Replacing pistons
- Thread starter Yfs
- Start date
Blaaster that is some good stuff there . I actually have a ceramic piston and a coated cylinder . ceramic does not expand or contract . on a high end race engine most are running Ceramic bearings also . the only thing that will wear ceramic is a Diamond It is expensive because the tolerance have to be very precise because it does not expand but is does not wear . Of coarse I do not have this in my blaster but I could have one made pretty easy . could easily hit the 500-1000 hour mark 
It is the little person that fits the powerband inside the expansion chamber trying to attract attention, as he cannot get out because someone has fitted an exhaust plug to stop varmints getting in.
My piston shed a skirt due to piston slap , it is a rattle that is more noticable at idle and mid range rpm while revving freely, if you get a little load on the motor it seems to quite down some. There are some noises on a blaster that you don't hear on alot of water cooled bikes.
One is the air cooled fins actually have a ring to them if you know what to listen for you can hear a bit of a Ring that almost echos the little tink tink tonk of the pipe on bikes with alot of compression and /or thinner pipes.
Another is the sound of the counter balancer and it's gear lash, I am not sure how to explain the sound, but it's metallic, and can be sometimes mistake for rod or wrist pin bearing slop.
When I experienced piston slap on my bike if you touched a finger to the clutch actuator and held forward with gentle pressure you could actually feel the jarring of the piston in the clutch actuator. Wrist pin, rod, or even crank bearing noise should also be felt in the actuator a bit as all will jar the crank and the gear mesh to the clutches.
If you have noticed an new noise in the motor, particularly if your are not sure of its history, I would leak test, and check the spark plug. If the plug looks good and the leak test doesnt show any problems, i would get some ultra copper gasket coating spray, base, exhaust, and intake gaskets.
Turn off the fuel, remove the silencer, pipe and exhaust flange (Clean at least the inside of the flange, stand the bike up on the grab bar and shine a flashlight down in to the exhaist port. This will allow you to examine both the exhaust side, and top of the piston , as well as a portion of the cylinder, any scuffing scarring, burnt or melted metal should be addressed.
You can do the same on the intake side by removing the carb, and reed block.
The head can also be removed, u will need a new head gasket or a torch to anneal the old gasket.
By the time you have pulled the intake, exhaust, and head you should have a good idea if the piston and rings need replaced.
I would report my findings here along with detailed photos. In my case some scarring in one place on the piston showed where a leaking exhaust flange had let in water and grit, I didn't pull the cylinder,spec and redo my top end and the piston skirt cracked and broke right across the center or the damaged area!!
Basically it only takes an hour or two, and less than $50 in materials to tear the top end down and check for piston, ring, and bore damage or wear.
A piston kit is around $50 to $150, and usually about $75 to reborn a cylinder. All in a top end job can be around $200 -$300 dollars.
A simple re-ring runs $25 for the rings, and of course the cost of the gaskets you already have bought for inspection of the top end.
This may seem like alot of money particularly if you don't have it laying around, but if the piston breaks, chances are you are going to need a new set of cases, main bearings, and a crank set or rebuild. Cases run $200, main bearings and seals around $50 a set, crankshaft set about $200- $300, or around $150 for parts and a rebuild.
The cost of doing a top end job while the bike is still running may seem high, but running it till it quits could easily cost triple in tools or labor and double or triple in parts . Leaving you with a $500 to $900 repair bill and much longer downtime.
The cost of maintenance can be high, but the cost of riding it without doing the maintenance is much higher.
One is the air cooled fins actually have a ring to them if you know what to listen for you can hear a bit of a Ring that almost echos the little tink tink tonk of the pipe on bikes with alot of compression and /or thinner pipes.
Another is the sound of the counter balancer and it's gear lash, I am not sure how to explain the sound, but it's metallic, and can be sometimes mistake for rod or wrist pin bearing slop.
When I experienced piston slap on my bike if you touched a finger to the clutch actuator and held forward with gentle pressure you could actually feel the jarring of the piston in the clutch actuator. Wrist pin, rod, or even crank bearing noise should also be felt in the actuator a bit as all will jar the crank and the gear mesh to the clutches.
If you have noticed an new noise in the motor, particularly if your are not sure of its history, I would leak test, and check the spark plug. If the plug looks good and the leak test doesnt show any problems, i would get some ultra copper gasket coating spray, base, exhaust, and intake gaskets.
Turn off the fuel, remove the silencer, pipe and exhaust flange (Clean at least the inside of the flange, stand the bike up on the grab bar and shine a flashlight down in to the exhaist port. This will allow you to examine both the exhaust side, and top of the piston , as well as a portion of the cylinder, any scuffing scarring, burnt or melted metal should be addressed.
You can do the same on the intake side by removing the carb, and reed block.
The head can also be removed, u will need a new head gasket or a torch to anneal the old gasket.
By the time you have pulled the intake, exhaust, and head you should have a good idea if the piston and rings need replaced.
I would report my findings here along with detailed photos. In my case some scarring in one place on the piston showed where a leaking exhaust flange had let in water and grit, I didn't pull the cylinder,spec and redo my top end and the piston skirt cracked and broke right across the center or the damaged area!!
Basically it only takes an hour or two, and less than $50 in materials to tear the top end down and check for piston, ring, and bore damage or wear.
A piston kit is around $50 to $150, and usually about $75 to reborn a cylinder. All in a top end job can be around $200 -$300 dollars.
A simple re-ring runs $25 for the rings, and of course the cost of the gaskets you already have bought for inspection of the top end.
This may seem like alot of money particularly if you don't have it laying around, but if the piston breaks, chances are you are going to need a new set of cases, main bearings, and a crank set or rebuild. Cases run $200, main bearings and seals around $50 a set, crankshaft set about $200- $300, or around $150 for parts and a rebuild.
The cost of doing a top end job while the bike is still running may seem high, but running it till it quits could easily cost triple in tools or labor and double or triple in parts . Leaving you with a $500 to $900 repair bill and much longer downtime.
The cost of maintenance can be high, but the cost of riding it without doing the maintenance is much higher.
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