After 6000 miles, as many dyno runs (It feels like that ) and a ton of modifications it was time to sync the throttle bodies.

When switching to the Monster Big Air Kit, Cylinder #2 (left rear) did an occasional back fire into the TBs. Sure enough the TBs where slightly out of sync at idle and low throttle.

Syncing the TBs on the VMax is easy and can be done in 15 mins if you have the right tools, highly recommend an electronic vacuum gauge.

All ports and screws can be access with the bike just sitting there. No covers or bolts need to be removed.

Make sure the bike is fully warmed up. Thats 20 min of riding around. Bets you do it when you get back from a ride. If the bike is not fully warmed up, the reading will drift around and drive you crazy.

Attache #1 to front left cylinder, #2 to rear left, #3 rear right and #4 to front right culinder vacuum ports (the ones that have the rubber plugs on them (remove the plugs first with small pliers).

The set screws are right next to them (brass - golden looking - recessed inside the throttle boddy).

On my bike #3 was full closed but not the cylinder pulling the highest vacuum. Therefore I made it the reference to which I set all other cylinders vacuum.

I highly recommend against a mercury based vacuum gauge as this big engine pulls some serious vacuum! Blip the throttle and all you mercury will be gone in a blink...

The adjusting part take 5 mins.

What a difference! Bike is ultra smooth again around idle and on take offs, no more occasional burps into the filters from cylinder #2.

Case you wonder what tool to use:
www.klsupply.com/TUNINGDIAGNOSTIC/VACUUM...bid/154/Default.aspx

Next on the list:

Cylinder individual custom mapping.

Hope this helps!

Any information on the electronic vacuum gauge that you are using?

The link above take you to the webpage on K&L for the electronic vacuum sync tool.

Here is it again:

www.klsupply.com/TUNINGDIAGNOSTIC/VACUUM...bid/154/Default.aspx

The tool is called vacuummate and is used by Yamaha to train technicians on how to do this.

K&L also offers a second model:

35-9589 Digital Vacuum Tester (download their catalog to see details)

As I said before, K&L does not sell to the public, but our site sponsor San Jose Yamaha can get any and all parts from their catalog for you. Call them up and they will get you pricing and availability.

Hope this helps!

Thanks Oliver. I too get the occasional burp, and have noticed it mostly since the airbox mod. I think having the air box open allows us to hear things we couldn't before. Like yours, it's only occasionally at low rpms (off idle)..

A turn with a small screwdriver took care of it, same as you, #2 was a little lean.

Glad to see more infomation on this topic, it helps alot! That gauge looks like a must have.

Not electronic but works. Works counts

Ya, I was wondering if there might be a cheaper way to go and acomplish the same thing. THANKS

Might want to check these for accuracy.

Good point, maybe no need to scimp on this.

Oliver, how are these throttle bodies linked to each other?
I'm asking this because on the GEN 1 you always left one without touching and using it as a reference; it was the one that had the trottle idle adjustment screw.
I know there is a reference throttle body here, and it is normally a front one (front left maybe?) It must be marked some how or another.
And in my case, trying to save for better causes such as the pipes and tuner, I think I will skip that fancy electronic gadget of yours and pull out my old CARBTUNE (www.carbtune.com/).
When tuning with this unit, same as you would do with four different gauges, it is healthy to swap hoses around, just to make sure they are all reading the same (or properly).
GEN 1 old school knew this tool very well....
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