Our KFX80 wasn't running well so I replaced the carb with a new one from Amazon. It still didn't run well so I took it to a mechanic who quickly noted the Chinese carb and proceeded to disassemble the carb and check jets. He said the jets were the wrong size so he corrected them. The quad runs pretty well now...once you get it started which is a real chore. He then checked compression and found it to be really low. He recommended inspecting the cylinder/piston/rings/gaskets. I don't have a lot that I can spend on it at this point before I'm upside down in it but it is really a nice bike and I'd like to get it to run for my son. I think I can do the work myself but would certainly appreciate any advice you may have!

The mechanic recommended only buying Wiseco. I'm seeing top end kits on Ebay with Wiseco pistons for about $130-$140. Are these decent kits? I don't want to waste money on a bad kit or spend unnecessarily on an overpriced one!
https://www.ebay.com/itm/87-06-Suzuk...8AAOSwDnld3UXx
https://www.ebay.com/itm/Cylinder-Wi...6/383421182926

Do I need to replace the wrist pin bearing? Will a generic be okay or do I need that to be Wiseco? Will the gaskets in these kits be okay or do I need Cometic?

I've read about chamfering and checking the ring gaps but can't find where the chamfer should be or what the ring gap should be for this bike. Does anybody have the specs? I've watched rebuild videos, are there any writeups for rebuilding?

@LT80 I've read a lot of your posts and they've been really helpful, thanks for all your contributions!

 

You need to use Suzuki parts. Not Wiseco.
If you are buying the cheapo junk off ebay/amazon, you may need to champher the holes.
It is best to replace the pin, pin brg, and cir clips.
If you can see a gap in the rings, it's ok.

 

Thanks for the quick reply!

One thing I'm trying to understand is the "cheapo junk"...is it just a matter of chamfering and possibly filing the piston rings or are they inferior parts due to metallurgy or other issues?

I'm okay with doing a little extra work to save hundreds but I don't want to do the extra work and then it end up breaking in a short period anyway.

I don't know where I could get the cylinder bored locally but would that be better than replacing it with eBay parts?

 

Many will tell you they are great.
I don't like them because getting a good running one is a crap shoot. The metallurgy is of a terrible mixture. Some ppl use the china cylinder and gt ea Suzuki or Wiseco piston. This does help.
Let's do the math. China kit 40 bucks. Then time to put it together ie: installing one cir clip and installing on the rod. Then a cir clip is going to fly around the room or into the bottom end. Now once all together, we'll give it a go.
Next step would buy a new Suzuki or Wiseco (preferably Suzuki) piston and parts for 80 bucks and put it in your China cylinder. 120 bucks invested and a fair chance it'll be a go.
Or for 40 more bucks (160) you can send me your cylinder and get it back ready for years of use with new Suzuki parts..
Oh yea, you don't need to tag me.