2002 VMax 700 mid range bog

N

NHGuy

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Joined
Feb 14, 2014
Messages
6
Location
New Hampshire
My 2002 Vmax 700 ER ran perfect all last year. I purchased it with 4000 miles on it and put about 300 trouble free miles on it. In December I had the number 1 rated Yamaha mechanic go totally through the sled. It has run great this year for about 300 miles until yesterday. While out for a 45 mile drive it bogged twice while going 25-30 miles per hour and almost cut out but kicked back in and ran fine. It did not backfire. It started, ran and idled fine after bogging. I also keep the tank full or near full all the time. Yesterday when it did this it was down to slightly less than half a tank for the first time this year. Could this be an ethanol or water in the fuel issue? Should I be adding Starbright fuel treatment to me gas like I do me Sea Doo and boat in the summer? Or Isoprpyl Alchol to my gas?

I did check the plugs when I got home and all three were coco brown in color. I also just switched from Yamaha S Injector oil to AMS oil. It seems to burn a quart of AMS for every 80 miles or so. The Yamaha S was about 100 miles to a quart. Is that normal? My 2001 Vmax 500 also burns about a quart of AMS oil every 80 miles. I use Yamalube in my 2001 Yamaha Venture and it seems to burn about a quart every 130 miles or so. None of the machines are beat on or run hard.

Any advice or comments would be appreciated.

One more thing. I purchased the 2001 600 Venture this year. It has not been gone through. Starts and runs fine. When cold if I leave the choke on half to long when I start to go it bogs out and backfires a couple times. After a couple minutes of warm up it rund fine and never does this again until the next cold start. Does that sound like a dirty pilot jet or air screw adjustment or something else? The sled runs great as soon as warmed up for the day and gets about same mileage of the 700 (13-14mpg) all trail riding. My 500 VMAX is a pig and gets 10-11 mpg.
 
Could be water....but be sure that the oils are compatible... could be clumping. I think the carbs are dirty and the pilots needs to be cleaned... its an easy test to clean and run it again.
 
John Carson in Weare, NH. Grass dragged Yamaha's for years and was very successful. When Yamaha dealers service guys have a problem they cannot figure out, I heard they call John.
 
I am sure Woody is good. Goggle John Carson Yamaha and look at comments made about him on Hardcore Sledder. You can also find comments on him under the Four Stroke section of TY.
 
For the Vmax I'd suggest checking for rub throughs at all the reported places. If you're using E10 you won't need to use Isopropyl. If you PM the carbs at the start of the season and use fresh, in season fuel, you don't need fuel additives.

Check the oil cable adjustment or for it being pulled out.

As for the Venture - sounds like you aren't letting it warm up enough and are also leaving the choke on too long.

Start it with full choke, flip to half choke right after it starts then flip it off within 5 seconds. You may have to blip it to half choke a few times (the colder the ambient the more blips), but it should stay running without choke a minute after you start it... provided the carbs are clean and adjusted properly.
 
Thanks. The carbs on the Vmax were totally disassembled and gone through. They replaced one of the pilot jets that was slightly bent. I have only put on slightly less than 300 miles this year. I believe I may have some water in the gas. Was going to try some Seafoam and Startron this weekend. I believe you are spot on about the Venture. It does it worse if the choke is left on a little longer. The Venture has not been gone through. I will have that done before next season. Once warmed up it runs great.
 
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