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JD jet kit for 300RR

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i bought & installed at the JD kit last week. It's for a '17 300rr. I used the chart as a guide. Within 20km I fouled a plug for the first time ever. Looks like its time to start tuning the carb yet again... A few questions:

-which increment is larger, needle clip positions or main jet size? For example, I need to lean out. Am I better to leave the needle and go down in main jet, or vice versa? Should I just jump to the 6-9000' settings?

-I also feel like I have a pilot jet problem, yet the JD kit only comes with the 38. The AS doesn't start to "sound" right until 2.5 turns(maxed) out & the bike still idles when its full in. Should I go to a 35 or 40? In what I think is a related problem, I have been battling an ongoing idle issue since I've owned the bike. Whenever I go down a hill, the bike stalls. The idle is turned all the way in on the carb.

Thanks for any help in advance!

Oh, I ride at about 4500' (1350m) and about 20 degrees celsius on average. The current JD settings are: blue/clip 2, P38, Mn162

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Yes, I did set the float height. The bike pissed fuel when I got it. I adjusted it to 8.5mm (carb base to top of float when the fuel shut off was engaged- used the blow in a straw technique). Maybe I need to go more? What happens if I go too far? What are the things that caught your eyes for blaming the float?

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2 hours ago, Theo87 said:

Yes, I did set the float height. The bike pissed fuel when I got it. I adjusted it to 8.5mm (carb base to top of float when the fuel shut off was engaged- used the blow in a straw technique). Maybe I need to go more? What happens if I go too far? What are the things that caught your eyes for blaming the float?

The only reason I questioned the float is you stated you have an ongoing battle with jetting. You can't jet accurately until the float is correct so with all the problems you've had I figured start with the float. I would suggest you ensure the float is correct then go back to the stock jetting as a baseline then go from there, the chart in the manual has been accurate for me.  Most people find that the stock jetting is a little rich but for the most part the Beta 2 strokes are pretty easy to jet. I ride year round in Alberta so I typically have 3 different jetting setups, summer, winter and spring/fall. All settings are based off the stock chart for the temp and elevation and then I usually go one adjustment leaner, so far with 50 hrs on my '16 300 in all sorts of weather differences it's been clean and crisp and the original plug is looking good.

Do you have injection or pre-mix?

You asked about needle clip vs main jet as well, they are independent of each other as the main is for mid to open throttle position and the needle is low to mid throttle position.  

 

 

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That's good advice, I'll take it. I'm thinking I need to lower the float again and try once more with the near stock jetting. Thanks!

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On 7/4/2017 at 7:35 AM, Theo87 said:

i bought & installed at the JD kit last week. It's for a '17 300rr. I used the chart as a guide. Within 20km I fouled a plug for the first time ever. Looks like its time to start tuning the carb yet again... A few questions:

-which increment is larger, needle clip positions or main jet size? For example, I need to lean out. Am I better to leave the needle and go down in main jet, or vice versa? Should I just jump to the 6-9000' settings?

-I also feel like I have a pilot jet problem, yet the JD kit only comes with the 38. The AS doesn't start to "sound" right until 2.5 turns(maxed) out & the bike still idles when its full in. Should I go to a 35 or 40? In what I think is a related problem, I have been battling an ongoing idle issue since I've owned the bike. Whenever I go down a hill, the bike stalls. The idle is turned all the way in on the carb.

Thanks for any help in advance!

Oh, I ride at about 4500' (1350m) and about 20 degrees celsius on average. The current JD settings are: blue/clip 2, P38, Mn162

I agree with silver_fox and freeboard_78: start by getting the float setting correct. There have been threads on TT about Betas and what it takes to get the float height perfect. EDIT: http://www.betarider.org/forum/viewtopic.php?f=15&t=357

Regarding the relationship between idle  screw, pilot screw, pilot jet, slide cutaway, needle type, taper, and clip position, A/P timing and main jet, this should help:

http://www.keihin-na.com/assets/1/7/slide_valve.pdf

Also, regarding the influence of elevation and temperature (I forget where I found this, don't mean to plagiarize):

"...elevation and temperature have a big effect on jetting. Your ideal main jet and air screw setting can vary with every 10 degree temperature and 1000′ elevation change. The pilot jet and clip position vary about every 30 degree temperature and 4000′ elevation change."

