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Discussion Starter #21
The darker plug is my original plug. The lighter one is the one I just bought and rode home with.
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Oh hell no. I moved here for that exact reason. I live in an outdoor paradise high up in the mountains.
Haha! I was just kidding. You said you lived in a small town and didn't see speeds above that. I was trying funny that if you moved to a big town your tw would go faster. Lol
 

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Not sure what is happening. On a flat road with no wind, my TW tops out at 55 mph. I am running 15/50 sprockets and weigh 175 lbs. At 8000 ft with stock jetting and fuel screw out 2 turns. Bike feels great up to 45 mph. I live in a small town and don't see speeds much more than that. My plug looks like it could be lean or rich and i'm not sure how to tell. I was running a pod filter but just got the parts and got my air box back together and reinstalled on the bike. Any suggestions would be great.
I think at that altitude, you'll need to drop to about a 125 main jet. maybe smaller. Air is thinner up there, so even when you dial in the jetting, you won't have the overall performance as sea level. Your filter is also less restrictive, so I'd estimate at the very least, a 125 will either get you there or pretty damn close. I see you ordered a 122. If you experience any backfiring, you'll know you've gone too far. As for reading a sparkplug, do keep in mind, the only way to really read it right is to install a fresh plug, run it and check right away. Good luck!
 

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Just a couple of comments: first, rule of thumb is 3% power loss per 1000' elevation, at standard temp, barometric pressure, humidity (air density). You've lost 24% of power on a standard 59 degree F day. Up the temp to summer temps and you lost more. You may have lost 30% right there.

You've changed the gearing "taller" which lost some torque which is just compounding the power loss from altitude. That's about 7% torque loss over stock gearing. Now your getting close 35-40% power loss total.

Carburated engines run richer as they go up in elevation because there are less air molecules per cu ft. The tw has a CV carb so it does compensate a bit for altitude, temp, and air density in general, to a point. You might be above "that point" but I don't know where "that point" is on those carbs.

To try to get more speed, I'd drop that 15 back to a 14 tooth front and keep the 50 rear to get that 7% torque back. I'd check the plug reading to see if you are rich or lean.

I've never experienced a black plug on lean, only on oil fouled or carboned-too rich running. Brown or tan is good. I shoot for light tan when I setup a carb. White to very light gray is lean and or hot, darker gray is OK but I'd richen it to tan. Black chunks building up can be too rich or too cold.

I rode my 01 last night at 4800' and 94F here on WY. I have stock gearing and it hit 70 mph, albeit the engine was screaming. I have a Chinese carb as that came on the bike as the PO threw the oem carb away instead of cleaning it. My sparkplug is tan.

My $. 02.
Jay Dub
Funny enough, my PO also installed a Chinese carb and gave me the OEM carb. Funny thing is, other than being a bit lean at the moment, the Chinese carb is doing remarkably well. Usually, I'd toss it, but I might just milk this thing and see how it lasts.
 

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Not sure what is happening. On a flat road with no wind, my TW tops out at 55 mph. I am running 15/50 sprockets and weigh 175 lbs. At 8000 ft with stock jetting and fuel screw out 2 turns. Bike feels great up to 45 mph. I live in a small town and don't see speeds much more than that. My plug looks like it could be lean or rich and i'm not sure how to tell. I was running a pod filter but just got the parts and got my air box back together and reinstalled on the bike. Any suggestions would be great.
Just me maybe but I don't much enjoy riding the TW over 55 and the bike isn't too happy there either. As someone else once wrote, The TW is slow but the Earth is Patient.
 

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Discussion Starter #28
Just me maybe but I don't much enjoy riding the TW over 55 and the bike isn't too happy there either. As someone else once wrote, The TW is slow but the Earth is Patient.
Where I live is an outdoor paradise. The next nearest towns are over 30 min away in each direction. To leave my town there are only four roads out. All but one would require me to at least cruise at 60 mph. I just want to expand my exploring.
 

