LOWBOWTIE, Is the problem you are having being rich in the middle and lean on top? I had this problem with the dynojet needles and with the stock jets it was way lean on top with decent low and mid range. It took modding the stock needles with the correct taper before I got it right but I went through 1 set dynojet needles and 2 sets of stock needles alot of blisters on fingers with some other time consuming mods before I got it right. It was worth the time though once I did get it right. Some of the other mods that I did some might not agree with so I will keep them to myself but with what I did it picked the bike up bigtime on top with plenty of low and midrange and allowed me to start running more power additive than I was running at one time. All the mods to the carbs. are pretty simple but time consuming. You can get it right! Slim

 

Slim, I am just a little lean on the upper mid range and just lean enough on top to create a small hesitation at WOT. The top end is leaner than the mid range. I'm running 190/195 Mikuni jets. It feels as if I would go to 195/200 jets that it will go away. and I may have to richen up the upper mid range by raising the stock needle to the 4th groove. I just have not had enough time to play with it latly. Anny suggestions would be cool.

 

Blister...WTH are you doing with the needles?[img]i/expressions/face-icon-small-shocked.gif[/img][img]i/expressions/face-icon-small-wink.gif[/img] J/K
Chuck that sucker up in a drill.[img]i/expressions/face-icon-small-cool.gif[/img]

 

Ward, I cut the needle down a little at a time with sandpaper by hand and to keep the taper I was trying to get on the needles this slow process was the only way. This allowed me to do a little at a time while maintaining the smooth angle on the needles until I had a set of needles that started out wide and tapered down to almost a sharp point on the very end of the needles to allow as much fuel flow on top as possible at WOT without having to do anything to the fuel supply tubes that the needles ride up and down in. I also figured out how to do some other mods to the carb. caps and top of the slides to allow the slides and needles to move further up at WOT which allows the needles to move further giving more fuel flow. All in all it took some figuring out but it was well worth the time. I did hate the blisters!! Slim

 

I like the drill method ward is talking about, this will give you a perfectly round needle and ease the blisters, sort of like using a lathe...........good tip.

 

All this sharing, I feel the love:-) Here's mine:

Bob Craycraft - $300 to fix the stock carbs
Edelbrock - $500 to replace the stock carbs
FCR from Sparks - $800 to replace the stock carbs

Before I gave up on them, I had opened the needle valve seat by a few thousandths, trimmed the float stop tabs, replaced the diaphram springs with Dynojet, replaced the needles with GYT-R (Mikuni 190/195 had a better top end), and tried a couple of brands of race fuel. With each of those changes, a different limitation of the stock carbs was uncovered. At the time, dual fuel feeds were on Bob's radar screen but the total package wasn't finished so I GAVE him my stock carbs in hopes that others wouldn't have to suffer the same aggravation. I didn't try to re-engineer my stock shocks and I didn't want do it to the carbs, to me there is no difference.

BTW, I do all the work on my quad. Other may have built parts but I chose every component and assembled/adjusted every bit of it. I'm proud of the work that I do also, especially the fact that it's as reliable as a stock 400ex. I'll let you fellows get back to your fun and sincerely wish you all the best luck.

 

Thank you all for sharing this info. It's great seeing that this forum is still about helping out the other guy. My plans at this point are to check out the local Yammy dealer today. They told me yesterday that they have a selection of different needles that I can spec out. Maybe I'll get lucky. If not, my father works for General Dynamics and I'll try to get him to machine down the lower portion of the stock needles on a lathe. No blisters. LOL