Drop in K&N+slip-on+stock jets?? advice please

[radodrill]

Well with the carbs off I found the mixture screws were out a lot further than I thought (5 turns rather than 2.5); so taking care of that helped the low end a lot.  I also lowered the needles.

Right now the low end and top end are on the lean side; the mid range pulls a bit harder at WOT than the top end.
Previously I had the best top end performance with the 142.5 main, so I'm going to put that back in see how that affects things overall now that the floats and mixture are fixed.

[The Buddha]

Well with the carbs off I found the mixture screws were out a lot further than I thought (5 turns rather than 2.5); so taking care of that helped the low end a lot.  I also lowered the needles.

Right now the low end and top end are on the lean side; the mid range pulls a bit harder at WOT than the top end.
Previously I had the best top end performance with the 142.5 main, so I'm going to put that back in see how that affects things overall now that the floats and mixture are fixed.

5 turns out is richer than 2.5. So you leaned it out there.
Lowering needles makes it leaner too.
You have lean down low and high ... OK 142.5 and 22.5 may get it there ... however I cant believe everything is right ... you're 2-3+ on the mains ... 22.5 mains meeeh ... I started with 22.5, decided it was a bit over kill and went to 20.

Cool.
Buddha.

[cheddle]

So much schooling, I have just had... Am I correct in assuming that if I simply take out my carbs, remove teh float bowls, unscrew old jets, screw in new jets, that my float will be unchanged??

How many "washers" are installed from factory? any at all?

I have some jets coming in the post, I ordered 20 pilots, leaving the stock 60 mids, and going 140 mains - I intend on leaving the needle and mixture screws as is and I expect to adjust the idle slightly.

With this setup I am hoping that it will warm up faster and pull harder up top as currently my bike just runs out of puff past about 7-8k rpm (or at least I get a beefy midrange and a flat top end) with stock jetting and a k&n drop in, interestingly removing the restrictor really feels insignifigant, I do notice a little more induction noise and thats about it...

[The Buddha]

You dont need to remove the floats to swap all these jets.
The brass caps on the mixture screws - drill emd and pull em before opening the float bowl and you wont need to clean that crap out of the floats and jets.
140 IMHO is far too rich for stock or anything close to it, and too lean for K&N lunch box and pipe.
20/60/132.5 for stock or stock air filter and pipe. <- This I think is what you should run.
20/60/135 for K&N drop in and pipe or stock pipe.
137.5 (maybe) for K&N without restrictor.

147.5 for K&N lunch box and pipe.

Cool.
Buddha.

[cheddle]

cheers Budda - I will remov the caps to start with.

I have the stock airbox with a K&N filter currently installed running stock jets (i think its lean, takes 4 years to warm up and runs out of puff up top)

I am rejetting in conjunction with fitting a straight-thru 4in diam / 15 inch length aftermarket can (unknown origin/brand)

What say you?

[The Buddha]

cheers Budda - I will remov the caps to start with.

I have the stock airbox with a K&N filter currently installed running stock jets (i think its lean, takes 4 years to warm up and runs out of puff up top)

I am rejetting in conjunction with fitting a straight-thru 4in diam / 15 inch length aftermarket can (unknown origin/brand)

What say you?

OK you may need that 140 ... pipe I have noticed isn't that big a factor ... the airbox is the biggest choker there is this side of south africa in cricket.

Cool.
Buddha.

[cheddle]

lmfao. Well I will follow up in bout a month and let you know how it has gone, I will try and get use of an exaughst gas analysier and check mixtures at WOT, cruise and idle.

no doubt ill make a new thread when i f$%k up the change of jets 

[radodrill]

Just an update; I've now got my 500F running perfectly without the restrictor on the K&N drop-in.

After raising the float level to the top of the bowls, I had accidentally left it in prime and had fuel run over into the airbox.  So I set them back to factory (3mm below bowl mating surface) and started fresh from 20/62.5/140.  This had decent power delivery, but felt quite flat throughout.  Using a 142.5 main I got the absolute hardest pull (way more than 140) and 145 resulted in less power and an obvious rich condition.

Once I found the 142.5 main, the mid range was slightly lean compared to the top end, at WOT this resulted in a marked jump in pull at 7K RPM; 1 washer under the needle took care of that and gave a smooth transition to the top end.  Now the low end was a bit rich with a soggy feel at WOT.  I lower the float level to 6mm below the bowl seat (bike straight/level) and now it nicely takes WOT at any RPM.  I set the idle/mixture screws at 2 turns to get a smooth idle performance.  The bike now has smooth power deliver at any throttle position and way more power and better acceleration than the stock jetting.

TLDR: My best jetting is 20/62.5/142.5, 1 washer, 2 turns, and float level 6mm below bowl seat.

[The Buddha]

OK You may need to make a 3/4 throttle 8K plug pull - as in under load, ride it in 5th ot 6th, get to 3/4 throttle, hold for 5 sec, hit the kill and coast to the side ... wait a few mins and plug pull. It may be lean that far up. Lean makes more power, but its bad for the motor.
You could also do it with an O2 sensor in the exhaust - a lot safer. Though you would need to find the sensor (94 cavalier sensor works) and wend a nut in the exhaust and screw it in.
Or, you can try 145, and larger and larger till you feel a drop in power, then back 1 jet size.

