new pipes installed

Airborn,

I thought about trying the 260's, but I was afraid of doing some damage. I figured it'd be better to go bigger first, then try smaller???

Im a novice with this two stroke stuff. How will I know if the 260 is too small?

FMF recommends 260 mains, and upping the pilot to a 30 from the 25. Cleartoy mentioned that this doesnt work well, and suggested trying something around a 280 main and keeping the stock 25 pilot.

The main jet only controls WOT, right? if so, and FMF says use a 260, then I'd think I'd be all set. Especially considering that I currently have a stock airbox and filter with just the snorkel removed. Maybe when I get a better lid and a K&N the 270/280 would be better suited.

anyone?

I would leave the pilot jet at 25 and set the mains at 260. If you have problems at wide open then up it a bit.
Funny enough, I need to up my mains on mine, but I havent had time. I am upping my mains to 260 on my ride. They are 220 now and when i crack it wide open, and it gets there it bogs out...lack of gas.

One thing to remember that not many will tell you is that the needle valve....change the E clip!

One way to look at it is this, when you richen the Main and pilot, make sure you richen it accross the board...people tend to forget this and have mid and wide rich but low is not changed. This can cause problems in the long run by scoring pistons and/or walls.
needlevalve=idle to 1/4 throttle.(0-1/4)
Pilotjet=Middle Throttle.(1/4-3/4)
Mainjet=Wide Open Throttle.(3/4-full)

Hope this helps and it isnt a bunch of babbling

AirBorn!!

I would try the 260's, but to be safe why not wait to get the 280's, several bikes that I have piped have required 280's even a few upwards of 300, 320. It all depends, it's far to difficult to sit a computer and simply say here's what you need. We can get you into the ballpark range, but there's some tuning required on your end to get it spot-on. AirBornBanshee is slightly confused on which carb circuit affects what throttle setting.

Air screw; Idle to off-idle
Pilot Jet: Idle, off-idle to 1/4 throttle
Needle taper, length and diameter: Off-idle thru 3/4 range
Main Jet: Slightly less than 3/4 to WOT.

Each circuit overlaps; with the most overlap coming from the needle length to the main jet size. Moving your E-clip on the carb effectively changes the length, but smaller diameters and more taper accomplish the same. But obviously moving the needle clip is the easiest and most common.

Running your bike lean will not gain power, only cause harm. Most engines run best ever so slightly on the side of rich. When it bogs and falls on it's face, you are oh so close to burning a piston, if damage has not been done already(at least to the piston crown edge on the exhaust port side.) Mid range seizures are a very real problem as well, mid range has to be one of the toughest to tune.

I reccommend looking into buying aftermarket needles from Toomey, they certaintly help clean up throttle response across the range. Thier length, diameter and taper vary from that of OEM, therefore they are a tad more performance minded.

As a rule you should ALWAYS start larger than you think you may need for jetting across the board, but most crucial is the main jet size. Think of it this way, would you rather spend an hour or two swapping out jets to get it down to where it needs to be, or spend several more hours and a handful of cash to get a top-end rebuilt.

--Backcountry

Wasn't sure if it was a typo or ?...The air screw actually can be viewed as a sub circuit of the pilot jet. It provides the adjustability of the pilot jet to get a steady idle and easier starting. But I still think it's important to include.

As far as new needle, yes the stock needles do have plenty of adjustment and do perform thier job well, but...the Toomey needles are more performance minded and can help clear out some of the flat spots that all bikes have.

Well, it's sounds like you're headed in the right direction. White is death. So. Here's a article written by the "Godfather of Two Strokes" Gordon Jennings.
http://www.strappe.com/plugs.html

This should start to give you an idea of what you need to be looking at when you look at your plugs. It's always imperative that anytime you make any changes you check your jetting again(different filter, no airbox or lid, pipes, porting, fuel/oil ratio) Differences in temperature too. If you jet your motor for August(mostly like have to go leaner to due to the warmer less dense air) that if you try to ride it again come December and it's 20 degrees outside(cooler denser air, better for power, but requires more jet), you risk engine seizure.

An excellent description of how your mid range may react to particular jetting set-ups. Blubbering at steady throttle setting, 1/2 throttle cruising, indicates rich, while surging indicates lean.

Good luck!!

--Backcountry

If you are running the stock lid, then by all means start at the pipe manufacturers reccomendations. However, it is always better to start out rich(bigger main) than smaller (lean). 260 is the MINIMUM id start with, assuming the rest of the bike is stock.

