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So is the Rt Carb really all it's cracked up to be?

The ins and outs - carburetors, manifolds, mufflers, expansion chambers and more to keep your motorized bicycle running the way you like


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Old 09-14-2011, 03:38 PM
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Default So is the Rt Carb really all it's cracked up to be?

I've been looking at various carbs and comparing pros and cons. I hear great reviews about the RT carb- better pulling power and high end performance than the NTs. My question is is it worth the $30 to replace my old NT carb with an RT?

The CNS seems to cause to many problems for most people and I hear the RT "blows the CNS out of the water". Does the RT really perform this much better?

I will have an SBP expansion pipe by the end of the week- does the RT perform good with the pipe?

And one more question- will I need to modify my intake manifold(if the RT is a larger diameter carb then I would benefit from a larger intake manifold)
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Old 09-14-2011, 08:25 PM
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Default Re: So is the Rt Carb really all it's cracked up to be?

The RT is a good carb but it needs to be jetted way smaller for HT engines.
I've found that the RTs have a really crisp mid throttle cruising feel.

The stock NT carbs also work very well if you jet them smaller... Some of the fastest bikes i've ever seen run the NT carbs!
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Old 09-14-2011, 08:42 PM
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Default Re: So is the Rt Carb really all it's cracked up to be?

Your stock intake manifold will work fine with the RT. No need to increase the size.
It's been my experience that the plastic sleeve that comes in the RT needs to be sealed to the intake manifold. I ran them for a while without sealing but then they developed some air leaks. I used Seal-All, gasoline resistant sealer and no more problems.
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Old 09-14-2011, 08:46 PM
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Default Re: So is the Rt Carb really all it's cracked up to be?

Thank you Venice!
So the thing I'm looking for most is some low end torque for getting around the mountains here- it sounds as if both carbs are good for speed- are either any better for low end?

Also why is the slide on the RT flat? I'm curious to know the benefits of that.
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Old 09-14-2011, 08:53 PM
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Default Re: So is the Rt Carb really all it's cracked up to be?

2door- Yesterday i opened up the end of my manifold a little with a dremel for better intake- and these manifolds aren't able to be wide enough to match the port because of their small diameter. So my thoughts were to expand the end of the intake(maybe a larger pipe) to match the port, but that wouldn't be worth it because the manifold will still wind up at the same diameter because of the small carb- so no benefit. So it seems to match the size of the port , you would need a larger carb, and then you would be able to increase the intake manifold's diameter to match the size of the intake port, offering more power because of increased intake.
That's why I was asking whether it would be a good idea to get a bigger intake manifold with the larger carb.
So is all my thinking there wrong? What do you guys think?
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Old 09-14-2011, 09:12 PM
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Default Re: So is the Rt Carb really all it's cracked up to be?

A better carb than the RT is available off Treatland, but is out of stock at the moment. Personally, I'd reccomend that you pay more and get a real dellorto. I have an RT and while it runs well, it has an aggrivating air leak, and isn't all that tunable. I've been looking at Walbro carbs as a possible solution, but haven't found the right one.

Check out www.treatland.tv moped parts superstore and look at their carb selection.
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Old 09-14-2011, 11:03 PM
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Default Re: So is the Rt Carb really all it's cracked up to be?

I'll repeat this... "some of the fastest bikes I've ever seen have NT carbs".
You should try installing a size (or two) smaller jet first! (It's cheap enough, & you might really like what you get!)
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Old 09-15-2011, 09:46 AM
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Default Re: So is the Rt Carb really all it's cracked up to be?

I used the NT carb for about 6 months, I had it jetted and dialed in perfect. Then Duane released the RT carb, I bought it to see if it would be worth it. Since then I have not taken the RT carb off. It is definitely smoother through-out the RPM range and has better top-end fuel delivery then the NT (no sputtering). It has a staged jet and flat slide instead of a needle, clip, and barrel slide. If you compare the 3 carbs side by side (price, performance, reliability) the RT in my opinion will win. You can't beat the Performance and reliability for only $30.
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Old 09-15-2011, 09:50 AM
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Default Re: So is the Rt Carb really all it's cracked up to be?

Quote:
Originally Posted by F_Rod81 View Post
I used the NT carb for about 6 months, I had it jetted and dialed in perfect. Then Duane released the RT carb, I bought it to see if it would be worth it. Since then I have not taken the RT carb off. It is definitely smoother through-out the RPM range and has better top-end fuel delivery then the NT (no sputtering). It has a staged jet and flat slide instead of a needle, clip, and barrel slide. If you compare the 3 carbs side by side (price, performance, reliability) the RT in my opinion will win. You can't beat the Performance and reliability for only $30.
Works really good with the manic ported intake.
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Old 09-15-2011, 07:40 PM
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Default Re: So is the Rt Carb really all it's cracked up to be?

https://www.treatland.tv/SHA-15mm-cl...lone-cable.htm
They're sold out for now, but I've seen one of these carbs in person. I may buy one off my local moped shaman tomorrow though. Mixture Screw, and quality looks way better.
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