250RR Jetting

Jetting, Reeds, Air Filters, etc.

Re: 250RR Jetting

Postby bryanaverill » Wed Dec 09, 2015 3:40 pm

OK, I'm fairly knowledgeable about the process. I've tuned three KTM's and two Yamaha street 2-strokes with excellent success. Biggest challenge is getting the dynamic response right which I've done before. Constant throttle adjustments are easy. Just wondering what a good starting point for the 250RR is.

Thanks very much for the info. This will help a lot.
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Re: 250RR Jetting

Postby GMP » Wed Dec 09, 2015 9:16 pm

Just start where Hammer suggested you do. Good advice.
Glenn
'13 Beta 300RR Racing
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Re: 250RR Jetting

Postby Bandicoot » Wed Dec 09, 2015 11:06 pm

bryanaverill wrote:OK, I'm fairly knowledgeable about the process. I've tuned three KTM's and two Yamaha street 2-strokes with excellent success. Biggest challenge is getting the dynamic response right which I've done before. Constant throttle adjustments are easy. Just wondering what a good starting point for the 250RR is.

Thanks very much for the info. This will help a lot.


With the 16' 250rr then I have jetted a lot of bikes to this >>>

NEDJ .. 2nd Clip
38 PJ
165 MJ
AS 1.5 turns or there about's

This works for me on my personal 16' and I ride slow more technical terrain where 2nd to 3rd is the most I use and this gives a more grunty & torquey feel to the bike ...
This has given the most success to riders as a baseline, some have gone to the NECW/NEDW needles when Head work has been done to help with a slight ping in the bottom end range when the bike has been getting warm/hotter than usual.
Darren ..
If your not ridin' ... Your dyin' .. !!!
Keep on Roostin'
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Location: Melbourne, Australia

Re: 250RR Jetting

Postby GMP » Thu Dec 10, 2015 6:57 am

From listening to another friend I converse with often from Australia, also very knowledgable in jetting, it seems you guys always end up just a shade leaner regardless of the bike, other conditions being approx equal. Must be some slight fuel differences. Should be able to get that bike running perfect anywhere with one of the NE*# needles.
Glenn
'13 Beta 300RR Racing
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Re: 250RR Jetting

Postby bryanaverill » Mon Jan 25, 2016 1:44 pm

So, I'm in Oregon USA. Just went for a ride yesterday with my new jetting:
MJ: 162
PJ: 35
Needle: NECJ 4th clip position
AS: 1.5

Altitude: 500 to 1500 ft
Temp: 45 to 55F

The NECJ needle was like somebody else said. It transforms the bike. My settings are very good for my conditions and riding style. I thought the #35 PJ would be too lean but it's not. No bog whatsoever and very clean, strong, and responsive everywhere. If you haven't tried this needle yet, I strongly suggest that you do. It transforms the bike.
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Re: 250RR Jetting

Postby T.Read » Fri Jan 29, 2016 11:43 am

I've been playing around with this myself. Since it's been pretty cold around here, below 50 and below 40 a few times I've been out, I put the richer pilot in. I only had the 35 and 38 in my little kit that came with it. 35 definitely works good in the summer to late fall, but I still had it in when riding on New Year's Day and it was sounding like it wanted to detonate. Put the 38 in and haven't had time to really test it, but it seems better just running around in the back yard. Needle I'm not so sure of. According to the chart, I should be using the NOZJ with my altitude, but I have it at the leanest clip. Main is 168 even though the chart says 170. Still kinda new to 2stk jetting so I could be going the wrong direction.
2014 250RR Racing
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Re: 250RR Jetting

Postby BassMan » Mon Oct 03, 2016 7:45 am

I have had my 2013 250 for 3 seasons. I have tried various combos over the last 3 years. In my bike, with gnarley and stock fmf silencer, marathon premium 92 octane (10% corn) 1 oz of stabil 360 per 4 gallons, Lucas premix 32:1. Twin air filter with fliterskinz. Powervalve screw flush. The hands down best combo for 60s to 80s at 500 to 1500 feet is 35 pilot, 1 turn on a.s., NOZJ needle 2nd clip, 168 main. Nothing is better. When it gets up in the 90s, drop to 165 and NOZK 2nd clip. When it gets colder, step up to the 38 pilot 1 turn a.s., 170 main. You will have zero sponge, no hesitation, sooth power, no flat or blubber spots. The secret is proper oil ratio of 32:1, make jetting so much easier and everything works as intended. The other needles make up for the rich 50:1 mix and decrease of power from less ring seal. I recommend starting there before chasing needles.
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Re: 250RR Jetting

Postby OscarFox » Fri Apr 21, 2017 5:14 pm

Reviving this thread...I've been reading through most of the material here and it's all very good. I'd like some confirmation that I'm moving in the right direction. Just bought a '15 250RR Race. PO said he was running the stock jetting. Per the beta manual I should be running a different needle (NOZL), smaller main (162) and AS at 2 for 4900-7500 ft ms and 60-75 temps.

I'd like to try out the NE** needles so my plan is to order the NECJ, NEDJ, and NECK and NEDK. The latter ones are leaner. My thinking is most people I see running the NECJ are at lower elevation so I should need a leaner needle. But maybe start with the NECJ expecting it to be richer and make adjustments from there? Hope I'm on the right track here, someone please chime in if I'm all phuckerd up.

My first 5 gallons of gas have been at 50:1 with Motul 800. I think I'm gonna switch to 40:1. I don't want to make too many changes at once, but I feel like the bike could be running better. I'm new to 2 strokes (I also own a 350RR) so I'm not that in tune to what a clean running motor should sound like.
'15 250RR Race
'18 390RR Race
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Re: 250RR Jetting

Postby newbeta » Fri Apr 21, 2017 10:48 pm

Same bike and year and running the NEDW 3:rd clip close to sea level - spot on with 38 pilot and 168 main.
Got this info from another jetting thread here.
The NECJ seems often to be too lean for the 250 that need some fatter jetting than the 300.
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Re: 250RR Jetting

Postby OscarFox » Mon May 01, 2017 2:03 pm

Here's where I'm at now:

MJ: Went from a 165 to a 162
PJ: Unchanged @ 35
Needle: Unchanged @ NOZK 2nd pos.
AS: From what seemed like 1/4 turn to 1 3/4 out. (The screw hadn't been messed with in awhile it was initially difficult to make adjustments until I cleaned it up a bit)

I need the choke for initial startup and it takes some throttle to keep it running. But man it feels like it pulls well throughout the range. Still have some splooge although not as much as before.I got the Suzuki needles to play with so I think I'll do some more testing with those since I'm curious now.
'15 250RR Race
'18 390RR Race
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