Was out riding this morning and my Raptor died on me for the second time in two weeks. Had been riding fairly hard for about 15 minutes when all of a sudden it started to sputter and pop and then it just died. Would crank over and not fire. If it did fire it would just sputter for about two seconds or so and die.
It happened last week too. So I changed the plug, was fine anyways but wanted to change it. Cleaned the air filter thoroughly and made sure the carb boots were secure. Both times, if it sat for an hour or more it was fine.
I'm beginning to wonder if its over heating. My only guess. I don't think its a jetting problem since it only occurs after a period of time. But for the record I have a K&N filter, White Brothers E Series, and I'm running DJ144/146 for the mains. This has all been in for over 4 months and no problems and the machine was running outstanding. This has just all of a sudden happened.
Was just wondering if anyone else out there has had similar problems. Don't have any proficient or reliable service shops in the area so I'm relying on the knowledge of you forum members. You usually pull through. Thanks for any insight!

 

i`m not to sure about 4-strokes but on a 2-stroke when weather changes so does ur jetting in other words if you have had your mods about 4 monthes you had your jetting set for cold weather and now that it has started to get warmer you will need to change your jetting and once agine i`m not to sure about on a 4-stroke but on a two when it gets warmer you need to jet down when it gets cold you jet up cause the colder it is the denser the air is i hope this helps some

 

Your advise is well taken, but this year in New England the weather has been crazy. So I've been riding in all kinds of conditions from 20 degrees to 65 degrees in the last four months. But the last two weekends have been milder. Hopefully it will get colder again in the next couple days and I can see what happens. Its free service and I only need someone with a tow rope. Thanks for the info. Anyone else have any ideas?

 

raptorguy

you Did not mention your altitude but Im thinking you a very lean on top .you state you have a pipe and a k&n filter ...you should be in the 160/165 range at 0 alt... and maybe a little richer on the bottom to 27s or so .....are you boiling the coolant out ? temp light? fan runnig ? just some thoughts .....

 

When was the last time you checked your vavles? I would definately take a peek at them. Do you have any crap in the fuel tank that could be blocking the fuel line intermitantly? I had some friends play a prank on me like that and my quad would die every once in a while for no reason.

 

You might be running lean. You might try 146/148 Dynojet mains. If you are running with the airbox lid off or with holes in it, you should try 148/150 Dynojet mains. I have a GYTR tip with the factory headpipe, no airbox lid, White Brothers Powerfilter, Dynojet kit using 148/150 mains and operating at sea level.

I would also check the vavles to make sure they are adjusted within range. After that, I would check the floats.

/NotuRaptor

 

The jetting was what was recommended by K&N, and I'm at about 2000'. But maybe I'll try going up. As far as the valves, that was going to be my next question. I had read in the service manual about them being adjusted every 20 hours or so and the way it was written it seemed like Yamaha was trying to get extra service in. If it is true then I'm a little disappointed that they build such a machine as this only to have to have it go into the shop every twenty hours.
As far as the coolant goes, it seems to be full and fan hasn't kicked on anymore than normal. I will definitely pay more attention to it.
Just for my own curiosity, why would my machine all of a sudden be running lean. I've had this setup for atleast four months and no problems. Is this just a product of more use changing the needs of the motor? Thanks again for all the help.
Lastly, what is the time it takes for the valve adjustment. Was wondering how long its taken you dealers and who much its going to run me. I'm trying to locate a service shop other than a dealer, but having trouble so I might have to resort to them.

 

The jetting im using is dj144/dj146 The clips are in the 2nd position. with a Prodesign filter kit and a White Bros. E-serise pipe. I had toadjust the clips because it was way to rich.

 

valves would be something to check, the other thing could be your plug wire coming loose, mine has popped off a couple of times on rough trails, how is your ground wire? if loose it could cause intermittent failure, and lastly your floats if stuck they could also cause this to happen, i dont think its a jetting problem since that would be a constant problem

 

MNWILDFAN may be on the right track. Do you have a fuel filter? If so it may be clogged. If not WHY DON'T YOU!! If you don't there may be crap in your line or carbs.

If you don't have a Factory service manual get one. The valve adj is easy enough for a shadetree mechanic to do with just basic tools. The first time I adj my valves it took abour 2 hrs, the next time it took less than an hour. Don't pay a dealer for something you can do yourself. It is also a good way to get familiar with all the diffrent parts of your raptor & you don't have to be without your quad for a week or more while waiting for your dealer to do the work.