Taffy's jetting phylosophy

[Ynahg]

I ordered following parts at Alle's R & D Performance and received them before the weekend.

160 MJ

160MAJ

35 and 38 PJ

EMM

+ PAS

I removed the air-cut valve, installed the MJ and the MAJ the PAS 3/8 or 55 and the 38 PJ.

Left the DXM on 6#

The bike started from the first kick, smooth power but a big bog when rolling-on (tried to eliminate it with the fuel screw) from in the low rpm's.

Whithout any logic thinking I swapped the 38 PJ for the 35 and installed the EMM needle on clip 5.

Starting was not as easy as before, still a little tickover when rolling too fast or wacking the throttle from in the low revs. Idle hangs for approx. 5 s after giving gas in neutral.

Guess the pilot circuit mihgt be a little lean (close the PAS ?)

On the other hand midrange and top are very satisfying. WATCH OUT FOR WHEELIES !!!!!

How cold I eliminate this tickover problem in low revs ?

Oh yes pump squirt is really small -0.5 s

Thanks Taffy, midrange and top rips ?

[Taffy]

that's a tough one to answer. you've dumped everything straight in and then made a major swap of needles! ?

i would drop the needle one clip and see how it goes. as far as the PC goes i would go back to the 38PJ and try that after.

i'm just shooting in the dark here. sorry!

it could come down to the fact that i said that a D serries was good for WR timing and an E series for YZ timing.

Taffy

[MN_Kevin]

Hey Taff,

I am running the same: 38PJ, 162 MJ, EMN #2. I have my PAS at 1/4 turn out...

What do you think?

On decel (and NOT in neutral ? ) the backfiring is severe. I turned out my Kouba 1/2 turn and then the bike would stumble bad if the throttle was whacked open.

[Taffy]

i'd open the PAS a little further kev. i know this sounds like leaner but it could be that both are needed. PAS and PJ up.

is it ok higher up?

Taffy

[MN_Kevin]

I did not have a great area to test.

I have to put my license plate, headlight & tailight back on and take her on the road.

I DID search the forum and came up w/ that 1/4 turn open initial position.

At least I am not screwing w/ that carbon fibre airbox... ? That was a hassle to do carb work!

[MN_Kevin]

Hey Ynahg,

You did receive your Kouba...right??

[Ynahg]

Yes indeed Kevin, I received my Kouba.

By the way, forgot to thank you for that..so thanks for the Kouba

Taffy,

You suggest to go back to the 38 PJ, but with the PAS 55, but I think this was too rich, ran ok and a good idle with PS fully closed and started to run rough when opening 2 1/2 turns. Maybe put the 38PS and set The PAS to 60-65 ?, Or yust stay with PAS 55 and let the needle down a clip.

The more I'm understanding about jetting, the more this jetting compromise is getting complex. ?

[Taffy]

Kev

without looking i think that 1/4 turn out on the PAS is #45 kev, so you had better start again!

i would drop the needle for the midrange pull test first. this has a side effect of very slightly leaning the PC. THEN do your PAS out to 3/8 turn. that is your second test.

the top end should ideally be done first. when i did jetting Qs i was going where the work was but you will have cut 90% of that out. the final testing in jetting Qs saw me doing three changes at once even though near the end it's ultra critical. but the fact is that by then i knew exactly what would happen if i did what to what.

good luck

Taffy