modifications and the law

Hi all,

I always been fan of modified bikes ( like cafe racer style, scrambler…) and yesterday i saw a kawasaki special, sort of scrambler style that was amazing…

Can you tell me what the law says here in uk?

In Italy every modification should be updated in our equivalent of V5 and it’ very very hardto do this, since you should pass all the safety and approval and all that…

we all take the risk, when is only a race can or similar you can hope in the cops having sympathy and let you go, but a proper special will not pass at all…

what’s the law here in uk?

all i could find was this, from

The DVLA must always be informed when you’re making the following modifications:colourengine sizecylinder capacityreplacement or modifications of chassis or body shellframe number

You’ll probably find two different standards. The DVLA only need to know of the above changes but your insurance company ask you on modifications. Again it all depends on the insurer but for some you even have to declare things like Heated Grips! (well they’re on their lists of mods). Technically you should declare them all to the insurer…if only to not give them any wiggle room to not pay out.

Personally I would only declare something that has a performance upgrade or a value increase so that they don’t come back in the event of a claim to say: “well your bike can go faster because of that, therefore that’s why you lost control”. You may find that if it puts the value up, they increase your premiums.

Having said that ebike gave me money back for declaring R&G (brand specific) crash bungs but I have never heard of anyone else doing that.

Be aware that when not declaring things, in an event of a claim, you will not get them retribution if they are damaged

Hope this helps and hopefully someone with a little more ‘certainty’ in their response can further clarify :slight_smile:


yeah i’m also with ebike and for example I told them about the aftermarket indicators, but the premium didn’t go up only they told me that in case of a claim the indicators will not be refunded, since modified…

Ok for insurers, but what about the police?


I’m thinking of doing a special based on a Honda Dominator, which has 21 front wheel, if i want to fit a 17 in italy it would not be allowed as in the V5 it only says, approved only with 21 inches front wheel…

but here, there is no mention on the v5 of all these details…

Better wait for someone more clued up than me to comment on the legality of something like that

I’ve never been one for much tinkering :smiley:

If say I “mod” my Kawasaki 650r down to a 598cc would I pay less tax?

if that’s below the tax break then I don’t see why not.