper06 Posted September 1, 2015 Report Posted September 1, 2015 Do u know how to read the timing marks on the ground steap, are you using a cel needle, if so might wanna try a series needle taper it's longer than a c. With 35 s I liked the dek needle on the last two cubs I built send me your cell number I wanna send u a pic of some literature I have . And no I wouldn't run more timing unless the plugs tell me too Quote
mike0chek Posted September 1, 2015 Author Report Posted September 1, 2015 Do u know how to read the timing marks on the ground steap, are you using a cel needle, if so might wanna try a series needle taper it's longer than a c. With 35 s I liked the dek needle on the last two cubs I built send me your cell number I wanna send u a pic of some literature I have . And no I wouldn't run more timing unless the plugs tell me too no cell at the moment man but if you can some how pm that to me i would love to read it. if its too much of a pain that way i understand. Quote
mike0chek Posted September 1, 2015 Author Report Posted September 1, 2015 and i am running the cel's right now. Quote
mike0chek Posted September 1, 2015 Author Report Posted September 1, 2015 a cub and stock cylinder are not the same. i understand that, could you explain to me why a stock cyl can handle the higher timing compared to a cub? Quote
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