Puch head milling

i keep on reading about head milling on puchs... How much difference does it really make if you sand the head down to the fin's? It can't be more then a mm or 2. I keep on seeing the name steve on posts about head milling so i'm assuming you are the expert on this one. Will i really see a noticable gain in low end by sanding down my cylinder head.

(stock 50cc e50, i'm making winter performace plans. port matching, upgrade exhaust, possible head milling since i have to take it off to get to the cylinder anyway.)

Re: Puch head milling

read a book called two stroke performance tuning by a. graham bell. he has a lot of info and formulas if you want to do it. also outlines the shiny turd you can turn your head into if you mess it up.

Re: Puch head milling

have you every done it? i want to know from people who have done it if its worth the time and energy to do it.

Re: Puch head milling

yes you will a noticeable gain if done correctly.

gives you higher compression which will result in better torque.

Re: Puch head milling

i haven't taken any measurements of the stock head of an e50 but i don't think that you'll need to take off more than a mm.

Bell gives squish clearance of .5-.7mm. any less than that and you risk a piston banging at high rpm.

Re: Puch head milling

yup...you dont take off much at all.

search the forums this has discussed many a times.

Re: Puch head milling

Gunther McCilicutty /

some peoples just don't use a gasket and skip the milling...I for one don't trust that..I have posted questions before on this.

Mill it down to the fins they said...then I heard sanding it down.

I think I may just get mine milled about 1mm then use a gasket.

Re: Puch head milling

I have mine down to the fins with the gasket. Very high comp., perhaps a bit on the high side, like me. Watch your piston, don't let it hit anything!!! Plug too!

Big torque improvement.

Re: Puch head milling

do some measuring of your squish band clearance before you start milling anything..

Re: Puch head milling

ok i'll try it.

i've seen both wet and dry sanding on this site. What have you found worked the best for you?

i found a guy near me that has a box full of puch cylinder heads and cylinders that he only wants 5 bucks a piece for so i'll get all of those to practice with.

Re: Puch head milling

I was going to say that those heads are easy to get. At least take it down to the fins. I f the piston hits the head use a dremel or files in the squish band of the head until it doesn't hit You can put a dye like prussian blue on the piston and after torqueing down the head take it off and the dye will show where the head is being hit by the piston

Re: Puch head milling

there's steve... i was hoping that you would step in the room.

so what do you think is best wet or dry sanding (and would there be any difference)?

Re: Puch head milling

The only problem with the otherwise better wet paper is that it's hard to find in a grit larger than 220. Apackage of the better dry papers of 150 or 100 grit will work. The 150 actually has more cutting points per square inch. Stroke the head about four times in one direction and then four at 90 degrees from there, etc etc. It will go faster that way. If you want to go beyond the fins like I do it's easier to take a big file just to the fin sections to wack em down so you are not laboring sanding the fins too. A compression test of 200 psi is 13.6 to 1. I go up to 230. The stock piston is strong and can handle it

Re: Puch head milling

If you want to check your piston to head clearance go to your local automotive machine shop and ask them for some Plastigage. It come3s in a flattened paper tube about 9" long. Inside is a round piece of soft plastic.

You snip off an inch or two and peel the paper back. (don't throw the piece of paper away. It has marks on it that will tell you the clearance.) Then you take out the piece of soft plastic and place it on the head where you want to measure the clearance. You then assemble the engine and slowly rotate the engine over by hand for one up and down of the piston.

Then you take the head off. You will see that the piece of soft plastic has been flattened out. You compare the width of the flattened plastic against the markings on the little pieces of paper that you saved. When you find the marking that matches the plastic the paper will tell you what clearance that equates to. Simple huh!

Re: Puch head milling

another easy way to do it is to buy a roll of large diameter flux core solder and bend it to fish down through the sparkplug hole and to touch the side of the cylinder. Roll the motor over and then pull the solder out, Measure and there you go. No need to remove the head twice to do it either. Although plastigage is amazing and you should know about it.

Puch head milling

Not sure on the clearance, but has anyone ever milled a high comp head to get even higher compression?

Re: Puch head milling

I don't know but over 16:1 CR you need some fuel other than premium

Re: Puch head milling

ok guys never mind about the head milling. I went to go get the heads from a guy that lived near me... he had a shead with a bunch of High Compression heads

In the puch parts manual it says there are are some heads that are not supposed to have gasket, How can you tell which on it is?

When looking a the inside... 2 of the heads have the 4 holes then the tab on the bottom (shape of the head gasket) 1 of them does not have the "tab". which is which?

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