Hello all, I'm going to jump on this thread since I'm having some like issues. I've received some great help and advice from LT80 and others in the past and their expertise is rock solid imo. So here goes...I bought what I believe is a 1999 LT80 a couple years go, and with help from this forum I got it
running in no time, it's been fine till this past month. I just couldn't get it to start without spraying go go juice. A comp test showed 35 psi, so I went a bought a ebay cheapo kit and installed it. (45.00) for jug, piston, rings etc., comp tested at 112 psi, ATV ran great for about 45 minutes then died, took comp again it's down to 55 psi. Pulled cheapo apart and piston is trash. Seller provided a full refund. Now I look over old piston (which looks in good shape) and I believe what has been in the atv for last few years is a wiseco 2 mm os piston. Top of piston has 673M05200 stamped in it. My question is, can I reuse the wiseco piston (I know not a LT80 fav) and just buy rings??? But what size and type? Can I just buy 2 over rings online or do I take piston and cylinder to Suzuki to measure for rings? I'm sure I can cross-hatch the bore? Old rings have nothing stamped on them and they don't seem to be angled. Any input and info from the knowledge base here would be greatly appreciated. Grandkids love this atv! Thanks all



2 over wiseco ?

 

You need to measure the bore too. I'm betting that the bore size is wore too much for any of your mentioned options.
52mm has to be a wiseco. Suzuki only goes 1.0 over. Pro-x has 1.5 over pistons.
Maybe try a stock Suzuki piston in the china cylinder (after clearances are checked).
I have bored (.5 over) Suzuki cylinders/pistons here if interested.

 

 

Not sure why pic overwrote my text.
Anyway, I was able to look up that number on top of the piston and it is wiseco 2 over.
Thx for the reply LT80,
I cleaned cylinder and took the measurements at top and bottom. I don't have means to measure middle area. I would be interested in what you have. Probably my best option.

 

LT80, let's talk about the .5 over Suzuki set you have. That might be my best bet. I sent you a pm.

p.s. Besides the measurements I sent in above post, is there a way to measure middle bore without an inside mic? Also with those measurements posted above, what do you think chances are of getting 2 over wiseco rings to seat??? Slim to none? Thanks

 

You can measure with a inside but your measurements would indicate a pretty straight bore.
So anyways, your cylinder/piston has 7-8 thousandths of clearance which puts it in the wore out stage. A new piston and rings may snug it up a lil. I'd guess it'd bring it down to 5-6 thousandths. Clearly a waste of money.
Anyways, I'll respond to the PM and you can get a good life out of a Suzuki cylinder and piston.

 

Thx for everything LT80, and all members for the support and knowledge they post. I can't wait for the parts and grandkids are excited to be riding soon. Their little jr50 is fun, but one bike for 3 kids just ain't cutting it 😉 I'll post back once atv is back in action. THANKS

 

I did get parts ordered, thx LT80. Any expert advise from the community on break-in, or assembly? I'll use good bearing grease on pin and bearing. Lube cylinder wall a bit with fresh oil. Didn't plan on using anything on gaskets. Is 90 inch lbs ok for head bolts? How about routine maintenance to keep it running tip top? For fuel I run pre-mix and I use Amsoil interceptor 2 stroke. Would you suggest something else and at what ratio? Thx all!

 

If you got it from LT80 the "assembly" should go smooth. I don't use anything but a high quality 2 stroke oil for initial start-up and break-in. Bathe all the bearings in oil...make sure you wash the jug with warm water & soap before assembly. I use a small syringe and insure I get everything oiled (especially the main bearing ports). When ready to slide the jug on lightly coat it with oil...it will lubricate the piston/rings for initial start-up and makes the jug install easy (should just slide down...ensure ring gaps are on the pins and just use fingers to compress). I think manual says 110 inch/lb for head tourqu...just don't go crazy as they are pretty thin bolts. Mine always fire right away (ensure your carb is clean and good-to-go)...I let run for 5-10 min...at varying throttle positions (you'll need to raise the rear wheels off the ground for this)...then I let cool down completely...then re-light it and drive around for however long...just make sure they vary the throttle speed. If you are running the injector I'd pre-mix the first "break-in" tank with a few ounces of oil...if not running the injector I'd premix a little heavier than normal for 1st tank...

My $0.02...

 

Thx dirtdrvil for the input, greatly appreciate that for sure. I don't run injector, had too many issues, its all plugged off and have strictly use Amsoil interceptor 2stroke premix. Should I use something else for breakin? My son got back in town yesterday, so we made an assembly attempt today, but ran into a snag. LT80, I'll send you a pm. Thx again to this forum and all you share.