charcoal black piston

[Rick73]

so I put on a new carborater and head on my 2 stroke (as pictured) and after a five minute ride my engine was hotter than normal and my piston was charcoaled.. as pictured.
guess my question is why? is it to much air? Any help would be helpful .
and this is a picture of my ride.

 

[Will'smotobikes19]

How many miles on the motor? My neighbor's bike has 1200+ miles and same thing when we took the head off he has the same carb and head only its not anodized. Looks like carbon buildup to me. What gas to oil ratio are you using and what grade of gas? try changing the gas to oil ratio if you want but I'd just wire wheel the top of the piston every once and a while. The head is a high compression one so more compression=hotter engine. Maybe adjust your idle screw.

 

[Will'smotobikes19]

Chances are your'e running it rich if those deposits weren't from long periods of running and happened in a short amount of time.

 

[Frankenstein]

Chances are your'e running it rich if those deposits weren't from long periods of running and happened in a short amount of time.

Actually long trips tend to resist this more, short trips run colder for most of the journey and so carbon is much easier built up. I would switch to at least a cheapish synthetic to cut down on some soot, also don't take what the head of the piston looks like in terms of jet adjustment, use your sparkplug or use a fresh one to meter it if yours is badly carbonized.

Another possibility is the spark plug is bad or getting there, or not gapped right and so misses more often, compounding the problem

 

[Rick73]

How many miles on the motor? My neighbor's bike has 1200+ miles and same thing when we took the head off he has the same carb and head only its not anodized. Looks like carbon buildup to me. What gas to oil ratio are you using and what grade of gas? try changing the gas to oil ratio if you want but I'd just wire wheel the top of the piston every once and a while. The head is a high compression one so more compression=hotter engine. Maybe adjust your idle screw.

the piston was clean before I put the new carborater and head on. not sue on the mileage been running more or less about 6 miles a day for 6 months.
I'm running a mix of 4 ounce per gallon of 89 gas.

 

[Rick73]

the piston was clean before I put the new carborater and head on. not sue on the mileage been running more or less about 6 miles a day for 6 months.
I'm running a mix of 4 ounce per gallon of 89 gas.

I'm reaching 37 mph but averaging 30 - 32 mph

 

[Will'smotobikes19]

My neighbor's bike only goes 28 not sure why it has the same head and carb as you. He uses turbo blue oil and hes using a thrust racing muffler now. I might do a 2 stroke build in the future but I want a charging system if I do. I have a 4 stroke 79cc bike now rode it around today. Ill probably sell the bike and get a hona ruckus though since they're safer, road legal and not chinese.

 

[Rick73]

My neighbor's bike only goes 28 not sure why it has the same head and carb as you. He uses turbo blue oil and hes using a thrust racing muffler now. I might do a 2 stroke build in the future but I want a charging system if I do. I have a 4 stroke 79cc bike now rode it around today. Ill probably sell the bike and get a hona ruckus though since they're safer, road legal and not chinese.

really? I'm 230 lbs and tow a 10 lb backpack. shoot I must be doing something right.i am using a 36tooth sprocket to.

 

[HeadSmess]

im looking but i aint seeing anything particularly abnormal... just a standard two stroke piston thats been running a bit too rich and or with too much oil.

tune the carb that is, smaller main jet.

define hot...

dont go judging the state of tune by the cylinder/head temp. judge by the way it sounds and how it FEELS. "seat of the pants" tuning system.

the bit of the piston you SHOULD be concerned with is the UNDERSIDE. once that starts turning to grey ash...its too lean and about to blow. normally it should be a tan sort of dark honey colour, bordering to black.

if youre going to pop the cylinder and piston regularly, i recommend getting a proper set of circlips and pliers for them, dont rely on the stock standard wrist pin clips.

toss that (looks like copper) head gasket in the bin and use a strip of teflon tape instead.

 

[FurryOnTheInside]

IMHO your engine getting hotter than before could be related to the raised compression and the fairly small surface area of the new head.
What is your current cranking pressure?
You might want to experiment with retarding the ignition timing by filing the magnet key.

I like twisted Teflon tape for a gasket. It is very cheap and easy to replace; but it is very thin, so be aware and check the clearance between piston and head and cranking pressure before using that. The stock aluminium gasket is 0.7mm thick, the copper ones can be 0.4 or 0.2mm thick, but my tTt gasket is 0.05mm thinnnn.