New exhaust & KN LB...Rich or Lean?

[tussey]

Hello all, I haven't posted in a while. My apartment's internet went down (piece of equipment got fried).

So I just upgraded my setup and got the stuck exhaust bolt removed.

150 mains, 40 pilots, 2 #4 washers under the needle, screw 3 turns out.

K&N lunchbox and full Yoshi pipe.

Results. It runs MUCH better then before. Noticibly much more powerful. But....here are the problems.

1. The bike HATES being below 4k. Anything below 4k and it stumbles, 4k+ and it flies.
2. It is very hard to start the bike from idle, it chugs and feels like dying then BAM it hits 4k and the RPMs skyrocket. I had to pull off the road from a stop light because the bike wouldn't go.
3. WOT seems to work real well but when cruising the bike noticibly stumbles, seems at any RPM. This is the most noticble problem. The ride is not smooth.
4. The idle bounces between 1.5k and 2k. Very strange. Sorta like the wind is blowing it and it affects the motor, if that makes sense.
5. when I synched the carbs the level of the fluids would bounce. I got them as close as I could but they wouldn't really stay level together

I suspect it's rich, I sorta detect a secondary explosion in the combustion and the sound doesn't seem very smooth. I think I detect two distinct explosions.

GS Gods I need your help 

[dgyver]

150 is too big. You really should be running 145 or at most 147.5.
Floats may be off, exagerating the richness. Might need to increase their height by 1mm (this decreases the fuel level in the bowl).

[The Buddha]

I think your 150 is fine - your 2 #4's may be too much. Try 1 first. But before that -
check for vacuum leaks, synch (no idea ... I eyeball them not oil synch - ever) and floats. That is fundamental.
Cool.
Srinath.

[scratch]

Hello all, I haven't posted in a while. My apartment's internet went down (piece of equipment got fried).

Surfin' too much hot pr0n.  Stop it.

150 mains, 40 pilots, 2 #4 washers under the needle, screw 3 turns out.
K&N lunchbox and full Yoshi pipe.

Too many washers.  And, always with the lunchbox...haven't you guys learned...the lunchbox is too difficult to dial in jetting.

1. The bike HATES being below 4k. Anything below 4k and it stumbles, 4k+ and it flies.

Sounds like a typical GS...

2. It is very hard to start the bike from idle, it chugs and feels like dying then BAM it hits 4k and the RPMs skyrocket. I had to pull off the road from a stop light because the bike wouldn't go.

Set the idle when warm.  I'll bet it's too high.

3. WOT seems to work real well but when cruising the bike noticibly stumbles, seems at any RPM. This is the most noticble problem. The ride is not smooth.

Now, when this happened to me it was because I was too lean; and it hesitated.

What is your's doing?  Hesitating, or surging, or bogging?

4. The idle bounces between 1.5k and 2k. Very strange. Sorta like the wind is blowing it and it affects the motor, if that makes sense.

That's not good; something wrong with the carburetion...

5. when I synched the carbs the level of the fluids would bounce. I got them as close as I could but they wouldn't really stay level together

Normal.

I suspect it's rich, I sorta detect a secondary explosion in the combustion and the sound doesn't seem very smooth. I think I detect two distinct explosions.

That would be the number two cylinder firing after the No.1 cylinder.

[Alphamazing]

1. The bike HATES being below 4k. Anything below 4k and it stumbles, 4k+ and it flies.

Sounds like a typical GS...

My bike pulls cleanly from 2500. In first and second gear it pulls cleanly from idle to redline. 4000RPM in top gear? No problem.

[scratch]

I'm lit.  this post will self destruct as soon as I sober up

[dgyver]

There is not a problem dialing in lunchbox's. It is the operator using the wrong info.

I had a lot of problems using a 150 but after dropping to a 145, everything ran better. Srinath has even said a 150 is on the rich side. But do what you want.

[tussey]

There is not a problem dialing in lunchbox's. It is the operator using the wrong info.

I had a lot of problems using a 150 but after dropping to a 145, everything ran better. Srinath has even said a 150 is on the rich side. But do what you want.

