New Vinson.
145 miles and the rear pads are worn down to the metal. (caliper guides are free and lubricated)
Backfire on deceleration including varrient flames discharged but the plugs consistently read rich.
Sudden stalls after engine heats to normal operating temp and will not start unless it cools or you
use the choke.

Any input would be helpful. I asked the dealer and the tech said to bring it in which tells me he has no idea either. I would be wasting my time because they would just give it back to me with a doc stating "cannott duplicate customer complaint" since the unit has to be operated under trail conditions for the symptoms to appear.

I have soaked the carb and cleaned the gas tank. Also have installed a gas filter. This has had no affect.
Also, can anyone tell me how much gas mileage they get ? Mine seems to be a pig!

Thank you,
JustMe

 

Check your coolant/radiator. Sounds like it could be over heating.

 

Hey Just Me , I had a similar problem with my Vinson when it was new. It definitely is
a Jetting problem. I bought the DynoJet Kit, installed it, and my Vinson came to life !
No more popping on decelleration. My quad was running like crap, and it sounds like yours
is also. The Kit is about $60, but well worth it. You will get crisper throttle response because
the Kit comes with a jet neede that has slots so you can move the clip up or down, affecting
the low to mid to high transition of throttle better. I think this area is where the popping
comes from. Hope that helps you. Good luck !

 

Vinson man,
How many miles were on your vinson before you installed the jet kit. Is this the kit that you can change "on the fly" without removing the carb? Where did you get it and what was your starting point for the settings. Thank you for your help.

JustMe

 

Maybe you should give your dealer a lil more credit. They are the ones that have the know-how to get er right. The dealer will never diagnose a problem over the phone. If they want your continued business they will work with you on it.
145 miles on the brakes is reason enuf to get it to the dealer.

 

The backfire on decel, is caused by a lean condition in the pilot circuit, try turning the mixture screw out, 1/4 turn and if thats not enough, go another 1/4 turn. Its possible to have the main circuit look rich and be lean in the pilot circuit, and the plug will look black.
I found that the brakes need to be kept clean, or the dirt and mud will really chew up the pads.Wash them good after a ride.
The stalling, could be the pilot circuit being lean, or idle set too low. The hard starting could be from the lean pilot circuit too.Try starting the motor, with the throttle open to 1/4 way, ill bet it fires right up.

 

OK,
Brakes were clean and had lubrication on the caliper guides. I adjusted them so that the master cylinder piston would retract more therby relieving the hydralic presure so that the caliper piston can retract.
I richened the low speed mixture screw and had a lot of success, however the bike still will backfire sometimes and always once after it is shut off.
As far as having more failth in my dealer is concerned, remember that they are the very people who put the quad togerher and sold it to me with a tank full of cosmaline, a carb on crooked, unblanced tire presure, as well as the brakes not being adjusted right. I also obviously have some experience with dealers (25 years of buying, fixing and riding) and have learned that it is always better to fix it yourself whenever possible rather than bring it to a mechanic that is on commision and gets next to nothing for warranty work.
I was hoping that someone had a similar experience and was looking for a quick resolution to my problem. Thank you everyone for your replies and advice. I will put some more miles on the Vinson and see if the problem(s) persist.

JustMe

 

Glad to hear, that things are improving. Sounds like you could go more, on the mixture screw.
Read this article on carb jetting, and it has a list of symtoms for rich and lean. You may need a bigger pilot jet, if you get to about 3 or so turns out, and still have a lean condition.
carb
Does it start better, both hot and cold?