Got it to idle at 1000, though when I hook up the Motion Pro to the main carb, it vacuum's the fluid to the top, still. Even if I push down the the valve to near-kill the engine, the fluid level is still being vacuum'd out. Can't figure this one. the main carb is the only one that this happens on.
Help Support VMAX Forum:
Which carb is really high? Front, left?
Turn the left sync screw clockwise a 1/4 turn. Does it get better or worse? Try a 1/4 turn counter clockwise and see what the result of that is too.
Turn the left sync screw clockwise a 1/4 turn. Does it get better or worse? Try a 1/4 turn counter clockwise and see what the result of that is too.
shawn kloker
Well-Known Member
Sounds to me like you better pull the carbs and do an exploratory on that carb.See what's screwed up.
Pulled the carbs again tonight. I've looked over the main (non adjustable) carb, broke it down, looked at every piece, made sure it was clean, put it back together carefully, put the carbs back on, did the shotgun again......still nothing. Vacuum is still high. I've started the bike and hooked up the carb tool, placing my finger on the main carb throttle valve and pushing it down to almost kill the engine, and the vacuum is still high even though the bike almost dies.
Was thinking, I've also got my stock enhaust drilled out, and did not make any adjustments to the carb. Could there be any link to the modifications that I've made to the exhaust, and the vacuum problem I'm having in the main carb?
Have you tried hooking the tube that reads high to another carb to make sure it's not a bad tube? Also, try closing the tube valves a little bit. Maybe they're open too much.
Yeah, I've tried that. I've tried all tubes on all carbs, a little mix to make sure that that it's not just one tube in question. All of the other carbs have normal, or somewhat normal vacuum. The only carb that just has too much is the main (non adjustable) one. When you close the valves on the Motionpro, it just raised the fluid, so that would just mean that it would get sucked out faster. I don't think this one works the same as the mercury models with the vents.
Does the reading change if you remove the air box? That cylinder is pulling vacuum from somewhere. Did you replace all gaskets? I'm just grasping straws here, but is you spark plug tight?
Okay, high vacuum means the throttle valve is closed too far. The only way to open the throttle valve to the fixed carb is with the thumb screw. Another cause for high vacuum at idle is a plugged idle circuit or the mixture screw is too lean. I may have asked before, but does the mixture screw have any affect? If you close it down completely do you notice a change in engine tone?
Sorry, one more thing. Check and make sure your float bowl vent isn't plugged. Blow some air in there with a straw.
Have you done the Peashooter? Basically putting some seafoam in the PAJ1 and choke vent?
Have you done the Peashooter? Basically putting some seafoam in the PAJ1 and choke vent?
You've got me thinking here.........Ok, it's too late for me to check now (neighbors don't like the pipes) but I remember adjusting the mixture screws before, and it did have a change. Right now, they are all 2.5 turns out. I'm wondering though.......the reason I have the thumb screw all the way down was because it was making the other carbs idle high-er........maybe I can just adjust the idle screw to get the throttle plate to open a little more on the main carb, hopefully reducing the vacuum. Then I can just back off on the idle adjustments for the other carbs??? I'm thinking that could put me at a starting point. Does that sound right? If the idle goes up (throttle plate opens) on the main carb, the vacuum should go down?
I agree! Try the thumb screw to get the fixed carb's vacuum down.
WOO HOO!!!! That was it. I just needed to adjust up the ilde screw on the main carb, and tune down the other 3. That gave me a starting point to where I can hook the Motion pro up, and begin the sync process. Thanks soo much for all the help, I REALLY appreciate it.
Anyone know how to change valve cover gaskets??? LOL!!!!
Anyone know how to change valve cover gaskets??? LOL!!!!
shawn kloker
Well-Known Member
So # 2 was doing all the work and the rest were way behind.Seriously out of sync?I'm surprised it would run.
Oh, man.....you have no idea what a relief it is to finally (hopefully) be done with these carbs. I only had the bike for a few weeks when the problems began. It all started with the "puke can" in the air box was not properly sealed, the screws were missing, so the airbox was full of oil!!! I'm sure this problem went unoticed for some time because the carbs were a mess!!!!
I've broken them down, done a thorough cleaning several times. I had to replace all 4 coasting enricheners (they were all rotted and hardened. I replaced all 4 float bowl gaskets. Replaced the o'rings on the drain screws because gas was leaking around them. And then this whole sync problem.
It's good to know that there are web sites out there, such as this one, that can help and provide advice with our specific bikes. I've talked to people at the local dealers/service shops and NOBODY even knows what a VMAX is!!!
Now, my next project is going to be the valve gaskets (leaking oil) and I should be all set for the riding season. Again, thanks so much for the help!! :biglaugh:
I've broken them down, done a thorough cleaning several times. I had to replace all 4 coasting enricheners (they were all rotted and hardened. I replaced all 4 float bowl gaskets. Replaced the o'rings on the drain screws because gas was leaking around them. And then this whole sync problem.
It's good to know that there are web sites out there, such as this one, that can help and provide advice with our specific bikes. I've talked to people at the local dealers/service shops and NOBODY even knows what a VMAX is!!!
Now, my next project is going to be the valve gaskets (leaking oil) and I should be all set for the riding season. Again, thanks so much for the help!! :biglaugh:
I just did my valve cover gaskets last month. It was my first time wrenching on my Max.
It's not really difficult. You just have to take your time and remove everything that is in the way to get the valve covers off.
The things that tripped me up...
the cable coming off the v-boost servo motor was a pain so I removed the screws that hold the servo motor in place.
When you put the valve covers back on, make sure you don't knock out the rubber cam caps.
And don't crank on the valve cover bolts with a large wrench. They will break off long before they feel tight!
It's not really difficult. You just have to take your time and remove everything that is in the way to get the valve covers off.
The things that tripped me up...
the cable coming off the v-boost servo motor was a pain so I removed the screws that hold the servo motor in place.
When you put the valve covers back on, make sure you don't knock out the rubber cam caps.
And don't crank on the valve cover bolts with a large wrench. They will break off long before they feel tight!
V4bandit
Well-Known Member
I'm so glad to have found this thread. My carbs are doing the same thing with my Motion Pro trying to sync the carbs. I had no idea what to do to fix it, then I read this. Now I can't wait to try it out 
