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- Basic two-stroke tuning - Tuned Pipes - Fuel
- Tuned Pipe Theory - Cylinder Mapping Primer - Porting the Zenoah
Porting the Zenoah .. A step by step photo gallery / updated
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Because of on going requests for something more step by step
I followed my porting tasks today by taking photos so you can see the sequence.
This engine utilizes all the porting tricks talked about on earlier threads, without going crazy on making massive size ports requireing a LOT more effort.
Degree of work should be fairly easy for a novice too do and those who want to do more servere cutting ?? Visit the F.A.Q's or grafics area for related threads and see how WILD you can go.
Enjoy
This first photo, the tooling marked 1 thru 4 ..... And referanced at each photo to one used.
#1) a 1/2" eliptical on 1/4" shank
#2) a 1/4" ball end cylinder
#3) a 1/4" ball on 1/8" shank
#4) a 1/8" ball end cylinder
All being CARBIDE with chipbreaker profiles.
This shows 3 steps, 1st being the transfer bridge has been cut down @ 1/2" from cylinder base.(In a mill) 2nd the eyebrow cut made to transfer window facing intake port.(cutter #3) 3rd a vertical cut made to meet eyebrow so entire vertical edge of port can be opened up & blended into eyebrow area.(cutter #2)
This photo the intake side transfer runner all cut and blended into eyebrow. (blended in with cutter #4)
The shortened transfer passage bridge is sharpened. (cutter #4)
***** This next step DO WITH CAUTION !! ... If unsure you can be VERY steady & use the right cutter, Omit this step & leave Ex side transfer passages alone *****
Now we have moved to the Exhaust side transfer passages & cut out the EX edge of upper transfer area to increase the width (This done with a 1/4 ball end cylinder (cutter #2) Keep cutter against outside area of transfer passage so the radious of the cutter makes an undercut edge that maintains the flow away from ex port. ( See above *****)
Now the intake window, raised slightly next to ring nub & widened to give @ 1/8" sealing edge width. (cutter #2)
The otherside of intake port, just widened. (cutter #2)
View once intake port was cleaned up and finished. (cutter #2 & #4)
Stock exhaust port & once modified to @178 degrees. (cutter #2)
.002" cut made on top of piston (Total of .004" of diameter)
V shape cut out to increase area, also 1/2 of lightening process removing materal that would support a second ring. Other side not done yet. (cutter #2)
Area outside of pin boss area cut to force flow outward into transfer passages. (cutter #2)
A stock cylinder shown above ... below the modified one.
The finished cylinder having had ALL the finishing blending work done & port edges chamfered. (cutters 2,3 & 4) Port chamfering done by hand with 220 then 600 wet dry paper.
Crankshaft Turbo mod, shown with a stock one. (1" belt sander)
Close up of the finished turbo crank mod.
The crankcase done like this on both halfs (cutter #1)
How cases look with crank installed. ( view is crank position 90 degrees BBDC)
Crank position just BBDC (Note : factory ramps in cases left there & for GOOD reason) ramps dirrect charge up Ex side transfer edge.
The intake manifold opened up to match cylinder & carbs end opened up to .625" diameter. (cutter #2)
A pile of chips from this job thats 1/4" deep and bigger than a silver dollar !! @ 2 1/2" around ( .50 cent shown)
Bron: http://www.bigscale-tourwagens.be/tuning.php?page=5" onclick="window.open(this.href);return false;
Greetz Rob
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,gr.Dr.Dre. 