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Heads and Cylinders All about your porting, compression, rings, cylinder and piston modifications to your bicycles engine

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  #1  
Old 01-04-2016, 08:19 PM
Flathead Flathead is offline
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Default Piston

How to cleanup piston black charcoal top and head Both look pretty cooked .I'm replacing gaskets and piston rings
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  #2  
Old 01-04-2016, 10:51 PM
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sbest sbest is offline
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Default Re: Piston

Rub off the chunky stuff with a piece of wood or plastic and then sand it with something like 100grit paper. Do NOT sand the sides or round the corners. Just polish the black off the top. If you cut back on the oil and use synthetic the chamber will not soot up:

Many many highway miles on that right hand cylinder, 40:1 Ipone synthetic with a lean fuel mixture.


This is a well worn Blaster 2 stroke, jetted rich but still 40:1 Ipone Synthetic.
Shiny glob is a bit of oil dropped on during disassemble.
4 shiny lines at corners are mixture wash blank areas from edge of ports.
As you can see, soot wipes off with a finger or rag even after a year of running.


This is what the head looks like:


My point? Use synthetic at 32:1 to 40:1 and jet proper for less carbon.

Steve
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  #3  
Old 01-05-2016, 06:21 PM
Flathead Flathead is offline
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Default Re: Piston

Thx again Steve
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  #4  
Old 08-17-2016, 05:01 PM
bcredneck bcredneck is offline
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Default Re: Piston

don't clean the piston if you do anything to the carbon ring above the top ring your going to lose compression and cause damage to the jug.
The carbon ring is created during break in and prevents the top of the piston from touching the jug and helps with compression.
during running the carbon on the top flakes off and builds back up even if you remove it it will come right back
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  #5  
Old 08-27-2016, 12:40 AM
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maniac57 maniac57 is offline
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Default Re: Piston

Ignore the post above. It is incorrect and misleading.
Clean the carbon every few months.
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  #6  
Old 08-27-2016, 01:24 AM
Slogger Slogger is offline
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Default Re: Piston

I just had the head off mine the other day and noticed the brown carbon had a few shiny spots right in the middle where it had flaked off. Tuned right it always looks about like this. Some carbon, not too bad. When I was running it rich for break in I did clean the piston crown and barrel once, with a wooden popsicle stick, a stiff brush and seafoam. I thought it softened it up if I wet it and let it soak for a while.
I just run regular 2 stroke oil, I figure the engine is primitive so its oil might as well be traditional. Plus its cheap and I like the smell.
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Old 08-27-2016, 04:38 PM
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Springfieldscooter Springfieldscooter is offline
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Default Re: Piston

Its my belief that a little carbon build up on top of the piston is NOT a bad thing.
It increases compression ratio, and also absorbs some heat!

But if keeping it clean is an issue, it can be reduced by adding a small amount Seafoam to your gas/oil mix on a regular basis.
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  #8  
Old 08-28-2016, 02:39 PM
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sbest sbest is offline
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Default Re: Piston

Hard to keep carbon off the piston.
Synthetic 2 stroke oil like Motule 800 or Ipone will keep things clean inside.
The cleanest cylinder head here has years and 1000's of miles on it, with synthetic oil.


If you are riding it any more than moderately hard, no worries about carbon.
Plus, you will never feel the difference it makes on compression.
The worst thing for carbon is lots of cheap oil, and the worst place for it is in your exhaust.
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