Skip to Content

Modified Motorcycle Insurance – Is Your Bike Legal?

Whether you have swapped out the factory exhaust for a set of aftermarket pipes, given the bodywork a custom paint scheme or had the engine tuned, you should be aware you probably need to contact your broker and arrange modified bike insurance.

Which Bike Modifications Effect Insurance Premiums?

Most brokers will have a list of acceptable modifications that you don’t need to declare. For instance, in the example above I used an aftermarket exhaust system. If it’s a like for like replacement due to damage or wear then you don’t need to declare it. If it’s none standard you do have to declare it (even if it’s road legal) to ensure you are covered.

Some modifications that don’t need to be declared or effect your insurance policy include:

  • Tail tidy
  • Heated grips
  • Tank pads
  • Lights and indicators
  • Braided hoses
  • Aftermarket seat
  • Seat cowl

These were the most commonly acceptable motorcycle modifications that appeared on multiple lists but you should always check with your own insurance broker to confirm you are legally covered. Most specialist motorcycle insurance brokers will have a list on their website.

Any modifications not accepted must be declared or your insurance could be void. Similarly, if you contact new insurers for a quote and don’t declare all modifications and then later have an accident, you are giving your insurer a get out of jail free card and leaving yourself out of pocket or worse.

One Off Custom Bikes

If you have a heavily modified bike you are more than likely already aware you can’t just get insurance for whatever make and model your donor bike was before you took the angle grinder to it.

Sure, you would have a policy to show the boys in blue every time you get pulled over but the fact is, putting in a claim for a full write off should you end up sliding down the tarmac wrong side up would almost certainly mean that at best you only get paid out for the value of the donor bike and at worse, you receive nothing because you failed to declare it as a heavily modified motorcycle.

A one off custom bike would be any motorcycle that has had the frame altered and/or a unique paint job. It can be either be a shed build or commission built by a professional custom house.

Is Modified Motorcycle Insurance Expensive?

Depends on the modifications. If they are to improve the bikes engine or overall performance by more than 5% then it is likely to increase the cost of your insurance policy. Similarly, if they increase the bikes value the underwriter is again going to want to reassess their risk.

If your modifications improve your bikes security then it would reduce the cost of your insurance.

Sometimes the insurer may be happy with your bike modifications but it is agreed they won’t cover them in your policy so your cost doesn’t increase. If you have added expensive parts you might want to think hard if this is offered to you.

If you answer yes to any of the 3 questions below then almost certainly your bike insurance premium will increase.

  1. Is your modified motorbike more desirable to thieves?
  2. Is the performance better than when it left the showroom?
  3. Is your modified bike now worth more than if you had left it standard?

When doing modifications that you know will increase your insurance premium why not include a tracker or immobiliser to your shopping list? Adding either will mean your bike insurance will actually come down so will counter any increase.

The amount your premium goes up will obviously depend on the modifications and the insurer but in most cases it won’t be as much as you expect and quite often, won’t increase it at all. Stick a supercharger on the side of the engine and common sense tells you it’s going to bump the price up considerably.

Custom Motorcycle Insurance

Modified motorcycle insurance is required for custom bikes like this
Custom bike insurance will need an agreed value with your broker to ensure you have cover for the full value of your modified bike

A one off custom bike will require a motorcycle specialist broker. Similar to classic motorcycle insurance, they will offer a policy that includes an agreed value so that should you need to claim for a write off you get the amount your custom bike is worth rather than the market value.

They will also have a referral team who specialise in heavily modified motorbikes. Once they have all the custom bike details they will value it themselves and so that you and the broker can come to an agreed value.

A referral team will need receipts and photos to help them value your custom motorcycle. If your bike has a custom paint job be sure to include photographs of it.

How to get Modified Motorbike Insurance

If you already have bike insurance and you have modified or plan to modify your motorcycle it’s as simple as contacting your broker and giving them the details of your modifications.

They may ask for the manufacturer and part details of any aftermarket parts you have used. If your modifications are to the engine they may even ask for an engineers report.

You might have to be prepared to cancel your policy and move on to one of the more motorcycle friendly brokers if your current insurer isn’t prepared to cover your bike with the modification you have made.

Motorbike Insurance Specialists

When it comes to modified bike insurance it is always going to be easier talking to a specialist broker who’s staff have a full understanding of motorcycles. This is particularly true when trying to insure a one off custom bike.

Companies like Bennetts, Carole Nash and Devitt all offer riders free quotes, have decades of experience and have seen it all when it comes to modified bikes. They make it pain free and easy to get a quote either online or by phone call.

Motorcycle insurance specialists will generally include the agreed value option as standard for heavily modified or custom motorcycles rather than offer it as an optional extra.

If you shop around online then please ensure you check they are authorised and regulated by the financial conduct authority and displaying a registration number. You can then check the details on the financial services register website by entering the registration number.

Just because a website looks genuine doesn’t mean that it is. There have been reports in the news of fake insurance websites popping up so do your due diligence before giving out your credit card details.


A specialist insurer of custom bikes, they prefer you to phone in person. They promise no long waits for your call to be answered and all customers get 10% of Sports Bike Shop. Details and a number to call for a quote here.


Well known as a specialist motorcycle insurance broker, Bennetts offer custom bike and modified bike insurance along side their other policies. Get a free quote and more details here.

Carole Nash

One of the biggest bike insurance brokers in England. They offer free forensic tags with their custom bikes policies. Custom parts are tagged so that if stolen the owner can be traced. More details here.

These are listed for your convenience. I have no affiliation with either company.

Why Declare a Modified Bike?

It’s often forgotten that the main reason we have bike insurance is that it protects us against liability.

Forget the fact you lose financial compensation should your bike be stolen or written off and always remember your bike insurance protects you against liability should you hit someone’s pet, car, or worse, their child.

Please support by sharing