piston and sleeves

[OldMoIron]

Where can ya get higher compression, and better quality piston and sleeves for a 125ci for a CA

 

[steve(ill)]

i dont think i have seen any high compression pistons advertised.. maybe someone else will answer. THE head is domed, the pistons are flat. You can mill the head to decrease volumn of the dome and increase compression.

 

[OldMoIron]

how much can you mill it down, what other things could be done to get, say thirty horses. thanks

 

[wbecker319]

I have been told you can take off .150" without a problem. I do not have first hand experience.
Bill B

 

[steve(ill)]

I have not done it yet either, But Dick Leemons has written it up several times. The stock compression is about 6 to 1 and you know you would prefer maybe 9 to 1. Dick took about .200 inches off the head. You can port and polish the intake and exhaust ports to get better flow. In addition to that, you might change the gov spring and get a couple hundred more RPM, and possible a slightly larger jet in the carb might help. I believe Dick also built a motor with enlarged valves installed, but thats more $$.. Maybe he will see this and comment. I hate to steal his thunder on all the good information.

 

[Dick L]

I have taken as much as .200 without any problems. You just have to check the thickness of the water jacket thru the water holes as you go. You never know if some might have taken some off before. I have rebuilt several of those heads. Done what most are afraid to do without a problem. I did cut and dice one head to start with years ago so I could tell how far to go.

I TIG welded my pistons to enter the firing chamber .250 along with removing .150 on the head in the picture

 

[Dick L]

To get 30 horse you might need a few bucks. I have two of those engines with a four inch stroke. Any time I rebuilt an engine in the past I took at least .150 off the head and put in larger valves. I buy good condition used SB Chevy valves off Ebay and spin grind to the diameter I want for that rebuild.

 

[Dick L]

Thas alright Steve, at my age I am not looking for thunder. I would like my nane spelld rite. ^D

Lemmon

 

[OldMoIron]

I dont have a machine shop, and really dont know of one that could do that kind of valve work. taking the head down might not be a problem for a good machine shop would it. thanks for all your tips.

 

[Dick L]

I understand. If I was you then I would get a 3 7/16 over bore kit. Take the head to an engine machine shop and get a good valve grind with the head milled. That will give you the mostest for the leasetest. You can set with a dremel and smooth and remove some of the jageded edges below the valves and the inside of the ports for better flow. You can remove the valves and do that before taking it to a machine shop.
Just a good overhaul job will make a CA pretty snappy without the extras but the extras are fun.

 

[steve(ill)]

Dick, can you elaborate about the valve steam, length, springs, keepers ? What diameter increase do you get above the stock B ? Do you replace the original seat or ?

 

[nl00sb]

dick when doing a 4 inch stroke what are you useing for rods and is it just a offset grind
any block clearanceing being done