I hope one/some of you might be able to help me, I just installed the Alba pipe, K &N air filter, and did the cam mod, the jetting I used was 45 and 170 with the clip on the 5th space on the needle, now it runs horrible, it wont idle, and pops very badly, when it pops there is a reddish blue flame that shoots out of the pipe about 6 to 12 inches. the air mixture screw is 2 1/2 turns out. anybody got any ideas? thanks so much,

Ian

Bout the only help I can offer is that it sounds lean. That's what popping usually means anyway. Does it pop bad when you let off the throttle after revving it (Deceleration)?

I think you are way lean. Try a 48 pilot and a 175 main. Thats where I am at without the cam mod. I am not sure what the cam mod does to the jetting. That should get you closer.

If you havent already check out www.yfzcentral.com

lots of info there

late

I would try the 48 pilot put the needle clip in the 3ed pos. run the 175 main and ck to make sure that there are no air leaks around the carb. Also ck the cap to the slide is on right and not cross threaded...

why not go pull the plug out and tell us what color it is....then we will be able to help you!

timing? did you double check your timing marks?

On the 450, you have to remove the gas tank to check the plug. Besides, on the four strokes, the plug does not give as much info as the 2 strokes. It is not really worth pulling the plug of the 450.

late

thanks for the input, I tried running the bike with the choke on and it just dies, in my driveway I have to give it gas to keep it running, and it pops and flames come out when the gas is on or right when I am letting off, I will run to Alba or somewhere and get the bigger pilots and mains, play with the needle and see what it does, I will keep you posted, I am sure I will need some more advice.

thanks again, Ian

havin any luck? if not...try the guys at yfzcentral.com or PM testostaRob @ theatvcompound.com

I rode Robs out at dumont...his bike friggin rocks!!!!

If it's the YZ needle, consider the 4th clip, and a 48 pilot.

Its best to do 1 mod at a time so you can tell where ya have the problem.

Here's a tip that helped many a Raptor rider.....check the connections at the parking brake/clutch mount. Yama-geeks decided to add an electric contact that senses when the parking brake is on, and keeps you from riding the bike...unless you are desperate. The symptoms you are describing sounds just like all the posts that came from puzzeled Raptor riders. Sometimes the electrical plug gets scrfewed up or comes loose....causing the engine to act like it is. Wortha shot..before you pay Yamaha.

they have that stupid thing on banshees as well, last season we were ready to pull the carb out after messing with it for over an hour, some guy from the next camp over heard us, came over and took the parking brake off, that guy had free beers all weekend, man we felt dumb.

Anyway, as it sits now, 45 pilot, 170 main, 2.25 turns on the air screw, clip on #4, The head pipe still glows a little bit, so just for fun next time I am out I am throwing in a 48 and 172 or 175 to see what it does, I get no popping or hesitation as of right now. I just dont like that pipe glowing.

I did notice that if I pull on the throttle cable itself the enging revvs up and down, is this normal, I dont notice it on my raptor?


My mods are:
Alba full pipe
K&N pro flow kit-lid off
cam mod
jetting

If it makes you feel better the pipe on my WR426 glows when idling... somethin to do with no air movin over it...

Definately go with the 48 pilot and 175 main but put your needle on the 3rd clip, this might be a long shot but did you take off the top of the carb?, my buddy did this and put the little diaphram upside down , we messed with it for 2 days straight till we found out the prob..