ok im just wondering if this is a jetting problem or a float problem. but some friends and i took a trip to colorado and were riding in the mountains, and we were up a little over 10000 feet. and up that high while riding uphill my raptor wouldn't hardly run at all. but on flat ground or downhill she ran perfectly. but i checked the floats afterwards and they were way off, and so i adjusted them and got them within specification using the clear tube method. but now we're planning on going to the white mountains here in eastern arizona and we'll once again be up around 10000 feet. so im just wondering if i should rejet, or adjust the fuel/air screw, or if it was just the floats causing the problem. thanks.

 

This is one reason I will be purchasing a 700R next year!

First is the bike in stock jetting or modified, i'm assuming it's a 660R Raptor because you said floats (2) and not a 350? If you are constantly riding at that elevation you'll want to re-jet it to that specifications. Just buy a set of two jets from your dealer with there recommended specifications, at that height your not getting enough air for all that gas.

 

Depends on which way the floats were off.

If they were too low, then it would have been running leaner, which actually would have helped. You would have noticed at lower elevations, if the floats were the cause, because at lower elevations the low floats would have caused alot of lean symptoms.

If the floats were too high, then it would have been making it rich, and going higher in el. makes the mixture richer anyway, and it would have been a double wammy...the motor would have been running in a way too rich mixture.

I would assume you were running too rich from the discription you gave(it was hardly running at all). There was probably smoke coming out the pipe, and it sounded blubbbery. If it were too lean, you would have noticed popping and backfires, and severe missing.
If you dont plan on riding in high alts very often, its probably not worth it to rejet, especially if its running good at lower alts. Id put some holes in the air box lid, and at lower alts, id keep them covered with duct tape. When the quad starts running crappy at alt., then start removing the duct tape, which lets more air in, and leans the mixtures out. Then dont forget to recover those holes as you come down in alt, or the motor will be running too lean. If uncovering the holes doesnt quite do enough, then just totally remove the air box lid, once youre up , and put it back as you encounter lean symptoms.

 

yeah its a 660 raptor with modified jets...but the weird thing is, is that sometimes it would backfire quite often, and then later there would be black smoke coming out the pipe. so what was the reason it was running fine downhill but not uphill? but the floats were low i believe so maybe that was the problem. but thanks for the response.