400ex's drag racing with weird results??

[cals400ex]

well i will list the two quads first.
1. 406ex with 10.5:1 wiseco piston, stage 1 cam, ceramic x-4, jetting.
2. 406ex with 10.8:1 ross piston, stage 2 cam, stainless x-6, jetting.

here are the two bikes. my bike, the second one, is getting beat pretty bad by my friends, the first one. here is the deal. i would beat him by at least 8 bike lengths in a drag race by the time we hit fifth gear when he had his big gun exhaust. he just recently put a ceramic x-4 on. now he beats me by a good 5 bike lengths by the time we hit fifth. the only mods he did to his bike was the pipe and a heavy duty timing chain.
so, i have come to the conclusion of one of the following:
the x-4 just makes more power than the x-6, the ceramic coating really helps out for power due to heat transfer, or the heavy duty timing chain increases power.
i honestly don't have a clue but we are both jetted good and when he changed from big gun to the x-4 and put the crf450 timing chain in, his bike flies. he even has more top speed than me. i don't understand this. we both have the same gearing and we switched bikes with the same results.
could it be that the x-4 makes more power than the x-6 unless you really bore it out? i know i didn't get anything near the gain he got when i put my x-6 on. unless the timing chain or ceramic coating makes a difference? i am stumped.

[mustang93]

probably the ceramic coating helping his motor scavange out the exhaust gasses better. if you try the ceramic coating and get good results let me know.

[H_W]

Originally posted by cals400ex
well i will list the two quads first.
1. 406ex with 10.5:1 wiseco piston, stage 1 cam, ceramic x-4, jetting.
2. 406ex with 10.8:1 ross piston, stage 2 cam, stainless x-6, jetting.


To me, it seems like the first one should be making more bottom end power because of the stage one cam. How far are you racing? The shorter the race, the better the chance the first one has. The second one should have more top end, so it would favor a longer race.

[cals400ex]

Originally posted by H_W
To me, it seems like the first one should be making more bottom end power because of the stage one cam. How far are you racing? The shorter the race, the better the chance the first one has. The second one should have more top end, so it would favor a longer race.


that is exaclty what i thought. he doesn't pull too much in the lower gears. he pulled the farthest when we hit fifth???? :confused: we raced up to half way through fifth gear.
i guess i can try to get my pipe jet hot coated. or would ceramic coating help more than jet hot? i also have a crf450 timing chain that i will be putting in but i probally won't install it until the summer depending on how busy i get with school.

i will admit, i do not have the instant torque that he has. i think his products just match better also. for example, he has the stock carb which is good for low and midrange. his pipe is a good mid range pipe. his cam makes good power at midrange. also, he has stock valves and head without porting which makes good low to mid range power.
myself on the other hand has the stock carb, which isn't made for best flow. i have the stock springs and valves which aren't made for the best flow with no porting either. then i have a stage 2 cam which wants to flow more than my carb and motor will allow. also, i am running the x-6 which wants to rev at a higher rpm than my motor will allow. my mods just aren't complementing each other where his are. possibly this could be the problem too. i will probally get my pipe coated if i can figure out if jet hot coating will be as good or better than ceramic. i will post the results but then again i may not do this any time soon.

[Chef]

You know what I think? I think when he did the cam chain, he got more work done...Thats what I would do, anyway.:p

[shamisc]

Originally posted by Chef
You know what I think? I think when he did the cam chain, he got more work done...Thats what I would do, anyway.:p

Exactly!! He did more than a timming chain! He got tired of you waxing him so he got himself a 465!:D

[cals400ex]

Originally posted by Chef
You know what I think? I think when he did the cam chain, he got more work done...Thats what I would do, anyway.:p

no, i can promise you 100% he didn't get more work done. i know this because i was the one to do the work. good idea though. i am still stumped.

[ATVer14]

His bike is probably just setup better with the X-4 for the smaller engine and the Stage 1 for the smaller engine. Everything is complementing everything else, freeing up more horsepower. Plus, you could have to identical bikes and one could still be faster than the other one just because every engine and drivetrain is different. One last thing, were both bike built at the same time, or is your's older and starting to wear out?

[cals400ex]

both bikes were built at the same time same night actually. its weird because i would beat him pretty bad until he put the x-4 and timing chain on. now its a different story.

