2011 300EC Jetting

[400exc]

Hi. I am trying to sort out the jetting on this, new to me, 300 EC Six Days . It came with the 36 Carb, 48 pilot and 170 main. It runs horribly rich till warmed up, waaay too much smoke. From what I read here seems like a 40 pilot, JD Blue #2 or #3, and the 170 main would be a safe start.

All advice gratefully appreciated. Thanks.

 

[Jakobi]

Ahuh A few Aussies have found love with 36mm carbs and that setup you listed.

A 48 pilot is well huge! Especially if used in conjunction with the stock needle

 

[twowheels]

Ahuh A few Aussies have found love with 36mm carbs and that setup you listed.

A 48 pilot is well huge! Especially if used in conjunction with the stock needle

Maybe a 38 pilot?

 

[n_green]

38p, JD Blue #2, 168 main was my best jetting with the Blue needle. That was at 1000m altitude so a 170 near sea level would probably be safe. Used to get about 75k's to reserve with that jetting which isn't too bad but it's not great either. The top end was also not overly impressive (something you'll find especially if you ride a 38mm equipped bike) Economy improved noticeably with the Red needle and so did it's ability to rev into a nice top end but torque really suffered down low and couldn't be fixed with larger pilots.

I'd try an in-between needle diameter, an N3CH would be a good place to start and it's a good taper which will produce good torque and a nice agro top end If you go down that route I'd start with a 40 pilot and similar sized 170/172 main.

 

[GMP]

JD Blue is a great 250 needle, too rich for 300s though. Too bad he chose such a lean straight dia for the red, its really useless as an incremental step from the Blue.

 

[Neil E.]

My 11 250 with a 36 works better on the red needle. When using a red needle, won't a larger pilot provide enough extra fuel or does it get too soft coming off idle? My understanding is that both the blue and red have the same tapers with just different shank diameters.

 

[n_green]

In theory that should be the case but in practice it isn't. With the red needle and correct sized pilot (based on the AS being 1.5 turns) it was still very flat just off idle and didn't make any decent power until it got onto the taper. I stepped up pilots until I was 2 sizes too big and the as was wound out past 2.5 and while torque got slightly better it was still pretty bad considering I was on a 300.
Funny thing is now I have the 36 mm oval bored the red needle is great. Not lacking any torque at all with the correct sized pilot. The blue needle is also way too rich on the diameter now and no amount of leaning off the pilot will fox it. There's obviously some technical explanation for it but I dunno what it is.

And I agree re the difference between blue and red needle diameters. Maybe there should be a purple needle, same taper as both but with a diameter in the middle of the red and blue, so a H?

 

[400exc]

Thanks to all for the advice. JD kit + a few extra jets, to cover all the recommendations, is on the way. Report to follow in a week or so.