Need help syncing carbs

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Hitock76

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I just purchased my first vmax last weekend . It's a 06 with a stage 7 and supertrapp exhaust . It seems to have a hard time at idle and I was reading you need an experienced mechanic to sync your carbs with a stage 7 kit . I live in the suburbs of Chicago and would like to know is there any dealership you guys would recommend to have this done ?
 
Is all your v-boost equipment still there, just unplugged? If so, plug it in and synch like normal.

If it's gone you can get something like the weber to set synch.
http://www.carburetion.com/Products/ProductDetails.aspx?part=STE-SK

No need for an "experienced mechanic". It's quite simple

I'm not sure why anyone would install a stage 7 jet kit with supertrapp slip-ons. Not saying it won't work if you fiddle with tuning, just no point.


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I just purchased my first vmax last weekend . It's a 06 with a stage 7 and supertrapp exhaust . It seems to have a hard time at idle and I was reading you need an experienced mechanic to sync your carbs with a stage 7 kit . I live in the suburbs of Chicago and would like to know is there any dealership you guys would recommend to have this done ?

http://www.vmaxforum.net/showthread.php?t=3959
 
Should I have a different jet kit installed?

No, its just that the main restriction is the stock head pipes, so the get the most out of the stage 7 jet kit, you need an aftermarket exhaust. Slip ons offer no HP benefit.
 
Should I have a different jet kit installed?

With your set up, I'd take the stage 7 kit out and make sure, like Mike mentioned, the v-Boost works normally, or is closed when syncing. I don't like bringing a vmax to a dealer. Unless there is a mechanic there familiar with them.147-150 Mikuni mains will work. Slip ons like Eric explained, are restricting. Or, if you want the performance and weight savings, buy a full header system.
Steve-o
 
Just using this thread on syncing as it 's all related.

What is happening when I sync my cards and adjust sync screws?

Ok so carbs 1,2 are on left side, labeled from rear to front. 3.4 rear to front of bike on right side. ok.

so say my manometer is hooked up, it has 4 lines, left to right are 1-4. so carb 1 is on tube 1, etc etc.

so left side are carbs 1,2 and sync screw syncs those 2 to each other.. what happens when i turn the sync screw CW? will there be more force/air pressure/whatever it is coming out of carb 1, or 2?

hoping someone knows same for right side info........ what happens for rear sync screw (carbs 3,4 syncing) when turn CW? then same for right side sync scrfew (sets left and right) when turn CW?

thing is, my manometer doesn't allow me a lot of time to adjust cuz the fluid will get pushed out of the weaker tubing and go into the carbs.... so i can't waste time til it gets close enough to let the bike run......... i dont have 1-way valves type things in there, just 4-way connected line and all air spouts/whatevr they are are fighing each other...
 
Just using this thread on syncing as it 's all related.

What is happening when I sync my cards and adjust sync screws?

Ok so carbs 1,2 are on left side, labeled from rear to front. 3.4 rear to front of bike on right side. ok.

so say my manometer is hooked up, it has 4 lines, left to right are 1-4. so carb 1 is on tube 1, etc etc.

so left side are carbs 1,2 and sync screw syncs those 2 to each other.. what happens when i turn the sync screw CW? will there be more force/air pressure/whatever it is coming out of carb 1, or 2?

hoping someone knows same for right side info........ what happens for rear sync screw (carbs 3,4 syncing) when turn CW? then same for right side sync scrfew (sets left and right) when turn CW?

thing is, my manometer doesn't allow me a lot of time to adjust cuz the fluid will get pushed out of the weaker tubing and go into the carbs.... so i can't waste time til it gets close enough to let the bike run......... i dont have 1-way valves type things in there, just 4-way connected line and all air spouts/whatevr they are are fighing each other...

By "manometer" are you using a motion pro with the blue manometer fluid?:confused2:

The height of the fluid does not matter-turn the screw on the left side to adjust carbs 1&2 and make them the same-----Then turn the back screw on the right side to adjust carbs 3&4 and make them match each other ---Then turn the front right side screw to make carbs 3&4 match carbs 1&2.:clapping:
 
Also if you did not install the correctors inline closest to the carbs you are not going to get a correct reading-:bang head:
 
Also if you did not install the correctors inline closest to the carbs you are not going to get a correct reading-:bang head:

i made a manometer using clear tubing and piece plywood etc... also using (2) 3-way connectors, and the fluid is motor oil ( gas will corrode etc, dont wanna keep gas in there like that, water isn't thick or viscus enough, so motor oil is in there) this is why I can't just keep the bike running while I do this. If carb 1 is pushing way more air, it'll fill up the lines on 2,3,4 faster, particularily the weakest one of them, and pushes that oil up and away quickly.... and air gets in between the oil and so I have to disconnect, and set aside for 15 minutes so oil settles back down so i can try again.

so for now, i gotta hook it up, start up bike real quick, take notes on what I see, turn bike OFF, adjust screw (this is why I need to know what does what.. CW or CCW of sync screw on 1,2 side will either make carb 1 push more or less air)........ and same for the other 2 screws...

see my dilemma? so i gotta start up bike, see whats going on with manometer, stop bike, adjust, start bike, look again....

