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Oct 12

Posts: 1

eurouk says:

Engine Number anomaly (cat B??)


I bought my bike from a dealer just over a year ago. It was my first purchase and somewhat naively I just took it for a test ride, and bought it without checking the engine number - reason being it came with a warranty so I thought that would cover me.

Now that I am coming to sell the bike, I checked if the engine number matched the V5 logbook, and it doesn't.

Furthermore, there is a label on the exhaust pipe, just in front of the engine that mentions category B.

I've checked the HPI and there's no mention of anything there, it all checks out fine.

I'm puzzled as to what has happened to it. It seems either:

-  to have have had a replacement engine fitted before I bought it, but which was never updated in the V5 logbook (perhaps the engine may have come from a cat B motorbike)

- it was a category B itself, but somehow has managed to avoid being registered as one (surely this is unlikely, given that the VIN number would show up in the HPI check)


Questions I had are:

- How can I find out exactly what the history of the engine saga is?

- How can I update my V5 logbook, given that I did not change the engine and have no idea when it was put in, I have no supporting paperwork or invoice ?

- How should I answer questions from buyers regarding the change of engine, as I don't know why it was changed in the first place?


Thanks for your help,






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  • Posted 2 years ago (04 October 2012 08:01)

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Mar 09

Posts: 8930

jaffa90 says:

Cat B

Sounds like the engine was from a cat B,

You cannot put a cat B back on the road.

The V.I.N. number comes with the frame so i would update details of the engine number.

Please note i`ve never experience this. 

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Apr 08

Posts: 3042

AdieR says:

What bike

is it? Age / mileage?

Cat A has to be destroyed in it's entirety, Cat B is unfit to go back on the road, but any salvageable parts may be re-used / sold.

I'm thinking the same as Jaffa, your motor has been replaced with a Cat B, for whatever reason.

How many owners has the bike had?

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