FMF- wtf!!!! Never again!

[WheelsUp]

You don't think that for that kind of money, he should be able to call up and get some solid advice, at the very least some good starting points?

Ya... and the starting point is, go up 2 or 3 on the main and one on the pilot.

There's only so many jets available in the range that'll work properly on your bike. You'd be hard-pressed to tell a 185 from a 182, but you might see a difference on the 185 to 180.

Personally, I'd go with a JD jet kit, at your altitude, start with a 180, 40 leak jet, 42 or 45 pilot (depending on the fuel screw adjustment).

Note, the 180 will probably be too rich without the JD needle (depending on what needle your YZ has).

In all honesty though, the FMF pipe is going to be more restrictive than your stock YZ pipe. You are probably just fine with stock jetting.

[MikeyMike]

Just my opinion, but I would think FMF could supply a dyno sheet with the jetting specs, altitude, temp and humidity. You know that they have this info when they developed the pipe. As said, this would at least give the guy a baseline for jetting.

[ovrrdrive]

Well, I suppose they could tell you guys if it was going to use less or more fuel than a stock pipe, but I still think there are way too many variables than they could compensate for.

For example, who's to say that at 8000 feet, 30% relative humidity, 85F, in June; a completely stock bike and a bike with a big bore kit, modded airbox (little mods or big mods?), aftermarket cams, dirty spark plug, dented header pipe, higher compression piston, and race gas will both have the same jetting influences by changing to one of their pipes?

It would be a waste of time to even make a recommendation in my opinion... If you're changing your pipe, you should at least be able to tell if your jetting was affected by the swap by one or two jet sizes either way. It really isn't rocket science....

[STRAIGHT EDGE]

In my opinion, humidity, and temp. is for fine tuning. Anything I have learned about my bike has come from everyone that has helped myself or others out on here. They pointed me in the right direction and I would follow it, and then it would be fine tuning it after or a trial and error period. He should have been able to ask FMF, I have this bike with these mods and I ride mainly at this level. FMF could have said try such and such jets, with ______ turns of the fuel screw. For just a starting point. Everyone on here was not born as Jetting EXPERT. All the ones that think you are, remember you started from the beginnig once too, where you had no idea what a jet was. Thank you to all that have helped him out by trying to steer him in the right direction, and not clowning on him. I for one am clueless on working on these bike and am barely starting to learn how to tune it, etc.......... COMMON COURTESY

[YZ250F_Rider]

In my opinion, humidity, and temp. is for fine tuning. Anything I have learned about my bike has come from everyone that has helped myself or others out on here. They pointed me in the right direction and I would follow it, and then it would be fine tuning it after or a trial and error period. He should have been able to ask FMF, I have this bike with these mods and I ride mainly at this level. FMF could have said try such and such jets, with ______ turns of the fuel screw. For just a starting point. Everyone on here was not born as Jetting EXPERT. All the ones that think you are, remember you started from the beginnig once too, where you had no idea what a jet was. Thank you to all that have helped him out by trying to steer him in the right direction, and not clowning on him. I for one am clueless on working on these bike and am barely starting to learn how to tune it, etc.......... COMMON COURTESY

And then after all that, someone might make the connection that FMF has hundreds of employees, with very few being jetting experts. Making it improbable at best to get anyone on the phone that even knows what a jet is. But probably not, most prefer to bash without cause.

Jetting is simple, period. The only reason it seems difficult is because you havent done it before, or you were taught an incorrect method. http://www.thumperfaq.com/jetting.htm

[rick2900]

Thanks for the input All I wanted was a straight answer from FMF. When I purchased my 2001 YZ426F Pipe from White brothers they told me over the phone how to get it close and the rest was fine tuning. They also sent a paper on how the carbs work and what jet does what.

[brian_huber]

hey guys your being a little harsh.............

out here in So-Cal, the weather's the same year round.....btw, all Shops know the riding areas, high Desert , low desert, Mountain, sea level and all the TRACKS..............so, FMF could have easliy had that info he was requesting, but they didn't........

on my last two pipe purchases, Pro Circuit & Dr. D, knew the recommended jetting requirements for my bike..........

it was a VALID question.............