Look isn't this funny, I've been saying you're rich till now you have 2 up from where I would put em, now I'm thinking you may be lean.

6mm may be 2-3 sizes on the mains. Maybe more ... maybe less.

Cool.
Buddha.

[radodrill]

Look isn't this funny, I've been saying you're rich till now you have 2 up from where I would put em, now I'm thinking you may be lean.

6mm may be 2-3 sizes on the mains. Maybe more ... maybe less.

Cool.
Buddha.

What made you come around? You used to be convinced the bike wouldn't run with such a large main.  My current jetting seems to be close to what the wiki recommends for the LB and stock exhaust.

And the float level is only 2-3mm lower than stock.

I can certainly try the 145 again and see what that does (leaving everything else the same).  If I can scrounge up parts to make an O2 monitor (or borrow one) I may do that as well.
I'll have to see about doing an 8K plug run; in 6th gear that would put me around 100mph.

[RossLH]

Playing with the float level is adding an unnecessary variable into the equation.

[The Buddha]

Look isn't this funny, I've been saying you're rich till now you have 2 up from where I would put em, now I'm thinking you may be lean.

6mm may be 2-3 sizes on the mains. Maybe more ... maybe less.

Cool.
Buddha.

What made you come around? You used to be convinced the bike wouldn't run with such a large main.  My current jetting seems to be close to what the wiki recommends for the LB and stock exhaust.

And the float level is only 2-3mm lower than stock.

I can certainly try the 145 again and see what that does (leaving everything else the same).  If I can scrounge up parts to make an O2 monitor (or borrow one) I may do that as well.
I'll have to see about doing an 8K plug run; in 6th gear that would put me around 100mph.

You have floats set so low. Essentially you have changed somehting in exchange for somehtng else. These are all related. DJ runs a 118 main jet, down form a 122.5, which we all agree is leaner than Gwen Stefani. Cos, they shaved the needle to 1/4th the diameter.

I will run a stock level float, and smaller mains ... but hey that's just me. Floats affect the mixture as you open throttle, not just how it runs as it reaches steady state. No way to determine how it is as you're opening throttle without an O2 sensor.

Leaner jetting makes more power. Which is why I'd make sure its not lean cos it will make more heat ...

Cool.
Buddha.

[The Buddha]

Playing with the float level is adding an unnecessary variable into the equation.

True, and lower float will let the gasket dry out cos its sitting above the level of the fuel. Fuel keeps the gasket alive longer.
Cool.
Buddha.

[radodrill]

I didn't really notice any change in the mid-top end performance as a result of lowering the floats; what I did notice is that the low end was leaned out a bit and would more easily accept WOT at low RPM.  Also, the performance in the transition to/from closed throttle was improved.

[RossLH]

The low end wouldn't accept WOT at low RPM because there was too much fuel. That's not a float problem, that's a jet problem.

[The Buddha]

The low end wouldn't accept WOT at low RPM because there was too much fuel. That's not a float problem, that's a jet problem.

He he he ... I think its too lean down low ... but you may be right ...
But radodrill, what is low rpm ? And its elated to throttle position ... please relate it to that.
Cool.
Buddha.

[The Buddha]

as many jetting questions we get, could make you a few $$

He he, I sell more jets than boeing ... just thought about it yesterday shipping someone's jets. My wife then added, and thankfully they're not catching on fire.

Cool.
Buddha.

[radodrill]

The low end wouldn't accept WOT at low RPM because there was too much fuel. That's not a float problem, that's a jet problem.

He he he ... I think its too lean down low ... but you may be right ...
But radodrill, what is low rpm ? And its elated to throttle position ... please relate it to that.
Cool.
Buddha.

Before lowering the floats, if I'd hit full throttle at around 2-3K RPM it felt like it was stumbling a bit; holding full throttle it would then pull a lot better once it got over ~4K rpm (all still full throttle).

After lowering the floats, I no longer have the low end stumbling at full throttle.  It now pulls hard with any  throttle position at any rpm.


I guess I'm not well versed in Buddha-ese, but but in my opinion it's running great now with a huge improvement over stock.  I'll try to post a video of it running warmed up (including revving the engine); unfortunately I don't have a GoPro to get action shots while riding.

[The Buddha]

You dont need a GoPro, you need an O2 sensor.
You can be lean and make lots of power ...
If you are lean by more than say 1-2 sizes it could cat upon steady throttle, but if you are just this side of that you may not have any discernible symptoms, you'll just run hotter ... just not have the coolest running you can.
In effect I think you're a little bailed out by the mids. The 62.5 - its somehting we leave as the stock 60 except in rare cases when the K&N LB filter is used with pipe. The lower floats have been covered up by the 62.5.

Maybe you have landed on the perfect spot a different route ... But float gasket needs the gasoline to "moisten" it for its life.
Anyway, test it out, this point my suspiscion is you're lean especially above 1/4 throttle - but may not be.
Cool.
Buddha.

[grimah1w]

Great thread, cements why I hate carburetors.