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The Tdub has 1/4th the HP and is 50 lbs. heavier than your dirt bike, so that's not a fair comparison and that gearing is killing any real trail riding.
Arizona trails are alotsa rocks below the Mogollon rim and less rock with more dirt and forests up on top. I ran 13/55 gearing (all off road) and now run 14/55 to connect the trails. With this gearing I can ride 55-60mph and possibly faster but don't cuz I'm running around with single digit tire pressures.
With a 75mph speed limit (and everyone driving 82mph) you will never safely ride the Tdub up the I-17 .

I've taken my TW up abandoned mining trails and spurs that I would not consider on my dirt bike, look up "Smiley Rock Trail", the TW just motors thru those rock chutes.
Learn to really ride the TW, the lack of horse power, suspension and brakes will make you a better rider. I practice all my stupid stunts on the TW, low and slow hurts a lot less.
 

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The Tdub has 1/4th the HP and is 50 lbs. heavier than your dirt bike, so that's not a fair comparison and that gearing is killing any real trail riding.
Arizona trails are alotsa rocks below the Mogollon rim and less rock with more dirt and forests up on top. I ran 13/55 gearing (all off road) and now run 14/55 to connect the trails. With this gearing I can ride 55-60mph and possibly faster but don't cuz I'm running around with single digit tire pressures.
With a 75mph speed limit (and everyone driving 82mph) you will never safely ride the Tdub up the I-17 .

I've taken my TW up abandoned mining trails and spurs that I would not consider on my dirt bike, look up "Smiley Rock Trail", the TW just motors thru those rock chutes.
Learn to really ride the TW, the lack of horse power, suspension and brakes will make you a better rider. I practice all my stupid stunts on the TW, low and slow hurts a lot less.
With the right gearing, a Singer sewing machine would do just fine crawling the rocks. Ha!
 

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2004 TW200
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Discussion Starter · #44 ·
The Tdub has 1/4th the HP and is 50 lbs. heavier than your dirt bike, so that's not a fair comparison and that gearing is killing any real trail riding.
Arizona trails are alotsa rocks below the Mogollon rim and less rock with more dirt and forests up on top. I ran 13/55 gearing (all off road) and now run 14/55 to connect the trails. With this gearing I can ride 55-60mph and possibly faster but don't cuz I'm running around with single digit tire pressures.
With a 75mph speed limit (and everyone driving 82mph) you will never safely ride the Tdub up the I-17 .

I've taken my TW up abandoned mining trails and spurs that I would not consider on my dirt bike, look up "Smiley Rock Trail", the TW just motors thru those rock chutes.
Learn to really ride the TW, the lack of horse power, suspension and brakes will make you a better rider. I practice all my stupid stunts on the TW, low and slow hurts a lot less.
As I’ve said previously I’m not comparing to the KTMs, but to what others say about their TW performance. The off-road trail performance is fine because I do actually know how to ride a dirt bike. I’m not sure what you mean by “learn to ride a TW.” The weakness shows itself when riding on a road at speed. Many people report cruising at 60-65. My bike has a hard time just getting to 50-55. People describe the TW as a dual sport bike which would imply you could ride it on a highway at highway speeds. I’m not talking interstate speeds, but just comfortably riding at 55 would be nice.
 

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I'm not questioning your abilities, I meant that coming off powerful dirt bikes, I had to relearn to ride the TW as you cant simply wheelie over an obstacle with a flick of the wrist. You cant pick a poor line on a hill climb and power out of it and with 6" of suspension you quickly learn to pick smooth lines. It really has improved my skills.
 

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Discussion Starter · #46 ·
I have no complaints about it’s (or my) ability to negotiate difficult terrain. I bought it specifically for riding very loose, rocky, steep, sandy, bouldery areas in the Bradshaw mountains and surrounding desert. It’s the perfect bike for that. I use it instead of a quad or in places where I couldn’t even get a quad. My KTMs don’t like going slow. Their suspension is set up for going fast. The low seat and low center of gravity of the TW along with the soft suspension are some of the reasons I bought one. I can just paddle my way along through the rocks if necessary. I put a Tusk rack on the back to carry my crap for adventures.

