[ShimminOut]

Okay, I know if I get a new exhaust, I'll have more air flow through the engine and, therefore, will have to re-jet to maintain the correct air/fuel ratio. So, then what the hell are the mixture screws for? That is what the little screws that you can access under the gastank from right side with a long screwdriver are, right?

 

[Glovis]

Installing a slip-on or a full exhaust system will change the backpressure and may require adjustments to the carbs to compensate. However a slip-on has a relatively small effect on the fuel mixture compared to a full exhaust system. I installed a Yosh RS-3 slip-on and all it needed to run right is adjustment to the fuel mixture screws and adding a 0.5mm washer under each vacuum slide needle. Unfortunately I made the mistake of buying a Dynojet carb rejet kit which after installation per the instructions made the bike run crazy rich. I'm talking spitting raw fuel out the exhaust and getting 20 mpg. After removing all the DJ parts and just using the above mixture screw adjustment and needle shim the bike runs great.
The fuel mixtures screws affect air-fuel mixture between closed and 1/8 throttle opening. Off idle accel and highway cruise are where this throttle opening range is most used. On our bikes there are pressed in brass plugs covering the fuel mixture screws. You will need to completely remove the carbs from the bike to remove these plugs. (The ends of the plugs face toward the rear of the bike so I'm not sure what screws you are looking at that are visible from the right side of the bike but those are NOT the mixture screws.) Once the carbs are removed you must VERY CAREFULLY drill a small diameter hole through each plug without going too far and damaging the mixture screw. Then using a small diameter sheet metal screw threaded into the hole you drilled and pulling on the screw with a pliers you can pull the plug out. If this sounds like more than you are comfortable doing at home then by all means go to qualified shop or bike mechanic because a mistake with the drill can result in a ruined $400 carbset.[B)]

FactoryPro has a great website with a lot of information about tuning CV carbs:
http://www.factorypro.com/

If you decide to go with a full exhaust system then a lot of people on this forum have had good results with either the Ivan's or FactoryPro jet kit.

Good Luck![:M121]

 

[Knucklehead]

The screws you are probably seeing on the right are the carb bowl drains screws. The mixture screws are on the bottom of the bowls and face the rear like Glovis said.

 

[zx6r2k]

do they require an allen key and they have the little clear funnel covers on them? These are the carb bowl drain screws?

should the poilet screws remain in the same place since they are behind those plugs they shouldnt need adjustment right?

 

[Knucklehead]

Yes, the ones with the little funnels are the drain screws.

The pilot screws do have the plugs covering them to keep people from tampering with them un-necessarily. However, there are cases where they've been out of spec right from the factory. If you do not have carburation issue though, don't mess with them.

 

[ShimminOut]

Yes, they are the ones with little funnels covering them. Thanks. It definately sounds like this upgrade will be left in the hands of professionals when the time comes. I will probably be installing a new exhaust that I got pretty cheap. My nearest shop is quoting me about $400 for tuning on the dyno, does that sound about right?

 

[zx6r2k]

so when people say go out 2 1/2 or 3 turns and go from there, what does the go from there mean? How do you dial them in right. one was all the way in and another was out by 6 turns and the last 2 were out 3 turns and mine still had the plugs in them. i turned them all out 3 turns and it seems to idle a little smoother but what am i listening for i also notice when i rev it up slightly a small amount of gas shoots out of the top of the carbs

 

[Knucklehead]

Sounds like yours was pretty messed up from the factory being out by that much. Well three turns out from being seated(fully turned in)is the factory spec for the mixture screws. The more you turn out, the richer the mixture. Most people find that 2 1/2turns, which would be a bit leaner from spec, works the best and is a good starting point because it's near the middle of the road mixture wise. Depending on how it's running and how your plugs are looking after some use would depend if it needs a bit more tuning either richer or leaner.

 

[zx6r2k]

i also wanted to ask if a full turn (to me at least) is from 12 o clock to 12 o clock or do some people consider a full turn from 12 o clock to 6 o clock

 

[Knucklehead]

12 to 12 for a full turn. 12 to 6 is half.

 

[scrumble]

4 to 4 is also a full turn. and 11 to 11. it's all relative.

 

[jbreit]

Jet kits are made for the track...they will usually load up on the street...DJ is especially junk. A rejetted bike will only miss 1 or 2 hp peak from a jet kit bike, but get better fuel mileage, have better mid range power and not be so tempermental with hot starting, humidity and so on....and rejetting will cost $20 in parts...not $100....labor is the same or less.

If you don't know what you are doing with carbs, let some one else do it....I've been doing my own and ones for friends for 12 years...I've seen some really messed up stuff...

If you want to save some money, take the rack of carbs off yourself and bring them in. They don't need the bike to change parts out unless they are going to run it on a dyno. Either way, $400 sounds steep to me. If you pulled in my driveway, I'd install a pipe and rejett your carbs for $150 plus parts.

My 1998 I sold had a full Muzzy system and rejetting...pulled 99rwhp on a local dyno and it gots 50mpg on the highway, 40 city, 27 on the track.

 

[zx6r2k]

wow what "stage" and brand kit was that. I like the factory pro sets i want to try the 1.7

 

[ShimminOut]

Man, I wish I lived up your way, jbreit. I'd let you fix me up. I decided the value added for this mod isn't worth the cost. Especially since this is a daily driver. My shop does tend to be pretty steep on labor, they're the only one within 50 miles, so they kind of have a monopoly.

 

[lowthrizzle]

Shimmin out, take it out towards DFW more, there are lots of great shops out my way.

 

[zx6r2k]

when i was adding the shims all 4 carbs had what appeared to be shims on them they were just on top above the c clip and between the spring. also when putting the spring holder above the needle it seems the o rings are swollen they look kinda fat and when i went to reinstall them they cracked the black holders that hold that piece in and i tried all different ways of installing them softly and they still cracked now i need 3 diaprams if anyone has them i will be willing to buy them and i lost 2 springs when that happened so i need those 2 springs as well. What a shitty day i hope somone has those parts or you can direct me to a place that sells those parts

 

[zx6r2k]

are carbs from a 98 the same size as 2000 and are the parts interchangeable

 

[Knucklehead]

Check the fiche at Ron Ayers and compare both years and see if the part numbers are the same.