Allan Clough's Page

"Yes that would say too lean ! I would go richer on the 54 and it will be quicker than you had as it was too lean.Some changes in atmosphere do change the tuning and others don't. The power valve will not effect that bogging as that is…"

"Didnt try any bigger jets with the K54. As we are runnig twilights next wknd I didnt get up to the track till around 3pm......tried to be there around similar race time. when I lifted the choke with the 54  the engine appeared to pick up,…"

"k54 seemed lean and certainly could off been and that will slow things in certain areas and did you try a bigger jet to see ?.Yes 98 has some holes in certain parts of the rev range but can be driver friendly with some.Did you try just lifting the…"

"Well, interesting days testing.... Started with the K54 Needle & 162 Jet, avearge lap times low 43.....blahhh!  spark plug appeared a tad lean, then changed to the K98 & 165 jet using same rear sprocket....biff bam whollop....down…"

"yes correct "degree F", sorry about the error.  This is a good example of the need to consider everything you are told at the track and from others. Have fun, rotax is a great class. Colin   "

"Yes testing is the way and write things down and the the jetting and weather station readings so you get a history to work from, and do not have the weather station shut in a confined space as you will get silly readings as well."

"Thanks Colin & Ross for all your advice, Guess I'm off to the track this wknd for another test day......We have first rnd of Twilights on the 14th so it would be nice to have a good starting point without being too far back. The long range…"

"Yes some tuning programs are unadjustable and will not be telling you the correct jetting for your carb ! I used Jet-Tech and that is adjustable for your settings,carb,fuel etc and once you fine tune it to your setup it is totally accurate and I…"

"Well the 168 jet is reasonably safe as this is what is supplied by rotax in the standard carb, same with the K98 needle.  If you keep the needle ring at 1 or 2 you won't end up with it being too lean out of the corner at 1/4 to 3/4…"

"Thanks Colin for the great advice, like you said the best thing is for me to keep on doing laps & recording my data huh?. So are you saying start on say a168 jet with a K98 Needle, clip 2??? Guess if it were too easy everybody…"

"Hi Allan for what it is worth, there are so many variables in the carb set ups that weather stations and jetting programs will only get you somewhere close (within 3 jet sizes is my experience).  Even the specific gravity of the fuel makes a…"

"Thanks Ross, From memory my revs did'nt change a great deal.No I have'nt got a logger, im just going off my mychron. I have tried the Jet-Plus program.....only the free trail version though,along with a weather station…"

"Ok, 14k is where you want to be and putting 2 extra teeth on may get you out of the corner easier but be flat in the mid/top. Did the revs increase ? From what you say this may not be the case,you can do splits of sections of the…"

"Thanks Ross, Im still real confused....this is what was on the kart when I got it: 11T front, 81T rear, K98, Clip 2, 170 jet. Pulled 14K RPM down the start / fin straight......THEN was told to run 11T / 83T Rear, K54, Clip 1 & 162 jet. the…"

"See what drive sprocket you have on and then that will give you a ratio.Also with what you have on what max revs are you getting. On the engine make sure all is clean including carb,jetting and fuel and air filters to start with and…"