Ask Sparks Racing

 

What’s up guys? Your whole team is kickin’. I want to know what to do to a stock 400ex to give it a major racing wake-up call! Please help me out here.
Sean White

Sean

The 400EX’s that get raced at the nationals are typically 416cc motors. The one that Curtis raced at the Legends 2000 race that Fast Trak Promotions put together was a 416 that has been heavily modified. Whenever you plan to modify any race ATV, we recommend doing a little research. That research would include taking a look at what the front-runners at the nationals are doing to be successful. Ask some other riders,
and call the companies that you have considered getting parts or service from for your ATV. Take all of that information and make your decision.

The Legends 2000 race that Fast Trak put together at the Pine Lake TT national this your was an awesome event. Sparks Racing would like to applaud Fast Trak for their hard work and dedication to the ATV racers and enthusiasts.
Sparks Racing

Curtis,
Is it possible to change a manual transmission to a man-auto trans, I have only one hand, a right one; I would like to do a raptor. Your help is appreciated
JMW

JMW
I have seen a product that claims to do this. It is put out by Cycle Country and is distributed by Parts Unlimited. Most ATV dealers have access to Parts Unlimited, so
it shouldn’t be a problem finding them. We have no direct experience with this product, so I can’t tell you much about it other than it exists. It is on Page 204 of the Parts Unlimited ATV 2000 catalog.
Sparks Racing

We have just bought some new 2+2 a-arms and were wondering how to set them up. What caster and camber adjustment you use and how much toe-in and what tools you use to do this. The machine is a 400ex.Thank you for your help.

Although Curtis is knowledgeable on chassis set up, we would defer this to one of the aftermarket chassis companies.
Sparks Racing

I was just wondering if a Honda 350X engine would fit in a banshee frame. If so, what kind of mods do I have to do to the frame to make it fit. How much would it cost me? Also, if the 350X engine will not fit, then what other 4 stroke engine can I put into a banshee frame.
Thank you,
Brian Ransco

Brian
Why a Banshee frame? The 250R and even the 400EX chassis will out perform the Banshee chassis and you have more options as far as aftermarket chassis companies.
I am sure that an aftermarket chassis company could make a Chevy V-8 motor fit if
you paid them enough. Stick with what works. There is a reason that the top ATV professional racers choose a particular chassis combination, and they usually work great. Follow their example.
Sparks Racing

Hi my name’s Clint and I race a 2000 300ex. What do you think is the best cam that
I can put in it without it being soft?
Thanks
Clint

Clint
As far as a camshaft that isn’t “soft”, I can’t imagine anyone offering a setup that
would slow down the 300EX. This would be answered the same way that any general performance question would be answered. Look at what the racers with the fastest 300EX motor are doing, ask some other riders and call the perspective aftermarket performance suppliers and ask questions. Take all of that information and go with the company that you trust the most.
Sparks Racing

Hello, I Have a 2000 400ex and all of my friends have banshees. I have around 500 beans and I want some more kick from the start. I’m also interested in racing the 400
if you can give me some tips, it would be greatly appreciated! Can also tell me were
the closest tracks are in or around NJ.
Thanks,
Henry

Henry
There are some great ways to make your 400EX faster for under $500. It is inexpensive to modify your air box and air filter to increase airflow without sacrificing dirt-filtering ability. Carburetion can be modified to increase flow to the motor for a reasonable cost, make sure that it is done properly. Not just any guy in his garage with some tools can machine the carburetor or any other part on your ATV for that matter. Remember you get what you pay for. Be careful to only use reputable performance shops that you can trust. The exhaust is a great source of gain for the 400EX, although a good system will chew up a good portion of that budget. There are a few other little items for the ignition system that can be upgraded, such as a high rev CDI or an
Ignition advance key. Both of those items are within your budget. The bolt on items are the best place to start on the 400EX. They are easy to install and are usually cheaper than tearing your motor apart and having internal parts changed or modified. Once you get all of the bolt-on goodies, then I would recommend having the internal motor work done. Be certain that you make good decisions, because it is costly to buy something twice.
Sparks Racing

I just installed a Yoshimura exhaust on my 400ex what are your thoughts
or opinions on the Yoshimura exhaust systems.