[mustang93]

Get a cobra and show him / noise him who's the boss

[markeg192]

He gets a pipe and makes up the 8 lengths plus beats you by another 5? Oh yeah sure it's the pipe.:rolleyes:

[cals400ex]

Originally posted by markeg192
He gets a pipe and makes up the 8 lengths plus beats you by another 5? Oh yeah sure it's the pipe.:rolleyes:



that is the exact same thing i thought? all he did was the pipe and timing chain. the only other possibly thing is that he had his rev box on and i didn't. now, that will make a little difference with my high revving 406. i not only installed the stuff, but i also ordered it for him too. i am honestly stumped. now, i can tell you after he sold his big gun pipe he put the stocker back on and it was just as fast as the big gun pipe. however, i still beat him very easily when he had both of those on. then, I took his motor apart and installed the timing chain and that was it. i then put the motor all back together and he put the pipe on. it seems pretty odd to me. however, he has been telling me that the x-4 made a lot more power than his big gun but i wasn't believing it could make much difference. i can tell you that either the pipe or timing chain really woke his up. i know the rev box lost me a little bit, but i still had the edge without too much problem when i raced him before the pipe/timing chain install when using the stock rev box.

[pnut420]

Dude get a fcr39mm and stop worrying about it ;) .

Seriously though, the FCR39 wilk make a huge improvement with the mods you have, and if it is mid to top you want, the FCR will surprise you. You brothers quad is stock with a HMF pipe and FCR and after putting the FCR on it just flat hauls( no improvement down low much). You are right about your friend's quad being setup right though. Seems everything he has matches about perfect and you are still missing a few things. As far as the X-4 exhaust, Im pretty sure mine is a X-4 (bought used) and it seems to make awesome power throughout the powerband, it also has about 6 inches cut off the can and I might have got a little power from that, but mainly noise and its out of the way now.

[UglyMotha™]

the only imput i got for this and more than likely the right answer is "a properly tuned bike will make a world of difference" :o

[pnut420]

Originally posted by UglyMotha™
the only imput i got for this and more than likely the right answer is "a properly tuned bike will make a world of difference" :o

Or he got rid of the big gun exhaust :macho . Im sure they both were jetted pretty close, seems like cals400ex knows about jetting.

[jerry-89-250R]

switch pipes with him and run them again

[duneittilludie]

Are you both running the same octane levels in your fuel and if you are not that could make a difference.My wifes 440 likes a particular mix of "race fuel"mixed with 92 pump gas and if we stray from that mix we lose a lot of performance.In my experience with the rev boxes they can make quite a difference especially on the top end so the answer may be as simple as that.I also know that "just a pipe change" can affect the top end quite a lot as i have seen on my 686 raptor.

[ATVer14]

If his cam chain was really stretched out when you replaced it, it would have affected the timing, so with the new chain his timing is correct again and could be making more power, maybe. Also, could you have accidentally changed the timing when you put the chain in? (I don't know what makes more power, advancing or retarding the timing)

[cals400ex]

well, both bikes seem to be tuned pretty close. we are both running 42 pilot jets. both have clips in 4th position on stock needle. i am running a 160 main while he is running a 162 main. i tried to go up on the main one and two sizes and the more i go up, the more i gradually loose a tad bit of top speed. so actually, i am a tad bit leaner than him which should not harm but help my speed. so, tuning shouldn't be the factor.

we are not only running the same octane fuel, but we get the fuel from the same station.

atver, i am not sure what your saying about switching the timing chains?? i did think about his timing chain being stretched and now making more power but i don't think it was stretched much if any. we compared the new crf450 chain to the stock 400ex used chain and we couldn't tell any difference in length.

yeah, that big gun exhaust sucked. in a drag race after i gutted my stock pipe out and i would more than likely win every time. this is when we only had the pipes and jetting done. in other words, i wouldn't ever get a big gun pipe.

[markeg192]

Did you try switching bikes? Are your valves adjusted properly?
There is no pipe that can gain that much power so I would think your bike must be running poorly. Check your bike over....valves....filter....carb....and so on.

[Aceman]

His engine mods compliment one other as you stated previously. Doesn't the x-4 have a smaller headpipe or silencer than the x-6? If that is the case the x-4 he's running has more backpressure creating more bottom/midrange power than yours in addition to the stage 1 cam. The x-6 that you have will have more noticeable power on the topend since it has such a larger headpipe in addition to the stage 2 cam. x-6 exhausts seem to be better suited for larger displacement motors or engines seeking mostly topend power.

