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Higher idle with new muffler

1186 Views 2 Replies 3 Participants Last post by  The Ring-In

I installed a Yoshimura RS-3 muffler on my 1998 TLS and the bike sounds much better. I noticed that the idle is higher now when the engine is hot, around 1,500 rpm and turning the idle adjuster screw does not do anything.

Does the different muffler (I took out the baffle) make the engine run leaner which would result in a higher idle speed?
Wouldn't the ECU compensate for the freer flowing exhaust? Do I have to get a PowerCommander to adjust air/fuel mixture...?

Thank you in advance for any insights!
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A new exhaust, or even mufflers, will affect the fuel mix, and often impact the idle speed slightly - just as you have seen.

Even so, the idle speed screw should still raise and lower the idle speed because it merely opens or closes the butterflies to accomplish the task. You'll want to take a closer look at its attachment point on the throttle linkage. It is possible to back it out too far which allows it to completely disengage from the bracket. It will still turn, but it is not changing the throttle position.

If the adjuster is still connected properly, check all the vacuum lines for possible leaks. Also recheck the TPS setting and TB balance.
there is a low limit set screw on the throttle bodies. ( maybe even one on each butterfly )

you can lower this slightly to extend the range of the normal adjuster
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