Jets included with my FMF exhaust?

[pulp_friction]

Hi all,

 

 

I just put on a FMF Fatty complete system including Power Core 2 cans to my 2004 Banshee.

 

The supplied jets with the package were 260's, when I pulled the carbies apart I noticed there were already 280's installed.

 

I am fairly sure the engine is stock with the only visable changes being a White Power balancer and no lid on the airbox.

 

Will I do any damage running with the 260 jets, or should I slam the 280's back in?

 

What are the symtoms of wrong jetting?

 

Let's call my ridding technical at sea level. (In Australia if that makes any difference)

 

Thanks in advance.

[wfobasheeboy]

Hi all,

 

 

I just put on a FMF Fatty complete system including Power Core 2 cans to my 2004 Banshee.

 

The supplied jets with the package were 260's, when I pulled the carbies apart I noticed there were already 280's installed.

 

I am fairly sure the engine is stock with the only visable changes being a White Power balancer and no lid on the airbox.

 

Will I do any damage running with the 260 jets, or should I slam the 280's back in?

 

What are the symtoms of wrong jetting?

 

Let's call my ridding technical at sea level. (In Australia if that makes any difference)

 

Thanks in advance.

 

 

Well frist off welcome to HQ.

 

I have a stock banshee too with FMF gnarly with power core 2. K&N & no lid. Also +4 timing .

I am running 320 on the mains & 27.5 poilts & needel 4th spot. I ride at sea level & 80F

 

I hope this helps you out.

[12 0 Clock P I M P]

I have a stock banshee as well with FMF gold series on it......I run 280's at 500 ft with 25 pilots

IT is spot on and very crisp

[Burt Reynolds]

What type of pipe came off of it. If it was another aftermarket pipe i would try the 280's. If your replacing stock pipes i might ty a little richer

[pulp_friction]

What type of pipe came off of it. If it was another aftermarket pipe i would try the 280's. If your replacing stock pipes i might ty a little richer

 

 

Thanks Burt,

 

Previous pipes were stock.

 

A little richer....say 300?

[pulp_friction]

I have a stock banshee as well with FMF gold series on it......I run 280's at 500 ft with 25 pilots

IT is spot on and very crisp

 

 

Thanks mate,

 

 

Sounds like at least the 280's should go back in.

 

Can I screw anything up by taking it out this weekend for a couple of hours with the 260 jets installed?

 

I have run out of time.

[madjimmax]

Personally I think even the 280s are going to be to small. If I was you I would pick up a few sets from 300 to 340 you can hit Jeff @ FAST to get single jets. Then I would try a 300 and do a proper plug chop and then go from there. All bikes are a little different and all anybody can do for you is give you a starting point. If you run the thing lean you will burn it up and also just to let you know a shee will run its ass off with a slight lean condition until it blows, so whatever you do make sure you do a plug chop.Oh and make sure you have a 27.5 pilot jet all shees with aftermarket pipes should be running a 27.5 pilot jet. Good luck and welcome to the BHQ.

[luv2ride]

Ok, call me crazy but I'm running 250 mains with 27.5 pilots. Stock air filter and stock exhaust. This thing screams. Other than that its all stock.

 

To me it seems Yamaha purposely under jets em

 

 

 

Personally I think even the 280s are going to be to small. If I was you I would pick up a few sets from 300 to 340 you can hit Jeff @ FAST to get single jets. Then I would try a 300 and do a proper plug chop and then go from there. All bikes are a little different and all anybody can do for you is give you a starting point. If you run the thing lean you will burn it up and also just to let you know a shee will run its ass off with a slight lean condition until it blows, so whatever you do make sure you do a plug chop.Oh and make sure you have a 27.5 pilot jet all shees with aftermarket pipes should be running a 27.5 pilot jet. Good luck and welcome to the BHQ.

[bansheesandrider]

Thanks mate,

 

 

Sounds like at least the 280's should go back in.

 

Can I screw anything up by taking it out this weekend for a couple of hours with the 260 jets installed?

 

I have run out of time.

Yes, you can fuck it up big time, like sieze it or melt a piston, etc. A melted piston could lead to even bigger damage, like a crank. My wife's bone stock 96 with a 2 into 1 AIR FILTER by Toomey with a K&N element, and FMF Fatty's with Cascade silencers ran a 290 main, 27.5 pilot and clip in the middle, and was jetted perfect.

[pulp_friction]

Personally I think even the 280s are going to be to small. If I was you I would pick up a few sets from 300 to 340 you can hit Jeff @ FAST to get single jets. Then I would try a 300 and do a proper plug chop and then go from there. All bikes are a little different and all anybody can do for you is give you a starting point. If you run the thing lean you will burn it up and also just to let you know a shee will run its ass off with a slight lean condition until it blows, so whatever you do make sure you do a plug chop.Oh and make sure you have a 27.5 pilot jet all shees with aftermarket pipes should be running a 27.5 pilot jet. Good luck and welcome to the BHQ.

 

Thanks madjimmax,

 

My carbie overhaul kit arrived today, I wan't expecting it but it came with some 290 & 300 jets.

 

I popped the 300's in and will see how it goes.

 

There were also some pilots, I coudn't see any #'s on them....how do you tell the size of pilots?

 

I had better search "plug chop" as I have nfi what that means, sorry to be a nuff nuff!

 

 

Thanks for your assistance.

[Jereme6655]

the numbers are on the pilot jets....they're jsut really small and a bitch to read.

 

and a plug chop tells you if your runnin rich or lean .....here's how to do it

 

Warm up shee on old plugs.. Ride shee to area where you can make one pass as fast as she'll go. install 2 NEW plugs. start the shee and pin it to win it. run it as HARD as you can all the way through 6th gear......THEN (VERY IMPORTANT) when you hit top end pull the clutch in and shut the motor off. Then remove your plugs and take them home using the 1st plugs to get you back......and chop the threads off the new plugs to see the color of the porcelan on electrode.

 

you want a nice milk choclate ring 2mm tall from the base of the plug. if its dark brown your running rich and need to jet down......if its too light then you're running lean and you need to jet up some.

[madjimmax]

the numbers are on the pilot jets....they're jsut really small and a bitch to read.

 

and a plug chop tells you if your runnin rich or lean .....here's how to do it

 

Warm up shee on old plugs.. Ride shee to area where you can make one pass as fast as she'll go. install 2 NEW plugs. start the shee and pin it to win it. run it as HARD as you can all the way through 6th gear......THEN (VERY IMPORTANT) when you hit top end pull the clutch in and shut the motor off. Then remove your plugs and take them home using the 1st plugs to get you back......and chop the threads off the new plugs to see the color of the porcelan on electrode.

 

you want a nice milk choclate ring 2mm tall from the base of the plug. if its dark brown your running rich and need to jet down......if its too light then you're running lean and you need to jet up some.

 

Also remember that after you shut motor down keep the clutch pulled in until you come to a stop so that motor dont turn over, this could give you a false reading if the plugs get wet.

[sootman73]

and that wont hurt anything in the clutch system to run wot and top speed and just kill the motor? i thought i read earlier this week on here that that would well a ball in the socket or something like that?