How To Get More Speed From A Trailmaster Challenger 200EX For Street Driving

[GK Newbie]

Greetings all! I wasn't sure where to post this but this Forum seemed the most logical place so here goes:

I'm about to buy TrailMaster Challenger 200EX that I plan to license for street driving. I live in Arizona and have miles of County Roads to cruise. Tons of people around here have street legal Karts that they drive to the store, running errands, and just cruising around the Arizona landscape. I already know what the equipment requirements are for street use and have that under control. The Challenger comes stock with most of the lighting, mirrors, windshield, turn signals, reverse, etc - However - the speed limits around here average 35 - 45mph. I understand the Challenger tops out at about 38mph and I imagine that's with the pedal to the floor...and I don't wanna have to run it that hard for any length of time.

Is there any way I can make a tweak or two so that I can I can squeeze out about another 10mph or so so I can keep up with traffic without running my kart with my foot to the floor? I've watched vids about adjusting the governor skrew (obviously), replacing a chain gear to change the torque, and several other tips. I am mechanically inclined but don't wanna cause any permanent damage or risk blowing something up!

So - if anybody has done this, knows what to do, has a video to recommend, has the magic answer, etc it would be much appreciated! I just wanna get it right without skewing anything up. I need about another 10mph and I'd be set.

Thanks in advance for any and all assistance...

 

[bob58o]

Gokarts have two driving modes. stomped to floor - or braking. lol

38mph is probably near the limit for a street legal kart powered by a 200cc engine. Might need mo’ powaaa to get mo’ velo.

You don’t get extra top speed for free.
It costs wear n tear on clutches, and/of belts.

It costs acceleration. Might be more dangerous trying to merge with traffic with less acceleration even if you can keep up with traffic.

without knowing anything about your kart or its engine… ways to increase top speed.

1.) Increase RPM-

Remove governor (if it has one)
Change ignition (if it has Rev limiter)

2.) Adjust gear ratio-

Let’s say you want to increase top speed from 38 mph to 45 mph… That’s an 18.5% increase.

If the current sprocket teeth ratio is around 60T on rear and 10T on front ( 6 : 1 ), you could try 5:1 such as 60 : 12 or 50 : 10.

This may help or not depending on current rpm vs mph compared to TQ vs RPM

3.) Larger Rear Tires-

This is similar to changing gear ratio.

4.) Performance Parts? with gear change
(Are loud as hell open exhausts street legal?)
Might need extra power at higher RPMs or more TQ to make up for gearing change.

5.) Engine Swap? (420cc engine) with gearing change
More TQ to make up for hearing change.

 

[Master Hack]

 

[Denny]

You could throw it off the top of a mountain?

 

[panchothedog]

All of the suggestion by bob58o in post # 2 make a lot of sense. Bigger drive sprocket, or smaller axle sprocket is probably the easiest and least expensive way to go. It's going to hurt acceleration. ONLY YOU can decide what is a happy medium. Watch out for those fools in their full sized cars that have their eyes glued to their cell phones. They won't know that they have run you over until they feel a bump.

 

[Whitetrashrocker]

View attachment 150634

CH³NO² is mo better.

 

[Master Hack]

Mo bedder!
where were you in school?

 

[Denny]

Licking windows probably.

 

[GK Newbie]

Greetings all! I wasn't sure where to post this but this Forum seemed the most logical place so here goes:

I'm about to buy TrailMaster Challenger 200EX that I plan to license for street driving. I live in Arizona and have miles of County Roads to cruise. Tons of people around here have street legal Karts that they drive to the store, running errands, and just cruising around the Arizona landscape. I already know what the equipment requirements are for street use and have that under control. The Challenger comes stock with most of the lighting, mirrors, windshield, turn signals, reverse, etc - However - the speed limits around here average 35 - 45mph. I understand the Challenger tops out at about 38mph and I imagine that's with the pedal to the floor...and I don't wanna have to run it that hard for any length of time.

Is there any way I can make a tweak or two so that I can I can squeeze out about another 10mph or so so I can keep up with traffic without running my kart with my foot to the floor? I've watched vids about adjusting the governor skrew (obviously), replacing a chain gear to change the torque, and several other tips. I am mechanically inclined but don't wanna cause any permanent damage or risk blowing something up!

So - if anybody has done this, knows what to do, has a video to recommend, has the magic answer, etc it would be much appreciated! I just wanna get it right without skewing anything up. I need about another 10mph and I'd be set.

Thanks in advance for any and all assistance...

Bob58o: THANK YOU for your response...and so quickly! You come across like you really know your s**t and I learned a lot with your post.