I'm not questioning your abilities, I meant that coming off powerful dirt bikes, I had to relearn to ride the TW as you cant simply wheelie over an obstacle with a flick of the wrist. You cant pick a poor line on a hill climb and power out of it and with 6" of suspension you quickly learn to pick smooth lines. It really has improved my skills.
 

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As most of us “long timers” with the TW have discovered, you first have to get used to the bike, and then meld your own abilities to those of the bike – it has to be a meeting of both, you can’t “force” a TW

Fred can get them to dance, Admiral can get them to stand up and be counted – for my part, I can (at least) get them to put a grin on my face

That’s what it’s all about – the rider accepting the bike, and the bike accepting the rider. It’s more about “faith” and less to do with coercion – a partnership, almost a meeting of minds

This whole “concept” is why the TW has such a close knit following – the TW is more than “just a bike”

(If you haven’t read it already), there’s a book called “Zen and the Art of Motorcycle Maintenance” – sure beat the heck out a Yamaha manual ……
 

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(If you haven’t read it already), there’s a book called “Zen and the Art of Motorcycle Maintenance” – sure beat the heck out a Yamaha manual ……
That’s a great book. It’s not about Zen, nor motorcycle maintenance, but a philosophical good read indeed.
 

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I think you have a problem with the motor in some way and that this is not normal. I'll quote you here why I think that:


You then jetted and adjusted valves and said that helped with low end.
But then you said this:


That contradicts what you said previously that the jetting and valve adjust:


Your gearing is going to lean towards less low end torque and need for higher rev launches, but I doubt it's enough that you have to rev the engine much to do so. Your gearing leans toward higher top end speed, which you are not getting.

So let's first confirm your sprocket gearing. You said:


Let's confirm what stock is first: 14/50 front/rear. So +1 up front is 15 teeth and -1 in rear is 49 teeth. Is that what you have?
Now let's go to the website Gear Commander and put in the TW200 years 87-13.
Leave the stock ratio as-is and modify the current ratio to yours at 15 and 49.
View attachment 231896

Now scroll down to the next chart and notice that the stock gearing at 55mph is turning the motor at 7200 rpm.
View attachment 231900

Now click on the "Current" tab and enter 6500 in the minimum rpm box. Notice the current gearing you have at 55mph is turning the motor at 6500 rpm. (Note: the ZERO rpm default has the top speed somewhere between 6300 and 7200 rpm for the speed we want of 55mph, so I adjusted the minimum rpm box to discover exactly how many rpms it takes to go 55 mph with your current gear ratio)

View attachment 231899

As these charts show, you are turning 6500 rpm at 55mph.
So from what I can see and read from your post, you have both poor performance in the lowest rpm range and the mid to upper rpm range. Just for clarification, a TW200 should be able to run reliabliy at 2,800rpm all day long grunting through rough terrain and at 3,000 to 4,000 climb anything short of near-vertical without stalling. These things really are goats when running right. Also for clarification, they should easily reach 8,000 rpm on flat ground. Both of these clarifications will not be affected by gearing, since I'm talking rpm, not mph. Most times you want to ride off road, you gear down so you can ride at a pace you can manage the terrain. Most times you want to ride on-road, you gear up so you can ride at prevailing speed limits without screaming the motor rpm.
In YOUR case, you have neither low end rpm grunt power nor upper rpm speed.

With that established, let's discuss why your bike is so weak at lower rpms to the point you can't even launch or ride off road without revving up the engine and why your top end speed can't get you to over 55 on the flats.

