New EX Motor vs Modded Z Drag Race Results

[Quadzilla]

Ok, here is the deal.

I just broke in my new 416 (specs below). My good friend has a nice Z400 that has a full CT Racing Exhaust, jetted properly, Pro Flow airbox kit and filter, Vortex ignition. It runs real nice and is fast.

Prior to my new motor, I had only a Sparks X-6 and a stock carb that was jetted. In a drag then (with the stock motor), he would beat me by 2 quad lengths. It prob should have been more, but he is 50 lbs heavier than me and I'm a slightly better rider (if that means anything).

Now with the new motor I beat him by three bike lengths or so. So I gained 5 bikes lengths total. This is a drag 1st - 5th. In 5th I even start to pull away more but we run out of room on the straight and we can't rev out 5th all the way. Both quads have 1 tooth less on fronth sprocket and stock rear sprockets and same tires (size and all) front and rear. I did not use the GT Thunder ignition on mine because I was still on the tail end of break-in and did not want to rev above the stock limiter. One thing I can tell you is that the motor revs much quicker and smacks the stock rev limiter in no time. Feels like it's still making power (not dropping off) up till it hits the stock limiter. It seems like it needs more RPM and the GT Thunder will give me about 1500 rpm more than stock and 6 degrees more advance timing. Hopefully this will help. Oh, just for info, I'm running a 70/30 mix of 110 and 94 gas right now.

So does gaining 5 quad lengths on a drag race sound reasonable for what I did to the motor? Thanks!

[woprs50]

what jetting are you running in your 40mm Fcr carb ?

[cals400ex]

put that rev box on and you will gain a few more bikes for sure. my 406 was the same way. with the stock rev box i would definately hit the limiter in the first 3 gears and sometimes even in 4th when drag racing. also, every time you hit that limiter, your buddy will be gaining time on you becasue your slowing down.

yeah, i forgot what jetting your running too?? also, did you rig up a boot to fit that carb or buy the adaptor? i remember woprs made an rubber boot and didn't buy the adaptor?

[Quadzilla]

Jetting turned out to be 165 main, 4th from top on needle, 42 pilot (stock CRF and I didn't have others sized pilots to try). I did the boot trick. Bought some 2 1/4" OD exhaust pipe. Cut about a 3/4" section and then used radiator hose to couple it with the airbox boot and carb. Worked like a champ!

The power is deceiving because it does not want to wheelie much, not even as much as before the motor mods. I think that it's due to 2 things.

1 - The power is now moved to the upper part of the power band vs low to mid.

2 - I got all new suspension (see below) and the quad has a good bit more sag and sits a lot lower. The new suspension is like "butta" compared to the stock. Handling, jumps, whoops are so smooth now. Even ruts and big rocks are better. WIth it being lower, I think it makes it harder to wheelie. Puts more power to the ground.

So do my drag race results sound about right for what I did to the motor? Moved from 2 quad lengths back to 3 ahead of him...

[cals400ex]

your results sound ok. i think i gained alittle more than that though but i always ran the rev box which helps a decent amount for dragging. well, it did on my bike anyways. however, your gains should be similar as mine with the rev box. also, did you put other stuff on the bike when you added the carb? i am going to add some more stuff to my bike and break it in with the stock carb. i then will put on my fcr 40 that i have and compare it. i will give results when i get it all done. however, my parts won't be in for a good 2 weeks and then i will break it in a bit. so, i won't be able to post results for while yet....

[Quadzilla]

Correction, meant to say 4th from BOTTOM on needle, not top. A local shop (Performance Cycles) did the jetting with a 02 sensor.

[Quadzilla]

Originally posted by cals400ex
your results sound ok. i think i gained alittle more than that though but i always ran the rev box which helps a decent amount for dragging. well, it did on my bike anyways. however, your gains should be similar as mine with the rev box. also, did you put other stuff on the bike when you added the carb? i am going to add some more stuff to my bike and break it in with the stock carb. i then will put on my fcr 40 that i have and compare it. i will give results when i get it all done. however, my parts won't be in for a good 2 weeks and then i will break it in a bit. so, i won't be able to post results for while yet....

Yes, I did all my mods at once except for the Sparks pipe which was already on there. All motor work and suspension was done at the same time. It's like getting a new quad!