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Not sure what is happening. On a flat road with no wind, my TW tops out at 55 mph. I am running 15/50 sprockets and weigh 175 lbs. At 8000 ft with stock jetting and fuel screw out 2 turns. Bike feels great up to 45 mph. I live in a small town and don't see speeds much more than that. My plug looks like it could be lean or rich and i'm not sure how to tell. I was running a pod filter but just got the parts and got my air box back together and reinstalled on the bike. Any suggestions would be great.
Your issue is quite simple. At 8,000 ft and with little or no oxygen it is a miracle that you and the motorcycle are running. Have someone familiar with high altitude show you how to adjust the carburetor. If you plan to ride at lower elevations, you will need to change the settings back. There is not enough oxygen at 8,000 ft to burn the gas you are putting into the motorcycle. Try running a few miles and see if you don't have oxygen issues yourself.
 

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Z
Your issue is quite simple. At 8,000 ft and with little or no oxygen it is a miracle that you and the motorcycle are running. Have someone familiar with high altitude show you how to adjust the carburetor. If you plan to ride at lower elevations, you will need to change the settings back. There is not enough oxygen at 8,000 ft to burn the gas you are putting into the motorcycle. Try running a few miles and see if you don't have oxygen issues yourself.
With factory settings almost all carburator vehicles run like crap at 8,000 ft. They won't start, and barley run at 9,000 ft.
I would leave the gearing alone since you can simply downshift as needed. You can drill holes in the air box to install aftermarket vents for more air, keeping in mind that water will then be a possible issue.
 

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Errtu, have you checked to be sure your rear brake is adjusted properly? Sounds odd, but this happened to my son the first time he tightened his chain and failed to loosen the rear brake - riding around with the rear brake applied he couldn't get his tw over 55 either. He was sure happy when the brake was adjusted and his bike was back to normal. It happens.
 

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Discussion Starter #32
Errtu, have you checked to be sure your rear brake is adjusted properly? Sounds odd, but this happened to my son the first time he tightened his chain and failed to loosen the rear brake - riding around with the rear brake applied he couldn't get his tw over 55 either. He was sure happy when the brake was adjusted and his bike was back to normal. It happens.
I will check the rear brake but the last time I had the bike up the rear tire spun freely.
 

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I will check the rear brake but the last time I had the bike up the rear tire spun freely.
When you sit on the TW-200 the rear swing arm can radius and possibly tighten the rear brake. Also check the rear brake pedal for free play. I still recommend finding someone familiar with the high altitude to help you with the correct carburator settings. Don't expect to much from that small mother at the higher altitudes.
 

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Just a couple of comments: first, rule of thumb is 3% power loss per 1000' elevation, at standard temp, barometric pressure, humidity (air density). You've lost 24% of power on a standard 59 degree F day. Up the temp to summer temps and you lost more. You may have lost 30% right there.

You've changed the gearing "taller" which lost some torque which is just compounding the power loss from altitude. That's about 7% torque loss over stock gearing. Now your getting close 35-40% power loss total.

Carburated engines run richer as they go up in elevation because there are less air molecules per cu ft. The tw has a CV carb so it does compensate a bit for altitude, temp, and air density in general, to a point. You might be above "that point" but I don't know where "that point" is on those carbs.

To try to get more speed, I'd drop that 15 back to a 14 tooth front and keep the 50 rear to get that 7% torque back. I'd check the plug reading to see if you are rich or lean.

I've never experienced a black plug on lean, only on oil fouled or carboned-too rich running. Brown or tan is good. I shoot for light tan when I setup a carb. White to very light gray is lean and or hot, darker gray is OK but I'd richen it to tan. Black chunks building up can be too rich or too cold.

I rode my 01 last night at 4800' and 94F here on WY. I have stock gearing and it hit 70 mph, albeit the engine was screaming. I have a Chinese carb as that came on the bike as the PO threw the oem carb away instead of cleaning it. My sparkplug is tan.

My $. 02.
Jay Dub
Bingo! After working in a Yamaha dearship for 35 years I'll bet it is jetted too rich. Check with a dealer at your elevation for recommendations.
 

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Discussion Starter #36
Bingo! After working in a Yamaha dearship for 35 years I'll bet it is jetted too rich. Check with a dealer at your elevation for recommendations.
I have a 122 main jet on the way.
 

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Really, not over 45... Unless you want vibration protest...
Vibration?
Ride a pre 2004 1200cc Sportster at 80 MPH for an hour...after that nothing will seem to vibrate!
 
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