my performance oriented thread

A puch head is a great upgrade.I fully recommend them, one of the best bangs for the buck.

I doubt you will fit a Puch head in that frame?

The Puch head may not fit in that frame, but I got a similar frame with a Fred head and it fits nicely with about 1/4 inch of clearance at the top bar. There's also a new head called the Diamond which is very similar in build quality to the Fred head but it's square instead of round and the price is similar to the Fred head so it's just a matter of preferance there. the Puch head will cost a lot less tho if you can get one to fit, but chances are that it won't fit in that frame.
Either head Puch, Fred, or Diamond will provide much better cooling than the stock head as well as more compression so again, it's all about preference and fit.
the CNS carb works really good once tuned but the Walbro will be easier to tune and will add a bit more top end and overall performance.
A good expansion chamber pipe like the SBP or the snake pipe that JNM sells will probably give you the most bang for the buck or you could modify a pocketbike pipe to fit and get good results.
There's a lot of us who also use the Opti2 oil and mix it at the recommended 100:1 which gives a nice clean and smoke free burn but it also protects the engine quite well along with making things easier to tune and easier starts. Many of us have over 1000 miles on our engines running this oil at 100:1 without any problems.

good choice with royal purple ! i have been useing it for auto aplications for years.

i run lucas oil in my bike cause i cant find a royal purple dealer who has the 2 stroke oil in my aria

i also run 42:1

and yes the puch head is a great head but needs to be modded to fit ... it needs the holes reamed to 8mm and the squish band widend from 45mm dia to 47mm diamiter to propely fiy the jugs bore and piston crown. its well worth the 35$

They are a good head, it may need to be modified, the stud holes are not a direct fit, but can be redrilled to suit. Also the squish band does not suit the China Girl piston, but this can also be fixed.

There's a site to go to and look for the Puch Hi Hi head... http://www.treatland.tv You'll see the different heads there but the one you want would be the one they call the hi hi. Also lots of other goodies for your engine and bike to be found on that site.

You can trim off some of the fin to help with clearance issues since these heads have way more cooling surface than a stock China Girl head, Roger and Theon both gave you good advise on making the head fit your engine, just a few minor mods and these heads fit really well, make nice power due to the higher compression, and your engine will run considerably cooler. I went with the Fred head on my build, but the same or better performance can be had with a properly set up Puch head, mainly keep a tight squish band with .25 to 1.0mm piston to head clearance. The squish clearance can be adjusted by head and base gasket thickness. I buy the copper head and base gaskets from http://juicemotoparts.com/products.html in both thicknesses available then when I do a build I am able to get the right squish by using the different thicknesses at the base or the head and you can run double gaskets in either location to get the proper squish or to modify the port timing to give more low end grunt or more top end power. I like to raise the ports by adding thicker base gaskets then using thinner head gaskets for better high rpm power, but the opposite can be done for better low end power as well... just be sure to keep the squish clearance under 1mm but at least .25mm to prevent the piston from hitting the head and causing premature engine failure. My last engine worked out well with a .75mm squish clearance with excellent all around power, I've done some extensive porting to mine with about 12 degrees more port timing than I originally planned, but the tight squish clearance and good expansion chamber helped make up for that. The copper gaskets work best if annealed before using or reusing by heating them up to red hot then quickly dunking them into cold water, this will make the copper dead soft and help to seal even after several re uses.

Hope some of this helps you on your way to a much faster bike

a.graham52 said:

i got looking around today and found a "high compression" puch head. now i ordered just an oem part-out head. will there be a difference? or is the high compression head a gimmic?

Click to expand...

The high compression head is no gimmick, but you can surface any head by using the sandpaper on a piece of glass and running the head over the sandpaper in a circular motion you can shave off enough to get a good combustion chamber size, anything under 8cc's combustion chamber volume will do very well, you can also gauge your compression with a compression tester and set your compression above 130 psi but stay below 160 or you'll run into detonation problems or need to use racing fuel to keep it alive. My Fred head has a 6cc chamber and it makes about 145 psi on a compression test with no detonation issues using 93 octane premiun fuel mixed with the opti2 oil at 100:1
I think my engine gave me about 80 or 90 psi stock so there's a lot of room for improvement here.

You can get a shorter plug, but hard to find,
BL-6H.
Can't remember who made it,
but it say's made in Japan.
I use it in my bike as the exhaust is in an awkward spot running over the center of the head.
I have the push hi comp heads,as the hi hi was not availiable at the time, they are the same as the hi hi but not shaved.
I then shaved and altered the combustion chamber.
Yours has a larger combustion chamber than the hi comp heads, but looks to be of good proportions. I'd give it a shave, and adjust the squish band to suit.

This is one of my Puch heads, very happy with them.