You are absolutely right... I had the same experiance with DR.D the guy knew

I lived in Cali just from the area code number he called me back at. I told him the areas I ride, and his suggestions were spot on.

[sjwr450]

I bought the same combo and opted to not put on the Megabomb once I saw how small the pipe opening was. I can understand the 'Powerbomb" SX versus MX pipes but that is not the case with the megabomb. To me if you want to make a smaller diameter pipe first they should say it is smaller, second the ports should still line up then get smaller. With this pipe the exhaust gases are hitting a wall that is 1/4" smaller by my measurements. Any engine builder would have a fit if they saw this.

[Whoya]

You gotta ask for Tech support. they got tech support dont they?

I would think going up on the main and raising the needle would be good starting points. Gotta go out and ride. just pay attention to the motor, the way it sounds and feels, and responds to throttle. If you pay some attention to it you will begin to understand how it works and wont need some yahoo sales guy giving you advice.

Basic jetting is not difficult to understand if you put some effort into it. and besides then your friends will think your a freekin genious!!

[ATAZ]

I called pro-circuit and they gave it to me straight and it was a chick she knew her stuff!! you might have talked to the wrong guy or in my case girl, good luck

[Reyndogg]

Aftermarket strikes again...

Probably the reason to buy an exhaust that uses stock jetting, like DR.D

think about what you're saying here...any pipe, including OEM, can use stock jetting, but that doesn't mean the jetting couldn't be better.

Stock is only what it comes with, and is certainly not right for every riding environment (i.e. altitude/humidity/temp/etc) and exhaust.

[WheelsUp]

Keep in mind though, that he's going from a very non-restrictive exhaust (stock YZ) to an FMF with a sparky...

All of the normal rules about ballparking your new jetting go out the window.

Stock jetting is probably going to be good.

[rick2900]

OK, went with a 178 main, 45 pilot and thats was it, she runs/starts great with no hesitations or poping. she hits hard down low and keeps pulling all the way up. This was at about 2000 feet elevation in San Jose California, with the FMF Q2 titanium and the Mega bomb header.

[YZ250F_Rider]

See, was that so hard?

I still think the Q2 signs off a lot earlier than my T-4 did though.

[Reyndogg]

Glad to read you got your bike running well!

[godov]

Aftermarket strikes again...

Probably the reason to buy an exhaust that uses stock jetting, like DR.D

And tell me with the stock jetting do you feel anything different on the bike or is it just the sound it makes?

I always thought that a different exhaust would necessarily have a different tunning!!

[WRider995]

How is the guy an " IDIOT " for wanting to vent some frustration and looking for some help or solid direction. It seems to me that all he was looking for was a starting point.

I agree. I had the same problem a few years ago when I called FMF for the specs on WR400F jetting setup. The main they told me to go with was like 5 sizes larger than stock and Yamaha didn't even have a part number for that big of a MJ. They were so far off it wasn't even funny. I ended up going up one size from stock for riding most of the year.

I will say the FMF idiots at least knew to go a size richer on the PJ.

Still, give us a baseline estimate for fine tuning FMF, you morons! You're probably making 400% profit on each exhaust. I'm done with that company, too.

[ttr225ttr]

I paid 80 bucks to get my bike tuned on a dyno - thats the best way to do it.

The rest is guessing and/or hoping - IMO.

$80? my dealership said about $200 for my bike so instead I did it myself and its close but not perfect(but much better than 198 more dollars!)

[oleskool]

$850 for a pipe ? And one guys claims it's more restrictive than the stock yzf pipe? What's the point?

[NoFiddyPilot]

This thread is now in the jetting forum, where it should have been to begin with. The BS has been delete b/c a few can't seem to discuss without talking like a couple of zit-faced teenages, trying see see who can be the crudest and rudest. If you have something intelligent to add, please do so. If you want shoot your mouth of, please do it elsewhere.