Unfortunately, there's only two things I can do at this point: First, adjust that stopper under the accelerator pedal. I'm getting the Kart fully assembled and I imagine they govern it down a tad. So I'll open that up. Finally I'll tweak up the governor itself and try to squeeze a few more mph out of it. You're other suggestions are awesome but I can't afford any of those options right now - so between the two things that I can do myself they'll hopefully get me closer to my target speed.

Any idea where I can find either a vid clip or a photo of the Challenger governor set up - like where is it located? I have no idea what I'm looking for. On some engines they're quite prominent, but hidden on others. And one final question: Is it bad for the engine if I drive it with the accelerator pushed to the floor? Any increase in wear and tear? I only weigh 145# so weight certainly won't be a problem. Occasionally my wife will ride along so you can double that.

Thanks again for your excellent suggestions; they were quite educational. And if anyone else has any ideas please post them here. Everybody have a GREAT weekend, and I'll keep an eye on this thread. That is all - Thanks for playing.

.

 

[bob58o]

I’d have to look to see what engine is on your kart. There are two “main” types of engines used on karts. Based on the name, I’m guessing it’s a 200cc 4 stroke.

There are gx200 style knockoff off utility engines, but I suspect you have a GY6 style motorcycle/scooter engine.

The former probably has an internal governor.
The later may have a rev limiting CDI box or something.

 

[bob58o]

It’s a big and heavy kart with a gx200 knockoff engine. Probably near the the limits of the available power at 38mph.

I’ll try to find a video of the method I like to use to remove governors from these engines. It involves taking off the flywheel to punch out a pin from block that holds the governor assembly gear.

There are other methods to remove and or adjust the governor. Can remove it without taking off the flywheel by removing a clip on that “pin” from inside the crank case.

If you search gx200, or clone engine, or Predator 212… Governor Removal… you find a bunch of videos. All of those engines have the same type of governor assembly as you will have, which limits RPMs to 3600-3800 RPM.

 

[bob58o]

Accelerator floored isn’t a problem.

Let’s assume your kart with stock gearing goes 38 mph at 3800 RPM. To go 45 mph, you need to turn the engine 4500 RPMs. Adjusting (or removing) the governor could possibly get you there, but I suspect the kart may struggle to accelerate above 38 mph because of lack of TQ at higher RPMs.

The benefit of not changing the gearing is that you don’t lose the low end acceleration. By only removing the governor, you just allow for higher top speed IF the power to do so is there.

 

[GK Newbie]

I’d have to look to see what engine is on your kart. There are two “main” types of engines used on karts. Based on the name, I’m guessing it’s a 200cc 4 stroke.

There are gx200 style knockoff off utility engines, but I suspect you have a GY6 style motorcycle/scooter engine.

The former probably has an internal governor.
The later may have a rev limiting CDI box or something.

Bob: Here's the specs on the Challenger 200EX stock engine:

EPA certificated
Engine type: 4-stroke, single cylinder, air cooled
Displacement: 168.9cc
Max HP: 11.1hp/8000rpm
Max torque: 8.1 lb ft/6000rpm
Bore x stroke: 2.4x2.28 inches
Max speed: 35 mph
Climbing ability: 20-25 degrees
Ignition: ECU
Starting system: Electric
Battery: 12V 10Ah
Engine oil: SAE 15W-40

 

[Whitetrashrocker]

I'm gonna say your not gonna get much more out of this buggy with out spending lots of cash and time.
It's a 160cc gy6. They do make a big bore kit to make it 230cc or so. But I'm gonna guess it might need the case bore machined out to go that big.

It has an ecu controlled ignition. There might be a flash for the computer but that's gonna cost too. There is no mechanical governor to adjust or remove.

I think the -ex means it's the efi version. Again. Computer controlled. Can't just bolt a bigger carb cause it don't have one.

If you want to go faster you could get a wrecked hyabusa and do an engine swap.

Enjoy it for what it is. It's not meant to go down the interstate, it's meant for trails and back roads.

 

[GK Newbie]

Thanks for your reply. As I said earlier, I live in an area dominated by County Roads and you rarely see a speed limit above 45mph. If I can squeeze 40 out of it I'll be happy. I don't plan any "road trips" - I'll primarily be making quick runs to the grocery store, pharmacy, etc - and just out joy riding - not doing any racing or the like. So I'll see what she'll do out of the box and maybe adjust the governor just tad. Again thanks for the replies - you've all been very helpful. Mucho Gracias!

 

[bob58o]

I guess the photo I found was of the wrong buggy. Sorry. Like WTR said, no governor on that type of engine. The photo I found showed a clone style engine. The specs you gave don’t match the photo.