New pipe and silencer

Got questions? We got answers....
Post Reply
User avatar
cfspawn
Member
Posts: 202
Joined: 05:22 pm Oct 18 2005
Country:
Location: Hobart Australia
Contact:

New pipe and silencer

Post by cfspawn »

Hey all
Just put a new FMF fatty and silencer on me E2 KDX and got instant massive reaults the bike is ideling perfect now and smokes less.. and of course a massive power difference like a new bike. just wondering is the any point re jetting my carb to suit if it is running this good? will it hurt anything if i dont ive always beleived if it aint broke dont fix it !
User avatar
bradf
Gold Member
Gold Member
Posts: 703
Joined: 02:17 am Dec 11 2004
Country: USA
Location: Anderson, SC

Post by bradf »

You can ride it and listen/feel, and the sound and feel can tell you somewhat if you are rich or lean (bogging). Plug checks and pipe wet ring will be the definitive signs of proper jetting though. But for kicks, you can get new plugs and do a full throttle chop and see how close you are on the main jet. There are other techniques for feeling the needle's characteristics but you really need to know what perfect is to feel and hear these as you would base this on knowing perfect. The point is unless you are extremely intimate with your machine and know what it is supposed to be like in sound and feel when jetted perfect, as mine is, and then you may never know that the jetting is off. How do you know you are not lean? That would be the same as "almost broke" or "could seize real soon". Do yourself a favor and become a jet wise expert on your own bike. It doesn't take but a couple of needles and mains, possibly a pilot. Run it, make changes if needed. Then there is the slide cut...

***unpaid plug***
Send the carb and head to RB and when you put it on you will be extremely close to perfect and the SSS will only be a tweak away.
'04 220 w/'01 KX250 USD forks, '02 RM125 Showa shock, Rekluse EXP 3.0, LHRB & all RB'd
User avatar
cfspawn
Member
Posts: 202
Joined: 05:22 pm Oct 18 2005
Country:
Location: Hobart Australia
Contact:

Post by cfspawn »

Yeah cheers Bradf.
when you buy the pipe you get some info on jetting with it specs on what jet to use on models etc should i go by this or judge it on the bike itself any suggestions would be great cheers
User avatar
m0rie
Supporting Member I
Supporting Member I
Posts: 2220
Joined: 10:25 pm Nov 29 2004
Country:
Location: Crescent City, CA

Post by m0rie »

How is the carb jetted right now?
1989 KDX 200
2007 TTR-50E
User avatar
bradf
Gold Member
Gold Member
Posts: 703
Joined: 02:17 am Dec 11 2004
Country: USA
Location: Anderson, SC

Post by bradf »

The recommended jetting from FMF is like a neighborhood jetting guide. It'll get you in the hood but you in fact want to find a certain homey's house, in which case you either say to yourself your homey will one day find you or you can do a tad more tweaking and find yourself in the crib. OK, this ghetto crap has got to stop right now. FMF assumes you will leave the carb pretty much stock, with the crappy 1173 needle and rich all over jetting.

The only true jetting guide is your bike, barometric pressure, air temp, air density, reeds, air filter/box, head, porting, pipe, there are more...
Even the way you ride or where you ride and the varying riding conditions can determine certain jetting changes.

If you are asking "am I close"? That is relative to what? Not fouling? Not near a lean seizing condition? Bike idles great...but you don't ride at idle. Are the transitions between circuits OK? How is the 1/4 throttle? 1/2 throttle etc?

Judge it by the bike itself. Don't be afraid to make logical changes.
'04 220 w/'01 KX250 USD forks, '02 RM125 Showa shock, Rekluse EXP 3.0, LHRB & all RB'd
motorhed220
Member
Posts: 215
Joined: 04:23 pm Dec 30 2005
Country:
Location: Hamilton Ontario

Post by motorhed220 »

Hey u said u got a Fatty, I didnt know that FMF made a fatty for the KDX...how is it sompared to the Gnarly?
Live to Ride, Ride to live!!!
motorhed220
Member
Posts: 215
Joined: 04:23 pm Dec 30 2005
Country:
Location: Hamilton Ontario

Post by motorhed220 »

PS: Just checked the FMF website...they make a Fatty Gold Series, but the latest year is a 94 KDX...is that much of a difference from a 2005, or am i gunna have to stick with a Gnarly?
Live to Ride, Ride to live!!!
User avatar
cfspawn
Member
Posts: 202
Joined: 05:22 pm Oct 18 2005
Country:
Location: Hobart Australia
Contact:

Post by cfspawn »

I heard the gnarly was better anyway
yeah gonna do a plug chop this weekend see how things are running and rejet from there..
Rhodester
Member
Posts: 63
Joined: 07:24 pm Feb 06 2006
Country:
Location: Meridian, Idaho

Post by Rhodester »

Remember, they're talking about the 'E' series of the KDX not the '95 and newer 'H' series KDX. The Fatty (for the 'E' series) is probably similar to the Gnarly Rev pipe for the 'H' series. FMF used to make a Fatty pipe for the 'H' series when the 'H' series first came out (I have one). It is exactly the same as the Gnarly Rev pipe that they make today. It even has a -30 on one of the mounting tabs. The only difference is that the Fatty uses slightly thinner metal than the Gnarly series pipe.
'95 200H
Post Reply