Advise on upgrades

come on guys, i am looking for things i can do to make my 2001 400ex faster. I have put a K&N jet kit and filter, no airbox lid, pro circuit t-4 pipe and geared the counter sprocket up 1 tooth to a 16, and jetted to a 155 main. I am looking for things like tips and tricks to make more power. I have heard the following and would like to know how they are done

1. adjust throttle cable ? how and why?
2. grind off welds on header?

any more sugestions would be great. would going to a 14 tooth counter sprocket make it faster? i like the 16 tooth one but if it will be better then i will switch to the 14 tooth. i want to hang with or outrun stock banshees and kinda hang with modded ones.

PLEASE HELP:confused:

[Guy400]

Unfortunately, there's going to be more money involved with modding to the point where you can beat Shee's or hang with modded ones. You're going to have to at least go with a high compression piston and XR cam to beat stock Shee's in a drag. You're asking a lot to be beating modded Shee's. My best friend has a '01 Shee with Toomey T-5's, Uni filter and 12 Uni-vents. Everything else is stock and in a drag race against 2 different piped EX's it was ugly. We've raced a total of 3 times and all the times was a run away win on the Shee. One race was very close through the first 3 gears and then when the Shee grabbed 4th gear and came on the pipe it was over. Remember, the Banshee has one more gear than us so when we run out of gear he's still got one more to go. The other 2 races were just outright wins for the Shee. If there's one thing that Shee's do well it's go fast in a straight line.

Go with a 416 or 440 kit and you shouldn't have any problems with stock Shee's but you'll still have your hands full in a drag race with the modded ones.

i know i won't beat a modded one but it is fun to try. i want to exaust every other mod before i rebuild the piston and sleeve. I hear that the grinding of exaust welds and also adjusting the throttle cable helps but not sure how too. Also timing adjustment? is it worth it? i am looking for just some good mods. don't have to be free but you know little stuff that will help me destroy my best friends 400ex. We have the same stuff so far. T-4, K&N jet kit and filter. I want an advantage and blow him away............:D

so gimme some ideas

[Wheelie]

Have the flywheel shaved and put in a Curtis Sparks advance key. That will help the engine rev faster, and might achieve the edge you're looking for. Cost: under $200

Adjust the throttle cable until it has about 1/8" slack. Supposedly the stock header pipe welds near the head restrict the flow a bit, you would have to remove the stock header and clean up the inside with a die grinder. If you decide to go that route, it would be a good idea to get new header gaskets.

Try going back to the stock 15tooth front sprocket.

Good Luck!

[400exdad]

Wow, I'm suprised the stock 400, more or less, pulled the 16 tooth sprocket. I'm running a 14 myself and we ride mainly in the woods. I have heard of grinding the welds just inside the inlet of the header, bad thing is, I didn't here about it until AFTER I had it ceramic coated!

From what I've read, I'm going to go with the h.c. piston and xr400 cam. For less than 3 bills and its done.:D

the 16 tooth sprocket is not really all that bad. It still pulls the front wheels and you can still goose it and get them to lift without pulling on the bars. I was really happy with the 16. I did notice that in 2nd gear at almost a dead stop to turn around it does lug more than it use to but as soon as you gas it it slides and picks up th front. The timing key, is it really worth it? I don't know if i want to shave the flywheel. I don't race pro just trail ride and like to drag and jump.

[crday98]

if you are looking for more power and not top speed,you don't want the 16T,go with the 14T.i tried the 16T with my mods because i thought i had plenty of power and was curious on what a difference it would make.it was good for those long flat open trail rides but didn't fit the style of riding i do most so i put the stocker back on and kept the 16T for such occasions.i was skeptical about going with the 14T because i already have enough bottom and snap.well as Leo said in his review"curiosity got the best of me so i went out and bought one":huh i was just about kicking myself in the *ss for not doing it sooner.it is the best $20 i have ever spent.i could go on forever why i think it is the shiznit but,just spend the money,buy on and see for yourself.i don't think you will regret it.

so you are saying the 14 will be faster all around. i trail ride, jump and drag race. like i said before i want to run away from my friends 400ex. will i get better top speed in a drag race with a 14 over the 16? with the 15 tooth i started in second gear with the 16 i start in first. i want more speed at the end of the drag because that is where everything passed me with the 15. And also the aeras where we ride there are sections of wide open running. i guess what i am looking for is all around performance increase. Do yall think the 14 is the way to go..

[Guy400]

Desperado, you'll lose top speed by going to the 14 tooth. If you're getting the holeshot on your friend and he's still passing you on the top it's simply a matter of HP, he's got more than you. There's no gearing you can do to make up HP. I don't even know if they make a 17 tooth but you could alter the rear sprocket ratio or buy taller tires. Both of those will give you some more top end but I doubt your motor would pull it on the bottom very well.

[400exdad]

As I said in my earlier post, I am running a 14T now and have been since I started riding my 400. All stock. I am hoping that with the new compression and camshaft, I will be able to go back to the 15T.. Not that I go top end that much, but so I can stay in 1st and 2nd a little bit longer from tree to tree. As it is now, 1st gear is almost useless except for starting at the bottom of a steep hill. As it is now, I climb most all hills in 2nd and hammer it. With the 14T, I can also go to 3rd while going up especially long hills. I'm not sure I'll be able to get to 3rd with the 15T.

As far a drag racing with the 14T, you will DEFINETLY want to start out in 2nd.

Look man, I used to sit and read and speculate on what to do to make my 400 run better. I read articles, hundred of different post on this site and talked to lots of people. Here is my two cents
Bore it .080 --416 and go to an 11/1 compression
Cam it use any all around type of cam. For example Web cam, xr400, I got mine from Tom Carlson (tc racing) Just get one!
tail pipe- get one they all work reasonably well just get some info and get one.
It will run like a completely different quad you will get gains every where. The piston and gasket $100. The cam $130-175 the tailpipe $200-225.
I paid $35 for the bore job $50 to install every thing.

Mine runs really good- it flat out gets it. I went back to the 15 tooth front and fifth gear pulls real strong and has a good bit of bottom It flys in fifth gear but it is set up mostly for woods.

thanks for all the advise....:)