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

[radodrill]

Everything I've read on the forum points to much difficulty correctly jetting radodrill's setup ... I don't think I've come across anyone on the forum who has gotten tried and true results with the K&N drop-in, using no restrictor ring, and a stock exhaust.   They always get mixed results with rich at one end and lean at the other end and vice versa... first example that comes to my mind is bombsquad's '93 refresh' build thread... had a heck of a time dialing that in, kept stepping it up here, dropping it there... couldn't land anything too good, and finally just went back to stock setup... said that he rather spend time riding than fiddling.  I also think of the many jet threads started with K&N drop-in, first couple questions are if they are using the ring or not, first suggestion is always to use the ring with it if they aren't.. and if that didn't solve it, it was switched jets or float height/needle issue...

Rado, please let us know when you land on it, if you continue to work with it.  But as Buddha says, if it runs then fine. The only thing odd is that it is rich low-end with stock 17.5 pilot, which is known to be lean even using a stock air filter. Kind of goes against general logical thinking when you use a freer flowing intake. 

I'll definitely keep working on it and update with my progress.  I certainly will not go back to stock jetting as IMO it didn't have a good top end and not much pull for hard acceleration; according the specs, the 0-60 time is about the same as the Ninja 250 I had, but the 250 pulled a lot harder off the line just topped out sooner and needed more frequent shifts.  Being used to that I wanted to get more top end out of my GS, which I am now quite happy with, just need to get the low end sorted out.


@ Buddha,  Do you have any further insight on how the mid-main affects the mixture?  I saw one entry in the rejetting wiki table where a guy with a LB referred to using 62.5 with 2 washers or 65 with no washers

[The Buddha]

Mid mains are really only needed in the K&N lunch box and pipe setup ... IMHO. 3 needles is excessive, in fact if someone with pipe and K&N is @ 3 needles, I recomend he go to a 65 mid and back to 1 washer and try it.
62.5 = 1 washer on the needle.
65 = 2-3.

I cant imagine your bike even running over 1/2 throttle ... so i am the last person to ask on it.

See I run 20 pilots in mine, some people have run 22.5 ... honestly 20 is a bit lean ... the right size may be 21 or 22 or something like that.
You're rich with 17.5 ... that there tells me you got somehting else way off the path.
I dunno you have all the carb hoses connected ?
You dont have any vacuum leaks ?
Where is your float level ? @ the top of the bowl and no more ? Or in your case less, if you're 2-3mm low that explains your bigger main jets.

su-5589 is your filter with no restrictor right ?

Seriously I'll run 135-137.5 mains, 60 or 62.5 mids, and 20-22.5 pilots with 3 turns out and floats set @ the top of the bowl.

You're +2 on top, +0 in the mid and -1 down low. I cant think of why - check the setup.

Cool.
Buddha.

[yamahonkawazuki]

Aye. something aint jivin 

[The Buddha]

You're +2 on top, +0 in the mid and -1 down low. I cant think of why - check the setup.

Cool.
Buddha.

That math is from where everyone else has their bike jetted with similar setup to yours.
Not vs stock.

Cool.
Buddha.

[radodrill]

Mid mains are really only needed in the K&N lunch box and pipe setup ... IMHO. 3 needles is excessive, in fact if someone with pipe and K&N is @ 3 needles, I recomend he go to a 65 mid and back to 1 washer and try it.
62.5 = 1 washer on the needle.
65 = 2-3.

I cant imagine your bike even running over 1/2 throttle ... so i am the last person to ask on it.

See I run 20 pilots in mine, some people have run 22.5 ... honestly 20 is a bit lean ... the right size may be 21 or 22 or something like that.
You're rich with 17.5 ... that there tells me you got somehting else way off the path.
I dunno you have all the carb hoses connected ?
You dont have any vacuum leaks ?
Where is your float level ? @ the top of the bowl and no more ? Or in your case less, if you're 2-3mm low that explains your bigger main jets.

su-5589 is your filter with no restrictor right ?

Seriously I'll run 135-137.5 mains, 60 or 62.5 mids, and 20-22.5 pilots with 3 turns out and floats set @ the top of the bowl.

You're +2 on top, +0 in the mid and -1 down low. I cant think of why - check the setup.

Cool.
Buddha.

The air filter is indeed SU-5589 no restrictor.  There does not appear to be any sort of vacuum leak; when I spray WD-40 on the intake boots (before and after carbs) the idle is unaffected.
All the carb hoses should be connected correctly, unless there is a cap missing on an unused vacuum port.

I'll have to double check the float height as I have not messed with that; so it's probably still at stock.

Also I have not tried to remove the PAIR system or the solenoid valve; not sure if/how that would affect things.  As I understand it the solenoid is merely to vent the vacuum side to atmospheric when the ignition is off.

[The Buddha]

You're @ 3500 ft or something too right ... I cant imagine why its running fine ... anyway what is important is that it is running fine.
Cool.
Buddha.

[radodrill]

You're @ 3500 ft or something too right ... I cant imagine why its running fine ... anyway what is important is that it is running fine.
Cool.
Buddha.

According to airnav our local airport is at 1243 ft.

I guess performancewise leaving off the restrictor makes the drop-in run like a bastard hybrid of the lb and stock replacement.

That said, I'm going to check on the floats.  It looks like with the carbs open/inverted the speced float height is 14.6mm from the bowl seat.

[The Buddha]

You're @ 3500 ft or something too right ... I cant imagine why its running fine ... anyway what is important is that it is running fine.
Cool.
Buddha.

