ARHG! Jetting an '03 220

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Mar 22, 2003
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#1
I have an '03 220 w/ no airbox lid and a FMF Powercore II silencer. Stock pipe for now. Can't get this girl jetted properly. Dad and I wore the screws on the carb out yesterday and the day before trying different things (not to mention two trips to town for various jets). Anyway, here's the skinny:

Stock was 145 main, 42 pilot, 1173 (stock) needle in the middle clip position. Very rich as you can imagine, had a bad case of the blubbers throughout range but roll-on was ok. Tried recommended settings from here (stock main, pilot, raise clip one notch) - still rich.
Went with recommendations from local dealer (135 main, 38 pilot, needle in various positions) - very crisp, ran like a champ mid to top, but from off idle I wick it WO it would bog (WAHH, then die). Borderline lean and had a serious problem off idle. Tried stock 42 pilot with needle in various positions; still bad bog off idle - unrideable.
Went to a 140 main, 42 pilot, needle in various positions. Now, borderline rich still with off idle troubles. What to now?
Here's my question - am I rich or lean off idle causing the bog? We've litteraly worn the screws on the carb out making changes, with no luck. I believe that the 140 main will be OK, but what about the pilot and/or needle position? Seems like anything other than the stock setup was causing the off idle problems. Any ideas on where to go now? We also tried all above mentioned setups with air screw in various positions.
 
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Sep 29, 2003
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#2
Big John--I thought you were gonna hold off on the jetting 'til you got the Gnarly. Anyway, here's my $.02. First, make sure you have a clean air filter and that the box is sealed well--I used blue rtv. Second, check your silencer packing---it could be gunked up bad. If so clean and replace packing. A couple of tips you might like: 1) get some small hemostats to make working with the jet needle more enjoyable. 2) go to your local hardware store and buy Allen screws to replace the Phillips heads that hold the carb bowl on---I believe yours are 4x16mm---makes it much easier to mess with the main and pilot without having to remove the carb. Now the fun part. I'm a seat of the pants guy---been involved with racing and high performance engines since knee high to a grasshopper. Oh, yeah---make sure the float level is correct and have good fresh fuel, not what's left over from last summer's lawn mower jug. Using the above tips, it should be relatively easy to put the bowl and go up on the main 'til it doesn't want to wind out. Then play with the needle to see if if you can get a smooth yet strong transition from about 1/4 throttle to wide open---if you can't, search the forum and look into a couple each of b,c series needles from Sudco at about $5 a pop---ei bek, bel,cek,cel. Search first though, because I'm not positive which ones you should get---I don't have a 220. Now the fun part---sounds like you had a lean bog if the engine dies when you hit the gas---mine will do the same thing if I try to get on it before it's warmed up. Whoops, make sure the bike is at operating temperature when jetting or you're wasting your time. I believe that if it starts on the first kick or starts without choking---WHEN COLD, that it's too rich. Follow the instrucions in the "tech tips" section on jetting to check if your pilot is close. Once you get that, it comes down to the air screw. You want very little, if any, hesitation when you peg it from idle---I know mine's right because the bike will stand straight up when i nail it---trust me---you'll know when it's right. Have fun. Please don't flame me too much!!! ;)
 
