Sell the Cobras. A stock exhaust makes more power.
At this stage send the carburetors to member (screen name, use the PM function to contact him) Dannymax or to
[email protected] Sean Morley for rebuilding. You already ruined one set. Get it running well & did I mention get rid of the Cobras? Really. The Cobras are looks-only. They cost you performance and drivability. You don't believe me read past threads & posts. From your desire to re-jet & etc, I assume you have the full set Cobras, the 4-into-4 system.
Riding a VMax with a Cobra 4-into-4 full exhaust is like using .38 Special cartridges in a .357 Ruger GP-100. You can do it, but the equipment is capable of so-much more! If you don't believe me, spend some time reading the Cobra exhaust comments in the many threads. The Cobras are pretty, they are impressive to anyone who doesn't know the cost they take on performance, but for someone who bought a VMax for what a VMax-stock- is capable-of (to say nothing of modified rides), you can't get-rid of them fast-enough.
I'd rather have a scraped-up set of OEM Yamaha full exhaust on my bike than a perfect-condition Cobra 4-into-4's. Take those off, and get whatever you can for them, and regain the horsepower and throttle response that your motorcycle was designed to give-you. I guarantee that if you rode two VMax'es back-to-back, one with a brand-new Cobra 4-into-4, and the other with a scabbed-up OEM Yamaha exhaust, you wouldn't care
what the OEM exhausts looked-like, given the difference in performance. It's that-big of a difference.
You got onto that bike for a decent price, now return it to the level of performance it was
designed to deliver! You will
never get there with a set of Cobras, don't waste your time and money. Of course a properly-operating set of carbs is an essential component in enjoying a trouble-free ride. If you decide to go with a Dynojet Stage 7 kit for use with a full exhaust where the system has the scavenging which the Cobras do
not, you don't have to eliminate the VBoost system as the Dynojet Stage 7 directions tell you to do. That will help you to properly synchronize the carburetors. Under the left scoop, is a round electrical M-F plug for the stepper motor which controls the VBoost. You can expose the plug, and when you turn-on the ignition and the VBoost cycles to an 'opened' position, unplug that connector. Now your VBoost will be always-open, which changes your exhaust note to a nasty one, sure to get people's attention as you idle through the crowd of people parked at your local bike night. Personally, I like the VBoost operation. The advantage to keeping it is that you have a much-easier time of it to synchronize your carburetors, and you do not need to buy a special tool to do it, if you already have a carb synch tool for 4 cyl bikes.
Sean Morley has a Morley's Muscle intake kit, jets, air filter in a modded airbox lid, and his instructions, instead of the Dynojet Stage 7, and did I mention, he often has used exhausts of various types and prices, as-well-as being a dealer for new ones?
FYI, it's usually not-necessary to replace the float needle seat, it's the needle valve piece, with its rubber/viton tip, which usually wears. Maybe after 100,000 miles, you need to-think about replacing them. I normally just replace the needle valves, and don't touch the seats. I use an ultrasonic cleaner to 'scrub' the carb bodies clean. Use a jeweler's loupe, or a magnifying glass to inspect the seat if you wish, for deposits (possible) or wear (less-likely). When disassembling the carbs, I leave them in a 'front' pair, and a 'rear' pair, unless I know there's a need to replace some piece requiring further disassembly.