According to airnav our local airport is at 1243 ft.

I guess performancewise leaving off the restrictor makes the drop-in run like a bastard hybrid of the lb and stock replacement.

Not if your low end is so rich the 17.5 makes it rich. In fact the right size for this bike is bigger than 20 ... 22.5 may be too much, but 20 is still on the leaner side.

You've got something off ... You buy the bike new ? Any chance previous owner goobered it up.
I've seen crackpot owners wallow out some of em air inlets on the air filter bell mouth.
I've also seen people screw in the air screw in so deep it gets the fuel passage so big, it makes the air screw work only if its like 1/2 turn out.

Cool.
Buddha.

[radodrill]

It's a 2009 that I bought just over 2 weeks ago with 2678 miles on it.  The first owner had purchased 2 of these bikes (one for his wife) and in 4 years only put 2100 miles on it then sold it to the dealer this spring.  As far as I know the only change he made was to set the preload on the rear shock to it's lowest setting; I don't think he messed with the carbs as the screws were all in tight and the idle/mixture caps were still in place.  The second owner (found out it's my new insurance agent) didn't make any changes (not even adjust the shock).

I did just pull the carbs so I can more easily check the floats etc.  Anything in particular I should take a closer look at while I'm in there?

[The Buddha]

You can check floats via U tube method on the bike - its easier. Get some silicone hose from a hobby store.
Cool.
Buddha.

[radodrill]

With the hose it seemed to only come up a bit higher than the bottom of the float bowl.

I actually had already pulled the carbs.  With them off, I held them upright and filled fuel into the supply tube, drained the supply, and then carefully removed one of the bowls; the fuel was essentially up the the bottom of the recess for the float hinge.

While I've got them off and the bowls open; I measured the float height at 17 mm (carb inverted, tongue just touching the needle spring).  I read on the wiki that for the <01 carbs the floats should be at 14.6mm; how different is this for the newer carbs?

I'm now guessing that the fuel level in the bowls may be so low that the pilots are just barely in the fuel (if at all) as they appeared basically dry.

Any suggestions before I adjust the floats?  I'll probably then go to the 20/62.5/140 jets (recommended in the wiki) and go from there (ATM I don't have any jets between 130 and 140).

[The Buddha]

The U tube is more accurate. I dont know that that number method is. U tube on the bike, with bike in prime was just off the bottom of the bowl ?

If so there is an explaination how your jetting is running right up high.

Set it to the top of the bowl. That is the stock 14.6 or whatever BS they specify in the manual.

Then try it ...
It will be rich as snot ...

You then install 135 or something, 20 and 62.5 is OK or try 60 ... 3 washers is too much 1 with 60, none with 62.5.
That is the correct carburetion method. The stupid floats ... I've seen bikes when you open throttle will fall on its face, and as you shut the throttle it will wheelie (it was a 92 GSXR750 not a GS).

Cool.
Buddha.

[yamahonkawazuki]

Hey buddha, you still doin jet kits? i know you did not too long ago. heck youve done just about anything gs lol

[The Buddha]

Hey buddha, you still doin jet kits? i know you did not too long ago. heck youve done just about anything gs lol

Yes still am.
Cool.
Buddha.

[yamahonkawazuki]

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

[The Buddha]

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

He he ... since 2004 I've made millions ... Lets see, On each jet kit, I lose like 13c ... but I make up for it in volume ... 

No Kidding, I've got it ironed out nice and good, I make a couple bucks on each kit, but I sell maybe 2 a month on average ... 25-30 a yr. The carb jobs are straight up labor.

Cool.
Buddha.

[radodrill]

Just lowered the floats a bit (raise the fuel level) and went with 20/62.5/140 jets, 0 washers, and 2.5 turns.  As a result, the low end is a lot leaner.  The top end is also a bit lean with reduced pull at WOT.  Looks like now I may be able to go back to the 142.5 mains and still be good on the low end.

[The Buddha]

Just lowered the floats a bit (raise the fuel level) and went with 20/62.5/140 jets, 0 washers, and 2.5 turns.  As a result, the low end is a lot leaner.  The top end is also a bit lean with reduced pull at WOT.  Looks like now I may be able to go back to the 142.5 mains and still be good on the low end.

Or you could set the floats @ the right level, and go to say 135 ...

Cool.
Buddha.

[radodrill]

Or you could set the floats @ the right level, and go to say 135 ...

Cool.
Buddha.

Doing the u-tube on the drain test (petcock at prime) the level is now right at the top of the bowls.  The bottom end is now a lot leaner than when I previously tested 20/62.5/140 without adjusting the floats (what initially led me to go back to 17.5 pilot).  I actually had to give it a little bit of choke for the first few seconds of warmup.

[The Buddha]

Or you could set the floats @ the right level, and go to say 135 ...

Cool.
Buddha.

Doing the u-tube on the drain test (petcock at prime) the level is now right at the top of the bowls.  The bottom end is now a lot leaner than when I previously tested 20/62.5/140 without adjusting the floats (what initially led me to go back to 17.5 pilot).  I actually had to give it a little bit of choke for the first few seconds of warmup.

What ... you raised the fuel level in the floats, and the bike got leaner ?
OK Lean and needing choke on cold start up is actually normal. It needs to be a hair lean @ idle. Too rich and it will have a hard time re-starting when warm.
I'd ride it and determine what it feels like.
Float being set right is almost the biggest factor as to how the bike runs when you open the throttle.
So leave floats at the level they are @ top of the bowl. You could try 22.5 pilots if needed.

Cool.
Buddha.