What EVERY NOOB needs to read.

KCvale

Motorized Bicycle Vendor
Joined
Apr 18, 2010
Messages
3,518
JUST HAVE THE BASICS TOOLS...
... and JUST WANT TO MAKE IT GO GOOD?



1. Pull the head.
If you don't have a torque wrench and know how to use it, do NOT pull the head off!

Milling the head, using other gaskets, bla bla is bunk in not for the beginner, you will never feel it riding and more likely to actually cause you problems or even a busted engine.

In any case I always pull the head to do quick inspection inside, paint the outside or ascetics, and rotate the head so the spark plug is facing forward, but your NEED a torque wrench to put them back on right or it's for naught...
This is your COMBUSTION CHAMBER guys, you need keep the explosive force INSIDE!

On a typical 66cc slant head the book says 12'# torque.
I torque in a X pattern 5# at time in roatations, to 20'#.
If you have sub-quality engine maybe stop at 15-16#. but as long as you do it in an X pateren you can go a 1# at a cycle and see how it 'feels'.

I have like 70 of these engine out there locally and NEVER had a head/compression issue.

2. Break the case.
Ohh come on, breaking a new engine in half before you ever have it running is just silly.
If it didn't run to begin with, Joe Beginner will likely make it that way.
Want to know what is involved in that?


3. Increasing Compression and Power.
Simple, for slant head engines just put in a a slightly longer NGK spark plug!
I use BPR7HIX Iridium but BR7HS works fine, but there is more to understanding what all the the numbers mean as they all mean something, just not something for the beginner needs to know.

The longer plug gives about as much compression boost as all that head milling/compression head stuff and it just involves changing the plug.

4 Jets/Etc performance Boost.
The single most boost you can get is from a properly tuned expansion chamber exhaust.
It acts like a reverse turbo charger as it shoves unburnt wasted fuel back into the combustion chamber to increase the gas/air fuel charger.

You have to watch the video for awhile to see how it work by return waves...



... the green is un-burnt fuel that escaped getting shoved back in.

Again, all fine important points above, but if just want to make it go and forget it, that should help.
 


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