The Jetting Matrix can't be right, can it?!

Bike WAS jetted 40/150 and I was experiencing severe bogging around 7500 RPM at WOT - no amount of needle adjustment changed a thing... slowly progressed from 150s to 147.5, to 145, to 142.5..... and am about to step down to 140s!!!!!! 

With EVERY main just swap I experienced more high-end acceleration and power, and less stumbling around 7-8k (adjusted and swapped needles with every step to experiment with tuning).  Originally started with a Factory Pro jet kit (included adjustable needles w/ thinner profile/taper) but am currently experiencing the best running setup with 40/142.5, stock needle at stock height.

This completely goes against the jetting matrix and I am wandering what all of you 40/150 fellas are experiencing - it was definitely not the proper jetting for my bike

-- K&N lunch box, V&H full exhaust, DIY timing advance

We've had a lot of spirited discussions about jetting, and some have come to pretty different conclusions as to what's the best setup for their bikes than I have for mine... doesn't imply "fraud".

No way we can make any real calls about somebody else's setup without being able to ride each other's bikes. I dearly wish we could do that, I think we'd all learn a lot from having that frame of reference. I have no idea WHAT we'd learn from it, but I'm sure it would be an eye-opener.

Personally, I've never gotten rid of the "flat spot" at 7-8 k without going richer. You're saying the opposite. Ok.

There are a LOT of variables in play here, and we tend to discount at least some. Model year, air filter, exhaust, mains, mid-mains if you've got 'em, pilots, needle shimming (even with just the stock needles), slide damping, diaphragm condition, maybe slide springs, carb balance, float height, valve clearances, engine compression and condition, who knows... I suspect a couple of guys have gotten weird results by using #4 washers instead of M3 on the later carbs, not having them sit perfectly flat in that much-smaller space where the needle sits, and then trying to compensate for it. Personally, I've recently had that flat spot at 7-8k return just from leaning out the mixture screws, which most say only affects the idle. That may be the theory, doesn't fit my experience.

So, figure out what the variable is that makes your bike behave differently than others, and we'll all learn something.

So many factors outside of your air filter and exhaust effect proper jetting......Humidity, and your height ASL for example.  The jetting matrix is meant to give you an idea of where to start not to be a dead on set of specifications.  Think and read before you go making wild ass accusations with no merit.

Jesus..... it was a joke, lighten up.

I am just suprised that my setup works but is sooooo far off from what I've found to be the norm.

I'm not accusing anyone of anything --- I wanted people to share their experiences w/ different setups.  not get offended. 

hence the statement "I wander what all you 40/150 guys are experiencing"  because I thought it was the right setup for me for a while, but was fed up with the glitches and decided to play around a bit and found something better.  My bike stats are listed below -- so as to provide a grounds for comparison among others' bikes.

mine worked flawlessly with 40.150 and no washers under the needle   But this has already been posted in a stickied thread that I believe was moved to FAQ.

140 mains - where is your floats set to
8 mm high may well do it, 2mm is 1 jet size.
Its not that far off ... ever. I can understand 147.5 or 145 even ...
BTW you have factory needles or stock with 140, and swapping them, how is it.
Since I've never seen a factory needle ... no clue.
Cool.
Srinath.

This is why I want to put together a carb tuning kit with different sized jets so people could try different jets and then go buy the ones that work best and pass it on.  However, I know what would happen to that kit....

     

if i thought I would ever get that kit back....

I have pairs of stock, 142.5, 145, 147.5, 150s and Stock needles and Factory Pro needles -- so I guess I have a decent tuning kit.

My floats are set so that the fuel is perfectly level with the high-end of the float bowl gasket (higher= the end toward the engine, because the side away from the engine is lower).  I checked that level like I had OCD.  Everytime I changed the jets I remeasured the floats the way the clymer manual suggests -- basically holding the carb sideways and tipping it until the floats rested under their own weight but not so much that they press in on the spring-loaded plunger on top of the needle valve.  Always between 13-15mm

I am not running STOCK needles at stock height with 40-142.5 jets and the bike is a beautiful thing.  Very balanced power band, and absolutely SCREAMS above 7k.  Still SOUNDS a bit rich in the mid-range, and my hypothesis is that going down one more jet size then raising the needles a bit will do the trick.

I myself am amazed at the carb setup I am running.  With all the research I put into rejetting before beginning work on the bike.  I live in Eastern PA, its 80* today and the bike never felt better than on today's ride.

The Factory Pro needles are a bit narrower than Stock, and also have 5 adjustment collars to put e-clips in, as opposed to the single slot on the stock needle.  In the 'standard' position (2nd slot from top) the needle sits about 2mm shorter than stock, and in the top slot it is a hair longer (sits lower) than stock.  The factory projet kit came with 140 and 142.5 jets and I thought it was a joke/mistake at first - immediately traded them at a local shop for 150s...... now I know that I should have tried them first. 

When/if I switch to 140 mains from my 142.5 currently, I'm guessing I might actually get to use those Factory Pro needles (should hope so, for $90!!!!) -- because of their thinner diameter/taper I am guessing they will run similar mid range to the 142.5/stock needle setup I currently have -- my first concern will be to see how the top-end is affected by going even lower on the main size -- right now it's bout as crisp and powerful as it's ever been.

I am really blown away that the 40/150 setup wasn't what worked best for my bike, after all the research and testimonials I read.....

My opinion:  Try going back to the larger mains but dropping the shims off the needle   That's what I did when mine was running way mid-range rich.  Dropping the shim off the needle will lean it up with a larger main and still give excellent top end performance

Top end performance is better than ever with the 142.5 -- top speed of about 115mph..... barely could reach 110 w/ the 150s AND a tailwind.  not that i should know that.  AND my needles are not shimmed, i am running stock needles in stock position.  everything is working great - couldn't be happier

Hey, if it works ...
I cant help but think something is different on yours.
But anyway do an high rpm kill and plug pull underload, makesure you're Normal to rich.
BTW, 150 mill not make the best power and hence the best top speed, lean bikes make more power. 150 is just the largest you can run before it starts to woosh off and drown in its own juice. However for most people its left a clean running bike with very little to complain about ... yea maybe down will make more HP, but it also will run hotter, you'd have to run premium gas, and it will take longer to warm up and misbehave in very cold weather. You jet it to clean up all of that.
Cool.
Srinath.

Just so I don't sound insane....I do want to reiterate that the "Stage 3" Factory Pro Jet Kit (designed for high-flow air filter and full aftermarket exhaust system) came with 140 and 142.5 mains -- which I thought must have been a mistake in the first place.  There was even a data card with the kit that described the avg setup as "K&N with a V&H Exhaust, mixture screws out 2.5 turns, needle at position #2"

And because all of your comments made me second-guess myself - i did more riding, plug chop, and pulled the plugs and everything looks perfect.    def not running lean, just leaner than the rich 150's i had!

Taking a road trip to the shore this weekend - hoping to see some better fuel mileage.  I'll letcha know if i scorch a piston.

I was lucky I think when I re-jetted my bike.

Being a 2005 model I have three jets. After reading a few posts here I ordered

20 pilot, 65 mid mains and 145 mains

I basically just swapped out the old ones, put in the news ones, reassembled the float bowls and the bike went perfectly. No need to adjust needles, washers or mixture screws.

My bike had a K&N Filter and a Jardine Exhaust system.