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Discussion Starter #1
I just wanted to post what my top speed was with my 2004 TW200.
My mods are as follows:
49 Tooth rear sprocket
DG Muffler
132 main jet
2.5 turns out on air
1 shim on needle
Air Box "opened" up on top with snorkel removed
Air Box "screen" removed
JimBo windshield
Tusk Hand Guards
Rider is 150lbs and was hugging the gas tank.

I managed to squeeze 78- 78.5mph (don't think I hit 79) with these mods as listed.

The tach showed 10100 rpms! Yes she was humming at that those rpms!

I'm attaching a pic of my RPM gauge, When I switch the bike off, It displays the may rpms during that ride.

:)





 

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Wow nice! My 1998 isn't nearly that fast and I can't figure out why. My performance related mods are as follows.

115 main jet
Uni pod filter
DG muffler
Kenda K270 front tire at 18 or so psi
Slightly raised compression
I weigh 200 lbs, and was tucked against the tank

A couple days ago, at sea level I maxed it out and got to 67 mph. After 60 mph it started getting really wobbly, and by the time I got to 67 I couldn't stop the wobble with all my strength, I had to just keep it at a controllable level until I slowed down past 55. I'm not sure if it was low tire psi or what. I get to ride on pavement maybe once every couple months, so it's not a big deal.


Zack
 

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Slightly raised compression?
 

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I'm really curious - are these speeds an anomaly? I have an '87 and it's been abused for decades. From the minute I got it running though, it's been able to hit ~75mph. It takes a little bit and I have to lean forward a hair, but it hits 75. I always hear people saying their bike maxes out in the mid-60s... My 1991 also gets above 70mph, but just barely. Is this a thing because of the old slide carbs? Maybe I just have bad speedometers that overestimate my speed.

To the OP - how loud was your DG exhaust at that speed? That tachymeter looks amazing, that is going on my wishlist for sure!
 

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Lol it was a little experiment to see if I could get more power. I took off the cylinder, and removed the base gasket and used silicone, which lowered it. My compression went from 125 psi, to 160. Definitely pulled better throughout the entire rpm range. It sounded quite a bit louder also from the higher compression. The thing that I didn't realize at the time was that over time, the rings had worn down the cylinder ever so slightly. Now when I move the cylinder down, the piston moves higher in the cylinder, and bumps over the slight edge created by the rings previous position. There is also a carbon deposit that you need to scrape off the walls of the combustion chamber. Ever since I did the mod about 3 months ago, there has been an audible ticking noise from the top ring as it bumps over the edge. Compression has also fallen from 160 to about 135 now. I think it's wearing that ring out. Another problem is that I can not get the silicone to seal in the base gasket. I tried 3 different kinds, then decided "forget it, I'm gonna try epoxy". Well, guess what, it still doesn't seal. I think I'm going to just order a new base gasket and rings, and forget about the extra power. It comes at a high price. I always like functionality over performance, and this isn't turning out to be very functional.

Zack
 

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I'm really curious - are these speeds an anomaly? I have an '87 and it's been abused for decades. From the minute I got it running though, it's been able to hit ~75mph. It takes a little bit and I have to lean forward a hair, but it hits 75. I always hear people saying their bike maxes out in the mid-60s... My 1991 also gets above 70mph, but just barely. Is this a thing because of the old slide carbs? Maybe I just have bad speedometers that overestimate my speed.

To the OP - how loud was your DG exhaust at that speed? That tachymeter looks amazing, that is going on my wishlist for sure!
The 87's were faster and more powerful than any other models. They had to tone them back in 88 on, cause folks couldn't handle the power and top end. ;) Mine's a 87 too. Wicked fast bike.
 

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Lol it was a little experiment to see if I could get more power. I took off the cylinder, and removed the base gasket and used silicone, which lowered it. My compression went from 125 psi, to 160. Definitely pulled better throughout the entire rpm range. It sounded quite a bit louder also from the higher compression. The thing that I didn't realize at the time was that over time, the rings had worn down the cylinder ever so slightly. Now when I move the cylinder down, the piston moves higher in the cylinder, and bumps over the slight edge created by the rings previous position. There is also a carbon deposit that you need to scrape off the walls of the combustion chamber. Ever since I did the mod about 3 months ago, there has been an audible ticking noise from the top ring as it bumps over the edge. Compression has also fallen from 160 to about 135 now. I think it's wearing that ring out. Another problem is that I can not get the silicone to seal in the base gasket. I tried 3 different kinds, then decided "forget it, I'm gonna try epoxy". Well, guess what, it still doesn't seal. I think I'm going to just order a new base gasket and rings, and forget about the extra power. It comes at a high price. I always like functionality over performance, and this isn't turning out to be very functional.

