ZEPHYR550/400 – Reusing the secondary air pump with “forced decompression” inside the crankcase for high performance!

I’m working on this between jobs (*´ω`*)
This is actually from a bit earlier.

This secondary air pump is a really nice system.
It would be such a waste to cut it out.

Please note that emission-controlled bikes cannot have it removed.


First, let me introduce the materials I gathered!
Hose and blowby extraction adapter

T-REV 1953 M30-P1.5 14φ Blowby extraction adapter
The ZEPHYR550/400 has an oil filler cap thread size of M30-P1.5
I chose the thickest hose available.

When installed, it looks like this
and it does give off a bit of“young vibes”.

I found an interesting hose.
It’s silicone with reinforcing thread inside – very durable.

It’s thick but surprisingly flexible and looked interesting, so I bought it.
uxcell Silicone Vacuum Tube Heater Hose
14 mm Inner Diameter 1 M 101psi 392F Blue Reinforced High Temperature Engine Hose


The only colors available are“blue and red”which is a bit limiting…

The internet is amazing – I’m amazed by it every day ( ;∀;)
I’ll continue this in the next blog post!

(‘◇’)ゞ The ZEPHYR550/400 is so much fun!
*Though I haven’t registered it yet…

テラモト(TERAMOTO)
¥6,397 (2026/09/20 12:33時点 | Amazon調べ)
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