260 is based upon sea level elevation assumption. What elevation do you ride at?

The local dealer will have the right jets. Jetting gets way out of hand when running without a lid, or clamp on KN filters, and or porting. For example, i ran [email protected] level, when i only had pipes, kn filter on PD mount with Outerwear and no lid. I ported it, and eliminated the stock box, with clamp ons, and currently run [email protected]

As to the spark plugs. THey should be cocoa brown. White is LEAN, black is rich.
You may not get the jetting right on the money the 1st or second time, dont give up, it takes trial and error

Are you running teh PC2 or TC silencers?

Toomeys are the loudest.

-cleartoy

Well, my local yamaha place didnt have any jets bitter than 240. I decided to stick the 260's in and give it a try. Man, those jets are a pain in the ass. You cant get the carbs out without taking the airbox out, and you cant take that out without taking the rear plastic off. Screwing in the jet while holding that plastic thing and washer in place without pushing the threaded part in was quite a chore, too. I dropped that washer about 4 times.

I did finally get it in. I started it up, and it seemed ok, but I havent driven it still. I need to put the filter in, and put the rear plastic back on.

I have the PC2's. Are you supposed to seal the connection between the silencer and pipe? I saw mine leaked, so I put a rubber clamp from the stock pipes over the seam.

I hope to try it today. If cleartoy needed 300 mains with the only difference being a K&N and no lid, then I'll bet these 260's will be marginal. We'll see.

I'll report back later.

Eric

youve got to be kidding me! Youve got to find another dealer or light a fire under their ass to keep a good stock of jets. Your not the only one in your town that needs jets!

Brother, i feel your pain about changing jets with a stock airbox on. Thats why i went to individual clamp on KNs! I can change jets in 20 min, with plastic intact, and silencers intact.

AS for the little plastic deal, it can be removed or installed after the main jet is on. For example, take it off before you remove the main jet, and install it after you install the new main jet. It just slides over the jet.

With these pipes, i purchase the Pro Design collars. They are polished alluminum with rubber o rings inside. They were less than the cost of the 2 stock rubber pieces and 4 clamps. They seal well, and look awesome!!!!!!

Please let us know your progress.

Always here for ya.

-cleartoy

Alright, I took the ol banshee for a quick burn yesterday, but it was brief. I warmed it up, and gave it 2 or 3 WOT blasts, but not for long. It pulled the front tires so quick I almost killed myself. Thank god the rear brakes work. No helmet and t-shirt would of sucked. I didnt have time to check the plugs yet, though.

I found a local place that has jets. I dont know anything about this place, or what their credibility is, but he was really pushing a dynojet needle kit. He spoke of a lean spot, even with a bigger main and bigger pilot, that would be cured with the needles, and would be advantageous to a trail rider like myself.

The kit with 3 different jets is 78 bucks. For 147 I get a K&N with it.

What do you guys think? He also highly recommended the 30 pilot jet. I'd like it to be as safe as possible and set up for trails as good as possible. I've learned a good lesson through drag racing a mustang not to believe everything you hear/read...

cleartoy, thanks for the tip on the plastic thing. I dont know why I didnt think of that before.

How many times can you change jets before you have to replace the bowl gasket?

thanks
Eric

I finally went for a ride with my new gnarley pipes yesterday. I rode mostly on trails in one sandpit. I have to say Im thoroughly NOT impressed. The whole ride basically sucked. I lost a lot of low end with this setup. Im really hoping that Im choking the motor up having the stock airbox, stock lid with the snorkel removed, and the stock foam filter. Either that, or I dont have the carbs setup right with the jetting and needles.

When Im at a low rpm and throttle it, the delay until the power kicks is much much longer than with the stock pipes. I bogged over just about every mogul. Keeping it up where it's making the power is about impossible.

When in the sandpit, it was even hard to keep it screaming. If I slowed down too much like say in second, and whacked it, it seemed like forever to get back into the power.

Im going to get setup with a vented box lid and a K&N, and maybe look into a dynojet or toomey needle kit. It was bad enough that if these mods dont improve it, the pipes are coming off.

Maybe I was expecting too much from these pipes, but I never thought I'd LOSE low end power.

It'll be too bad to take them off, because when this thing hits the powerband, its much faster than with the stock pipes. I had no trouble pulling the tires in 4th. I didnt even try 5th.

I might try to find a good local place that could set the carbs up for me, after I get the K&N in there.

any suggestions?

thanks
Eric