Sl 750

[Robert3]

How do i check if it is running lean on one of the cylinders

it is my main questions because the mag cylinder had a melted exhaust side pistion and on the fsm it said it was running lean so

[K447]

How do i check if it is running lean on one of the cylinders?

it is my main question because the mag cylinder had a melted exhaust side piston and on the fsm it said it was running lean so

That would indicate it was running lean.

#1 reason is fuel system problems or the carbs need cleaning. Many threads on here regarding the common checks and upgrades for the Fuji engined Polaris models.

A few searches, and you should have all the info you need.

With a repaired piston in place, and the fuel system and carbs all cleaned up, adjust the carbs for slightly richer fuel feed than spec, then you can use Randy's Watcon.com carb tuning method, using the MFD tachometer to dial in the mix.

Keep in mind that you need to break in the new engine parts, so you cannot just jump to the final carb settings right away. Run it a little rich until you have some time on the engine, then finish the tuning.

While breaking it in, keep an eye on the piston wash (more searching), and look for the desired wash pattern indicating normal or rich fuel mixtures.