After How many pistons does a 2 stroke cylinder need to be bored out? I have an lt250r and I wanna know how many pistons before a rebore?

You have a misunderstanding of piston wear and cylinder wear. Talk to a local motorcycle shop that services your brand motorcycle.

-Engine overhaul mechanic and general automotive mechanic since 1972. Retired in 2018.

Pistons???

Read: https://en.wikipedia.org/wiki/Suzuki_LT250R. Thatengine has 2 cylinders, but only one piston is in each cylinder.

? query is a bit confusing. 2 stroke pistons to stock bore? pistons rarely wear out first- sometimes get scratched from abuse. Iron liners usually can be bored out ..010,020, .030, .040- so maybe 4 pistons oversized with bore jobs before cylinder needs replaceing- and that is if .010 will clean up. Nikasil liners are harder wearing, may wear piston out so one replacement piston- then will need cylinder replaced with new piston. 2 times for most , then need to be carefull, might get minimal wear and find new pistons at .010 over previous- what some racer would do.

I don't really understand your question. To fit a standard size piston assembly, you don't need to rebore the cylinder.

If your cylinder has a steel liner/sleeve and you want to fit an oversize piston (because of wear or damage) then you must bore and hone the cylinder to suit the new piston assembly.

The Japanese usually make five piston sizes for a given engine;

1. Standard (+0 mm)

2. +0.5 mm

3. +1.0 mm

4. +1.5 mm and

5. +2.00 mm

If you need to go beyond those limits, you need to buy a new cylinder, re-sleeve your old one, or find a piston from another engine (or aftermarket big-bore kit) that allows you to bore the cylinder beyond the usual 2mm. Old style steel sleeve/liners can be bored until about 1mm thick. thinner than that they can warp. The NiSi or ceramic coated cylinders can't be re-bored. When the wear exceeds limits, they should be recoated by a specialist.

It doesn't work like that. You clearly know nothing about engines.

No guys I’m saying how many i can go through on the stock bite before the cylinder gets too worn and I have o overbore

T'other way around. If it needs a rebore you'll need a new piston to accommodate the new larger bore.

I think you're confused. The number of pistons would depend on how many cylinders you have. What you want to know how much can you increase the bore. Generally the maximum is 040.

A compression test is needed to determine piston and bore wear. Generally speaking the bore wears before the piston. But of course a new oversize piston is needed after a rebore. Do the compression test or your time and expenditure could be wasted.