Obviously the top speed on the road is the first concern to keep from getting run over or being a hazard. At 55mph, your gearing has your motor turning 6500 rpm and that's topping it out. That is a problem. A BIG problem. The causes are many, but you alluded to one that I have been recently made aware of by a memeber here that goes by oldworld124, AKA John. John and I have been discussing the TW's performance as it relates to aging engine components and something he made me aware of is how valve springs get weak over time and what the result in performance it causes. In a nut shell, the springs have a set of specs that John has measured on a couple top ends and he's discovered that they age out over time and get to the point that they no longer are at their optimal tension. This results in what is called "valve float". Valve float happens when the valve train is moving so fast, the spring can not keep up with the rpm and the valves do not fully close under the current spring tension, resulting in a couple problems; one is a loss of performance, much like you are experiencing. Another is the floating valve that isn't seating all the way before the cam lobe goes to open it again can hit the piston as it comes back up to TDC. Since the valve is floating, this should not result in catastrophic engine failure, but can put a dent in the piston crown. I've got such marks on my piston and suspect I have weak valve springs. I also notice I cannot ride flat ground above 8000 rpm even though the motor will turn 9000 rpm in neutral and revving the throttle. I have no issue with low speed performance though, so let's just hold off on that for now.
What alluded me to the possibility that your valve springs are weak is the age and milage on your bike. At 15,000 miles and being an 18 year old motor, it's quite likely your valve springs are beyond spec.

There may be other reasons for the poor performance, things like the CDI is on it's way out, a clogged air filter, low engine compression, etc. But I'll assume you've checked the air filter and the air feed from under the seat to the filter is not blocked in any way. Mice tend to use this area to store and nest, and while the filter is clean, the intake can be obstructed. Engine compression should also be tested. A compression gauge off Amazon is cheap, under $25 and a great investment as a means of testing motor performance.
I will also assume, but mention anyway, that you have changed out the spark plug for a fresh one. It's not uncommon for them to develop cracks that can only show up at higher rpm and compression but work fine at other speeds. Some other things that can affect top speed performance are:
tire pressure
chain condition
engine oil vecosity
engine timing (set by the rotor and wood drift key, the key can break and the rotor move out of position.)
valve timing (set by the cam gear through the cam chain and can either jump a tooth if the cam chain tensioner is not set properly or the chain has stretched excessively)
Carb jetting, especially the pilot jet, tends to easily get blocked or partly blocked. If your bike runs better at half choke at higher rpm, then it's a possibility. Try setting the choke at half way while at speed and see if the top speed increases. If a throttle chop at top rpm results in a popping back-fire, it's definitely too lean.

I would start with the easiest of these possibilities and work my way up. But if I were a betting man, I'd bet that either the cam chain has jumped a tooth, stretched or isn't tensioned correctly OR that the valve springs are weak and need replacing.

Keep us informed what you find as you continue troubleshooting your problem.

P.S. Some folks here might loan you a spare CDI if you get to that point. It's a way to confirm the problem by isolating without having to spend a few hundred bucks.

** EDIT **
I want to add a couple other things:
fuel flow: make sure you have full fuel flow. A clogged filter in the tank could restrict fuel flow and prevent top speed. There's also a filter screen inside the carb at the float needle. To test, open the carb bowl drain screw and the fuel petcock on the tank. You should see a steady, robust flow of fuel coming out that hose. Be careful seating the drain screw and only close it lightly. Many have damaged the screw or bowl by trying to over tighten.

Also be sure you have good quality fuel. Flush the tank by removing it and turning it over. Allow to air dry and inspect it with a flashlight. It should be spotless.

While you are at it, add an in-line fuel filter.
Best reply EVER.!
 

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Checked the compression. 110. Seems kinda low. Maybe that’s the problem. It’s not smoking or burning oil so I’m going to guess it needs a top end. Any tips on parts? I’ve googled TW200 top end kits and haven’t found anything yet.
Yeah, I'd say that's pretty low.
When you tested compression, was the motor fully warmed up and did you hold the throttle wide open as you cranked?
Did you do a follow-up test with a little oil squirt in the cylinder? If so, what was the compression reading after?
If the compression rose, then likely rings. If not, likely valves.
 

