Ignitions and Electrical› Ignition Boxes and Components
Big Gun
Big Gun 99-04 Honda XR 400 Rev Box
SKU: B0AC 40-R15
Moderate — 2–4 hours
Description
Part #: 40-R15
If you are looking to swap out the stock CDI box, the Big Gun Over Rev Box is an affordable alternative to highly-priced OEM replacement boxes. It increases the overall RPM limit over the stock box and advances the timing curve.
MIA's Description
This product is designed as a direct plug-in replacement for the stock CDI unit.
Fitment
Fitment Guaranteed
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Log your build in the MOTORMIA app and we’ll guarantee this part fits your exact setup — or your money back, return shipping covered.
Available on iOS & Android
Specifications
| Brand | Big Gun |
| Part Number | B0AC 40-R15 |
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Buy with Confidence
Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.
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