70 tccd piston port clearance

David Ciao /
davidw
Aug 09, 2008 03:02PM

i am having some trouble getting my tccd to run, head was hitting and then when i increased the gaskets a bit(too much?) at BDC when looking down into the intake port the holes thru the piston are juuuuuust visible now. i think that is a problem.

i checked against a running tccd and you could not ever see the piston ports, BUT his piston was an aftermarket one.

i am just not sure how they work or what they do, should they clear into the intake and have an extra fuel boost, or do they just play at some other point?

there are two matching trenches in the top of the cylinder so someone tell me what is going on here, is this a boost? how does it work? :)

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Re: 70 tccd piston port clearance

peter /
peter
Aug 09, 2008 04:13PM

i used 3 base gaskets, my ports were JUST clearing also. Head still hit so i used 2 headgaskets. the best option is to get a real 70cc head and use the gasket also.

it went mid 40's with a 14mm carb and such.

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Re: 70 tccd piston port clearance

No Lo /
noahl
Aug 09, 2008 06:29PM

I spy a high comp head with my eye.

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Re: 70 tccd piston port clearance

M A /
matthewa
Aug 09, 2008 07:54PM

i ran min with a single base and no head gasket

mine was 50cc kit tho

no issues..12mm carb and stock-modified pipe 37-41mph

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Re: 70 tccd piston port clearance

David Ciao /
davidw
Aug 09, 2008 08:32PM

when you look down the intake port you do or do not see the ports in the piston?

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Re: 70 tccd piston port clearance

peter /
peter
Aug 09, 2008 08:38PM

i did. a sliver.

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Re: 70 tccd piston port clearance

David Ciao /
davidw
Aug 09, 2008 10:18PM

ok, wasn't clear when i first read it if it was the same. thanks!

now i need to find me a highcomp

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Re: 70 tccd piston port clearance

SchijnHeilig /
schijnheilig
Aug 10, 2008 08:06AM

The idea is that you don't see the ports in the piston at BDC. If you do see them, you'll lose primary compression through the intake. Solution: Use a K-star piston (I do) or a custom made head for the TCCD piston.

The K-star piston also has boost-ports, but those are a lil bit higher compared to the TCCD piston.

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Re: 70 tccd piston port clearance

David Ciao /
davidw
Aug 11, 2008 02:20AM

which explains my compression issues, i knew it couldnt be right.

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Re: 70 tccd piston port clearance

William /
immonen
Aug 11, 2008 10:24AM

I wasn't able to see any of my top ports when I ran my 70cc TCCD. Although my ring broke and well it messed up my top booster port....so I know have a kstar on it and I still can't see anything. I think I have 3 base gaskets and a head gasket.

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Re: 70 tccd piston port clearance

David Ciao /
davidw
Aug 11, 2008 01:29PM

see that is the only problem, as i build up gaskets the piston stays in the same place, i need to find the sweet spot where it is high enough that th head doesn't hit, but low enough that the ports dont show....

seems like everyone has the aftermarket piston....

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Re: 70 tccd piston port clearance

Flagrant - /
stevew
Aug 11, 2008 01:41PM

You can cut or file the head's squish band to get to where you want to be. Round files at an angle or some dremel work will get you there. Then there is the piece of solder squished between the cyl and piston to gauge the clearance trick

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