Yamaha ATV Forum

I ended up welding a bombardier 400exhahst onto it ... And then it still backfired , I discovered more holes up near the head, I'm going to use some high heat jb weld to patch them

Most handlebar switches can be dismantled and cleaned.

My uncle bought a Baja 250, 2006. Knew there was no spark since the get go. He don't know anything about quads so is getting me to help him try to get it running... Battery is bad so I connected battery charger to it to crank it over , cranks over well , but no spark .... Lights and everything work fine , but with each crank over using the e start switch , the display reads 999 888 777 666 ... Right down to 000 and repeats itself . He managed to get a parts bike , I changed over the CDI and the coil and the stator from the parts bike and there was another black box by the voltage regulator I changed over ... I used my multimeter to confirm as much as I could works , it's hard without knowing which wires are which , and I cannot find any diagrams online for this bike ? Do you think it could be the Killswitch? There's so many wires coming from there I don't know where to start . Also I should mention it appears the fan on the front of the bike has been taken off (the wires have been cut too ) If this bike sparked it would run . The previous owner said he parked it one day and it just wouldn't start after.

Thank you for your insight. I will check on the oil in the sump when I get a chance.

Awesome are ATV's allowed there too?

The most common reason for that oil in the airbox, and especially if it starts doing it suddenly, is that the sump is full of fuel. A sump full of fuel would also cause the engine dieng once it starts to get hot. I'd suggest checking the oil level as the first thing. A lot of bikes also have restrictor valves or orifices in their breather hoses, and in some models if that restrictor blocks up it can cause problems like the oil in the airbox.

It took a lot of work and rejetting but I've managed to get the Motoku clone carb running pretty damn good on my Quadrunner 250. Part of the idle problem I was fighting ended up being a fuel pump issue, there was no fuel in the vacuum line but I think there was a pinhole leak in the diaphram. After replacing it I no longer have issues with it stalling every time at idle when warm.

Sometimes the chinese carbs are our only options unfortunately. I have had mixed luck. On a kodiak the previous owner put one on and then sold the machine because it ran so bad. I tried everything I could think of to get it to run right and never did. Found a used OEM and problem solved. Swapping jets and setting the float is minimum. Seems like they never cold start or choke right either. have gotten carbs where air passages were never drilled. Total fail. Seems like on lawnmowers they work much better. Not perfect but same scenario, OEM is just not available new or used so you have to make something work. I was fighting random problems with a 300 bayou. Bought a chinese carb just as a process of elimination. Ran pretty decent. So I swapped jets and been running it ever since.

Hi guys. I have a problem where the quad will start and run well for about 5 minutes and then it dies. On inspection the airbox has oil in it (quite a lot). The oil is pumping through the cylinder head breather hose. This problem first happened suddenly. I have since done the top end including, piston, gaskets, rings and valves. I have also done the carb (not that I thought that this was the problem). The compression seems normal. The only thing that I can think of, is that I did not grind the valves well enough. Anyone experienced this? If so, how did you fix it? Any other thoughts?

Never said I wasn't going to vote, even voted in the primary, just said I wish their there was someone with some brains to choose from rather than a couple of idiots