1985 KX80 bore?

[griffbones]

Originally Posted by jl22n

If i bor my old cylinder over 2mm i think i can use it but i took some pictures of the exhaust ports so mabey someone can tell me if they've been widened to much, so i dont rebuild this think and break a ring a ruin the cylinder. If they have been widened to much can i repair them by filling the corners with weld and grinding it smooth again?

Here is a GREAT deal, Eric Gorr has a used cylinder to fit your bike, it has fresh plating and comes with a new Wiseco top end kit for only $200!

Scroll down the page until you come to this item. It is a little over half way down the page.
Eric Gorr's Forward Motion - High Performance Dirt Bikes

[Stormdragon]

Kustom Kraft can do the whole thing for you. All you need to do is invest more than you spent on the bike originally.

[SlipKid]

I just posted this up in another thread, but this might be a better one to take this subject up in...

I have a KX80 chassis (mid 90's) that the previous owner disassembled the engine on (says it has a bad crank/rod endplay). But, as luck would have it, I have a completely assembled good spare KX100 engine of the same vintage sitting under the workbench. My question is if the KX100 engien would slot-in without much fuss. Would the 80cc radiator be sufficient, and would the 80cc carb work okay if rejetted properly? Would the stock 80cc expansion chamber work? Any other things to consider? Thanks!

[firemat]

according to Wiseco..the 1984-85 model years are not "Electorfusion Bore" cylinders...good luck man

[KDXGarage]

I have the owner / service manuals for the 1984 KX80 and the 1985 KX80. Each mentions the cylinder having the Electrofusion plating.

[firemat]

Then Electorfusion it is...I was just stating what wiseco said in their pdf file for piston kits

[steven27jack]

ya i have a 1985 kx 80 also,it looked like the big end bearing on the crankshaft went out allowing the piston to move an eighth of an inch higher and one of the ports snagged the piston ring,causing it to bend and score up the cylinder verry bad,check your big end bearing before running it with the new top end,if it was me i would replace the big end bearing anyway,just to be on the safe side

[steven27jack]

Originally Posted by KickassKX125

I wouldn't like to sleeve it myself even if I knew what I was doing, I would send it away, anyway where will you get a sleeve from??

you can get sleeves for 60 bucks off of ebay,i resleeved mine myself,im in
11th grade so i just used the school's machine shop,all you have th do is hone out the scored cylinder out to 1mm smaller than the circumfrence of the sleeve and use a hydrolic press and make sure the ports are all straight with each other,the bike used to run but thats a bad model,every time the big end bearing starts to go out the upper piston ring snags one of the ports and scores the hell out of the top end,you might as well spend 200 bucks every 2 races in a total top end rebuild,that small of a bike isn't even worth that much,just keep your eye out for a newer kx 85