200x top end on 200s bottom end?

[dc8fixer]

Has anyone else did this. I just put a 200s engine in my 85 200x(the kicker gears went out in 200x bottom end). I had a new top end on the 200x so i put that on the 200s bottom end. Its a wiseco 4394m06600 .002 os piston. I can hardly pull it over! I checked the compression. Its 210psi! I guess thats why my kicker gears stripped. I got the piston from my honda dealer. Is this a high compression piston? Or why is the compression so high. The plug looks real lean too. I'm concerned about blowing it up. Any suggestions?

[shortline10]

I hate to be the one to tell you this but the piston # your listing is for a 86/87 atc200x which has a different piston deck height than the later model 200's 1985 and older . The compression listed for that piston is a 10.25:1 which is a little hard to start with a pull starter untill you get the hang of it LOL .
I believe the deck heigth was a mm or so taller on the newer model 200's so your compression might be more than specked .
Prob need to fatten up the main jet to about a 114/120 or so . Good luck



Has anyone else did this. I just put a 200s engine in my 85 200x(the kicker gears went out in 200x bottom end). I had a new top end on the 200x so i put that on the 200s bottom end. Its a wiseco 4394m06600 .002 os piston. I can hardly pull it over! I checked the compression. Its 210psi! I guess thats why my kicker gears stripped. I got the piston from my honda dealer. Is this a high compression piston? Or why is the compression so high. The plug looks real lean too. I'm concerned about blowing it up. Any suggestions?

[dc8fixer]

I hate to be the one to tell you this but the piston # your listing is for a 86/87 atc200x which has a different piston deck height than the later model 200's 1985 and older . The compression listed for that piston is a 10.25:1 which is a little hard to start with a pull starter untill you get the hang of it LOL .
I believe the deck heigth was a mm or so taller on the newer model 200's so your compression might be more than specked .
Prob need to fatten up the main jet to about a 114/120 or so . Good luck


Yes it says right on the box 66mm honda atc/trx200 86-88. I told honda that when they gave it to me. They said the 85 was discontinued. Anyhow. Do you think its ok to run it like it is as long as i can jet it up to make the plug brown and not so lean? Thanks for the quick reply.

[shortline10]

Who did the rebuild ? I always check deck height on piston/cylinder before I install the head . If its not hitting the head I guess your good LOL . It might be the other way around that the deck heigth was less on the 86/87 model which would mean its less than what it should be but from my experance 210 lbs on the compression is prob closer to 11:1 or more .

Their full of it I ordered a wiseco 66mm piston a for a 85 model a month ago and it def wasnt discontinued LOL .
EDIT I just checked the wiseco wesite and pistons are in stock .



Yes it says right on the box 66mm honda atc/trx200 86-88. I told honda that when they gave it to me. They said the 85 was discontinued. Anyhow. Do you think its ok to run it like it is as long as i can jet it up to make the plug brown and not so lean? Thanks for the quick reply.

[dc8fixer]

Thanks shortline. Guess i will contact honda and wiseco and get the right piston for it. I had taken the jug and head to honda to have them rebuild it. I wanted all honda parts to begin with. Anyhow i can use the 200x head on the 200s bottom end right? Sounds like i just need a 85 200x 66mm .002 oversize piston and rings and things will be back where they should be.

[shortline10]

Yep heads and cylinders are interchangable on the reg 200/200x models




Thanks shortline. Guess i will contact honda and wiseco and get the right piston for it. I had taken the jug and head to honda to have them rebuild it. I wanted all honda parts to begin with. Anyhow i can use the 200x head on the 200s bottom end right? Sounds like i just need a 85 200x 66mm .002 oversize piston and rings and things will be back where they should be.

[leevarnado]

you could use a thicker gasket to lower the compression.

[AtcFactoryRacer]

Are their any power differences in doing this? I know visually looking at the two heads (200x,200s) while the engines are assembled, they look the same. Is the porting the same on both heads? same valves? same cam? Do you have to swap the jug too or can you run the 200x head on the 200s jug?

Lol sorry so many questions, but I have a good rebuildable 200s engine other than the cam journal is wore out and i need a new head (junk old design non rebuildable heads). I have a good 200x head laying around, my friend has a decent 84 200s roller he wants hauled off, I could have a new low budget project !

[leevarnado]

the jugs are interchangeable,but with the heads you have to use the same head and rocker cover from the same model bike.example a 200x rocker cover doesnt mate up with a 200e head.if you compare the rocker covers from diff models you will see what im talking about.

[ctbale]

Ok, this might be a hijack, but maybe it wont, while we are on the subject, anyone have experience with the top of the piston for a 83 200X ? I emailed bikerchick, they are the place I think I am going to drop a ton of $$ for my top end, and they said the piston is flat. the one that came out was flat, said "hon da" on the side, but dratv and some ebay sellers have concaved tops?

[oscarmayer]

if you get a 200s head (same as 200x except jsut swap cams out so you get he better cam) you wil get a decompression lever to make it much easier to pull ove th emotor. this will let you run that high comp piston.

they probebly decked the jug and head, which means higher than 10.25:1 your probelby 10.75-11:1 now. you will have to for certain run only 93 fuel, but you will gian a lot more performance! so good thing there!!!!

try that first before you go tryig to get another piston. the reason is the jug was bored/honed to match that piston. a decomp lever will solve your pullstart issues.