i gotta do this over and over til they are all close enough so i can keep bike running (cuz air pushing out of carbs is close to equal, so no worries about oil getting into carb bowls)..... see? so thats why i am doing and wouild like to know what CW turn does for example....
 
i made a manometer using clear tubing and piece plywood etc... also using (2) 3-way connectors, and the fluid is motor oil ( gas will corrode etc, dont wanna keep gas in there like that, water isn't thick or viscus enough, so motor oil is in there) this is why I can't just keep the bike running while I do this. If carb 1 is pushing way more air, it'll fill up the lines on 2,3,4 faster, particularily the weakest one of them, and pushes that oil up and away quickly.... and air gets in between the oil and so I have to disconnect, and set aside for 15 minutes so oil settles back down so i can try again.

so for now, i gotta hook it up, start up bike real quick, take notes on what I see, turn bike OFF, adjust screw (this is why I need to know what does what.. CW or CCW of sync screw on 1,2 side will either make carb 1 push more or less air)........ and same for the other 2 screws...

see my dilemma? so i gotta start up bike, see whats going on with manometer, stop bike, adjust, start bike, look again....

i gotta do this over and over til they are all close enough so i can keep bike running (cuz air pushing out of carbs is close to equal, so no worries about oil getting into carb bowls)..... see? so thats why i am doing and wouild like to know what CW turn does for example....

CW they will go down----never heard of oil being used in a carb sync. :confused2: https://www.youtube.com/watch?v=KHGPqP6G9cA
 
CW they will go down----never heard of oil being used in a carb sync. :confused2: https://www.youtube.com/watch?v=KHGPqP6G9cA

it's a homemade manometer, there's no safety preventing fluid from coming into carbs.... maybe a better option rather than oil, but, thats what i did. what do you mean by CW they will go down?

so i pinch off carbs 3 and 4 and keep the caps on them, but hook up carbs 1,2 and pinch off the lines of 3 and 4. say for example i start up bike and line 1 (for carb 1) shoots up and fills up with fluid... that means it's the weakest link and carb 2 air pressure out of stem of carb is way higher.... so will turning CW make the air pressure of carb 2 coming out of stem go down or up? in other words, in this scenario, will turning CW get me closer to even or make it worse, hence unbalancing them even more?
 
it's a homemade manometer, there's no safety preventing fluid from coming into carbs.... maybe a better option rather than oil, but, thats what i did. what do you mean by CW they will go down?

so i pinch off carbs 3 and 4 and keep the caps on them, but hook up carbs 1,2 and pinch off the lines of 3 and 4. say for example i start up bike and line 1 (for carb 1) shoots up and fills up with fluid... that means it's the weakest link and carb 2 air pressure out of stem of carb is way higher.... so will turning CW make the air pressure of carb 2 coming out of stem go down or up? in other words, in this scenario, will turning CW get me closer to even or make it worse, hence unbalancing them even more?

Actually by turning the screw on the left side you are adjusting #1 carb to #2 as #2 is set and cannot be changed-yes CW will make the fluid in the #1 carb go down. You should be able to turn the screw about 1/2 turn to see it rise or fall-then blip the throttle for a stable return. I tap the sync tool also and make sure it is in an upright position and not leaning.:clapping:
 
ok cool thanks donny that's right, carb 2 (should be carb 1 as in, it's kinda the carb leader).

ok so CW (towards carb #1) will increase air output pressure (make fluid go down) whatever out of carb #1.

so turn in the direction of the carb you want to increase output (at least on left side of bike.)

is this is same for right side of bike ? also, a CW turn will do what to the fluid sets (1&2, 3&4) on that front sync screw on right side.... ? will a CW turn increase left or right side sets?
 
The process with any any syncing tool will look something like this:
1) Connect all tubing to each of the carbs
2) Turn left side (shifter side) sync adjusting screw until 1 and 2 carbs are balanced
3) Move to right side and adjust sync screw until 3 and 4 carbs are balanced
4) On the right side turn the adjustment screw to balance carbs 1/2 with carbs 3/4
5) Once they are all balanced with one another your done. You may have to readjust the balance between the 3/4 to get the two sides(left and right) to balance but should only be minor adjustments at that point.
With my carbtune I can sync in 15 - 20 min which includes removing and installing carb covers.

Edit: Changed the term "even" to balanced as it better describes what your trying to achieve when syncing.
 
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yep I've done this before, but without a carbtune it's much more of a headache. can't leave the lines hooked up to the carbs cuz if they are way off sync, then the weakest carb will be taking in oil, which is my fluid in the tubing.
gotta get them close then they're ok to run all on and adjust sensitively.

so i'm assuming the right side rear is same as left side sync screw.. turn CW and that will increase output pressure (call it that...) on carb #4? someone confirm this for me please? then still need to know what a CW turn does (what carb set 1/2 or 3/4 will have increased air output) on the right side front sync screw....
 
If you don't have a restriction in the line it makes much harder to sync. I believe that one of the other homemade sync system used a section of cable tv wire to slow the engine pulses enough to be able to sync. I thought about making one the setups like yours but have nowhere to store it so I just went with the carbtune.
Anyway, I hope you get this issue worked out, a properly synced Vmax is fun!
 
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