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Author Topic: Kymco ZX50  (Read 102975 times)

Shaka

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Re: Kymco ZX50
« Reply #285 on: April 13, 2010, 03:24:43 AM »
Idk, doesn't look too good either.  I bet it would run much better with the ports fully exposed!  I agree with setting the squish first and then adjusting to the bottom of the jug to correct the port timings.  I just have a feeling that to be set up properly, the jug needs to be shaved on the top and the gaskets below need to be thicker to achieve the optimum squish.  Gotta get some accurate measurements and do some math!  I'm going to tear down my engine and take some measurements and see where I sit tomorrow afternoon.  I'll have a porting program by tomorrow evening, at least that's my goal.  If you can give me some numbers Sid, I'd be happy to crunch them for you!
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sidthesloth

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Re: Kymco ZX50
« Reply #286 on: April 13, 2010, 04:07:52 AM »
Hi, you have lost me, if we find the squish and transfer that to the bottom that will raise the jug, at the moment the piston is very close to flush (just a little shy). the piston is about 1 - 2 mm above the bottom of the trans. ports.
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ZX50, 47mm cyl. kit, TZR50 CDI. Michelin Pilot Sport tyres,
Next performance mod; pumping the tyres up.

zombie

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Re: Kymco ZX50
« Reply #287 on: April 13, 2010, 04:08:11 AM »
Right on Shaka!
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zombie

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Re: Kymco ZX50
« Reply #288 on: April 13, 2010, 04:16:44 AM »
Set the squish w/ no base gasket and = to the difference of the piston/transfers (That 1-2mm) Then you will have 1.5 or so mm to play with. If it ran well with 2 base gaskets just say .9mm then subtract that from the head side = 1.1mm, and you will still have the squish where you need it. all you are doing at that point is altering the jug timing, and keeping the squish. There are loads of spacers available to further adjust if you need higher numbers or lower squish, but you have to start somewhere.
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"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

sidthesloth

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Re: Kymco ZX50
« Reply #289 on: April 13, 2010, 05:46:19 AM »
G'Day, I have managed to get a squish measure, with no base gasket, no head gasket the squish is 0.51~0.55, reads from 2 points.
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ZX50, 47mm cyl. kit, TZR50 CDI. Michelin Pilot Sport tyres,
Next performance mod; pumping the tyres up.

Shaka

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Re: Kymco ZX50
« Reply #290 on: April 13, 2010, 06:13:27 AM »
That's a start!  You should be able to figure out how much to shave off the head and/or jug now.
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sidthesloth

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Re: Kymco ZX50
« Reply #291 on: April 13, 2010, 10:56:31 AM »
G'Day zombie and Shaka, I am sorry if I have got this wrong, but would it be better to raise the jug to have the piston level with the bottom of the ports and then shave the top back to the piston?
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ZX50, 47mm cyl. kit, TZR50 CDI. Michelin Pilot Sport tyres,
Next performance mod; pumping the tyres up.

Shaka

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Re: Kymco ZX50
« Reply #292 on: April 13, 2010, 02:34:08 PM »
It really depends on the top of the port measurements.  The duration of the port opening is the actual important measurement.  You have the right idea though!  I'm going to download the software and I'll run your rough numbers hopefully this afternoon.
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zombie

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Re: Kymco ZX50
« Reply #293 on: April 13, 2010, 03:14:46 PM »
That's GREAT sid! How thick is the head gasket you used to get the measure? From that you will know whatever you raise the jug by the equal will have to come off the head! Lets let shaka punch some #'s, and see what it says your set up is doing. W/ the indexing, and squish set, and your knowing the kit ran best w/ the jug raised the #'s will give the rest of the set up. I do see the light~go into the light baby~No wait Don't go into the light!  Anyone there?  Mommy??? Daddy???
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"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

Shaka

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Re: Kymco ZX50
« Reply #294 on: April 13, 2010, 04:36:22 PM »
In the first chapter of Bell's book it talks about cylinder head design.  I remember something about If you shave a certain amount off the head you have to increase the size of the combustion chamber to re-equalize the compression ratio.  There is a formula to figure out how much.  That is something an experienced head maker/tuner would have to do though.  I don't want to get Sid in over his head!  Pun intended! ;)
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zombie

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Re: Kymco ZX50
« Reply #295 on: April 13, 2010, 08:07:38 PM »
No Doubt! I read but didn't see. No head gasket. W/ .5, and a .5mm gasket you are almost perfect on the head/squish. A .3mm head gasket would be PERFECT. Forget about shaving the jug. Too much $'s/trouble. From this point raising the jug to where you need it, and shaving the head to = the base gaskets will be the most direct route. If you find it runs well w/ out further shaving of the head all the better. There is always a line where it all goes back to $hit. But w/ these constants figured it will be MUCH easier to recover using shims, and gaskets.
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"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

Shaka

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Re: Kymco ZX50
« Reply #296 on: April 13, 2010, 08:37:41 PM »
If I read it all right, it was .5mm with no head or base gasket.  I think the best plan of attack assuming that your gaskets are .5mm like mine, is to shave .5mm off the head and run one .5mm base and one .5mm head gasket.  That should raise the ports so they are closer to the top of the piston and leave a squish of .8mm.
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wordslinger

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Re: Kymco ZX50
« Reply #297 on: April 13, 2010, 08:39:27 PM »
...man...ya'll need to get a 4t....

 ;D
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zombie

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Re: Kymco ZX50
« Reply #298 on: April 13, 2010, 08:44:41 PM »
We ALL need better JOBS!!! Or maybe a benefactor, so as to play scoots all day. While my ex was here I was playing Lamb's in the basement...  Never got the lotion back...
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"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

wordslinger

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Re: Kymco ZX50
« Reply #299 on: April 13, 2010, 08:47:34 PM »
...been kinda following this thread...

..all this talk about jugs, and shaving and squishing....

...dang....
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