It should also be mentioned that if you have several cylinders in one engine you can also have these problems on some but not all pistons at once. A common thing is that the crank-shaft holes in the crank case isn't perfectly horizontal, or the crankshaft is imperfectly machined, often with similar problems in the connecting rods, which adds up to different stroke length from one cylinder to another. So if someone measures squish and top dead center perfectly on one cylinder, remember to also measure the others, or else the normally safe compression may be unsafe on certain cylinders. Too low squish can be equally bad if you're running on the limits of the machine, because the edges of the piston heat up more than they would with proper squish and then cause detonation from the edges.
Do i have to replace the piston if it has moderate blowby? like 1/4 of the circumference? If its 1/2 of the circumference or the hole around is it needed to replace it? :)
I noticed six or seven pings shortly after rebuilding my 48cc, and putting a high-compression get on it, but only after getting it really hot. I took apart the top-end and found no damage, luckily. I'm already running the highest octane I can, and the largest jet I can, so I figured I'd reduce compression, a very tiny amount, by polishing the crown of the piston, since I've already polished the cylinder head. Was this a bad idea? Any suggestions? Anything I can do to reduce combustion temperature, or help disipate heat in an air-cooled 2-stroke?
Hey , I have a 70cc engine that produces about 20 hp plus , has 21mm Polini cp carburetor . Have extremely high wear on the piston after 200 km of driving . if you can look at any picture ? will build engine again so will not make the same mistake . Checking distance of piston spring and proper squish and proper torque on the bolts . The engine started on the first step always so it was a surprise and see wear
i have scratched the clip groove in my piston where the piston pin inserts can you tell me what i can to fix without causing more damage. emery cloth and patience is my only thought I'd come up with..
Hi mx tech! I want to ask you if it is possible to detune the hardest hit in the high part of the rpms on a yamaha yz 250 without breaking the bank. To make it sort of a poor mans "thumper" More beginner friendley. Kind regards
Depends on the riding style all the way, doesnt matter if the rider is professional if hes going for a lazy ride. Professional racer changes pistons of 125cc almost every race or 5hours max and 250cc 5-15hours but you can easily ride around practicing enduro for 30-50hours on a 250 or even more.
Make sure you break it incorrectly do not go full throttle for the first two to three hundred miles and go 8 oz to 1 gallon during breaking y d100 50 mph with a big belly muffler and a 32 tooth sprocket
Before you buy a new carburetor check out you're piston because they are cheaper than buying a new carburetor and you might just waste your money buying a carburetor when it's your piston
4 corner seize is usually not using enough premix or not properly warming up the bike.
It should also be mentioned that if you have several cylinders in one engine you can also have these problems on some but not all pistons at once. A common thing is that the crank-shaft holes in the crank case isn't perfectly horizontal, or the crankshaft is imperfectly machined, often with similar problems in the connecting rods, which adds up to different stroke length from one cylinder to another. So if someone measures squish and top dead center perfectly on one cylinder, remember to also measure the others, or else the normally safe compression may be unsafe on certain cylinders. Too low squish can be equally bad if you're running on the limits of the machine, because the edges of the piston heat up more than they would with proper squish and then cause detonation from the edges.
Do i have to replace the piston if it has moderate blowby? like 1/4 of the circumference? If its 1/2 of the circumference or the hole around is it needed to replace it? :)
Thanks for the help. Godspeed
I noticed six or seven pings shortly after rebuilding my 48cc, and putting a high-compression get on it, but only after getting it really hot. I took apart the top-end and found no damage, luckily. I'm already running the highest octane I can, and the largest jet I can, so I figured I'd reduce compression, a very tiny amount, by polishing the crown of the piston, since I've already polished the cylinder head. Was this a bad idea? Any suggestions? Anything I can do to reduce combustion temperature, or help disipate heat in an air-cooled 2-stroke?
Hey , I have a 70cc engine that produces about 20 hp plus , has 21mm Polini cp carburetor .
Have extremely high wear on the piston after 200 km of driving . if you can look at any picture ? will build engine again so will not make the same mistake .
Checking distance of piston spring and proper squish and proper torque on the bolts .
The engine started on the first step always so it was a surprise and see wear
Probably wrong piston ring end gap.
Just make sure the piston ring is on the right side the intake side with a piston ring ends otherwise it will scrape against the out take side
i have scratched the clip groove in my piston where the piston pin inserts can you tell me what i can to fix without causing more damage. emery cloth and patience is my only thought I'd come up with..
Does that hole in the intake side of the piston empty gases from under the crown into the boost port?
Hi mx tech! I want to ask you if it is possible to detune the hardest hit in the high part of the rpms on a yamaha yz 250 without breaking the bank. To make it sort of a poor mans "thumper" More beginner friendley.
Kind regards
Make sure you do the right mix with oil and don't full throttle forever give the bike a break
Why is my 80cc bike motor piston hitting the head on up stroke
You need to either add gaskets to the head or your out of luck and your crank bearing is bad
Wrong gaskets or bad crank
how many m/h new piston can hold if rider is not professional ?
Depends on the riding style all the way, doesnt matter if the rider is professional if hes going for a lazy ride. Professional racer changes pistons of 125cc almost every race or 5hours max and 250cc 5-15hours but you can easily ride around practicing enduro for 30-50hours on a 250 or even more.
20 hour
Ernest S if a rider is not an ‘professional’, they’d not understand m:h and couldn’t therefore tell you.
Make sure you break it incorrectly do not go full throttle for the first two to three hundred miles and go 8 oz to 1 gallon during breaking y d100 50 mph with a big belly muffler and a 32 tooth sprocket
No, follow the manufacturer break in procedure. Not your own voodoo.
I can't here u from the background music
Why do pistons and cylinders at cheap enough if you keep having problems just buy new ones
Put your throttle pin clip on the second one down
Before you buy a new carburetor check out you're piston because they are cheaper than buying a new carburetor and you might just waste your money buying a carburetor when it's your piston
barking dogs?
Don't believe his lies...