Edited by Old Plonker
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My elevation and temp are quite different to you, but, the JD kit worked great for me.

I installed a JD Kit in my 300RR 2015 about a week ago. I used the red needle, clip 4 as per the chart, and also changed the jets as per the chart  and my bike is running real sweet and getting 10km + per litre.

At stock I was running to rich, so I lifted it a notch and it was a bit lean. JD Kit seems to have the right balance for me. Gonna pull the plug this weekend and see what that is telling me.

Just experiment mate as the JD Kit does make a difference.

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I tried rejetting my Beta with suzuki needles, larger pilots, and mains, however, until I got the float right nothing worked.  Honestly the factory jet table works great.  I just follow it now.

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i went for first good ride yesterday on my jd reject (no pv mod) and it ran really good, going to pop a fresh spark plug tonight but so far so good 17 300rr 150' 85 degrees f

 

i did adjust the float a touch as i was going to even with stock jetting due to some overspill

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Thanks for the help you guys! I'm going to ditch the JD kit and refocus on the float and chart jetting.

For those of you that have adjusted the float, did you go by a float height, or just level to the carb gasket surface as per the Beta manual? I've heard that the 8mm float height is better then the levelling method(which ends up around 6mm). 

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6 minutes ago, Theo87 said:

Thanks for the help you guys! I'm going to ditch the JD kit and refocus on the float and chart jetting.

For those of you that have adjusted the float, did you go by a float height, or just level to the carb gasket surface as per the Beta manual? I've heard that the 8mm float height is better then the levelling method(which ends up around 6mm). 

Beta manual method

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I set my float height and I use the JD kit on my 2017 and it's the bee's knees. I follow the chart exactly how it says and I never get spooge and it runs crisp. I've ridden from 700' to 9000' and that kit always runs awesome. I only use the 38 pilot as they suggest and never any problems and runs better than my KTM did with a Lectron. I think you are looking at a float or other issue, not a JD problem. Also don't hesitate to reach out to JD, they have awesome customer service.

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I should note my bike is the race edition without oil injection and run 50:1 and believe JD tests their jetting at 40:1-50:1. If your bike has oil injection you could be running all the way at 100:1 depending on your riding style which would cause your bike to run richer with more fuel. I would email JD and see what they say.

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1 hour ago, brysonrs said:

I should note my bike is the race edition without oil injection and run 50:1 and believe JD tests their jetting at 40:1-50:1. If your bike has oil injection you could be running all the way at 100:1 depending on your riding style which would cause your bike to run richer with more fuel. I would email JD and see what they say.

The 100:1 ratio would only be at idle so it wouldn't make any difference in the other circuits. 

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Thanks for the help you guys! I'm going to ditch the JD kit and refocus on the float and chart jetting.
For those of you that have adjusted the float, did you go by a float height, or just level to the carb gasket surface as per the Beta manual? I've heard that the 8mm float height is better then the levelling method(which ends up around 6mm). 


I set mine at about 8mm and it runs great. The Beta recommendation didn't work very well for me at all. The bike was hard to jet and I lost a lot of fuel. After I set the float I also looped the overflow hose over itself to prevent any extra fuel loss.

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OK, I'm winning the war with this bike. Lost a few battles to get here though. I put the float at 8mm and jetted as per the stock chart: N2ZJ (2 clip), 162, 38 PJ & AS 2 turns. Its pretty good. It still idles rough on steep hills but it doesn't completely stall anymore. Throttle response is good too. Once this experience wears off, I'll probably go back to the JD kit (I did pay $100 for it!). But for now I'm just gonna ride it and have some fun. 

My next Beta issue (never a dull moment with this bike...)is to solve the air bubbles in the oil line. As it runs, little bubbles are introduced into the line from the carb manifold. I can watch them form(almost a foam in the oil) as it idles. When the bike sits, they collect at the top of the inlet and they get big! Leaky reads to blame? Its like some piston compression defeats the power of the oil pump and forces air into the line. It only takes seconds for them to get pushed out into the engine so I haven't worried about the straight gas harming the engine...but maybe I should be? I've inspected the lines for kinks and they all look good- including the breather line.

 

 

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hehe havent had that problem but that kind of stuff the first time i see it im gonna pull the oil injection not worth the risk to me at that point

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