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NMS

Jet Kit Suggestions and Hot Start Part

11 posts in this topic

I have an 06 YZ450F. I got into a real bind recently. I broke a main jet off while screwed in. While trying to get it out at the track, I kind of messed the tip of the needle up. I took a fine sand paper and fixed the needle for the day, but want to replace it. I figured I would just get a jet kit. What type do you all suggest? I looked at the FMF , but it looks like it is more for using with the FMF Exhaust. I have the stock exhaust and plan to keep it.

Also, while messing with it I messed a part of the hot start up. The black threaded piece that screws into the top of the carberautor. I tilted the carb to far to the side trying to get under it. This knocked the piece out. It stripped one side of the threaded piece. It went back in, but I would like to get a new one. My question is, does anyone make an aluminum one? I would really like to get an aluminum one, instead of plastic.

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I have an 06 YZ450F. I got into a real bind recently. I broke a main jet off while screwed in. While trying to get it out at the track, I kind of messed the tip of the needle up. I took a fine sand paper and fixed the needle for the day, but want to replace it. I figured I would just get a jet kit. What type do you all suggest? I looked at the FMF , but it looks like it is more for using with the FMF Exhaust. I have the stock exhaust and plan to keep it.

Also, while messing with it I messed a part of the hot start up. The black threaded piece that screws into the top of the carberautor. I tilted the carb to far to the side trying to get under it. This knocked the piece out. It stripped one side of the threaded piece. It went back in, but I would like to get a new one. My question is, does anyone make an aluminum one? I would really like to get an aluminum one, instead of plastic.

Darn it Greyracer you beat me to it... :lame:

this is a "bad day" at the track...I have also over torqued the mj...get a small screw driver to remove the rest of it...on the needle jet...you have 2 options...

1. buy a replacement needle from Yamaha ..there a 2 different needles you can chosse..DRD swears by the optional one.

2. Buy the JDJetting kit. JD has specific red and blue tapered needle jets that add more throttle response and power than stock.I use this on my BB03...They work well

Zip Ty/Pro Circuit makes a alum nut for the hot start plunger...a must to replace once you mis thread the plastic nut

Take your time and be patient...that is why you broke stuff. :thumbsup:

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guys can you explain the nflr needle? it appears to be a leaner needle than the stocker.

i found the needle, pilot, and fuel screw to be lean at factory/dealer settings on my bike. currently i am running an 06 yzf 450 with stock needle on clip 4, 48 pilot, fuel screw at 3 turns with a 165 main, stock pipe, with twin air , no toil prepped filter. i am in michigan running 65-90* at 60-900 feet elevation.

with the stock settings i had a nasty decel pop, sharp and loud. went to a 45 pilot roughly the same outcome, loud decel popping. played with fuel screw, needle clip and mains. could not get rid of the pop. upping the mains helped but then the motor felt flat.

the current set up ran well a week ago, pulled hard very little popping.

i appreciate the input you all give us on our problems, thanks for the feedback in advance. ski

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I run a 45 pilot, and a 165 main with the needle in 4 (stock needle; NFLR is on its way). It pops a little, 1-3 times on decel, which means the idle circuit is about right. If you are running a 48 and still popping badly, check the exhaust for air leaks.

The purpose of the needle is to meter fuel at the right rate at any given throttle opening from a point near 1/8 throttle to a point near full. It makes the transition from pilot circuit to the main jet work. If you were to graph the fuel needs of the engine through that sweep of throttle, you would want a graph of the actual fuel delivery to match it as closely as possible all along the graph. The point of the NFLR is not so much a question of it being richer or leaner. If it was that simple, all you would need to do is change the clip position. The deal is that it is shaped differently, and so changes the curve of the fuel delivery graph.

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I run a 45 pilot, and a 165 main with the needle in 4 (stock needle; NFLR is on its way). It pops a little, 1-3 times on decel, which means the idle circuit is about right. If you are running a 48 and still popping badly, check the exhaust for air leaks.

The purpose of the needle is to meter fuel at the right rate at any given throttle opening from a point near 1/8 throttle to a point near full. It makes the transition from pilot circuit to the main jet work. If you were to graph the fuel needs of the engine through that sweep of throttle, you would want a graph of the actual fuel delivery to match it as closely as possible all along the graph. The point of the NFLR is not so much a question of it being richer or leaner. If it was that simple, all you would need to do is change the clip position. The deal is that it is shaped differently, and so changes the curve of the fuel delivery graph.

The 4 letters indicate the taper angle in each of 4 zones along the length of the needle.

GreyRacer let me know what results you get with this NFLR needle...theDR DRD swears by it...

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The 4 letters indicate the taper angle in each of 4 zones along the length of the needle.

The 4 letters are not identifying taper angles on this needle. The only letter with a specific dimension is the "R", which is a needle straight diameter of 2.755mm. The Nxxx is common for factory specific needle codes, whether single taper or multi-tapered. The NFLR has 2 tapers.

James

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The 4 letters are not identifying taper angles on this needle. The only letter with a specific dimension is the "R", which is a needle straight diameter of 2.755mm. The Nxxx is common for factory specific needle codes, whether single taper or multi-tapered. The NFLR has 2 tapers.

James

James how does this NFLR taper compare to your needles?

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At 0-1/4 throttle the NFLR is very close to the Red marked needle other than clip position. Above that, the kit needle will give a better mid-range and top-end power by having more tapers to more effectively deliver fuel. The NFLR is like a single taper needle past 3/8 throttle, similar to an OBEKR needle.

James

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I noticed the NFLR needle is listed in the 06 manual, and not in my 03 manual. Should I try the NFLR or go with the listed needles in my manual?

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