Vance and hines supersport 4-1 exhaust questions, can it cause lean issue?

[91_gsx600F katana]

Just got a 1991 gsxf 600 a few weeks ago. Have been messing with the carbs to get it to run right. Now Originally the bike had a K&N filter, stock jetting and NGK Hot plugs. But I dnt think the exhaust is stock. Its a Vance and Hines Supersport 4-1 exhaust judging by the tag on the muffler and it fits the description on this site.http://www.starcycle-usa.com/servlet..._GSX600/Detail

Now my question is, How much better is this exhaust over the stock setup? Does the increase in flow warrant a jet kit? or a richer idle A/F mixture?

I have my A/F screws set at 2.5 at the moment but i noticed when its cold (choke on) I have a empty NOT loud popping out the exhaust, like burbling noise. This goes away after it warms up but I also have a slight hesitation when i blip the throttle. ALso my idle is a little irratic it will fluctuate from 1200-1500 slowly. Does this sound like a lean issue? I wonder if the exhaust/bike would be better with a jet kit like the FP stage 1, or do i just need to richen up the A/F screws a little.

Ive put new plug wires, new stock NGK plugs, new air filter, carbs have been rebuilt and cleaned and synced.

[92xjunker]

If the header is a V&H then factory pro stage 1 jet kit.

[91_gsx600F katana]

How do I know if its a V&H header? The header was rusted so i painted them, then I painted the mid pipe as well.

[Wreckie29]

Looks like Vance and Hines to me, get the jet kit...
You know you want it anyways!!!

[ThAzKat]

Ummm what paint did you use? Remember that exhaust gets hot, very hot!

[91_gsx600F katana]

ugh the jet kits are like 106$ lol. Maybe my bike will run better now tho!

Originally I painted with 2000*F header paint, as a base then I used 650* engine enamel. The 2000* paint was silver on the headers and flat black on the mid pipe (2 diff companies and only had so much of the flat black) After that I threw on the 650* which is the cool copper color, which is bubbling off already in certain spots. but no worries as under that is the 2000* which will be fine. I went with the copper so it was all one color and I didn't want silver/flat black.

[Wreckie29]

So now it'll be the colors lol I gotta paint mine...
I'm just gonna go with black though lol

[91_gsx600F katana]

whats the best place to get these kits from, everyone says star cycle but I called them and they are out of them. I see them on ebay but my paypal doesn't have enough funds and I don't trust evil bay to much lol.

So now it'll be the colors lol I gotta paint mine...
I'm just gonna go with black though lol

I have lots of experience with spray paints and high temps, on my race cars. They are all not created equal!

Rustoleums 2000* paint is rather new and it works the best I think.
Ive used VHT header paint with some decent results but rust always follows quickly. Ive also tried BBQ paint, POR20 high temp paint (worst ever) and a bunch of 500-650* engine enamels. I never follow the instructions to cure the high temp stuff bc I dnt have an oven big enough to do it lol. I use a propane torch to quickly cure the high temp stuff and seems to work ok.

[91_gsx600F katana]

Today was the first time I ever rode the bike (just up and down my street, still need to get my LICENSE!) but holy cow this thing is quick, 5000 and up this thing just takes off. I dnt notice the throttle blip hesitation as I am always coming into the clutch/gear slowly and little RPM but it rides great brings back old memories of my moped and dirt bike.

I stalled it once on a very tight turn on a hill (turn around in a 1 way dead end street) and tried to start it again, no choke and id get almost a start, no choke and once it almost started id hit the gas and it would rev but then die with no throttle. I then pulled the choke all the way out and after a while it started but with full choke and hot engine would only rev at 1500 or so, eventually after 15 sec it went up higher and then it would idle with no choke and ran fine. I'm thinking I'm pretty lean if the bike doesn't want to idle well on the choke (which is added fuel). I think i need to turn the A/F screws from 2.5 - 2.75 or 3 turns. Originally the bike when I got it had slightly different on all screws but all were above 3 turns. Prob due to the exhaust leaning out the motor.

[Wreckie29]

Holy cow you must have had heavy dirt bikes and mopeds to have them feel like the katana... Mine all felt like bicycles compared to my katana...
Glad to hear it's running and it may not be lean that makes it hard to start, check the plug color to tell if lean or rich and also might look into coil relay mods...
Mine was like that warm and no choke hard to start and cold with choke kinda hard to start and if I choked it warm gosh it flooded...
Coil relay mod done and wow it starts with ease.

I mean it's a91 after all lol

[91_gsx600F katana]

Whats the mod? got a detailed link? I ended up getting the Jet kit but it won't be here for over a week at least 7/8 bus days. So i prob won't put it on till next riding year.

my moped was a 1979 and it looks like a harley lol, round headlight etc. Thing was slow as hell but it got me around. THe dirt bike was also a 1979 honda, and i abused the hell outa the thing when i took it down south jersey in the sand land lol. But the dirt bike wasn't street legal so it was just a toy. And that thing wasn't the lightest lol.

Im not sure if its lean or not but on deceleration in gear it pops out the exhaust, slight hesitation when i blip the throttle out of gear and it seems to hang just a little after i blip the throttle, say i blip it to 4000/5000 it will drop to 2000 for a sec and then drop to 1500 etc.

[Wreckie29]

That's how it works.

Use the original coil wire for trigger wire.

[91_gsx600F katana]

Im alittle confused on the "trigger kill switch" is that the run/off switch on the handle bar? If not what is the kill switch?

[Wreckie29]

Use the factory coil power wire as the trigger wire.

[91_gsx600F katana]

Ah ok. Now I have to look for that. I know each coil has 2 connections on it. 1 must be a + and the other a - so dies that mean that each + wire from each coil is connected somewhere from a single wire?

Also why run off the starter bolt? Instead why not just go right from the fuse box? My starters connections look wrapped and covered pretty well. Running a relay right of the batt for its 12v source seems easier to me.

Can I ask wat the cool relay mod cures? Obviously it
Must cure some power draw problem but why is the stock setup an issue?