Sorry if the title is incorrect, please ask me and I'll change it to a more suitable title so it can be found ho help others, also sorry if this thread has been made already but I've looked and haven't come across it so I made this. I baught a gilera runner of a mate and its running to lean, the spark plug is very oily, it has a 70cc polini sport, standard pipe and 12 or 17.5mm carb ( not sure havent checked ) it has an open air filter ( changing LOL ) and it has a 87 jet, I know this is way high and I should take the air filter and put standard one on which is what I'm going to do. What is the standard jet size: 53? What jet size should I have with the normal filter, standard pipe and 70cc polini sport ( 60 ish) ? What ratio pre mix should I use: 50:1? ( 20ml to every 1L ) Please can you answer these questions, mainly what jet I should start workng from.
Im no expert, but you contradict yourself... If its running lean the plug would be grey/shiny, rich would be black/sooty see here -http://www.theultralightplace.com/sparkplugs.htm an oily plug denotes that your using to much oil in your pre-mix, i'm 280 miles into running a new cylinder in atm and i use a cap full of oil in a tank of fuel... I've had the head and barrel off to check at 250 miles and it still looks like new... A 70 kit and a standard exhaust are a waste of time, bin the boggo pipe and fit a decent one, at very least a TT... There is no set size for a jet, a mate and i run almost identical set ups on a zip and a bw's both run 17.5mm carbs with open filters, both have Athena HP 70 kits, both run LV TT's, my main is a 92 and his is a 115... you will have to buy a box of jets and play around...
