ok today it was 55 out.. still no fire .. not even an attempt.. i believe its carb related.. they where just cleaned and rejetted (wrong size still ((to small) maybee the pilot circuit is lean.. it did backfire some when id let off but would that make it not start in the colder air?

 

i would think it would atleast start.. then run sh!ty...

 

probably the needle valve isnt allowing fuel into the bowls. They are probably stuck had it happen to a friend of mines. Take the bowls off and the floats make sure the needle comes out easily and even if it does it might have been a very small particle causing them to stick.

 

Have you check for spark?? Take out the plug and see if its completely dry or if its wet like its flooding and check for spark.....

 

Check your vavles. Mine didn't run until they were at the proper tolerances.

 

Put in a new plug and see what happens.

 

all great idea's BUT... none have worked.. i dont think its the valves being out of adjustment.. if i take a heater in to the shed and warm up the quad itll start fine.. just something when its cold... my 250R was the same way.. but i put in a new plug it would start even cold... this one just doesnt want to do anything until warm..i know the main jetting is wrong.. (im gunna buy a dynojet kit soon) but the pilot jets are stock and i believe only 1 1/4 turns out... i guess ill just rebuild these junk carbs again.. WHY OH WHY did yamaha do two carbs on a single cylinder...!!!!!!!!

 

I heard bad things about the dyno jet kit i would get the GYTR kit.

 

Yeah I wondering the same thing..... I wish they went single.. instead of dual...

 

Hey NY02 Have you done a compression check? to low of compression and it wont wont to fire unless things are perfect .
Could be the valves arent seating right or time for big bore kit
Good luck