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Going to make a 06 YZ262F, any suggestions?

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After researching all the threads on big bore kits and because I ride mostly MX, I'm going to go with a 262 kit. There is a big price difference in all the kits available. Anyone have a bad experience using the Lucas Racing kit, they seem to be the cheapest, but sometimes you get what you pay for. Will I have to change the jetting? If so, can someone suggest a starting point. I ride up in Colorado and still don't have my stock jetting where it needs to be. I brought my bike in to Vickery Yamaha (after giving up on my jetting skills) and they seem to have missed the spot on jetting also. As a matter of fact, I'll be going back to my original specs. I have a 162main (is that too rich?) a 48 pilot (which I know is too rich, I'll try a 40 next, stock 42 had too much bog) and I have a stock needle on #2. I have no clue on the leak jet, but Vickery put in a #70. Any suggestions or comments would be helpful.

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Anyone have a bad experience using the Lucas Racing kit, they seem to be the cheapest, but sometimes you get what you pay for. Will I have to change the jetting? If so, can someone suggest a starting point. I ride up in Colorado and still don't have my stock jetting where it needs to be. I brought my bike in to Vickery Yamaha (after giving up on my jetting skills) and they seem to have missed the spot on jetting also. As a matter of fact, I'll be going back to my original specs. I have a 162main (is that too rich?) a 48 pilot (which I know is too rich, I'll try a 40 next, stock 42 had too much bog) and I have a stock needle on #2. I have no clue on the leak jet, but Vickery put in a #70. Any suggestions or comments would be helpful.

I hate to sound like a broken record, but I had an excellent experience with Luke's Racing (I assume you mean Lukes, not Lucas?).

http://www.thumpertalk.com/forum/showthread.php?t=337416

Let's do some jetting comparisons, "just for fun":

Mine

----

2006 YZ250F

Dr. D pipe

262 kit

Main: 175

Needle: ELQ (stock) in position #4

Pilot Jet: 45

Fuel Screw: Approx 2.5 turns out

Leak Jet: #60

Yours

2006 YZ250F

???? pipe

Main: 162

Needle: ELQ (stock) in position #2

Pilot Jet: 48

Fuel Screw: Approx ??? turns out

Leak Jet: #70

So I have no idea what kind of pipe you have, but let's pretend that I didn't have my 262 kit installed. My jetting was the same, but I had a 178 main in it. You are from Colorado, it looks like, so your altitude is going to require a leaner main. But WOW! A 162 main? That's REALLY lean, not too rich at all!

"Just for fun", try a 175 main, needle in position 4, pilot 45. Your leak jet of 70, sure, why not keep it for now. I'd only change it if you have bog issues later, after the rest of your jetting is better sorted. My 60 is awesome for me, no bogs ever while riding, but the rest of my jetting is really good too.

Try that and let me hear how it goes!

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Thanks for the info. I already tried numerous different main jets including the 175. I got help from Burned in the jetting forum who suggested a 160 main jet which is what I had before Vickery changed it to a 162. Right now I can't even start my bike, hot or cold, without letting more air in by using the hot start. Our altitude is about 6,500 ft or so. Glad to hear about the Lukes Racing, yeah I meant "Lukes", kit. So I take it you did not rejet after adding the kit? By the way, I have a huge bog right off idle. That's the leak jet? I thought it was the pilot jet. My fuel screw is all the way in right now w/ the messed up jetting from "professionals". If I turn it out even 1 turn, the engine starts to run rough.

06 YZ250F

FMF Ti Powercore slip on

Twin Air filter

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Leak jets play a big factor in low end bog. If it were my bike I would just grab a jd jetting kit. I had one when I had my yz and it really rocked. Perfect jetting basically and its simple. Perfect for me.

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Thanks for the info. I already tried numerous different main jets including the 175. I got help from Burned in the jetting forum who suggested a 160 main jet which is what I had before Vickery changed it to a 162. Right now I can't even start my bike, hot or cold, without letting more air in by using the hot start. Our altitude is about 6,500 ft or so. Glad to hear about the Lukes Racing, yeah I meant "Lukes", kit. So I take it you did not rejet after adding the kit? By the way, I have a huge bog right off idle. That's the leak jet? I thought it was the pilot jet. My fuel screw is all the way in right now w/ the messed up jetting from "professionals". If I turn it out even 1 turn, the engine starts to run rough.

06 YZ250F

FMF Ti Powercore slip on

Twin Air filter

I think you KNOW you're running too rich, now do something about it!

For better starting, you need to go WAY leaner on the PJ - try a #40 or #38, fuel screw around 1 to 1.5 turns out. #2 clip position on the stock needle and do what Burned said - go with the 160MJ. There are people in Colorado running with 155MJs, so a 160MJ is fine for your altitude.

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