Mast372MIND

Open airbox w/ K&N needs a 290-300. Closed airbox you can run the 260. Do yourself a favor and go buy some more mains. I would just go ahead and buy 270s, 280s, 290s, 300s, 310s, and 320s to cover all riding temps. You will also need 27.5 and 30 pilots. 30s run better in cold weather (easier starting below 40 deg F). Run needle in 4th or 5th clip without reeds, and 3rd or 4th clip with aftermarket reeds, depending on if it is summer or winter weather conditions, respectively. I run 300s w/ 27.5 pilots at 70deg F (+/- 20degF) and 1200 ft. Mods are K&N, no lid, fattys, TC2s, and dual stage reeds.

I have just about the exact same mods as the OP: FMF fattys w/ turbine core 2 mod quad adaptor w/ K&N air box lid off boyesen dual stage power reeds My elevation is about 1200 ft. I've jetted my bike with just about every main/pilot/needle combo I could. I've tried 280, 290, 300, 310, 320, and 330 on the mains, 25, 27.5, and 30 on the pilots, and 3rd, 4th and 5th clip positions on the stock needle. For 60degF and above, I've found that 300 mains are the way to go. 30-60degF I run 310s and below 30degF I run 320s. The clip is best in the 4th position with the reeds and the fattys. For 50-60deg and below the 30 pilots help the bike start on 1st or 2nd kick when shes cold and no trouble when shes warm. When it gets above 60 or 70 degF, I run the 27.5 pilots and it starts fine when cold. So, as far as the pilots go, I think that the 30s are about spot on for me in cold weather. That being said, it does smoke quite a bit and will show some unburned premix on the exhaust tips until she gets warmed up. I really just think that FMF suggests 30s for easy starting. When I run 25 and 27.5 pilots in cold weather, it takes about 6-10 kicks to start her up cold. I honestly think that their jetting recommendations are just about spot in 60 deg F weather.

I'm no expert but if it was my shee, I would take the time to fix that problem correctly before riding it for long periods of time or in dusty conditions. I would not use silicone gasket on the balance tube boots. If the gasket material breaks down it would get sucked right into the cylinder. I'm suprised its not running lean on that side (if it is leaking air through it).

They are 320s.

I've only had the quad since November, but I think its been happening since I got it. I only say that because the carbs were very dirty around the bowls, suggesting that there was fuel/oil mix leaking slowly out and collecting dirt. Like I said, the leak is very slow (it doesn't drip or anything unless it is allowed to sit overnight or longer, even then only a few drops). I also noticed that if I let it idle for about 1 min with the fuel off before putting it up, it doesn't leak (obviously due to a lower bowl liquid level).

Thanks for the reply. I think I'll tear it down again after the weather warms back up in OK. I will pay attention to the things you mentioned when I go back through it and update the post with what I find out. If anyone else has anything else to add in the meantime, please do so. Thanks, Rob

Yeah, I shut off the fuel anytime she's not running.

Hey guys, I'm having a problem with my left carb leaking gas. It seems to be a very slow leak, so its not a problem when riding, but when I put it up for a few days there is an oily residue that forms around the bowl. Its only happening on the left side carb. I put a piece of paper under it and it only dripped once overnight, so its not that bad. However, i would like to get it fixed just to avoid pooling gas around the bottem end cases. After I looked at it this morning, I think there was a little reside above the bowl flange, so I dont know if its coming from the bowl or maybe a leak around the fuel line. Anyone else ever have this problem??? Thanks! -Rob

So, I went ahead and put them in. They fit well and the bike runs fine so far (only rode for a few minutes up and down the street). Thanks for all the replies!

So why do these jets have different engravings? Do you think that they are just an off-brand and the others I have are Mikuni?

Hey guys, Need help ASAP. I normally buy jets from jetsrus.com, but I wanted to get some 320s for rejetting today so I went to a Yamaha dealer. I have stock carbs and every size from 260-330, except for the 320s. So anyways, I go in and ask for some and he brings some out. They are the normal hex head jets and they have an identical hex head size and thread pattern to all of the other jets I have. Only difference is that the number is written on the side of the hex head rather than on the top like my others. Instead of just saying "320", they say "320RD" on the side. I also noticed that the beveling is different on the jet throat (viewing from top of hex head) than my others. All of the other jets I have use a larger (wider) bevel. However, the throat of the jet seems to be the right size (it is between the sizes of the 310s and 330s that I have). Are these jets just off brand? Are they okay to use? Will the different bevel make it perform different that the normal 320s? Let me know what you think. Thanks, Rob

Well, I wen't ahead and bought some 27.5 pilots today. Couldn't find them at any of the dealers or the shop I typically use. Ended up going to another shop out of town, which is a great place for banshee parts. Only problem is that they were $10 EACH and they look used!!! If thats not insane, I don't know what is. Double the price of the dealer AND ITS USED??? WTF??? Anyways, I went to install them and realized that I don't have a screwdriver long and skinny enough to access the pilots. Also, I decided to try the clip at the 4th position from the bottom rather than the 5th, due to all of the comments regarding it sounding kinda rich. Tomorrow I'm going tool hunting and will post again with the results. Thanks for all of the help!!!

Okay, I bumped up to 280 mains, ran it, bumped them up again to 290s -- much better plug color with the 290s, so I settled on that for the winter months (tuned at 35 deg F). Also went ahead and moved clip to 5th position from blunt end, 1st from needle tip -- this totally fixed the bog/hesitation problem at 1/2 throttle. Runs like a dream now. Pilots are still stock and air screws are 2 turns out. Plugs look good at idle, 1/2 throttle and full throttle. I had to adjust the TORS to get the carbs to sync right, which I hopefully performed correctly. Is there a way to tell if the carbs aren't sync'd properly by how it runs at idle, or must you just go by the little windows and the indicator mark with the throttle slide valve? Thanks for the advice!

i might go ahead and try the 280s, just to be on the safe side (plus its gotten a bit colder around here since last time I rode, dropped from 55 down to about 35 deg F). all the way rich would be the 5th clip position from the blunt end, right? I think I might try the 4th clip first, then move from there. Whats the easiest way to change the clip position? I still have the TORS setup on mine and I hate having to remove the gas tank just to get to them, but if it must be done than it must be done. Also, do the carbs need to be re-sync'd after moving the clip position? Thanks for the help guys... I appreciate it!

yeah, the pilots are the stock 25s and the air screws are 2 turns out.