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A couple things I would look at. Its totally possible the somewhere along the line someone put on a larger rear sprocket or smaller front sprocket to gear it to their own style of riding. I would go with the stock front and anywhere between the stock rear or a little smaller for a better top end speed. Also I don't know what elevation you are riding at. But these carburetors are elevation sensitive. But if its any consolation my TW also has a ton of NO power. LOL. Just saying. Its old 80's technology and that what you can expect.
 

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The TW is a trail bike with street legal accessories. Phenomenally easy to travel off road. Not safe on highways these days as it struggles to maintain even 55mph at a time where traffic travels well over 55mph. It’s only 200cc, low tech design. If you need to travel much on the highway, you bought the wrong bike. It’s not under powered, but is only 200cc designed in the 70s. As far as street use the units lack ABS which is a significant safety factor, though advantage off road. You’ll need to look hard at your needs to determine if a TW is going to work out. Currently there is still a strong market to sell a TW. Life’s too short and there is some amazing motorbikes out there to be compromising.
 

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arbolmano: you may be on an alternate cosmos; here trash-talking the TW on this, and at least one other thread.
 

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This is what happens when you walk on the dark side - the VanVan - it has claimed many victims ......
 

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Please no offense intended - But, I would not take that as "Trash Talking" Give the guy a little slack.
He is basically telling it like it is. The TW is a great little trail bike and it is very old-tech. It is a fun, very easy-to-ride little bike that nearly any person on the planet can sling a leg over and ride and probably be grinning. But in my opinion, It stinks on anything more than 40-50ish MPH.
It's a fun super simple bike. It does not have much power, half what my lawn tractor has, but it has just enough to do what it is intended for - fun and easy, little offroad, little on road. I really question in-stock form running and cruising at 65 mph as some have stated. I know mine really hates anything over 50ish.
That said - it is just my opinion and thoughts on the TW, which the poster above is also entitled to.
 

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Yeah, I'd say that's pretty low.
When you tested compression, was the motor fully warmed up and did you hold the throttle wide open as you cranked?
Did you do a follow-up test with a little oil squirt in the cylinder? If so, what was the compression reading after?
If the compression rose, then likely rings. If not, likely valves.
I would agree. Although I don’t know what compression should check at for the TW. Once you get under 90 or 100 you can have starting problems, and this isn’t too far above that. I second what you said about checking with the throttle wide open, and trying it a second time with a little oil to see if it’s the rings or valves.

Between that, 5,000 foot elevation and taller gearing, that would explain the low top speed. I have stock gearing and I’m at less than 1,000 ft., but I hardly have to rev it at all to take off from a dead stop. In fact I’m pretty sure I could take off at idle. Mine will top out at a true 70 mph (by gps not the speedo) but it’s revving it’s heart out at that speed. Again basically at sea level and stock gearing, which accounts for some of the difference. But I suspect not all of it.
 

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From memory, it's something like 140 to 150 on a good crisp engine - YMMV, it's not a precise art, and you have to take individual bikes into account

With a good tight fit, open the throttle wide, and crank the heck out of it - that should give you an accurate reading

Then squirt some heavy oil into the cylinder, and repeat the test above

If the two test runs vary due to the oil, this indicates worn piston rings - if there's not a lot of change, look at the valve closing first

Lack of compression plus the gear ratios would explain much ........
 

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According to a post from Admiral about 10 years ago it should be 128 PSI. However, not only does the throttle need to be held open, but on the CV carb, the slide needs to full up to get a decent read.
 

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My memory has been sent a slap - 128 it is (seriously thought it was higher)

The problem is - at 5000 ft, it's lower

Anyone got a slip stick ? .......
 
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