Ok, so just to go back over, by first testing with standard values to find where ur best state of tune is, then with a little thought, calculating & testing, u can fine tune. Suppose u find that by adding the 220 ohm u get better lo end power than without it, but if u add the 120 ohm u loose a little. So now u need to find which side of 220 ohms to go. Try 180 ohs. Still loose a little from wot 220 gives,., try 250 ohms. U just need to work oyt whicg way u need to move ur timing for optimum, & only move it a little at a time. Its simply a matter of testing, testing, testing, & using common sense. U can also make up in between value resistors by paralleling a couple, or putting them in series to make a value u need. The inly thing with putting them in series is that this ADDS THEIR VALUES TOGETHER, eg 68 ohm in series with 56 ohm gives 124 ohms. Ok, when u have the low end at its optimum u will want the hi end set as best as u can. Normally u have a 4.7uf tantalum cap soldered in place with its + marked leg going to ground & two 0.47uf tantalums that u can jumpet their + marked legs to ground. Again, jumpering these in is simply putting all of them in parallel, however unlike resistors in parallel, putting capacitors in parallel ADDS THEIR VALUES TOGETHER. Now, to fine tune the high RPM retard curve u take the same aproach as when u did the lo rpm setting, but u will first want to have a few different small value tatalums on hand. The common values u will want are 0.10uf,., 2 of these
0.22uf,,, 1 of & 0.33uf,,, 1 of. Now u can cover the range between adding 1 x 0.47uf & adding 2 of, plus more. So u take the same approach again. No matter wot setting u find gives the best hi end performance with the normal values, then work out which way u need to go to get the most out of it, (tho u may b lucky & find one of the standard values gives this). Say u find that the both 0.47uf caps jumpered in gived best top speed. To work out which way to go, add a 0.22uf, test, then remove the jumper from one 0.47uf while leaving one 0.47uf & the 0.22uf there. Its the same process, work out which way u need to go by testing, a bit of thought, more trial & error testing using smaller values each time to find the sweet spot. This is fine tuning the steepness of the hi RPM retard curve that starts to kick in at around 2/3 max rpm, roughly. I wont go into moving the point at which the hi rpm retard curve kicks in here tho it is possible. Hopefully this info might be usefull to some of u racers looking for the best level of tune possible from ur motor & are prepared to spend the time testing & testing again to achieve it. I would reccomend that u get all other motor mods done before fine tuning ur CDI, or u'll need to redo it every time u do another mod. Sorry about all the typing errors, damn PITA touch screen phone POS. Should anyone want to ask any questions on fine tuning a CDI u can PM me & then do it all by email. It really isnt that hard to do, just a bit time consuming but like getting anything right with ur motor, the resilts ate worth it once u get it right. Cheers
