[Simmo737]

Originally Posted by Jakobi

Modified head. 1.2mm Squish 13.1:1UCCR. BP Ultimate 98RON w/ Amsoil Dominator at 50:1. Far Northern Conditions (20-30C, 50+%RH). ASII 38mm Carb, #7 slide.

I've now put a bit of time in on the new bike, and strangely, even though the old 2010 has a very similarly setup engine (head work, carb, etc) they jet very differently. The carb on the new bike has an additional jet in the bottom of it. Perhaps a leak jet?

The new engine feels richer for a given setting. I'm wondering if changing carbs between bikes will identify where the differences are.

2010 model is running 40 N3CW#3 178, and runs with zero spooge, a little smoke, and a little fat at light loads. It NEVER loads up, and always takes revs cleanly through to WOT.

The same jetting on the 2013 runs richer over all. The pilot is very similar in its effect on idle and off idle response. On the needle though, its much richer in the 1/4 throttle range and doesnt respond as well. It will load up when initially started and takes time to clear out. Spooge is massive. Dropping to a 175 main showed little improvement. Moving a half a clip leaner (N3EW#2) was crisp and performed better but I believe gave up some mid throttle grunt. Also hard to test due to the day being particularly wet! Historically the N3 series needles to tend to be more binary (on/off) than some other choices.

Changing to 40 NEDW#2 172 showed some improvement in throttle response, less loading up, and a very smooth linear spread of power. Still spooged substantially, however much less blubber, still grunts down well, and has a super strong mid to top.

Changed to 40 N3CW#3 172, still blubbery off the bottom, did not ride it hard enough to test the mid, but would be same as previous, and whacking the throttle open hard (on the stand) caused a lean hesitation on the main. Obviously way too lean towards WOT as is expected with this needle.

So over all, I'm not sure if I should stick with the 40 N3EW#2 178, or the 40 NEDW#2 172. I think for now I'll save changing the brass and put some more time on the Suzi needle.

i agree. my bike is running leaner than the 11, im about to go back to a 38 pilot, i thought it was overheating due to an off idle lean condition but it was motul transoil expert gear oil - too good for a gas gas clutch, i've changed to the dirtbikeworld oil of choice penrite hpr gas 10 (10w50 universal style semi synth - probably like rotella t in the US) and it is like magic, lever feel has gone to completely progressive with no nasty grab point and the bike is quieter, can still kick in gear and no heat issue.