Jetting rr 250 racing part III

Jetting, Reeds, Air Filters, etc.

Jetting rr 250 racing part III

Postby david.bergen » Sat Oct 29, 2016 6:59 am

Thanks to the good people on Betarider I think I have good jetting for the moment.
Bike is strong, no sputter at low revs and flies in the high rpm's
Jetting is 38 pilot , 168 main and the NEDW needle #3 airscrew 1 turn out.
Elevation is 30 m and temp range 5C -15 C . Mileage has improved I can ride 110 km before hitting reserve ( trail riding)
I upped my oil ratio to 3% with synthetic 2t oil. I also changed from 98 octane fuel to 95 octane fuel (10% ethanol) and strangely the bike runs better and is giving me way less spooge so all is good.
One strange observation I had today is:
When I came on nice long straight dirtroad I pinned the throattle, bike reved till the moon . At the end off the dirt I turned arround as I was going to take another run I noticed a lot off smoke coming out the exhaust, light blue color. The smoke cleared after riding for some time at a moderate pace. Did took the dirt road again with same results ...
What is going on here ? Is that old oil in the exhaust being burned out ? Higher engine temp ? Rich condition at WOT ?
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Re: Jetting rr 250 racing part III

Postby david.bergen » Sat Oct 29, 2016 11:18 am

Plug color
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Re: Jetting rr 250 racing part III

Postby david.bergen » Sat Oct 29, 2016 11:18 am

Spooge exhaust
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Re: Jetting rr 250 racing part III

Postby david.bergen » Sat Oct 29, 2016 11:36 am

Sorry about the big pictures. First time posting and resizing didn't turned as I wanted
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Re: Jetting rr 250 racing part III

Postby Cactus Jack » Fri Nov 04, 2016 8:01 pm

Being a 2 stroke and running at 3% I would be very surprised if you weren't getting unburnt oil out of the exhaust. 3% (roughly 32:1)is quite rich, probably almost twice as rich as I would run it (60:1 or 1.7%). At that sort of ratio expect plenty of spooge in your PV and out of the exhaust.

The brown of your plug (around the electrode and porcelain areas) looks to be burning well, but there is some wetness and blacker burn around the outer edges, suggesting things are a little on the richer side. Difficult to know though, spark plug colour isn't always an accurate measure of how well the bike is running since the advent of unleaded fuels.

My feeling is that the long high rev stint has managed to clean up the electrode but wasn't long enough to burn through the richer deposits on the outer side of the plug. Lean out your fuel mix a little, maybe down to 40:1 (2.5%) and see if it performs any better.

This of course is an opinion. We all have them........

As for the actual question, the bike is probably burning off some of the excess oil that is soaking into the muffler matting from the richer fuel mix as the exhaust gas heats up at WOT, which is causing the excess blue smoke.
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Re: Jetting rr 250 racing part III

Postby BassMan » Sat Feb 04, 2017 7:09 am

Looks great and acts great.
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Re: Jetting rr 250 racing part III

Postby newbeta » Sat Mar 18, 2017 11:07 am

Hi David!

Read your threads on jetting here before I first tested my new to me beta 250 rr racing 2015.
Tried the nedw #3, 38 p and 168 main. Absolutely spot on at between 5-10 degrees C.
No need to test anything els. Never tried a bike jetted so good before :)
Tnx for sharing!!!
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Re: Jetting rr 250 racing part III

Postby newbeta » Tue May 09, 2017 9:36 am

Hi!

Still using the same jetting when temps reach 20+ C?
Thinking of changing the needle (nedw) position from #3 to #2 now when it's hopefully getting warmer. Have you tried that?
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Re: Jetting rr 250 racing part III

Postby sasrocks » Tue May 09, 2017 12:03 pm

for 16+ RRs with oil injection, jetting leaner such as raising clip (lowering needle) changes the fuels air ratio, but also results in gas/oil ratio getting lower, possible increasing spooge

Obvious statement, but to what degree is this an issue IRL?
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Re: Jetting rr 250 racing part III

Postby david.bergen » Mon May 15, 2017 2:21 am

When I get to 20-25 C I'll drop the needle onze clip . I also have NECJ needle that I can try.
Mine is still running great With temp arround 12°C at the moment.
Only adjustement I have done is the airscrew.
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