Raptor 350 back fire and cut out.

[sectorootz]

Hi everyone so I recently posted about carb issues since upjetting the carb the quad has been running pretty well still not idling well but once warmed up it seems ok. I've been on 3/4 decent rides traveling on and off road and maxing the quad out in 6th but not for long periods of time. Any way my issues is I've taken the quad out this evening to start with the quad seemed like it didn't want to start which was random once running I set off for about 20/30 minutes towards the end of my ride I noticed a little bit of back fire then all of a sudden the quad just cut out on the road I pulled over to the side and managed to get the quad in to neutral and for about 5 minutes I couldn't get the quad to start which was abit worrying I messed with the fuel lines etc and eventually it started on the button luckily I was close to home and managed to get it back I'm really getting stressed with this quad now as it feels like one thing after another could this perhaps be the valves? I've attached an image on the spark plug as this may be a clue I'm not entirely sure?

I also forgot to mention the quad seems to be using allot of fuel.

I look forward to seeing what to guys thing. Thanks.

 

[PineyPower]

Check the intake boot between the carb and the motor for dry rot splits, it's a super common problem and often overlooked in favor of more manly sounding solutions

 

[sectorootz]

Thanks mate have taken it all apart again no leaks.. also I noticed the quad ran out of fuel haha... It still had some in the tank which is strange but was struggling to get down the fuel line. I've now upjetted the 25 to a 27.5 and it's idling nice but the revs are so high when twisting the throttle. With a 25 jet it runs perfect but won't idle. Has played with fuel air screw also. I'm running out of ideas with how to get this motor running nice.... Any ideas?

Also the plug is now black/rich from upjetting to 27.5. Was lean with 25

Check the intake boot between the carb and the motor for dry rot splits, it's a super common problem and often overlooked in favor of more manly sounding solutions