This is a tough subject to comment on for us. We have had some experience with the Yoshimura exhaust on the 400X. A customer of ours brought his 400X in to me make
it faster and asked that we use his Yosh exhaust to save costs. We just told him that
we would let him try our exhaust to compare it to the Yosh and he could make the decision at that point. He tried them both and I will say that he happily spent the extra money for the Sparks exhaust.
Sparks Racing

HOW MUCH DO YOUR RACERS SPEND ON THEIR ATV’S?
THANKS
GARY

Jeremiah JonesGary
A rider must start by finding a good stock TRX
250R to get some of the basics to put into their aftermarket chassis. The motor is tore down and gone through to make sure that it is sano. The bikes are freshened on a regular interval to assure that the bikes run perfectly at every national. A number they often attach to a cost on the quad is about $16,000 and to maintain it for the season would be over and above that. Then you add the cost of maintaining your practice bikes, your race hauler, pay your mechanic, buy gas, pay for hotels, pay gate and race fees, and so on and so forth and you spend at least $50,000 each season. All of that for a $4000 Pro purse at each of the nationals
(except Fast-Trak’s events). These guys definitely deserve more than what’s out there for them right now, but at least you clearly know that they love what they do!
Sparks Racing

Hello. I own an 86 LT250R. I have a K&N air filter with no air box. Also it has an aftermarket mx pipe and power core silencer and aftermarket reeds. Also I am about
to get it bored 30 over. The carb is stock and I was wondering what jetting I should run. I also own an 87 LT500R with a 91 CR500 engine in it. The engine has been bored 60 over and is in need of a compression release. I was wondering what would
be a few possibilities that I could lower the vibration. I was wondering if that would be a good open class quad?
Aubrey Koopa Harland

Jetting questions are one of the most common questions that Performance Company
get asked. Of course most companies provide jetting recommendations for the
products that they sell. The best way to ask a jetting question is to start the way you started and then add what you have in for jetting and then comment on how it runs. From there it is easier to make some recommendations.

The vibration problem on the LT/CR 500R is a problem that is not easily fixed. I am
not certain that it has ever been eliminated completely. If it becomes possible to take a non-counterbalanced motor and put it in a Quad chassis without vibration, that would allow everyone to choose from the current crop of modern two-wheeler motocross motors. Those motors benefit from 12 years of factory development and a production rule that has forced the factories to put the good stuff in the two-wheelers so their factory racers can use it legally.
Sparks Racing

Hey Cutis,
I am a 15-year-old boy that needs to know a little bit about your motors. I am a very experienced rider even though I am 15. Right now I have a stock motor and am
looking to upgrade my motor because I am wide open everywhere I go. I was wondering if you sold a cylinder that was a 265 kit so I wouldn’t have to send you my cylinder. I am a mid pack A rider and even though I haven’t raced a national yet I
know this because I have raced against a dude that was 2nd in the national circuit in 1999 and I finished about 2 seconds behind him, (I am not lying, in case you think that
I am conceded or something.) I am a very serious rider, I have won 4 championships
in three years of racing and I really need a motor bad! I hope that you don’t think I am bragging because I am not I jump 90 foot triples and 85 foot step up triples and have
a really good reputation down here. I thought that you might need to know this stuff for what I need. If you could give me the information about selling new cylinders done by you so I wouldn’t have to lose time in the seat by sending you my cylinder I would appreciate it a lot.
Thanks Josh

Josh,
Thank you for the information on your riding abilities. I am certain that you are a very skilled rider. If you are skilled, beginning, or even a top professional a ported cylinder with all of the supporting pieces (carbs, reeds, exhaust, air filters) will help you a great deal. Performance shops would offer a new cylinder that has been ported for the exact reasons that you stated. No one likes it when his or her quad is down. It is no fun to
not be able to ride. If you can afford the additional cost of a new cylinder, I would definitely look into it. Another way to minimize the time that your cylinder is away from you, call the performance shop and schedule the best time to send your cylinder to get
it back quickly.
Sparks Racing

DEAR SPARKS,
AFTER ATTENDING A COUPLE OF NATIONALS THIS YEAR, I’M WANTING TO ENTER MY SON INTO THE AIR COOLED 2 STK. – 300 4 STK. CLASS NEXT YEAR. SO, THE QUESTION IS FOR TT RACING
WHICH MACHINE DO YOU THINK WOULD HAVE THE BEST CHANCE
TO RUN UP FRONT IN THIS CLASS? BLASTER OR 250X/300EX, IF MOTORS WERE LEGALLY ALL OUT, (2 STK VS 4 STK). AND ABOUT
HOW MUCH WOULD YOU SPEND ON A 4STK OVER A 2STK TO
REACH TURN ONE FIRST?
THANKS FOR YOUR TIME,
TIM

