melted piston

[george69mills]

I put on a Vito's BB Kit on my 06 blaster. I even upgraded to the forged piston. I have rejetted the carb. It now has a .340 main jet and is in the middle clip on the pin. I got rid of the oil injection and mix my own oil at 36:1. K&N airfilter no lid. It lasted about a year before melting the exaust side of the piston. Obviously i will have to rebuild but any ideas on the cause?

 

[Midwayusa]

I put on a Vito's BB Kit on my 06 blaster. I even upgraded to the forged piston. I have rejetted the carb. It now has a .370 main jet and is in the middle clip on the pin. I got rid of the oil injection and mix my own oil at 36:1. K&N airfilter no lid. It lasted about a year before melting the exaust side of the piston. Obviously i will have to rebuild but any ideas on the cause?

With a main jet that big I would think it would have to be an air leak. Torn intake? Bad stator side seal?

 

[george69mills]

i looked again an it is actually a .340. this is still a large jet. when i tuned it i tried several different jets and this one left the spark plug a chocolate color

 

[05blasterkid]

For one thing your mixing way to lean on the oil to fuel you should be mixing at 32:1 not 36:1, also give us the details on ur blaster. What it is and all that is done to it then we can be of more help

 

[Midwayusa]

i looked again an it is actually a .340. this is still a large jet. when i tuned it i tried several different jets and this one left the spark plug a chocolate color

Depending on your altitude, pipe, etc that is probably still a large jet. I don't know that 36:1 is a problem. I have heard of guys running 40:1 but I run my stuff at 32:1. I'd do a leak test to see if the seals are leaking. Leakdown might also tell you if there is a tear in the intake boot somewhere.

 

[blasterdude14]

I think you ran it too lean, when you get it rebuilt get at least a 34mm Keihin PJ carb and mix at 32:1. That was a lot to handle for a stock carb
Also I'm not sure at what size but when you get to a big enough jet the numbers won't match the actual size its unreliable

 

[royalt67]

When you put it back together, a leakdown is a must.

After you get it running and broken in (after all it took a year to melt) check your plug at various rpms, using a new one for each test. It is possible that you needed your needle setting richer. What looked great in general or at top end may have been lean, low to mid.

 

[george69mills]

For one thing your mixing way to lean on the oil to fuel you should be mixing at 32:1 not 36:1, also give us the details on ur blaster. What it is and all that is done to it then we can be of more help

It is a 200cc with a Vito's 240cc big bore kit. stock carb. stock reed valve. Vito's fat bastard exaust (I think. It says vito's on the side and was on the quad when i bought it). B8EGV spark plug.

Edit: it also has the triple port exhaust

 

[blasterdude14]

I'm betting you ran lean on the pilot jet, also that work is a lot to handle for the stock carb

 

[royalt67]

I'm betting you ran lean on the pilot jet, also that work is a lot to handle for the stock carb

Possible but it would be a noticable hesitation I would think. More importantly, most people don't run on the pilot. They cruise on the main, 25% to 50% throttle. The area controlled by the needle.

 

[royalt67]

As for the carb, yeah, kinda small, but it sounds like it had an appropriate jet. More than anything the 26mm mikuni was just limiting power.

 

[super noober]

air leak for sure man, we have a member "holeshotman" who sells leakdown testers for $30 a pop, you should look him up and get one. its a must have.

 

[Kennedy_Power]

When you put it back together, a leakdown is a must.

After you get it running and broken in (after all it took a year to melt) check your plug at various rpms, using a new one for each test. It is possible that you needed your needle setting richer. What looked great in general or at top end may have been lean, low to mid.

100% agree, a leak down a must
Use the adjustable core plugs to block off the exhaust flange and intake.
U can buy or make a kit to pressurize the engine.
I made a adapter that screws in the spark plug hole with pressure regulator
5 PSI for 5 minutes minimum

 

[george69mills]

thanks for all of your help. My buddy who helped me rebuild it the first time is a mechanic so im sure we will have everything we need

 

[Awk08]

100% agree, a leak down a must
Use the adjustable core plugs to block off the exhaust flange and intake.
U can buy or make a kit to pressurize the engine.
I made a adapter that screws in the spark plug hole with pressure regulator
5 PSI for 5 minutes minimum

/\/\/\/\ hey look who borrowed a set of balls, and showed his face ?????
we were better off with you hiding wherever snakes hide when cornered, you are a detriment to this sport, crawl back under your rock, cold weather is coming, and spare us your false jetting info/clutch burning 65 horsepower bullshit

 

[hotrodaj_2]

This might help tell you what happened. It's a bunch of pistons that have failed in different ways. It helped me once, I started to 4 corner seize but I had never seen marks like that before, this chart help alot.
Piston Diagnostic Guide