How to: Modify your 125

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Part of the joy of owning a bike is making it your own – but when you’re starting out it’s easy to get it wrong.

As well as the question of taste, there are also legal implications with certain changes, especially when it comes to increasing power and noise.

MCN has compiled this simple guide to getting the most from your first motorcycle.

Engine
125 owners, especially younger riders, often reach the point when they’d like to go faster.

Unless you’ve passed your test, modifying your 125 to breach the 15bhp power limit invalidates your insurance and means you’re riding a bike you’re not licensed for – two separate and very serious charges.

Four-strokes can often be fitted with an aftermarket exhaust without increasing power to illegal levels, which nets a nicer noise and the odd extra mph if you’re lucky.

Check power gains with the exhaust manufacturer first to make sure. Be aware illegal exhausts could invalidate insurance, fail MOTs and get you pulled over by the police.

Two-strokes are best left standard – de-restriction and simple tuning has a significant effect which is great for A1 licence holders, but highly illegal and potentially dangerous while still on L-plates.

Otherwise, sticking to maintenance schedules and using correct oils will ensure no loss of performance on any bike.

Chassis
As a new rider you’re unlikely to need more cornering capability than the bike offers (unless you picked a cruiser 125, in which case you bought the wrong bike for fast cornering).

But you can still make subtle improvements and keep the bike’s performance up. Performance brake discs and pads are widely available and are often cheaper than OE replacements, so make economical sense too.

Braided brakes hoses give a more direct brake action, especially on older bikes with standard rubber hoses.

Tyres
Fit the correct tyre type (sports tyres on sports bikes for example) and size from a reputable manufacturer – fitting cheap rubbish to an Aprilia RS125 is asking for trouble.

Don’t mix and match tyre types and brands – the profile and compounds will work differently which could cause handling problems. Set the tyre pressure before you use the bike once a week to pressure recommended by the tyre maker.

Buy a proper pressure gauge too – getting an accurate one is inexpensive and it will last.

Styling
Taste is a subjective issue – but keeping cosmetic changes simple will retain more resale value because more people will like it.

Generally speaking, avoid cutting anything off, painting or fitting parts in lairy/clashing colours and doing anything you can’t reverse – cutting wiring to fit new indicators means it’s hard to refit originals properly.

You’re also likely to keep your 125 for a relatively short period, so it’s better to keep changes simple – standard bikes are always worth more, and you’ll have just as much fun on it. Even expensive paint jobs don’t add value.

Stainless steel bolts, tank pads, carbon or billet aluminium parts are more useful and less garish.

Read the latest stories causing a buzz this week in New rider…

Chris Newbigging

By Chris Newbigging