Well I have 140 mains and 150's. I'll order some 145's and some 147.5's.

Today I will try 1 #4 washer see how that goes.

Float level is correct btw.

[dgyver]

Float level is correct btw.

There is not a single "correct" height. It will vary depending on the main jet used but usually pretty close if within 1-2 main jet sizes.

[pres589]

Srinath has even said a 150 is on the rich side. But do what you want.

When did he say that?  I'm using a full V&H Supersport exhaust and a Lunchbox, and looked through old carb posts and he said in a couple of them that #150's were a good size for main jets. 

I've got a single washer on the needles, #40 primary jets, and the bike seems a little farty at low throttle cruise situations.  That said, I have noticable acceleration in top gear at 65, 70, etc mph on the highway.  My bike is also rather jerky below 3k rpm, at which point it suddenly becomes very smooth and progressive in power delivery.  Makes low speed corners from stoplights on city streets a bit more interesting that I would have liked, but I've learned to ride around it.

[dgyver]

http://gstwins.com/gsboard/index.php?topic=29258.0

See the last post.

[pres589]

Dammit, I hate the idea of pulling the carbs again to go down to #147.5's; wonder if mixture screw tuning could help fix this instead.  Looks like I've got a sunday testing project ahead of me.

[The Buddha]

Bwaaaa ... Taken waaaay out of context.
Rejetting for power is not the same as rejetting for the bike to behave. Leaner = more heat = more complete combustion = more power. In my observation, 152.5 will cause a huge drop in performance - big enough to notice ... 150 will not as compared to 147.5. And 145 may actually be close to or worse than 147.5. 150 is no more than 1 size rich on most bikes. 147.5 probably will give you max power, 150 will send it just a shade over that perfect edge. Making sure you are rich. Richer = cooler = longer life for the motor = incomplete combustion = less power. But you dont compare it back to back with a 147.5 - you'll never know.
BTW swapping a main jet is extrenal work, once you swap the phillips head screws for allen heads and its made easier with a handle spinner ratchet and its easier on a 89-00.
Cool.
Srinath.

[dgyver]

"150 is the largest jets you can run before 90% of the bikes start misbehaving from being drowned out in gasoline"

"I like those cos the richer the cooler it runs."

"150 will send it just a shade over that perfect edge. Making sure you are rich"

"150 is no more than 1 size rich on most bikes."

What part of those quotes are taken out of context that you jet rich? WTF! You just said so several times!

[l3uddha]

Alpha what are you running for sizes?
you have stock exhaust right?

[Alphamazing]

Alpha what are you running for sizes?
you have stock exhaust right?

Stock exhaust, yeah. Runnning 22.5 pilots, 65 mid mains, and 137.5 mains, but I'm going to put 140 mains in there when I get around to it, just to be on the safe side of things.

[tussey]

Update. So yesterday I removed 1 #4 washer and the bike ran beautifully! It was a little slow to start off the line but I fixed this by just reving up to 4k then feathering the clutch. Bike was smooth all the way through the powerband and had no problem hitting 80 in 3rd gear. The pull was amazing. So I figure the bike is fixed.

Though it's still running too rich. I carbon fouled a set of plugs. Wanted to try smaller mains but I guess Sudco only sells in sets of 4 now. Retarded. 

[pres589]

I really think the next move I need to make to improve the power delivery on my GS is to step both the main and the primary jets down a size.  147.5's for the mains, what's the next drop below #40's in the primaries?  I think the other thing to do is get new plugs and wires since I don't know how old the wires are and plugs are so cheap it's not worth messing around with questionable plugs.  I didn't change the float bowl screws to allen head capscrews when I had the carbs apart but I think I should have enough space to do so on the bike this go around. 

The way the bike is just gagging and wanting to lay over below 3,000 RPM and then taking off hard at 3k with even light throttle input is getting old.  I wouldn't call this a surge condition only because it never really lets up all the way to 10k (I don't really trust myself or the bike enough yet to run out to redline).  If the bike ran that well and smooth down to 2k I wouldn't even think about it, but it makes doing things like right or left turns at interesctions from a stop a bit more interesting than I would like.