New Engine after 18,000 miles

[sidthesloth]

Hey rigpa, how did you go removing thd body panels? Was that guide any good?

[rigpa]

next week i plan the big ring replacement and cylinder cleaning.  i have some time off, which i'm sure i'll need.  i'm going to print out this entire thread as a helpful guide along the way.  thanks and i'll let you know how it went/goes.

[sidthesloth]

Good luck, you will be surprised at how easy it will be. When you put your cylinder back on, make sure you have the rings lined up with the pins in the piston, use a torque wrench if you can get hold of one and make sure your gasket faces are clean to ensure a good seal.

[rigpa]

Well..........i have taken off the cylinder and piston.  Both are badly scored from the seize a couple years back when the oil connector inlet came off (the thing that feeds oil into the carb).  Plus the oil expander ring that goes in the bottom most piston ring groove, was broken.  I peeled half of it out, i think the rest is still in the groove.  I gotta say, it was hard work getting to this point.  My biggest problem was not being able to easily get to that last engine cover bolt.  I tried to take the air box off for more room but one of the bolts is stripped.  I eventually got it off anyway.  From there it was pretty easy, although i did have to have help removing the circlips.  So, now i've got to get a new cylinder and piston.  that's what's happening.  thanks for all your help.

linda

[rigpa]

also,  what do people think if i just get the cylinder new and reuse the existing cylinder head, with carbon cleaned, of course.  is this a bad idea?  would save some bucks but worried about the fit.

[sidthesloth]

If you are going with the same size, that head will be fine. Do you really need a new cylinder? Can  your existing one be cleaned up and reused? I thought you got the piston kit? Can you post a pic of your cylinder bore so we can see the damage. When setting up my cylinder I had a lot of trouble and seized gt a few times, but it was still useable.

[thebatman]

im with sid...clean the cyl up and try to use it,just because piston has marks, maybe able to clean the piston, new piston,rings could be a good idea..i had to put some in at 14000...be carefull tho, you could accidently bore it out more.... cyl should be ok since you were riding it too......

[Hoolander2]

Yes, please don't jump to the conclusion you need a new one.  You can have the old one bored to the first oversize and buy first oversize piston kit.  Check for availability of this first of course.  I don't know if they even make oversize for these scooters but they're usually made for every other kind of engine I've ever seen.  Call a local machine shop or two and ask if they do boring.  Many do and it'll be cheaper than a new cylinder.  Perhaps faster than ordering a new one as well. 

They will be able to advise you on the condition of your current cylinder before boring. That is, they may suggest you just have it honed slightly and, if it's measurements are still in spec, it's good.  If not, or if honing doesn't get rid of the scratches, they can then bore it. 

You'll have to supply them with the specs for the cylinder from the shop manual for your scooter -- usually available on line for free. 

 

[Hoolander2]

ZX guys, am I right?  Or does it have like a coated bore which can't be bored? 

[sidthesloth]

I do balieve you are correct Hoolander, I don't know of any oversize specifically, a replacement cylinder is available for a very low price. Unless the damage is extensive I would clean it up and use it with the new rings while looking for a new one if you so desire. If the piston is scored you can clean it up with 600 emory cloth or wet/dry sand paper using a little WD40. If doing this rub around the piston, not up and down. Good luck and let us know how you go with it. Any chance of some pics of the inside of the bore?

[thebatman]

yeah, thats my next project i hope. oversize piston kit.....yeah, pro-x.com has the oversize kits for the zx i know....around the same price as getting a stock piston/rings for me from the localISH dealer..          ............i would venture to say the cyl. should be ok......

[sidthesloth]

Batman to the rescue, good to know that. I hadn't looked myself, went to a 50mm bore straight up.

[rigpa]

Hi ya'll.  okay.  i'll get some sandpaper and see if i can clean the piston and the cylinder.  i'm leary about boring to oversize since i've already ordered the piston rings.  i guess i could always return them but i'll see what some mechanics say about current condition of piston.  it would sure save money and i'd be on the road in no time. thanks.

[sidthesloth]

The piston kit is only about $25, it will have all you need. If you go easy on the bore you will be ok, the piston wont take much to clean. Just to step back a little, when removing the circlips, pack a rag over the crankcase opening to prevent anything from falling into the crankcase.

[rigpa]

here is a pic of the piston striations.