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Dec 14, 2002
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#3
I too had this problem. First, what elevation are you at where you are tuning? I am at 2000 ft and here are my specs: 140 main, 35 pilot, AS out 3/4 turn, stock needle on the top(leanest) clip. For every 1000 ft in elevation I rise, I turn the AS out 1/4 additional turn. My jetting is just rich enough that I don't need to mess with it as I go higher or lower in elevation. With this setup, and the engine warmed up, I can ride in 1st gear, clutch out, at an idle engine RPM and when I wick the throttle the front wheel will easily loft and loop the bike if I don't chop the throttle. Same senario in 2nd gear will loft the front wheel but not loop the bike.
Now for my secret weapon............Fuel. I discovered that the AS adjustment made almost no difference between 1/2 turn out and 2 turns out until I switched to VP C-12 race gas. I mix with Maxima SuperM 2 stroke oil, useing 3 oz of oil to 128 oz (1 gallon) of gas. Other gases may work too, but I KNOW what works in my setup so why mess around?
Other mods I have made to my bike that may or may not affect off idle performance: FMF woods pipe, FMF Turbinecore II S/A, FRP torque ring, VForce II reeds and cage, Wiseco piston, Airbox lid removed, Steahly flywheel weight, NGK BR8AIX plug, 12 tooth C/S sprocket.
If I were you, I would get my hands on some VP C-12 and give it a try. Also, there is a lot of information on this site discussing various fuel types you may find valuable. That is how I selected this fuel.
As far as wearing the screws out on the carb, stop in at the local hardware store and get some allen head screws.
As far as the order of mods to enhance low end performance, I would try this order: C/S sprocket, pipe, reeds, ring, flywheel weight. The flywheel weight is a blessing for preventing low rpm stalling in those akward situations and also smooths out any hit in the RPM range.
One final thing: make your AS adjustments in no more than 1/8 turn increments. If you use any more, like a 1/4 turn each time, you can easily pass up that sweet spot. This is very important!
 
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Mar 22, 2003
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#4
We made sure that the bike was warm when making changes. Some allen screws are a definite must purchase soon, as the stock el-crapos are already junked. Gas is fresh (last week) Chevron 93 mixed with Bel Ray H1R @ 40:1. A lean bog? Hmm, maybe a richer pilot?

Altitude is between 1500 and 2000 ft. As it is now, I'm thinking I may take her back to the dealer and have them "get it right"...
 
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#5
Wow! What a bunch of good info!! All in a couple of paragraphs!

Most allen screws you'll find (well, that I've found) are stainless. Make sure you use some never seize on the threads. Once you get things sorted out, you WILL have them in place so long that they WILL get stuck...allen head or no. The dissimilar metals thing......

As noted already....don't pass up the importance of the air screw. And after an adjustment, give the bike a chance to 'settle in' for a bit before you tweak it summore. A tweak followed by an immediate quick-wick-it, followed by more tweaking will just get you AND your bike confused.
 
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#6
Yes, the frustration/confusion has already set in. (Not to mention that during this process it was blowing a very pleasant rain/snow mix) ;)

I think I'll go back to stock and wait on the pipe before I do too much more. This is my first experience with jetting, so don't be too hard on me. The bike was rideable in stock jetting trim at least, although I know that there is a sweet spot that has more power in there. It's just lost in a overly-rich misjetted mess.

Thanks for the help folks.
 
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#7
Dude, don't let it frustrate you. Think, learn, and think again. Unlocking the power is the next best thing to riding it! It's not rocket science. Now if I were only confident enough to rebuild my shock and forks---the first time's always the hardest! As long as you don't run too lean, the worst that can happen is that you'll spooge yourself into oblivion. hehe--Good Luck! Jay
 
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#8
Once you get a feel for what change fixes what problem...and once you get that 'sweet spot' for a day's ride, you won't want to ride without it!


AND...it will be easier to GET to because of all the 'fooling around' you've done prior to!

Have fun! A circuit off a bit here and there will be a common occurrence. No reason to not have a good ride anyway!!
 

BJH

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#9
You may have already read this but here it is anyway.
http://justkdx.dirtrider.net/printcarbtuning.html
 

Braahp

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#10
John put the stock jetting back in...............raise clip 1 notch from middle..........then go get you a BR8"EG" plug and put in there and see how it runs. Might have to drop to the 140 main but the way the waether is around here now you're getting alot of good oxygen rich air in there.
 
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#12
Yep, it turns out I was experiencing a "lean bog". I went with a 140 main, increased pilot to 45, and the needle is in the middle (or raised one notch, can't remember now). Purring like a kitten. It's funny how different the same bike (make and model) can be from another one just like it. I'll be going through this once again when my pipe comes in (Gnarly Desert). Thanks for checking on me though!