Kymco ZX50

[sidthesloth]

  Cheers mate, I hear ya, mixed results, with the spacer in and using two 0.4mm gaskets the transfer ports are a touch above the piston at b.d.c, the exhaust port is as close to perfectly flush as I can tell, putting my finger through the ex. port it feels flush. Should I sand the spacer or accept it as it is? I can now see the light.

[sidthesloth]

Alright I was wrong there is a small difference in the piston and ex. port, piston is a touch high so I will sand the spacer, should I go for the trans. ports flush or ex. port? I suspect the transfer ports. B.D.C. is 44.6mm, deck height is 3.15.

[zombie]

 You can seal the jug/spacer w/ http://www.permatex.com/products/Automotive/automotive_gasketing/anaerobic_gasket_makers.htm   This may lose you some space vs. gaskets on top, and bottom of the spacer. I forget the #'s but you still need at least .5mm squish. .8mm is best. Or did I get the math wrong and you are now at -3.5mm. on the deck. Ok it's -. My bad... w/ the port height corrected, and the squish now beyond measure, How much of a recess is there in the head before the combustion chamber? That # will give you the amount to shave off the cyl.. - the gasket of course. My advise is to flush the transfers, and notch the piston to get the exhaust correct. The reason for this is to create a flow away from the transfers heading to the exhaust. It will keep the piston cooler, and get a better flow thru the engine. Picture a pie slice. That is what you want to do on the piston. From the dead center create a slope to the exh. port. I know it sounds like a $hit load of drama, but I have been tunning 2t's before any of these computers were around to tell me what I did or didn't know. FLOW is the key. You've come a long way my friend. I hope to see your scoot doing 65mph on the steady. Or at LEAST get some buddies into scootin'/modding w/ you. 

[Calothrix]

Sid, if that scoot's not doin" 65 mph soon.....then I'm a bloody dag!!!  I sense your persistence will pay off soon!!!

[sidthesloth]

Cheers mate, having a slack attack at the moment, out having lunch, will be back on the job soon. Will sand the spacer down a little more, feel more comfortable with gaskets. the piston grooving sounds interesting and look forward to trying it if needed. once that is all sorted will see what needs to come of the cylinder.

[zombie]

You are the best, MATE. Mid night Tues., and finishing my umpteenth beer.

[sidthesloth]

Spacer sanded the transfer ports are very close to flush, the exhaust is only a small section of piston above the bottom of the port.
Deck height is 2.76mm but if we try to machine that much off the cylinder it will be cutting into the top cooling fin. Piston @ B.D.C. is 44.26mm.

[zombie]

At this point I would suggest getting it as close as you can. You know the #'s for the top. I can't wait to hear how it does!

[sidthesloth]

Yeah, I dropped it off this arvo but the bloke who is going to do it wasnt there. I left a note saying what the deck height was but I expect he will ring to see what I want him to do. Will probably be a few days.

[Shaka]

Sounds like you made some good progress!  Good work on the spacer also!  I might have you make me one, I need it 1.3mm thick!    It sounds like Zombie put you down the right track.  You want the trans ports flush to just slightly above the piston at BDC.  You want to utilize the incoming angle of the port to direct the flow up and towards the back of the cylinder.  It's ok if the exhaust is a little lower than the piston as it has an outward flow and piston doesn't disrupt it as much on the way out.  As Zombie said, you can always shave down the piston a little if needed.  I would work on getting the jug shaved and getting the squish set before you have a go at the piston.  You may find it runs well with the current port timing.  I'll have to double check, but I think your exhaust port was a little tall to begin with.  At least comparing to my 2 cylinders.  The interesting correlation I found while port mapping my stock cylinder and my Airsal is the difference in height between the top of the trans. and exhaust port in both 7.5mm.  I'm not sure this is ideal, just found it interesting!

[sidthesloth]

1.6mm, should be doable, then happy sanding. will need a template to get the size and shape, cereal pack will do.

[Shaka]

Haha!  Thanks, I'm going to give it a go.  I just haven't had much luck finding any aluminum stock.  While at the hardware store yesterday I happened upon a gutter end cap for about $1.  I didn't have my calipers on me, but grabbed it anyways.  It turns out it is too thin.  I'll figure it out though. 

[sidthesloth]

Hardware shops around here only stock checker plate but a local fabricator had flat plate in 1.6 and 3mm. I got lucky.

[sidthesloth]

Hey zombie, I had a look at the permatex site, I do use ultra blue, but the other one I use was not on there, Aviation Forma~Gasket
No. 3, non hardening sealant, good stuff, sticky as. Can be messy but is a good sealant, I will use this if I remove a gasket for a test,
curiosity and all that. Permatex is a Locktite company and I think the Quality is still there.

[zombie]

That's the one I couldn't remember the name for #3. It has the same qualities as the OMC perfect seal. The one I was trying to point out was the anaerobic sealer. I will work on perfect surfaces w/out a gasket. It may be good for your spacer/jug set up. I shy away from the blue silicone based sealers. They tend to swell/soften around fuel. With most gaskets I will coat one side w/ sealer, and leave the other dry. That way the parts can come apart w/ out tearing the gaskets. I got the needle today... Thanks again Bro! Shaka, I will look to see if I have any stock that may help. Pretty sure I do.