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VMAX 500 Fuel Guzzler

9K views 3 replies 4 participants last post by  snowdad4 
#1 ·
I have a 99 Vmax 500 Deluxe- i bought used and i am only getting 45 Miles out of a tank,
I have been through the enitre carbs & fuel pump, and inspected the reeds they all look good.
I replaced the needle & seat under the float, & that did not seam to help any.
It is also running real ruff until about 30 mph then it takes off like a rocket.
It actually looks like the guy before me just replaced the carbs, I spoke with Yamaha and got the Jet sizes that are suppose to be in that sled
The Mains are 151.3 And the pilot are 50, they said they should be 45 could that be my problem?
It starts first pull everytime Idels excellent but is sucking fuel and but breaks up real bad till she gets around 30, it also seams like it takes alot of throttle to get it movin.
Any help would be great.
Thanks Kevin
 
#2 ·
Fuel guzzler 95 vmax 500

I have the same problem runs really rough until it hits 35 miles. Change the reeds went with Boysen power reeds, check floats, replaced jets, replaced needles and seats. Have change clip positions on needles and leaned out turning out screws still no change.
Need some ideas as well

Mark
 
#3 · (Edited)
Loosen you track to twice the recomended,lube everything ,(with the belt off it should turn pretty easy),,,if it ratcets tighten it a bit.

For the running rough I'd check that your spark plug boot springs arn't worn out,,and change the plugs.

I think the pilot jets just work to around 15 mph than the needle would come into play
 
#4 ·
take a look at your clutches and make sure they are clean. this will cause bogging issue as well as the extra throttle needed at starting until centrifical force take over. also, yamaha overgeared those from the factory and if you drop 1 or 2 teeth on the upper sprocket you will actually gain top speed and increase the bottom end power at take off, as well as increasing the fuel economy. what are the fuel screws set at on the carbs? they may be overadjusted to compensate for the larger pilot jets.
 
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