Anyone have a spare JD Red?

[Jakobi]

Some good info here. I just checked my current jetting on the 300 against the YZ250 jetting chart/table and everything falls into place for my elevation and temp. Well except the pilot, where I'm 2 sizes leaner but thats understandable as I'm on a 300 with more velocity at lower revs.

42 N3CJ#2 172 300M-1000M 20-35C
I had not checked this table prior to my jetting. All done by feel only.

I wonder how it would go for the 250? I might use this as my baseline fot the 250 top end too.

 

[Simmo737]

Hey Simmo

Could you post up the JD recommended settings for 20-35C 300-1000M high RH. Just as a base point.

What does lean lean lean to the fear of seizing feel like Glenn? I went lean enough once that the power fell really flat in the mid and their was some pinging present. I did the same trick you did and pulled over to swap it out.

I'm home Saturday so I'll do a photo of the jetting sheet then, if I remember right the 38mm setting was 42 jd red clip 4 180 0 3000' but that will be need to be confirmed. There are two kits, one for the as2 and the original for the older carb. I have the newer one.

 

[GMP]

rxmx,

Sounds like similar lean results with the Red needle. We are also in similar conditions. This is good though as it is telling me that a 250 with the ASII is still happy with the Blue and its a viable solution to try.

Jake,

I think you will find the 250 a breeze to jet compared to the 300. Also, you spend less time dwelling in the small(problematic jetting) throttle openings so even if it isn't perfect it seems a lot better.

What slide are you running? The fact that your so lean on diameter says perhaps you should go one up on the slide cutaway. Have you tried it? Generally, 250s seem to prefer #7s and 300s #8s for easiest jetting and less hyper sensitivity to needle selection.

The other variable I almost forgot is your fuel may be different than ours.

 

[Neil E.]

There does seem to be more bike to bike variation than we might expect so be aware that JD's test bike could be different than your bike.

JD's instructions show the sea level to 3000' preferred setup to be:
36 - Red clip 4, 38 pilot, 170 main
38 - Red clip 4, 40 pilot, 180 main
This is for BOTH the 250 and 300.
More settings are listed for higher altitudes.

He does recommend starting rich and going lean with the needles.
36 and 38 - Blue 4, Blue 3, Red 4, Blue 2, Red 3, Red 2
Based on this sequence maybe the tapers are similar.

I think his kit is good value and an easy choice for US riders. Good for everyone if your shipping costs are tolerable on a small package.

 

[GMP]

This brings us back to the question I asked of him: Are the needles from the two kits the same? I find it hard to beleive he would design a new needle specifically for a GG with such limited (relatively) production numbers. He's a sharp guy, what I think he did was pick a few needles that work reasonably well in a variety of bikes, and improve the balance with some custom tapers. Fine tune with brass. You can learn a lot with his spreadsheet guide. His needles are not in it though!

 

[Jakobi]

rxmx,
Jake,

I think you will find the 250 a breeze to jet compared to the 300. Also, you spend less time dwelling in the small(problematic jetting) throttle openings so even if it isn't perfect it seems a lot better.

What slide are you running? The fact that your so lean on diameter says perhaps you should go one up on the slide cutaway. Have you tried it? Generally, 250s seem to prefer #7s and 300s #8s for easiest jetting and less hyper sensitivity to needle selection.

The other variable I almost forgot is your fuel may be different than ours.

Glenn, I hope the 250 is a bit easier. If its not I have enough brass here to get it dialled in anyway. Pilots from 35 - 48, Assorted needles with varying diameters F - J, and Mains from 165 -185.

Just found a reply from JD on a thumpertalk thread comparing JDRed vs N3EJ.. his reply:

Re: Differences between Red/blue needles

On the YZ250 2-stroke kit, the Blue needle is only richer at 0-1/4 throttle. They are the same profiles above 1/4 throttle.

Thanks,
James

It still doesn't answer the question if there are differences between the Generic 2T kit, the Gas Gas kit, and the YZ250 kit. (Not to mention others).
He lists different kit numbers for each manufacturer, but thats not to say the only thing thats changed is the jets and the piece of paper. IE KTM/Husaberg 2T's have their own kits, but everyone knows they'd be the same thing as the bikes are the same.

 

[Jakobi]

There does seem to be more bike to bike variation than we might expect so be aware that JD's test bike could be different than your bike.

JD's instructions show the sea level to 3000' preferred setup to be:
36 - Red clip 4, 38 pilot, 170 main
38 - Red clip 4, 40 pilot, 180 main
This is for BOTH the 250 and 300.
More settings are listed for higher altitudes.

He does recommend starting rich and going lean with the needles.
36 and 38 - Blue 4, Blue 3, Red 4, Blue 2, Red 3, Red 2
Based on this sequence maybe the tapers are similar.

I think his kit is good value and an easy choice for US riders. Good for everyone if your shipping costs are tolerable on a small package.

I see typos on his page for the 38mm kit too. Initially install a 180main, then for elevation he continues to say try a 168, 162, 158. Oops. Think he means 178,172,168. Its not too far off the N3CH judging by what I read. I think he probably has a 3rd taper in the middle to richen up the midrange and smooth the hit. Then leans off into the third taper (thus the fat mains).

 

[GMP]

We have an answer!

"Glen,
Yes those are the same needles . We included more main jets in the g002 to compensate for the the issues that the factory was having in that they were not disclosing what size of carb they were using.Either a 36 or 38 mm carb and the only way to know is to measure the carb.
Thank You
Dave
JDJetting LLC"

So I was right, figured there was no special needle for '11. I'm thinking that out of all the kits, there re probably only a few different needles.

 

[Jakobi]

In saying that though Glenn, the ASII with its shorter bowl seems to pull more fuel than the previous model so you might find yourself jetting a little leaner than your current setup. Never the less it should only be a clip position and a slight change in brass at most.

Great news that you can re-use your JD Blue!

I've spent some time following the Australian KTM jetting discussions and although I'm comparing two different engines, using 2 different carbs, the results regarding needle and clip position are very very similar between them. Obviously the GG with its 38mm carb is always calling for a larger pilot and main.

 

[GMP]

I must have 50 different needles in my stock I've collected over the years, standard Keihin and OEM stuff. Of all though, the JDs just seem to always work best is everything I've messed with. We did a 38mm PWK (AS1) swap on my brother's Husky 250, just plugged in my GG specs with the JD Blue and he never looked back. They just work.

 

[Jakobi]

I must have 50 different needles in my stock I've collected over the years, standard Keihin and OEM stuff. Of all though, the JDs just seem to always work best is everything I've messed with. We did a 38mm PWK (AS1) swap on my brother's Husky 250, just plugged in my GG specs with the JD Blue and he never looked back. They just work.

When you compare the price of 50xOEM it makes the JD kit sound quite reasonable

 

[GMP]

I didn't buy 50, just a collection from all the spares that came with various bikes. Probably bought 15, mostly Keihin C and D series.