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Gizmo between Exhaust and carby

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No, not the motor.

On a DRZ400S year 2003

What is the Mikuni component mounted at the lower left hand side of the motor towards the front.

It has a small vacumn ? line going to the carby and a pipe going to the exhaust maniofold

What does it do ?

Can it cause problems

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dont have one on mine. sounds like the air injection system on some other models (Japanese or European). With the right instructions it can be taken off and the holes plugged. I don't know how to do it. For now keep everything hooked up to avoid air leaks in the intake.

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Thanks for that

I just searched TT under Air Injection System(PAIR) and found some more info.

My DRZ is a Japanese model, I believe US models dont have it.

I have an FMF exhaust and the bike is backfiring

Apparently the PAIR can contribute to this.

Can I disable it by just blocking the vacuum line from the carb or must I block all the PAIR ports ??

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Yes. Disable by just blocking the vacuum control line at the carb.

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Yes it is the pair valve, and yes it will cause lots of popping on the overrun

with an after-market exhaust.

Remove it completely, block the vacuum connection at the carb, and block the end of the steel tube.

It also has a tendance to inject water in to the exhaust, as the inlet is behind the sump guard.

Several ways to do this, if you run an M8 tap up the pipe you can use an M8 bolt, sealed with high temp gasket glue, I used Hylomar Blue.

Remove the pipe at the head and make a blanking plate.

Or tap the hole in the head to M6 and use a bolt, best done when the head is off.

All will work, as will a bolt in the end of the short rubber hose on the end, but it will blow off (sounds weird), best and easiest is the M8 bolt up the end.

Neil. :thumbsup::ride::applause:

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