2017 300RR RE carb

[aj_mariner]

Very true. I changed the pilot to a 40 and am off to the races. The blubber off idle is gone and air screw in now kills the engine. I'm happy with it. Got a 42 pilot coming just to see how it responds compared to the 40.

Washington 60-90 degF, 0-6000ft, Motul 800 at 50:1 mix, premium gas.

[Hammer]

Very true. I changed the pilot to a 40 and am off to the races. The blubber off idle is gone and air screw in now kills the engine. I'm happy with it. Got a 42 pilot coming just to see how it responds compared to the 40.

Washington 60-90 degF, 0-6000ft, Motul 800 at 50:1 mix, premium gas.

I need to know how going to a larger pilot gets rid of off idle blubber?

[aj_mariner]

Looks like you've been on here for awhile Hammer. Maybe I described it wrong, blubber meaning a slight stall period before the engine responds to the increased throttle.

[aj_mariner]

Pacific Northwest rider. Ran the bike with a couple different jets and needles and came to the same numbers as dibbs in his U.K. Jetting post.

0-5000 ft
70degF day
Motul 800 - 50:1 with premium gas
Power valve 1/2 turn in from flush
Carb float height was verified and is stock
Clean air filter, freshly packed FMF Q-Stealth
40 pilot, Air Screw 1-1/2 turns out
168 main
N2ZJ at clip 3

By far the best and am calling the science project done. On hotter days, I plan on going to clip two on the needle, and 2 turns out on the air screw. And on colder days going the opposite direction.

I found this to be very useful for general carb tuning and what to listen and feel for to figure out if you're too lean or too rich.

https://www.duncanracing.com/TechCenter ... etting.pdf

[mtnmanseth]

Great info - thanks for sharing that link

[katoom400]

well, I'm pretty sure I have the float height set just about level and with with the gasket surface of the bowl

38p
n2zw 3rd
165 main
as 3/4

I'm getting some lean pinging after a long straight or uphill. from what I'm reading, all of the pre mentioned specs should actually be a bit rich for my 1000' elevation in the summer months according to the Beta chart?

I'm wondering could I actually be a bit rich with the 38 pilot and maybe on the needle? since it does "gurgle" a bit sometimes off idle. but that doesn't explain the lean ping? I see guys are running 40p in the summer months?

I have plenty of brass, and N2ZJ and NECJ to try.

[aj_mariner]

My findings told me that the bikes are set up lean, probably to pass emissions. If you are getting a ping, it's from the engine getting to hot from being too lean. Richen up your pilot first. Once your happy with it, then go for the needle and main. The indicator that my needle and main were too lean was the hesitation when trying to get on the throttle from 1/4 to 3/4. She whined and felt like the power wasn't there. Richening it up made it sound and feel much better, as well as make the bike more aggressive. The difference was very noticeable. Also, the jetting chart is 2 steps too lean...in my opinion.

[katoom400]

My findings told me that the bikes are set up lean, probably to pass emissions. If you are getting a ping, it's from the engine getting to hot from being too lean. Richen up your pilot first. Once your happy with it, then go for the needle and main. The indicator that my needle and main were too lean was the hesitation when trying to get on the throttle from 1/4 to 3/4. She whined and felt like the power wasn't there. Richening it up made it sound and feel much better, as well as make the bike more aggressive. The difference was very noticeable. Also, the jetting chart is 2 steps too lean...in my opinion.

well the chart calls for n2zj 2nd 165, and I'm at the richer n2zw needle now with 165m, so maybe I'll try the 40p and bump the main up to 168?

I've got a dual sport this weekend that will be mostly fast trail, and some long connecting roads, not a place I want to be lean, but I took 5 miles of road home last sunday and nothing blew up so it can't be that bad!

[aj_mariner]

If you are running a 300 Race, I would honestly just try the settings I came to up above. After all the trials and switching everything around, as well as OCD'ing about every little adjustment, I came to the same numbers as "dibbs" in his post. I should have just gone there first and saved myself a lot of time.

I recently rode on an 85degF day at 2000' with:
40pj
Air screw: 2 turns out
168 main
N2ZJ at clip 2
PV - 1/2 turn in from flush
There was a little more spooge than the cooler day, but the throttle response was fun and no ping.

[katoom400]

If you are running a 300 Race, I would honestly just try the settings I came to up above. After all the trials and switching everything around, as well as OCD'ing about every little adjustment, I came to the same numbers as "dibbs" in his post. I should have just gone there first and saved myself a lot of time.

I recently rode on an 85degF day at 2000' with:
40pj
Air screw: 2 turns out
168 main
N2ZJ at clip 2
PV - 1/2 turn in from flush
There was a little more spooge than the cooler day, but the throttle response was fun and no ping.

running a standard 2015 300rr, does it make a difference? I thought in 15 they switched everything to the higher compression head?

I also have very little spooge with my current jetting and 40:1 lucas semi sythetic