NEEDLE DIFFERENCES?

[bikedude987]

So when I cleaned my carb yesterday i managed to bend the needle, which is apparently made of cheese, btw..., and ordered a new one. When I was on ordering stuff, i noticed there were six or seven different ones, with no explanation of the differences. I ordered the standard one, but should I have? can someone demystify this?

http://www.bikebandit.com/houseofmotorcycles/2005-yamaha-wr450f-wr450ft/o/m145334#sch521169

part number 13; DUP-K, DUR-K, etc.

[Rocky739]

Haha, This could be possibly the most confusing thing ever in the world of dirt bikedom so hold on and I'll try to explain...

The last three letters describe the needle, ie; NCVQ needle,

©is the taper measured in degrees, less taper equals a richer needle in the taper portion.

(V) is the length or (L1), different needle series can be used to achive 1/2 clip changes and where the straight versus the taper start to apply.

(Q) is the dia of the straight portion of the needle, larger dia equals a leaner needle.

Most OEM needles don't have a aftermarket direct match but IMHO dont use aftermarket anything inside your carb...

Most folks on here use a NCVQ, NCVS or NFLR needle (all standard needles for YZF's over the years). But if it jets ok on the stock needle and your happy with the performance then ride and smile that its a eleven dollar fix!

Edited May 22, 2012 by Rocky739

[Rocky739]

http://www.jetsrus.com/a_jets_by_carburetor_type/needle_keihin_N427-OC_FCR_35-41mm.html

http://www.carbparts.com/keihin/needles_tuning/jetting_your_carb.htm

Here are a couple links to helpful info, Just remember that we have fuel screws not air screws nowadays so think backwards on idle jetting compaired to the chart. The needle info is dead on..

[nuckingfutts]

while we are on this subject, I have an 01 wr426. Last week in my local cyclegear store, I spotted a jd kit jdy006(lists an 07 up wr450 compatibility) on clearance for $10. Couldn't pass on that.. jets r jets. With that said, would the needles in this kit work on my 01? The parts fiche lists completely different part numbers, but stock needle vs jd look almost identical.

[Rocky739]

while we are on this subject, I have an 01 wr426. Last week in my local cyclegear store, I spotted a jd kit jdy006(lists an 07 up wr450 compatibility) on clearance for $10. Couldn't pass on that.. jets r jets. With that said, would the needles in this kit work on my 01? The parts fiche lists completely different part numbers, but stock needle vs jd look almost identical.

For 10 bucks I'd buy it too!! Make some cash on ebay though as I'm pretty sure the 01 has the first gen of FCR carb which takes different style jets.. I'm not sure but I believe the needles are the same for all FCR carbs??.. And jets are not jets, as aftermarket ones can be inaccuratly made and be sized wrong enough to make jetting a nightmare (it's bad enough with out doing the math of this 42 pilot runs more like a 45... No thanks, Keihin jets are cheap especally through Yamaha). For not much more than 75 dollars I was able to rebuild my carb, add a fuel screw, heavy acc pump spring, acc pump diaphram, buy a medley of pilot, main, leak, and needle jets.. Just saying that JD is a bit proud of his kit which doesn't come with enough stuff to really make a carb 100%.

You can't really see the diference in needles as its all done in .10 or .010 of millimeters so they pretty much all look alike I've tried to measure them with calipers and can't even figure it out, always wondered how they make the things???

I am sure JD is just buying aftermarket needles that he feels run well in most bikes (probably dyno or using a exuast gas tester) and having them made without ID number/letter marks then marking them with red and blue paint to make all this simlpe (quite genius). He does provide a chart for alt and temp changes but merge racing has that for free on their website. I'm not a fan of the brass aftermarket needles as they wear quickly (I'm sure I'll get a firestorm of people who have ridden for years on them but trust me thats why Keihin makes them from anodized alu for the OEM's plus needle tapers you can't get anywhere else).

If you choose to use the JD needles or another size OE remember that a main jet change may be required with a needle change.

http://www.mergeracing.com/tech/pandora/

Follow this link and you will be able to get a idea about enviroment changes and jetting, your buddies will be jealous of your sweet running scooter!

[GCannon]

while we are on this subject, I have an 01 wr426. Last week in my local cyclegear store, I spotted a jd kit jdy006(lists an 07 up wr450 compatibility) on clearance for $10. Couldn't pass on that.. jets r jets. With that said, would the needles in this kit work on my 01? The parts fiche lists completely different part numbers, but stock needle vs jd look almost identical.

JD needles do not jet the same as Yamaha Needles in my experience the JD needles are fatter (larger diameter) which require at least one size larger main jet (maybe two sizes depending on the application)