Head Tuning

Predator303

Predator303

New Member
Hi guys.

I just ordered a new bottom end because I was sick of one part after the other breaking down in the old engine that came with the bike. I cleaned up the head of the engine and remembered how I used to tune my turbo engines by face the cylinder head to get the combustion chamber smaller.

My question: Has anybody here tried something like that with the china engine? Since I get a new block with especially new crankshaft bearings etc. it would be worth to try it. I ordered an additional head (cover) too, and plan to give it a try to take off a part of the head to get a smaller combustion chamber.
 
you could mill the head, it would certainly raise compression, but first i would simply lap the head with sandpaper and glass to just make it flat. i havent needed to do this because i have very high compression, but other members have done it with good results.
 
Its flat. The idiots that ha the bike before me didnt use gaskets for the head and exhaust but I bought the head gasket now because whatever they used to seal it, im guessing some sort of silicon, got out since I sealed the exhaust and all the pressure went to the next weak spot in the head. I would like to take off maybe 0.5mm but with a machine for that.
 
You can remove gaskets or replace with thinner to increase compression, you can double up gaskets to raise.

Any metal removed inside the combustion chamber will lower pressure.

I've herd copper or gasketless with YamaBond/Red sealer and let it sit for 24hr before running is better then gasket if the surfaces are flat and smooth.
 
The engine didnt had a gasket and the metal gasket I bought now is pretty thick, thats why Im thinking about to take something off the head. I mean they are just 10 bucks to test it.
 
If you fill the combustion chamber with JB weld in the shape you want, the best is to make a squish band around the piston so that all the charge is pushed into the center near the spark plug, I can make you a casting using yours as a pattern. PM me if interested. Read up a little on 2 stroke head design.
 
Hey Low Rider.

Yes, I have done a bunch of testing using modified cylinder heads. I carefully chucked up the head in a 4 jaw chuck and faced off some of the material. Then when sufficient material was removed, I machined a "squish band". Then I put the cylinder in the lathe and decked a little material off the top of that. This allowed the edge of the piston to come flush to the top face of the cylinder. I have tried these modifications to several styles of stock heads, and the one which performed the best was the hard to get GT-5 head cover.

But all this is a waste of time! I only did this for testing purposes. While power was great, the inadequate cooling of the stock heads made the engine detonate once it got hot.

By far the best thing to do is get a good billet head with adequate cooling fins. You will get the power you are looking for, and another thing you will get is amazing engine life!

My pistons and cylinders are looking great now that my engine is running cool. The stock heads are causing a lot of trouble with these engines!

Thank you!

.duh.

-Fred
 
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god, whats the matter here with the editing? let people post there connections and the places where i can get what i'm looking for. without the people, this forum would be empty..
 
Lowrider.

You make a good point. This is precisely why I sometimes "get into trouble" here. It can be really hard to judge when a post is leaning too much towards self promotion. For good reasons, they don't want their forum to be overrun by self promoting scum bags who could care less about your situation, and more about filling their own pockets with your money. Well, at least they have a dedicated section, called "swap and shop". That works. As long as they continue to allow machinists and designers, like myself to chime in from time to time, that would be great. In exchange for them to allow people, like myself to chime in every once in a while, I will respect that "line", and will try to not cross it, even though that line is somewhat grey to me. Sometimes I can get confused.

-Fred

.duh.
 
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