#2 mixture screw off from factory?

[06VMAXIMUS]

Well the dirty carb bitch finally bit me! Took the day off to go on a ride with the wife, and about 5 minutes into it, the bike develops a slight miss and pop at steady throttle. After about 10 minutes, it goes away and then comes back about 2 hours later. I took the advice here and let the "peashooter" and "shotgun" have a go at it. I had to remove the factory brass plugs from the mixture screws, and when checking the factory settings, I noticed that #1,3 and 4 were 1&3/4 turns out, while #2 was 2&1/2! Why the big difference in adjustments? Did Yamaha intentionally richen #2 cyl from the factory, or was a line worker half asleep when he set that carb? Anybody here have the same situation? The spark plug from #2 looked no different than the other plugs which leads me to believe it was an intentional mixture setting from Yamaha. :ummm: Confused.....Bob

 

[dannymax]

Well the dirty carb bitch finally bit me! Took the day off to go on a ride with the wife, and about 5 minutes into it, the bike develops a slight miss and pop at steady throttle. After about 10 minutes, it goes away and then comes back about 2 hours later. I took the advice here and let the "peashooter" and "shotgun" have a go at it. I had to remove the factory brass plugs from the mixture screws, and when checking the factory settings, I noticed that #1,3 and 4 were 1&3/4 turns out, while #2 was 2&1/2! Why the big difference in adjustments? Did Yamaha intentionally richen #2 cyl from the factory, or was a line worker half asleep when he set that carb? Anybody here have the same situation? The spark plug from #2 looked no different than the other plugs which leads me to believe it was an intentional mixture setting from Yamaha. :ummm: Confused.....Bob

That's normal Bob. They use an exhaust gasses analyzer to set the A/F for proper emissions control from the factory. When I checked mine they were from 1 1/8 to 2 1/4....with no two the same.

 

[06VMAXIMUS]

Good to know! Scared the crap out of me that the other three were "spot on" to each other. So when you guys add a full aftermarket exhaust system, how do you know where to set the screws? Do you "add" a turn out to each cyl?

 

[naughtyG]

Unfortunately there is no way to set them properly unless you have an exhaust gas analyzer or a laser temperature gauge, which most of us don't.

So we usually set them around 2.5 turns out as a start, then tweak according to spark plug color etc..

My understanding is that the A/F screws only affect idle and low revs - correct me if I'm wrong.

 

[06VMAXIMUS]

So when adding pipes you ignore the factory setting and go from scratch at 2.5 out?

 

[naughtyG]

So when adding pipes you ignore the factory setting and go from scratch at 2.5 out?

That's what I thought. Unless, of course, you have the right equipment..

With a full exhaust system, I believe jetting is way more important that the A/F setting, hence Morley's comprehensive jet kit.

 

[06VMAXIMUS]

Interesting. I assumed when adding aftermarket pipes and the settings were different, you would "add" an equal amount to your base setting. I hope my problem is cured, after shotgun, peashooter and sync, I didn't have time to take it out to see if it was better. I can't believe they got crap in them! I am faithful about winterizing the bike properly and have never had problems with my other bikes...I had my CBR for 9 years and never had to crack the carbs once. I guess the Vmax carbs are touchy. Thanks for the comments. Bob

 

[dannymax]

I tried the laser temp gun and found it didn't work very well at all....maybe just a cheapo...:confused2:

But the 3 1/4 turns out on each one worked very well with the Mark's and dyno'd right up there too....117.1 for a stock bike! PCW said I had it set up just right....purely accidental really, it just turned out that way. unk:

 

[gamorg02]

i couldn't hear the a/f differences to save my ass, so i have to have them done on a sniffer.

i also have an LM-1 i picked up that I should see if i can get hooked up.

 

[06VMAXIMUS]

I tried the laser temp gun and found it didn't work very well at all....maybe just a cheapo...:confused2:

But the 3 1/4 turns out on each one worked very well with the Mark's and dyno'd right up there too....117.1 for a stock bike! PCW said I had it set up just right....purely accidental really, it just turned out that way. unk:

I like that 117 number!!!:biglaugh:

 

[06VMAXIMUS]

i couldn't hear the a/f differences to save my ass, so i have to have them done on a sniffer.

How does the sniffer pick up the individual cylinders?? :ummm:

 

[gamorg02]

i couldn't hear the a/f differences to save my ass, so i have to have them done on a sniffer.

How does the sniffer pick up the individual cylinders?? :ummm:

on the dyno he had a cooper pipe attached to the sniffer he put down the exhaust.

now i have 02 bungs.

 

[06VMAXIMUS]

Its hard to beat having multiple "bung holes":rofl_200:

 

[m-cman]

i couldn't hear the a/f differences to save my ass, so i have to have them done on a sniffer.

How does the sniffer pick up the individual cylinders?? :ummm:

I believe the stock system already has the "bung" holes on each pipe.

 

[dannymax]

I believe the stock system already has the "bung" holes on each pipe.

Yup, it sure does.

 

[06VMAXIMUS]

I believe the stock system already has the "bung" holes on each pipe.

Ahha...now it makes sense! Took the bike out tonight, and it runs much smoother at steady throttle. But I am getting a slight backfire on decelleration....doesn't do it all the time. Gonna try some more seafoam and run a few tanks of fuel through it.

 

[gamorg02]

Yup, it sure does.

however i believe they are temp sensor bungs, not 02 sniffer bungs. 02 sniffer is i believe an 18mm thread.

 

[06VMAXIMUS]

Maybe I should tell the wife that the bike is screwed up and the only way it can be fixed is with a set of Marks pipes!

 

[gamorg02]

Maybe I should tell the wife that the bike is screwed up and the only way it can be fixed is with a set of Marks pipes!

"honey,

my bike isn't working properly. it can't breathe right. imagine if you had to breathe out of a straw all the time, you don't feel right, you get sleepy easier. now imagine you can breathe out of a bigger tube. you feel better, get less cranky, etc etc. thats the same thing i'm trying to do to the max so its more reliable."

done and done. and +100 points if u do it with a straight face.

 

[06VMAXIMUS]

I don't know if I could keep a straight face while telling her that....she can read me pretty well after 21 years of my B.S.! We talk alot while riding, and I am afraid that a set of Marks pipes might be too loud/ear ringing. Maybe a set of turndowns would take care of it?