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Why do 4 strokes have two throttle cables???

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Whats the deal, why do we need two instead of one? Even on the fuel injected bikes there are always two...

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I tried searching on google and couldnt find a definitive answer but people were saying it is a safety precaution that can help you pull the throttle back closed if it gets stuck open. And they also said its more of a pull/pull system. When you open the throttle it pulls one cable raising the slide. Then when you close the throttle the other cable pulls it back shut. Im just quoting what I read.

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One to push, and one to pull. But i've always wondered why they felt it was necessary to add more complexity to a very simple design that had been in use for decades on 2 and 4 strokes.

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.. That way on street/roadrace bikes too. SAFETY. Cables can get hung up, in a crash if the steering stops on your bike are pushed in a bit from hard falls, the cable can often get caught between the frame and fork tube. This crushes the cable housing a bit, and the cable will bind. If a rock or something gets caught in the carb housing (if somehow the cover fell off) the spring won't close the carb slide.

The 2nd cable pulls the carb closed so it isn't stuck wide open. Let me tell you, on a road race bike at 165mph+ approaching a tight turn with little run off area, you want that piece of mind that if you close the gas.. it will close. I have seen some remove the 2nd "close" cable. I have a name for them.. "stupid".. but to each his own.

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its more of a carry over from road bikes, most mx racers just cut the return cable off so its only the puul cable for a lighter pull, and most have done it without any trouble

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....to add to Ron's post.

A 4S has extreme amounts of vacuum.

Because the intake occurs 1/2 as often as a 2S, it is not as steady an effect, more off....on....off....on.... A 2s would be more like off.on.off.on..off.

This strong 'pull' can cause a slide to 'stick' momentarialy.

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I has a friend who had a 02-03? crf450r whos throttle was sticky due to the wheels on the slide were worn. Having a pusher could save a disaster in that circumstance. Slide wheels seemed to be a very flawed design.

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The #1 answer.

....to add to Ron's post.

A 4S has extreme amounts of vacuum.

This strong 'pull' can cause a slide to 'stick' momentarily.

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You can make more money by selling 2 cables instead of one.

There you are!!!! the slid in a 4 stroke carb works just like a 2 stroke. Cable pulls it up and a spring pushes it down..... I've seen a few 4 strokes that removed the one cable.... worked just as good....

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There you are!!!! the slid in a 4 stroke carb works just like a 2 stroke. Cable pulls it up and a spring pushes it down..... I've seen a few 4 strokes that removed the one cable.... worked just as good....

No it does not. FCR carbs use a completely different slide actuation method than most 2 stroke carbs.

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What lead/head said.. they are NOT the same. Most 2t carbs have the single cable come in from the TOP directly above the slide with a large spring. 4t carbs have it on the SIDE and the "spring" is a coil that rotates a shaft that actuates the slide..

If you REALLY can "feel" the 2nd cable (and it is in good shape) you should be a surgeon as you have some damn sensitive digits. The spring in the carb is what returns the carb to closed UNLESS there is an issue where it gets stuck, at that point you would be wishing you had the 2nd cable to close the carb when you try.. Under normal circumstances the 2nd cable is NOT closing the carb, the spring within the carb is. How else would it "snap" closed when you open by hand on the throttle tube then LET GO.. ??

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.. That way on street/roadrace bikes too. SAFETY. Cables can get hung up, in a crash if the steering stops on your bike are pushed in a bit from hard falls, the cable can often get caught between the frame and fork tube. This crushes the cable housing a bit, and the cable will bind. If a rock or something gets caught in the carb housing (if somehow the cover fell off) the spring won't close the carb slide.

The 2nd cable pulls the carb closed so it isn't stuck wide open. Let me tell you, on a road race bike at 165mph+ approaching a tight turn with little run off area, you want that piece of mind that if you close the gas.. it will close. I have seen some remove the 2nd "close" cable. I have a name for them.. "stupid".. but to each his own.

That makes most factory 4t riders stupid? and me when i raced 4ts

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Why wouldn't they? They have extra strokes, extra maintenance, extra expense, they make extra noise, they are extra fragile and they require extra tracks because of the ones the get closed.

Extra throttle cable? Well, DUH! It must be the one that turns the annoyance level of the bike up.

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If you REALLY can "feel" the 2nd cable (and it is in good shape) you should be a surgeon as you have some damn sensitive digits.

Or lube the cables more often.:thumbsup:

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Why wouldn't they? They have extra strokes, extra maintenance, extra expense, they make extra noise, they are extra fragile and they require extra tracks because of the ones the get closed.

Extra throttle cable? Well, DUH! It must be the one that turns the annoyance level of the bike up.

Eureka!:thumbsup:

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1. make more money

2. the saftey reasons

everybody is always terrifyedof the trottle cable sticking well if it does pull in the clutch and kill it, DUHHHHH :thumbsup:

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