Ok I m about ready to have a seizure

[timax]

Here is the deal, I had this same problem before the carbs were totally rebuilt,new carb boots,new vboost boots... I can sync both left carbs, i can sync both right carbs... The front sync screw does next to nothing, i cant bring both sides together, even standing on my head...

Using the carbtune, so i thought maybe its the carbtune... What i did was hooked up a single vac meter and used one of the lines from the carbtune..
just for shits to see what i had.. on the right side the needle remained very steady on both carbs... moved to the left side the needle is jumping like a pogo stick, i mean a 5 pound jump back and forth...

Like i said even before i pulled the carbs this past winter i had the same problem getting both carb banks to play together... after new fuel tank,sending unit,total carb rebuild,new plug wires,fuel filter,plugs:bang head:

Still the same problem... What the hell is causing this? The only thing left that i can think of is doing a leak down test on both left cyl, maybe a valve adjustment issue??? I should add when on the left side with the single meter hooked up, if i raise rpms the jumping of the needle does settle down somewhat... The bike i bought used with 2000 miles on it, it wasnt ridden much, but i would be willing to bet the valves were never set at the dealer after break in 1200 to 1500 mile mark.... bike now has around 11000 on it..

Come on experts, what the hell is causing this??????????:bang head::damn angry::bang head:

 

[maleko89]

Is this Ed? It's not your carbs if it was doing this prior to rebuild. Your carbs sync'd perfectly on my bike. Maybe manifold crack?

 

[timax]

Yes Mark its me... I agree with the needle bouncing like that its not fuel...

Have to do a leak down test, fixing to make a plug, if something is not sealed that should find it. Thats all i can come up with.:damn angry:


With a cracked manifold wouldn t the problem get worse when the rpms are raised? Anything is possible just dont think thats the problem.

The bike runs pretty decent now, its just not right. I can see a difference even at the muffler outlets.

 

[timax]

Ok i ended up buying a new carb tune and finally got around to messing with the carbs.. They were off somewhat, but not that bad... Got them synced up and man that front sync screw on the right side is very touchy... I think if you fart on the damn thing it would change the settings...

So turns out my old guage was ready for the landfill... The bike runs a bit better now, but i still have that awful flat spot anywhere from 3000 to 5000 rpms, if i use tboost it will mask the problem, if i raise the needle even 1/4 clip the problem pretty much goes away, as does my fuel mileage,,, its way rich..

Starting to think maybe its something electrical, i have not ruled out a valve adjustment but that wont happen till the snow flys.

Going to pull the plugs here shortly and see what they look like..

 

[maleko89]

Ed, did you try adjusting your mixture screws?

 

[timax]

Mark

If i remember right they are about 2.5 to 2.75 turns out right now... I just pulled the plugs, going to try and get a decent picture of all 4.... they are very clean looking.

Will the mixture screws come into play up that high in the rpm range?
I always thought they were more for idle and just off idle in the rpm range.

Damn it why dont you move to PA i will pay you to tune it:eusa_dance:


let me work on those pics...

 

[timax]

Keep in mind i use the copper high temp anti seize,, thats why the treads are so dark...

 

[timax]

Part of what i went through this past winter:bang head:

Back together with no extra parts:confused2:

I can tuna a fish but i cant tune a Vmax:bang head:

 

[davidon]

You're right mixture screws only effect idle/off idle. Your mid range problem sounds like it's needle related. Why not shim and check like you already suggested?

 

[timax]

You're right mixture screws only effect idle/off idle. Your mid range problem sounds like it's needle related. Why not shim and check like you already suggested?

Needles are at 2.750 clip,, when i went .250 clip higher to the 3rd notch you could smell the fuel and mileage went to shit... I have pauls shim kit, cant get any more presise than them...1/4 clip is not much...

I wonder if i go back to the 3rd clip and lean out the mixture screws:ummm:


Anyone here from PA ? I will pay anyone that is willing to help, and i will also throw in a cookout followed by as much booze as you can drinkunk:

 

[maleko89]

Ed, mixture screws have an effect up to 5K rpms. You can try a 1/2 turn more out otherwise put needles on 3rd clip and lean your mixture screws out.

 

[timax]

Ed, mixture screws have an effect up to 5K rpms. You can try a 1/2 turn more out otherwise put needles on 3rd clip and lean your mixture screws out.

Mark

Wow i didnt know that:ummm:

Sounds like a plan, will try to richen it up with the mixture screws first. If not i wil lbe taking shit apart again:damn angry:

Thanks Man!!!