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View Full Version : Fitting a early Ct70 piston into a Atc 70 for higher compression?



c20let_astravan
01-04-2014, 05:19 PM
Hi, a while ago I read that a early early 1970's Ct70 piston could be used with a standard Atc70 to raise the compression ratio.
I know the Ct70's have a higher ration and just wanted to confirm that this is due to the piston alone and if anyone has done it, which year of piston do I get?
Thanks

big specht
01-04-2014, 08:14 PM
Yea you can use the ct/sl 70 pistons and you could leave the the base gasket out and that will raise it more

c20let_astravan
01-05-2014, 04:34 AM
Thanks, thats exactly what i was looking for!

Do you just apply a little hylomar or something on the surfaces for the lower gasket to help it seal?

Are most of the ct/sl70 pistons the same or is there a specific year for me to order?

Thanks

big specht
01-05-2014, 09:09 AM
As for years I'm not sure I think they show pics of the pistons on http://dratv.com/info.html And all I did was when I built those old motors was to use the o rings around the oil fead and drain likw what was in there stock and just use some gray silicone around the base of the jug just don't use to much you don't want it to squeeze in to the oil feed or drain areas and plug them off

c20let_astravan
01-05-2014, 10:05 AM
Iv been searching for a while trying to get the Honda part number for a genuine standard bore size piston but I am struggling.

When I used Cmsl honda to find the part number they were giving the same part number for most all years of a ct70.
Dr-atv just has one section for ct70's and I looked through them but couldnt make up my mind on the correct one.

If anyone could help me find the genuine part number I would be in your debt!