Gearing or Power Issue

[JNork]

I'm looking for some input on something because I prefer not to throw parts at this thing. I have a GX200 on a Coleman CT200U. I added a 30 series TAV2 I got from Amazon on it and I can't get it to rev out past 4300RPM and that is on a longgggg wide open blast. The engine will turn 6500 RPM no problem with the back tire off the ground. Here are the mods and if someone could steer me in the right direction so I can use all of the available RPM, that would be great. Thanks

New GX200
ARC .010 longer billet rod
Flat top piston
.010 head gasket
ARC Billet Flywheel 32* Timng
K&N Open Air Filter
1" Header Pipe
18lb Valve Springs
Valve Lash .003
.022 Pilot Jet
.036 Main Jet
93 Octane
30 Series Torque Converter
10T front Sprocket
50T Rear Sprocket
19" Tires


On a full throttle blast the RPM will jump to 4400 quickly and slowly go down to about 3900 and then slowly increase to about 4300 as I hit a top speed of 50mph.

 

[itsid]

Hi and welcome
funny.. you're the third that has that weird issue with a cheap TavKit

first was
MrMonk (click to read the thread)

looking at your numbers, and knowing that the coleman is a hefty beast for a "mini bike"
I must say that you kinda asking for trouble with a 5:1 gear ratio and 19" rears
I can promise you now that you'll never hit 80mph+ anyways
So that gear ratio is kinda pointless IMHO

if you gear for a low 60mphs you'll might get a much better chance (like a 66T rear sprocket)
in fact chances are you'll be limited to 54mph in terms of top speed anyways..
so you might as well gear for that (76T rear sprocket)

but feel free to read the thread and draw your own conclusions,
give the juggernaut a test perhaps and if it doesn't work, the engine modification is just not working well enough
to achieve the required horsepower to reach the speed you're after

proTipp if you intend to hit 80mph you'll need 25.5 hp which is not within reach of a GX200 I'm afraid.

sooo.. still a stupid gear ratio IMHO

'sid

 

[jmaack]

mine does the same thing. same gearing I have predator 212. I think it is the gearing slightly too high. I just send it.
one day I'll change it out. ct200u ex stage 1 here.

 

[JNork]

I figured gearing was the issue and I'm fine with not being able to break a land speed record on a CT200 ��. So it looks like gearing and power are the issue. I'll likely swap out the the rear sprocket to a 60T and once I burn up the TAV swap it out for a Juggernaut. I was leaning that way since I'm getting a good amount of belt dust on those long runs. A better gear ratio should help the problem some. I appreciate it.

---------- Post added at 06:02 AM ---------- Previous post was at 05:18 AM ----------

I just finished reading that entire thread and who would of thought that you could be overpowering the unit with simple mods. It's funny because I refurbished a Yerf Dog for my 9 yr old son and I have the governor opened up some to run 4500 RPM and it accelerates hard all the way to it no problem. 20" tires with a 7" driven. I suppose I'll order the Juggernaut before the sprocket since his ideal ratio is what mine is now. Huge help. I searched all over the forum and somehow missed that thread. Big thanks.

 

[karl]

driven. I suppose I'll order the Juggernaut before the sprocket since his ideal ratio is what mine is now. Huge help.

It wont help, exactly what sid said, if you engine had enough power to open up the clutch to 1 to 1 , you would be traveling 73 mph, and thats too fast, asking too much from your engine.

The expensive clutch does not alter the gear ratio and will not fix the problem

I dont understand why people are bent on pulling the factory jackshaft that corrects the ratio, and slapping the belt clutch on.

So the starting ratio is like normal gearing, then too much overdrive from there on out= poor preformance

This will probally stir the pot, but All you got to do is grab a 3/4 Max Torque SS clutch, run factory jackshaft, and good to go! 6500 rpm and acceleration!

Anyway, good luck, have fun!

 

[JNork]

I'll ask around for a clutch since the engine that came on it was a 5/8 crankshaft instead of a 3/4 like I have now. I will post up results when I get it installed.

 

[karl]

I'll ask around for a clutch since the engine that came on it was a 5/8 crankshaft instead of a 3/4 like I have now. I will post up results when I get it installed.

Yes, Im aware, If you can borrow one to try, good deal. If its still not to your liking, throw the tc back on and regear

The chinese ones dont like much power, but the genuine max torque cost less than $30, I run a 30+ year old unit on my stage 3-4 predator.

https://www.bmikarts.com/Go-Kart-Gear-Ratio-Calculator-Jackshaft-Setup

http://www.diygokarts.com/speed-calculator.html

Just type the sprockets into the ratio calculator, punch the ratio is gives as the axle sprocket, 1 for clutch in the speed caculator, good to go.

That should get you an idea

 

[JTSpeedDemon]

with karl.

I'm running a possibly around 40 year old Max-Torque SS clutch(don't really know the age), and it can still LAUNCH!
I understand TAVs allow for partial throttle slipping and can "shift", but the extra moving parts aren't worth it to me, so I stick with centrifugal clutches. Max-Torque clutches.


And BTW - The Chinese fakes engage at 1800 RPM, genuine Max-Torques engage at 2200 RPM. The higher engagement is very nice.

 

[txluke]

I have a hopped up 196cc on my ct200u-ex with a tav. The problem is overdrive. My 300lb butt can get to 42 mph easy and then OD kicks in. I can creep to 48 on a long stretch. If you look around people make "lock out" bushings for the 30 series driver that keep it out of overdrive. My buddy got the Juggernaut driver and he gained 9mph on the top end. He can also climb bigger hills than before because the Juggernaut grabs and holds the belt better. I plan on ordering one soon.

 

[karl]

The problem is overdrive.

Yes, but without the 10% overdrive, 1 to 1 ratio from clutch assumed, 10t to 50t gearing, 19in tire, 73 mph @ 6500rpm

So the gearing will still need to be changed to take advantage of the additional rpm the motor turns at,

He needs to turn more RPMS at less wheel speed , not grip the belt more. The fancy clutch might help the OP somewhat, but thats putting a bandaid on the issue.