[cals400ex]

we switch bikes with the same results. actually, both have properly adjusted valves. as a matter of fact, his bike ticks a heck of a lot more than mine. mine right now sounds no louder than stock. the x-4 does have a little smaller headpipe. however, it isn't making sense because he pulled more on top speed than he did low end. maybe i just need a bigger bore with the x-6. the filter is clean and the carb on mine is dialed in a little better than his. i know things aren't adding up here but that is what i am trying to figure out. i think i will buy a rev box and see how that goes. when i hit the upper gears it doesn't seem to pull like it should. i have a feeling my stage 2 cam with x-6 pipe is begging for a ported head and a bigger carb.

[markeg192]

I just read through your posts and I would suggesr trying a smalller main jet. It sounds like your rich in the topend, I'd try na 155.

[pnut420]

Originally posted by cals400ex
i have a feeling my stage 2 cam with x-6 pipe is begging for a ported head and a bigger carb.


Yep :D .


His is louder also becuase of the stage 1 cam, the stage 2 is a little less "ticky".

[cals400ex]

i probably should go to a bigger bore. however, i don't even have 6 tanks of fuel through my ross 10.8:1. i wouldn't mind it if i could get a little cash out of the piston. about the jetting: my friend is actually running a 162 while i am running a 160. so, he is richer than i am especially considering his compression is lower and his exhaust is a smaller diameter. this is why i don't think it is the jetting. heck who knows, maybe i need a bigger carb, bigger piston, and a ported head. it just feels like the pipe wants to keep flowing but something is holding it back.

[pnut420]

Originally posted by cals400ex
i probably should go to a bigger bore. however, i don't even have 6 tanks of fuel through my ross 10.8:1. i wouldn't mind it if i could get a little cash out of the piston. about the jetting: my friend is actually running a 162 while i am running a 160. so, he is richer than i am especially considering his compression is lower and his exhaust is a smaller diameter. this is why i don't think it is the jetting. heck who knows, maybe i need a bigger carb, bigger piston, and a ported head. it just feels like the pipe wants to keep flowing but something is holding it back.

You dont need a bigger bore, just get the carb and porting and you will be happy. The porting is the first thing I would do, with the stage 2 and the bigger bore the head needs to be opened up to match all of it.

[speedy400]

what about compression? and break in? what if your rings are going bad or if you broke it in wrong? I know you(cals400) are a really smart guy and would know these things but ya never know. good luck. BTW I got a FCR 39mm yesterday, geez, pulls So much harder, you'd love one-darren

[cals400ex]

my bike isn't running bad or anything, just my friends is a little quicker. i haven't got beat by a piped z or kfx yet, so its not running really poor. the bike was broke in and is running smooth and quiet so i don't think anything internal is out of place or broken. yeah, i am thinking port job and fcr.

[trailburner]

Cal... My friend only has a pipe on his 400 & when we raced we where allways pretty close. then the ********* went out and bought a FCR carb, it made a big difference!!! he pulls on me real good know. if i ever do another mod to my 400 it will be a FCR carb!
PS: there's nothing worse than your riding bud smoking you!!!!

[montyjcm]

How many quad lengths ahead was your buddy with the fcr?

[trailburner]

When we where toped out he had me by about 4-5 quad lenghts....He really pulled on me through the mid range. when a motor has a strong mid-range it is very hard to catch them in the end....

[cals400ex]

yeah, that is what i was wondering. some people say that since i am only running a 10.8:1 406 that a fcr will make less power than the stock carb. i am not worried about low end power. i have it geared and set up so i don't have much in the first place due to the riding i do. i am just debating the 39 or 41mm. i am wondering about the 41 because all i usually am interested in is dragging like your in the dunes but i am on hardpack instead of the sand. we'll see.

[Knips178]

I would have to agree with the jetting suggestion. Anyone that has ever put a pipe on and jetted to fat knows that your top end just feels like your getting nowhere fast. It's noticeable that it isn't pulling as hard as it should. I would jet down to a 155 and check. A 406 with pipe should be around that range 155-160.