John Winkelbauer on his Honda 300EXTim,
There are advantages to both set-ups. The four-stroke motors are good for their smooth power delivery. The two-stroke motors are good for the peak power that they build. Cost at the end of the season would be close between the two.
Although the maintenance intervals are more frequent on the two-stroke, the four-stroke is
more costly to service. The two-stroke is easier
to work on (especially an aircooled motor) than the four-stroke motor. The best answer is ???, that is all part of the fun.
Sparks Racing

Hi Curtis,
Can you tell me what you recommend to run in a Pro-X 330? What plug, gap, fuel octane, oil ratio, carb specs, compression and a cool head or not? thanks DP

DP
Sparks Racing sets-up the 330 National kit with a B9EGV at .22?. The fuel should be 110 octane with Maxima Castor 927 at 5 ounces to a gallon. Be sure to mix only one to three gallons at a time in a five gallon can. This will assure that the fuel is fresh and mixed very well. Always shake your fuel before riding. We use a 38MM PWK Air Striker with a 190 main, 55 pilot, DEJ needle, and the air screw turned out one turn. The compression should be at least 220. The Cool Head is a nice addition to any motor.
Sparks Racing

What is the difference in a Kehin 38mm and a 38mm air striker on your 330kit?
Would they be jetted different? I’ve tried both on my bike with the same jetting you recommend for the air striker. And the 38mm bangs out through the rough stuff at
high rpms. What is the set up for the 38mm?
Thanks
JC

JC
The air striker carburetor has two air fins on the inside of the air filter side of the carburetor. This increases the flow characteristics of the carburetor. The Air Striker also has quad vents that allow the carb to vent better and that helps eliminate the problem of sputtering through the rough stuff. For the 330 national motor, use a 190 main, 55 pilot, DEJ needle and one turn out on the air screw.
Sparks Racing

Curtis,
I have a 2000 banshee and bought an aftermarket pipe package. It came with pipes, k&n filter, boost bottle and 2-260 main jets. I felt a lot of power change. There is just something missing. The old jets are 200, is this right to you, to go up to 260? Is there something else I can do to the carbs. Some of my buddies say I should go to a 34. Could you shine some light on this?
Torres

Torres
The 260 main jet is within a normal range. More than anything how does it run with
that jet installed. I would expect that it is ok.
Sparks Racing

Dear Curtis,
I have a 87 TRX 250x. After I ride it for a month or two and
check the oil it is low. But it doesn’t smoke or leak oil I was wondering
where is it going. And where can I get some of those cool Curtis Sparks
racing stickers.
Thanks,
Jonathan

Jonathan
How low is low? If you have to add a few ounces, that is not a problem. If you have
to add more than a quart, you may have a problem. It is normal for a four-stroke to
use some oil. As a motor wears, it will use more and more oil.
Sparks Racing

I have a 400EX. I use mostly for TT and flat track but also some Cross-country racing. The only performance mod I have now is an exhaust system. What would be the next step to gain more performance?
Thanks,
Todd Smith

Todd,
There are several easy bolt-on modifications that are offered for the 400EX. The air filter and air box can be changed or modified to improve performance. The ignition timing can be advanced or the CDI changed to increase the timing curve and raise the rev-limiter. The 400EX responds well to increases in displacement, more aggressive camshafts, and porting. The carburetion is also a source of good solid gains. The
stock one can be modified or there are some great aftermarket carburetors available.
Sparks Racing

 

ATV Scene is proud of our collaboration with one of the most successful, knowledgeable and respected race teams in the history of ATV racing! Curtis Sparks has brought a lifetime of know-how to the sport. Before, during and now after his personal racing career, he has fine-tuned Sparks Racing’s products and services resulting in some of the best performance products available on or off the race track!

Here’s your chance to get your ATV to run like a top pro’s. If you have a technical question (or any other question) for Curtis or any member of the Sparks Racing Team, simply click on the e-mail link below and submit your question. Your questions will be answered in upcoming issues, which are posted monthly.

(Please try not to aim your questions directly about Sparks Racing products. Instead be less specific so your question can can relate to all ATVers – not just ones that own a particular Sparks Racing product).

Send your question to asksparksracing@sparksracing.com. For a look at what’s available from Sparks Racing, check out their web site at sparksracing.com

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