Blue smoke from the exhaust on a Triumph Daytona 660 2026

Fuel/oil mix ratio (normal on 2-strokes)

On a two-stroke, a light haze of blue smoke is normal -- the mixing oil is meant to burn along with the fuel. What we're confirming here is excessive blue smoke -- thick, constant, with oil spitting from the exhaust -- which points to too much oil in the mix. The fix, in principle: bring the oil-to-fuel ratio back to what the manufacturer specifies. On a manual-mix 2T, that means being scrupulous about the ratio every time you fill up (often somewhere around 2% to 5%, i.e. 1:50 to 1:20 depending on the machine and oil -- check your manual). On a 2T with separate lubrication (a metered oil pump), it comes down to checking and adjusting the pump cable, which needs to be synchronized with the throttle per the manufacturer's timing mark. Risk level is low as far as the work goes, but be careful about which way you err: too much oil just fouls the plug and pipe (annoying but not serious), while too little oil starves the engine of lubrication and can seize the piston (an expensive failure). When in doubt, stay slightly on the rich side. On budget, this is essentially free -- it's a matter of method and ratio. A good quality 2T oil (semi-synthetic or full synthetic, correct spec) runs roughly 10 to 25 euros a liter. If the smoke stays excessive after correcting the ratio, suspect a crankshaft oil seal on the case side letting gearbox oil through -- at that point, you're looking at a bigger job. This tool helps you understand what's going on -- it doesn't replace a certified mechanic.

How to make the repair yourself

🟢 Within reach of any rider: no advanced mechanical skill or specialised tooling needed.

1. 1First identify your system: manual mix (you add oil to the tank at every fill-up) or separate lubrication (a distinct oil reservoir and a pump). The fix differs depending on which one you have.
2. 2On manual mix: go back to the exact ratio specified in your owner's manual (often around 1:50, but this varies). Use a graduated mixing container, never eyeball it. Write the ratio somewhere on the bike so you don't get it wrong again.
3. 3Use a 2T oil suited to your use and the required spec (semi-synthetic or full synthetic from a recognized brand like Motul, Castrol, Elf). An unsuitable oil smokes more and fouls things faster.
4. 4On separate lubrication: locate the oil pump and its control cable, linked to the throttle. With the throttle closed and then at half-throttle, check that the pump's timing marks line up with the manufacturer's reference mark (check the manual or the model's technical guide).
5. 5If the marks don't line up, adjust the pump cable tension via its adjuster, in small increments, until the mark sits at the specified position. Never reduce the oil flow below the specified setting -- you'd risk starving the engine of lubrication.
6. 6Replace the spark plug if it's fouled with oil, or clean it with a brass brush, since an oil-soaked plug causes misfires and will skew your read on the result.
7. 7Take it for a few kilometers' test ride, engine fully up to temperature, then check the smoke again under acceleration and when you roll back onto the throttle. Smoke that's gone back to light and intermittent is normal.
8. 8If the smoke stays excessive despite a correct ratio and adjustment, don't keep chasing the pump -- suspect an internal leak (crankshaft oil seal, dropping gearbox oil level on affected models) and have a professional check it.