Carb sync

VMAX  Forum

Help Support VMAX Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

ChuckMiller

Member
Joined
Mar 17, 2019
Messages
8
Reaction score
5
I have a cali no boost 90 model. I am having trouble finding carb 1 and 2 sync point. Any pointers out there.
 
You misunderstood my question.

This is the hose type which comes with a Dynojet Stage 7 kit. Part of the installation kit for the Dynojet Stage 7 calls for the installer to remove the Vboost butterflies, and to replace them with the kit's short tubes.

When you posted that you have a cali no boost 90 model the experienced members on-here immediately suspect you may have a Dynojet Stage 7 kit, because of the elimination of the VBoost butterflies.

I suspect that your "cali" reference may refer to the California model VMax, which does have slightly-different carburetors, but it does-not eliminate the factory VBoost. There is an additional canister which is added to the California models, identified by a CA-suffix to the model designation. It's there to provide evaporative emissions containment within the fuel system to comply with the environmental codes of the State of California. Here is a schematic of the canister added to the California bikes. 2006 Yamaha V-MAX 1200 (VMX12VC) Fuel Tank | Ron Ayers

Japanese Generation 1 VMax bikes and I believe some of the U.K. bikes don't have VBoost. That is to meet their licensing requirements in those countries. It also is why there is a business in importing full-horsepower bikes with VBoost into those countries once they meet whatever age-of-bike requirements there may be.

VMax engine venting from Germany.jpg

The double-end attaches to the front K&N air filters, the red-coded end is your oil filter cap. The black plastic container has a woven-wire mesh like a Brillo pad, which converts the oil in the air from the crankcase into a liquid condensate, which then runs back into the crankcase through the hose, avoiding over-pressurization of the crankcase. The short hose from the black plastic container bottom-aspect, attaches to the OEM crankcase breather hose which passes upwards from the top of the engine crankcase to where it would attach to the male port on the bottom of the OEM airbox. With the Dynojet Stage 7, it now attaches directly to the port off the black plastic container.

Here is the Dynojet installation sheet for their Stage 7 kit, explaining where the hose is routed from/to, and how the small black plastic L-fittings attach to the K&N pleated stainless-steel surgical gauze filters.

VMax Dynojet Stage 7.png

This should clear-up any misconceptions you may have had in-regards to my query.
 
Last edited:
You are aiming to get the same reading of one carb relative to the other and to do this it has to be done independently of the other. Once you have each pair balanced you then adjust one pair relative to the other to get the same reading.

When you have open tubes between the pairs of cylinders then you won't be able to balance each carb relative to the other as the gauge will be reading the avereage vacuum generated by both carbs.
If you still have the V Boost butterflies then put that back on and balance with the the butterflies closed. If you prefer the bike with open connectors then leave the butterflies open.

If you don't have the mechanism then use a small rod e.g. drill bit, as a gauge and adjust the butterfly so that it just nips it. Do the same with the other carbs and you will be near.
N very B! Whatever you use as a gauge make sure you can't drop it down the inlet - some thread attached so it can't come off is a very good idea.
 
Fire, I think the misunderstanding is due to you saying “oil filter cap” when you mean to say “oil filler cap”.
 
I agree, fire-medic is very helpful and deserves respect I understand you may have been frustrated but the guy was offering his free of charge help so maybe you could get your bike going don't be a dick. This forum is for getting help or hearing other people's experiences with issues you may be or have experienced
 
Last edited:
Fire, I think the misunderstanding is due to you saying “oil filter cap” when you mean to say “oil filler cap”.
Doesn't matter if he misspelled a word or not he was only trying to help no need to be an asshole to someone trying to help you.
 
Fire, I think the misunderstanding is due to you saying “oil filter cap” when you mean to say “oil filler cap”.
I know you weren't the one being a dick I was just explaining on your thread don't take it personal.
 
Fire-Medic goes to a great deal of trouble to help the VMax community with problems of all sorts. His explanations are detailed, easy follow, very informative and have helped a large number of people. He deserves more respect than he sometimes receives.


+++++100%%%

ALWAYS anxious to help others and provide details not often found in FSM but learned through trial and error (see write up on changing clutch master cylinder as an example)
 
It was all a bad misunderstanding. I have a modified VMAX. It has no vacuum lines going anywhere but to the vacuum advance. No canisters, no oil filter caps. The way the post read, I thought he was whacking on me. My mistake for and I apologize.
 
Thats awesome you maned up and apologized fire-medic is very helpful thats all he was trying to do. Very seldom anyone on here will make fun of anyone for any questions asked they are all very respectful no matter the questions or issues. Thanks again shows great character you apologized.
 
I wasn't angry, definitely having issues since resetting the float levels of my carbs. Two were set way rich. Seems to be something with the chock. Doesn't act right. The bike will scream then doesn't want to idle
 
Ensure that you have the proper slack in your throttle cables. The synchronization being off can also make the throttle 'hang-up,' and not idle properly.

Another issue is the cables aren't lubricated, or the helix (the cable tube) is either crimped somewhere, or it's rusty.

We also have seen where the screws for setting the synchronization are improperly-set, or the synch screw springs were installed improperly.

VMax synch screws.01.jpgVMax synch screws.02.jpg

The carburetor choke settings may be off (attach., see variance in choke plunger rod exposed length shown by white parallel bars).

VMax carb choke out of adjust..jpg
 
Last edited:
I appreciate the advice. I sealed each carb one at a time. Number 3 began gushing fuel. I revisited the float. While they were off I mechanically synced them from the bottom. Did that twice before the flow stopped. Screams for now, hope it lasts
 

Latest posts

Back
Top