Also, the combo of no rev box and a possibly stretched timing chain, which would retard the engine and lose power, could all add up to your problem. That's why sparks offers a timing key advance, to increase horse power. If his timing chain stretched he was losing power and replacing it fixed the timing curve and restore lost power.

[phebus]

Cal, if I remember correctly, you are running with the air box lid on. I would like to see what would happen if you dropped down on your jetting also. I assume you have already tried, because I know you like to play with your jetting, but I would be curious to see what a 158, or even a 155 main would do for you.

[pnut420]

Originally posted by cals400ex
yeah, that is what i was wondering. some people say that since i am only running a 10.8:1 406 that a fcr will make less power than the stock carb. i am not worried about low end power. i have it geared and set up so i don't have much in the first place due to the riding i do. i am just debating the 39 or 41mm. i am wondering about the 41 because all i usually am interested in is dragging like your in the dunes but i am on hardpack instead of the sand. we'll see.

I dont see why they are saying that. My brother went from a stock carb to a FCR39mm on a stock bore with a HMF pipe and it pulls way harder all the way through then it did with the stock carb. It picked up so much mid to top its not even funny, id say the carb did more than the pipe did for his quad.

[H_W]

Originally posted by cals400ex
yeah, that is what i was wondering. some people say that since i am only running a 10.8:1 406 that a fcr will make less power than the stock carb. i am not worried about low end power. i have it geared and set up so i don't have much in the first place due to the riding i do. i am just debating the 39 or 41mm. i am wondering about the 41 because all i usually am interested in is dragging like your in the dunes but i am on hardpack instead of the sand. we'll see.

Well I can tell you that when I got my 39 FCR carb, it was the last mod I did so I know how much difference it made, it was like doing everything else I had already done to my motor again. It felt as if it added the same amount of power as all the other mods put together.

[cals400ex]

Originally posted by phebus
Cal, if I remember correctly, you are running with the air box lid on. I would like to see what would happen if you dropped down on your jetting also. I assume you have already tried, because I know you like to play with your jetting, but I would be curious to see what a 158, or even a 155 main would do for you.


when going down on my jetting one size at a time i will gain a very very small amount of top speed. it isn't noticable unless you have another bike about the exact same speed as yours. however, i have friends with mildly built 400ex's that run about the same speed as mine so i do notice a very minor difference. through the gears it doesn't seem noticable. however, when i start going down on the mainjet my header starts glowing pretty good at full throttle. this means i am starting to approach the lean condition. actually, the header even glows at full throttle with the 160 a little bit.

however, i don't think it is the jetting. i will be putting in a 158 really quick here because the weather has been above freezing lately. in the summer i will probably run the 155. but, my friend is running a 162 in his bike and the only difference is his piston is a little lower compression and he is using the x-4 instead of the x-6. so, if i am rich, he is worse than me. this means his top speed should be slower than me.

we did a little more testing this weekend racing quite a bit. i think i would be able to keep up with him pretty close until we hit fifth if i had a rev box. i hit the stock limit then he jumps a little infront. he pulls some right into fifth. however, we level off pretty close about 1/2 mile later to have the same top speed. i don't have confidence leaving it pinned any longer. :D

[cals400ex]

Originally posted by pnut420
I dont see why they are saying that. My brother went from a stock carb to a FCR39mm on a stock bore with a HMF pipe and it pulls way harder all the way through then it did with the stock carb. It picked up so much mid to top its not even funny, id say the carb did more than the pipe did for his quad.



yeah, i agree 100%. i try to tell people that i don't care the power it has in the first 2 gears. i am not in those gears hardly at all. however, i do a lot of higher speed riding where 3rd to 5th gear performance is important. i think most people don't want me to put on a bigger carb and loose the low end torque so they recommend staying with the stock carb. many of the engine builders build torque bikes so they like the stock carb. i honestly don't know. i am still thinking fcr 41. :D

[UglyMotha™]

carbs help your rpm band not your different gears

[pnut420]

Originally posted by UglyMotha™
carbs help your rpm band not your different gears

Yeah. With the added rpm band you dont have to shift as much, but as far as 1st and 2nd gear that doesnt matter, its more like about 4,00 rpm or whatever. So say the FCR39MM looses bottom end, but the only time I felt that was when the carb was jetted to fat, other than that I have all the low end I need. and tons of mid top top. Also feels like the FCR39MM helped pick up as much torque as it did HP.