[cals400ex]

yeah i bet it was totatlly different. i was hoping you just put on the carb so we could get an idea if that is actually helping over the fcr 39 and even the stock carb....

so, with you changing carbs quickly i assume you weren't too impressed with the 39mm??

[Quadzilla]

I had a bad o-ring on my intake manifold and could not get my 39mm dialed in properly. I thought it was the carb so that's why I bought the 40mm. Turns out the 40mm did the same thing and that's when I discovered that the o-ring was bad. So I sold the 39mm on Ebay and it damn near paid for the 40mm (about a $20 difference) so I am pretty happy about that. Like I said, I did everything at once (motor and suspension) so it all made a big difference together.

[montyjcm]

Nice man, what kind of hp numbers are you putting up?

You just better hope you friend doesn't get some cams and a carb!;)

[Quadzilla]

I didn't have it dynoed. My friend with the Z estimates that his quad is putting out in the mid-30's according to CT Racing's dynos with that pipe. Mines obviously putting out a tad more, so I would estimate that my EX is pumping high 30's. If he got cams and a carb, he would have me for sure.

If I had to do it all over again, I'd probably go with the Hotcams Stage 1 vs the Stage II that I have. The Stage II does well on the monster coal hills that I do (east coast's version of the dunes) but in tight trails there is not enough low-end power in my opinion. His Z has more low-end for sure. Maybe the rev box with the timing advance will help this a little. I know it will help me in a drag and hill climbing.

[cals400ex]

that larger carb probably didn't help for low end power either. did you have a huge throttle response gain with that 40mm carb? just wondering because that is how the 39mm is. also, that x-6 i am not too sure about. i have one and my buddy has an x-4 and i can't keep up with him in the upper gears. my bike is more radical too. i think those d@mn headers are too big. by the way, i am in the process of getting my stainless steel x-6 coated. i will let you know if that makes a difference or not. the exhaust velocity is supposed to speed up and increase power. we will see how it turns out.

[Quadzilla]

Huge increase in throttle response, I would say no. Maybe mine still needs a little dialing in. It seems a little snappier, but nothing drastic. I need to adjust the carb because it still has a slight bog when wacked fully open down low. It rarely does it. I have the accel pump squirt duration adjusted as low as the carb will allow without modding it more. The mod is simple, and I will prob do it to get all of the bog out. I did it on the 39mm, but the 40mm mod is a little more involved (not much though).

[cals400ex]

i was talking to a jetting expert and he said they changed the pump diaphram in 02 i believe but maybe it was 03. anyways, i got a new one and put it in. you could barely tell a difference in looks. it almost looked like a screw in there would adjust the squirt but probably not. to be honest with you, my 39mm even missed pretty bad when i floored it quickly before and after the accel pump mod. i have a feeling this 40mm is going to be overkill. i don't think my bike will have enough power for this carb. i actually think the 39mm felt a little big. the companies i talked to said its best to go a little small than a little big. they claim you will get more power that way. who knows.

[Quadzilla]

I agree, smaller is prob better. I just wanted the newer generation FCR (40mm is the newer, 39 and 41 are the older gen). The newer gen is supposed to have less of a bog effect on the WOT from down low than the older. It's barely noticible on mine and only happens when I'm at very low rpm and nailed wide open. You can adjust the duration length simply by screwing the in the screw on the inside of the black cover (on the accel pump linkage) all the way in (this will shorten the duration). Mine only squits for about a second now, maybe a hair less. I have read that .5 of a second is optimal. Some of the older gen FCR's squirt up to 3 seconds I've read before mods. No wonder why they bog so much.

My carb is an 03 (2003 stock CRF 450 carb from servicehonda.com). Hope this helps!

[cals400ex]

so are you talking about the little black bolt that actually doesn't screw in but you can just push it in and out with a little force?

[Quadzilla]

I don't think that's it. I had to take off the black cover (held on by one bolt I believe and then there is a screw under there that has a spring on it. I believe it's a phillips head if I recall correctly. The more you screw it in (clockwise) the less the squirt duration. I have mine screwed in all the way and it's down to just under a second. Again, a very very slight bog when whacked open all the way from down low in rpm. It can be modded further by doing the "BK Mod" found on Thumpertalk.com.

[cals400ex]

thanks. i see what your saying now.