my zx50 issues

[Shaka]

Mine has changed so much i'm almost back to stock weights

Me too!

Batman, I think the stock head gasket is aluminum.  At one point I trimmed the stock head gasket inner diameter bigger to use with my BBK.  I just scored it with an exacto knife and used pliers to snap off the inner circle.  Pretty sure it is aluminum.  I also believe it is 0.5 mm thick.  The paper base gasket should be about 0.5mm thick also.  The squish clearance should be greater than 0.7 mm.  I think a lot of it has to do with the head and combustion chamber volume.   You should be good with about 0.8 - 1.0 mm though.  You won't know for sure until you try.  If you get detonation then you either need higher octane fuel, or a larger squish!  I know on my SeaDoo the factory recommends between 1.3 mm - 1.7 mm, they actually make many different thickness base gaskets to achieve the proper squish!  Man, I wish Kymco did that!

[wordslinger]

Oddly enough for us scooter'ers Beer cans make excellent gaskets

..i got's gaskets for sale!!

..how many you want!!

[thebatman]

whaaaat up??? ..ok, i found a local guy that will shave my head pretty cheap(maybe$20),(he has a rod shop here,knows the boss). anyway, i havent tore anything apart, since i didnt have anything set up.... now shakas making me nervous again, detonation???.. what detonation??.    now is the .90mm squish really ideal for a stock cyl, or is it another guessing game(if so, maybe i should play w/gaskets instead)....  he did ask me first thing if i was gonna be able to still use pump gas!!!  u told him i hope so, i will wont i??? i already use 93 w/ 1/2 oz of octane boost(half the time)..   now should i shave head or play with gaskets?   cuz i cant put the metal back..lmao... ....

[art]

You can always add gasket to head if needed.The the predetonation is more of a problem if you change the cylinder hight.If your guy is good he can calculate the squish on the spot for you at that price make him work Ha!While your there have him do the exhaust port too!Just got my people back with the squish and exhaust mods.Nice low and mid gains dont have the top dialed in yet(veriater)but I'm in the over 50 club!

[thebatman]

i was gonna take the head to him, do have gaskets on the way today also, and just shave the .015in. off..my measurement of squish revealed a 1.27mm/.050in. oem squish... what about the exhaust port??? how long does that take??..cant really have much down time right now, just match holes up???..easy/hard??...i wanna be in that club....lmao

[zombie]

That squish # is based on a 50% squish band. It is a generic # but it will work just fine for you bat, as the kymco stock compression ratio is lower than it needs to be. They do this so even regular pump gas will not pre detonate. Once you do shave the head the only draw back is you can never use regular fuel. Either hi test, or as you already do add Octane boost to regular. Cutting the exhaust port can be quite easy on some engines. I have used diamond blade hole saws for cast iron, and regular saws for aluminum. Its basicly the same as most shops will do. Cut an angle to match the flow of the gases. I haven't done this jug, but I have an nc/50 (sold) that I did. Just a few minor tweaks, and it went from 25mph tops to 32mph.

[thebatman]

so i should be good then since i run hi test anyway???guess that means i need to call mike eback and ask about the exhaust port then huh...since he has a car shop, this should be way easy for him...lmao.. got a set of gaskets be here in about 30min...well sh**, guess its on now!!. guess this will suck cuz i guess i will have to break down again to match in afew days later...maybe i can still use same gaskets till then... there wasnt much for matching on a euro ped, cant remember inside mine, never paid attention either tho...lol

[zombie]

If you let him cut the exhaust BE SURE he dosen't touch the port inside the jug. You just want to open the passage, and match it to the angle of the header.

[art]

Ha I'm not a machinest,The mods my guy did were very minute but that was the hold up he had to make a jig to determine the angle,and for $40 bucks I like.(he may be too precise)I know it's a different motor but,here's where i'm at.Still running pump gas(reg)great low and mid.Now running a #115 main could go bigger(don't have)running 8g rollers.Lifted the needle as much as possible(used gasket material)I think I'm running into the limmits of my stock carb,could use bigger pilot,richer needle and 1 to 2 sizes bigger main,at the moment running a bit to lean throughout,but just under 54 mph.I need more gas!ha!Anyway I'm pretty impressed out of a stock jug and carb with pod and pipe.

[sidthesloth]

Hey art, sounds like you have got it all going on pretty good.
You have done it now zombie, I think I will have to buy that die grinder now after all and see what I can do with the ex port, as well as the piston.
Good luck batman, when you get good results it makes it all worth while.

[art]

Ha! I got alot to learn,but I'm having a great time!My old dirt bikes only needed a couple jet changes to soot my needs,This is pushing my limmits and loveing it!

[wordslinger]

..just wanna make mine roadworthy right now....

..smoke is scary...but ya'll all say it's to be expected....

[sidthesloth]

Yeah, I am learning lots. I bought a cheap cylinder from an ebay seller, cheap, not much good but with a hell of a lot of help from the people on this forum we have got it up and running pretty good.

[wordslinger]

...smoke is scary...

..upgrading would be a frickin nightmare right now!!...

 

[sidthesloth]

Go with the smoke, just hang a piece of fish behind ya.