700 understanding fast idle circuit and idle stop. stuttering at idle - Yamaha Raptor Forum
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post #1 of 5 (permalink) Old 11-27-2012, 10:29 AM Thread Starter
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700 understanding fast idle circuit and idle stop. stuttering at idle

I am very familiar with injection system but it seems the manual for the 700 is worth it's weight in dog shi* on this... From what I can see, what they call the "idle screw" is actually an idle air needle valve? The stop screw is not even discussed in the manual..

Anyway, I just rebuilt one for a guy and it has the baffle removed, K*N filter with lid still on, and it is pretty cold here now. All things that may be causing a lean condition. Seems to run OK up top but idle stutters a bit and will buck at about 1/8-1/4 throttle cruise. I know I can sort of lie to the TPS with adjustments and have been all over the map and nothing is making it super happy yet.

I have the values of .68-.72V at 0% throttle off the TPS but not sure if the idle air needs adjusted or what. The "fast idle" circuit is vaguely discussed so not sure if this is purely an enrichment circuit for cold start or what?

I should add that a pure cold start is very clean and sounds perfect. As bike warms up, it will start to pop a bit at idle. As it warms more, it wants to die at idle so if idled down, the idle will just keep dropping until it dies. Almost like the bike is trying to adjust for something and cannot get it done. I have checked the TPS every way but Tuesday and cannot find a thing wrong with it. I am hoping the baffle being out of the muffler is really throwing the map off.

Last edited by fastline; 11-27-2012 at 10:40 AM.
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post #2 of 5 (permalink) Old 09-18-2019, 07:07 AM
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Did you ever figure out the problem, I’m having same issue now with my raptor
post #3 of 5 (permalink) Old 09-18-2019, 08:27 AM
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The quad idles fast until coolant starts moving. the coolant runs through the throttle body when it is moving and switches it so its a slower idle. Could be stuck maybe?
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post #4 of 5 (permalink) Old 09-18-2019, 07:12 PM
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Originally Posted by [email protected] View Post
Did you ever figure out the problem, I’m having same issue now with my raptor
You won't get an answer from fastline. Last time he was on was February of 2003.

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post #5 of 5 (permalink) Old 09-18-2019, 11:19 PM

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Originally Posted by [email protected] View Post
Did you ever figure out the problem, I’m having same issue now with my raptor
This was originally posted by DL700 (Cuervo Racing) and explains all the steps to properly setup your TB. I followed these steps when swapping to a new +3 TB and mine has run flawlessly for years and years.....

Originally Posted by DL700

Raptor 700 throttle bodies 06 and up, may apply to other similar models as well.

Setting up and adjusting a throttle body can be very easy when the correct steps are followed and in the correct order, doing so will result in a smooth consistent idle and easy starting.

We will go thru from the basic setup, say you switched to a bored throttle body or aftermarket unit, these are the steps to follow to ease setup...

To set BASE idle perform with a warm engine

Step 1: Back out the AIR BYPASS SCREW all the way until no tension is on the keeper spring.

Step 2: Adjust IDLE STOP SCREW, start by loosening 10mm jam nut, then use a flat blade screw driver to adjust idle speed to a very low idle 1350-1450 rpm range where the motor feels like it is about to die

Step 3: Adjust the TPS (throttle Position Sensor) to the .68-.72 VOLTS, or using OHM's set to .70-.74 OHM

Step 4: Adjust AIR BYPASS SCREW in to raise idle to appropriate speed 1600-1700 on Stock motors, 1650-1750 on mild modified motors with aftermarket cams, and 1750-1850 for Built motors with high compression and large cam profiles

a few notes:

Aftermarket throttle bodies without the sir bypass will have the idle speed adjusted solely by the IDLE STOP SCREW. Adjust idle speed when warm to 1800 rpm

Every time the IDLE STOP SCREW is adjusted the TPS should be adjusted

The air bypass screw should be able to take the motor from a very low idle to a very high idle in its proper operating range, if it does not have this affect then the IDLE STOP SCREW should be readjusted

TPS adjustments using VOLTAGE should be done with a fully charged battery using the negative V.O.M.(volt/ohm meter) lead to the negative battery post and the positive lead to the center wire on the Tps

TPS adjustments using OHMS should be done with the TPS connector unplugged and the two leads on the top and center pins of the TPS

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