Zack
I think that was a mistake to do that. The wobble? Tire balance? What were your tire pressures?
 

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I hardly ever check my psi. I fill it by feel and adjust it by feel. That is for off road though. I should have aired them up tighter for high speed.

I don't think it was a mistake. If nothing else, it gave me a lot of knowledge about how my engine works, what to do and what not to do, and many other things. The way I most like to spend my spare time, is wrenching on my bike. Believe me I put some time into taking the engine apart and putting it back together at least 10 times during testing and diagnosing. Piles of fun! I also now know that an actual base gasket is better than silicone, although, maybe next time I'll try cutting a cereal box gasket. Lol

Zack
 

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Discussion Starter #10
craig0ry,
Truthfully at a point the DG exhaust doesn't change in a lot of its tone. It still has its nice little thump to it but I think I was focused
mostly on the speedo (no gps used) and the sound of the engine itself. It was a nice little sewing maching sitting under me!






I'm really curious - are these speeds an anomaly? I have an '87 and it's been abused for decades. From the minute I got it running though, it's been able to hit ~75mph. It takes a little bit and I have to lean forward a hair, but it hits 75. I always hear people saying their bike maxes out in the mid-60s... My 1991 also gets above 70mph, but just barely. Is this a thing because of the old slide carbs? Maybe I just have bad speedometers that overestimate my speed.

To the OP - how loud was your DG exhaust at that speed? That tachymeter looks amazing, that is going on my wishlist for sure!
 

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Discussion Starter #11
Zack,
Would it be possible for you to Hone the cyclinder some and get rid of that piston "lip"?
What octane did you use for the extra compression?
Are you sure the ticking noise was detonation?




Lol it was a little experiment to see if I could get more power. I took off the cylinder, and removed the base gasket and used silicone, which lowered it. My compression went from 125 psi, to 160. Definitely pulled better throughout the entire rpm range. It sounded quite a bit louder also from the higher compression. The thing that I didn't realize at the time was that over time, the rings had worn down the cylinder ever so slightly. Now when I move the cylinder down, the piston moves higher in the cylinder, and bumps over the slight edge created by the rings previous position. There is also a carbon deposit that you need to scrape off the walls of the combustion chamber. Ever since I did the mod about 3 months ago, there has been an audible ticking noise from the top ring as it bumps over the edge. Compression has also fallen from 160 to about 135 now. I think it's wearing that ring out. Another problem is that I can not get the silicone to seal in the base gasket. I tried 3 different kinds, then decided "forget it, I'm gonna try epoxy". Well, guess what, it still doesn't seal. I think I'm going to just order a new base gasket and rings, and forget about the extra power. It comes at a high price. I always like functionality over performance, and this isn't turning out to be very functional.

Zack
 

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Discussion Starter #13
Zack,
On your top speed issue.
You should be able to run a larger main jet and adjust your needle up some. Also try removing your snorkel from the airbox for more air flow,
Make sure both tires are aired up to around 20psi.
You weight will also play a pretty big factor in the performance of that bike,
At 150lbs, I have a great advantage over you, Even less wind drag if you will.





Wow nice! My 1998 isn't nearly that fast and I can't figure out why. My performance related mods are as follows.

115 main jet
Uni pod filter
DG muffler
Kenda K270 front tire at 18 or so psi
Slightly raised compression
I weigh 200 lbs, and was tucked against the tank

A couple days ago, at sea level I maxed it out and got to 67 mph. After 60 mph it started getting really wobbly, and by the time I got to 67 I couldn't stop the wobble with all my strength, I had to just keep it at a controllable level until I slowed down past 55. I'm not sure if it was low tire psi or what. I get to ride on pavement maybe once every couple months, so it's not a big deal.


Zack
 

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George,
Yes I think it would be easy to hone the cylinder. I don't have a honing tool, and I don't live close to anyone that does though.
I wrote that my jet was 115. I made a mistake. That is my high altitude jetting for where I live. At sea level I go up to 117.5. That is what I had in it at the time. As for the air box snorkel, I'm not even running through the air box. I've got a Uni pod filter attached to the end of the carb. I just ran 91 octane and it was fine, with no detonation, as long as I kept my jetting a little on the rich side.

Zack
 
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