Can anyone find me an 86 200X 11:1 piston kit?? 12:1?? GOT ONE??

[Dirtcrasher]

I sent an email to Arias, no response yet, not sure if they make them.

They responded - 500$ for 2 of them :(

Some of you guys are GREAT at finding stuff.....

LAST POST IS EDITED....

Looking for a WISECO 12:1 now, just not a 120$ Dennis Kirk one :rolleyes:

[edog]

Why don't you go with the 10.5 to 1 and have the head shaved 2 thousands of an inch?

[SWIGIN]

.002 wont do anything

what i did on my 350x is started with a 12 to 1 and turned it in a lathe to lower the compression to about 11-1

i had a old 10.25-1 and this 12-1 so i just turned it 1/2 the difference in highth

[The Goat]

dirt...all the pistons interchange between years i believe. the difference in cc's is entirely with stroke.

I can get em pretty cheap if you're interested. wiseco...both 10.25 and 12:1

[Dirtcrasher]

Why don't you go with the 10.5 to 1 and have the head shaved 2 thousands of an inch?

And... who told you that .002 will increase the compression to 11:1??

Not trying to bust your balls but where did that amount come from?? :wondering , I'd think more like .020 but again, thats just a mere guess. Not too mention that they only offer 10.25:1 or 12:1.

I called ARAIS today and they will make 2 - 11:1 pistons for 500$ :lol: :lol: :lol: I won't be buying those. While I had him on the phone, he seemed knowledgeable, I asked him about buying a 12:1 piston, chucking it in a lathe and removing material like Billy did. BUT, I already knew what his answer would be. Without actual engineering information, how much material to remove would be a mere guess.....

So, you might ask why 11:1? I don't want to be limited to race gas for a 12:1 that goes bad if it sits around, nor pay the price tag for it. There has been talk about 12:1 running just fine on 93 octane but that certainly isn't what I have read in the past. I was hoping with the correct timing that I could run 11:1 on 93 octane and that would match the cam I have close enough. I'm not WAX or Driscoll or Bubba Stewart and I just want to end up with a strong running reliable motor that I don't have to worry about pinging with......


dirt...all the pistons interchange between years i believe. the difference in cc's is entirely with stroke.

I can get em pretty cheap if you're interested. wiseco...both 10.25 and 12:1

Hey Goat, see what you can get the 10.25:1 kit if you could please and thanks for the offer.............

[thefox]

dirt...all the pistons interchange between years i believe. the difference in cc's is entirely with stroke.

I can get em pretty cheap if you're interested. wiseco...both 10.25 and 12:1

Same size bore, correct, but different pistons. The Wiesco part # is different between the 1st and 2nd gen 200x and a member tried using a 2nd gen in a 1st gen 200x and it didn't work (I think the pin is lower on the 2nd gen piston, or something like that).

Anyways, make sure it is for the correct year.

[The Goat]

I'm looking at multiple wiseco listings now...including the one in my parts book, and it shows the same pistons for all 200 hondas...

[Dirtcrasher]

I'm looking at multiple wiseco listings now...including the one in my parts book, and it shows the same pistons for all 200 hondas...


Thats odd because there was definitely huge changes in each motor including bore and stroke. But of course I like the 86 mucho more :D and this ones gonna rip.............

[Bryan Raffa]

read the wiesco part number.. there diffrent!

[The Goat]

I'll have to hold off on that price dirt...I'm gonna call my distributor tomorrow and give em a piece of my mind. lol. actually just give em the info and help em out.

[edog]

And... who told you that .002 will increase the compression to 11:1??

Not trying to bust your balls but where did that amount come from?? :wondering , I'd think more like .020 but again, thats just a mere guess. Not too mention that they only offer 10.25:1 or 12:1.

I called ARAIS today and they will make 2 - 11:1 pistons for 500$ :lol: :lol: :lol: I won't be buying those. While I had him on the phone, he seemed knowledgeable, I asked him about buying a 12:1 piston, chucking it in a lathe and removing material like Billy did. BUT, I already knew what his answer would be. Without actual engineering information, how much material to remove would be a mere guess.....

So, you might ask why 11:1? I don't want to be limited to race gas for a 12:1 that goes bad if it sits around, nor pay the price tag for it. There has been talk about 12:1 running just fine on 93 octane but that certainly isn't what I have read in the past. I was hoping with the correct timing that I could run 11:1 on 93 octane and that would match the cam I have close enough. I'm not WAX or Driscoll or Bubba Stewart and I just want to end up with a strong running reliable motor that I don't have to worry about pinging with......



Hey Goat, see what you can get the 10.25:1 kit if you could please and thanks for the offer.............

I can't edit.:rolleyes:

[Billy Golightly]

And... who told you that .002 will increase the compression to 11:1??

Not trying to bust your balls but where did that amount come from?? :wondering , I'd think more like .020 but again, thats just a mere guess. Not too mention that they only offer 10.25:1 or 12:1.

I called ARAIS today and they will make 2 - 11:1 pistons for 500$ :lol: :lol: :lol: I won't be buying those. While I had him on the phone, he seemed knowledgeable, I asked him about buying a 12:1 piston, chucking it in a lathe and removing material like Billy did. BUT, I already knew what his answer would be. Without actual engineering information, how much material to remove would be a mere guess.....

So, you might ask why 11:1? I don't want to be limited to race gas for a 12:1 that goes bad if it sits around, nor pay the price tag for it. There has been talk about 12:1 running just fine on 93 octane but that certainly isn't what I have read in the past. I was hoping with the correct timing that I could run 11:1 on 93 octane and that would match the cam I have close enough. I'm not WAX or Driscoll or Bubba Stewart and I just want to end up with a strong running reliable motor that I don't have to worry about pinging with......



Hey Goat, see what you can get the 10.25:1 kit if you could please and thanks for the offer.............



Not trying to second guess a piston manufacturer (OK, I guess I am :D) But all you'd have to do is take a simple CC measurement of the combustion chamber with the valves closed and the piston at TDC. Determine the compression ratio then (Which should be very close to the advertised amount) and then play with the numbers of additional combustion chamber cc size until you get the amount your desiring. You'll have a more accurate idea too because of varying gasket thicknesses too. I can't remember the exact formula for calculating the compression ratio off the top of my head but if your interested I'll dig it out of one of my books and post it. Thats what I'd do if I were in your position.

[Dirtcrasher]

Not trying to second guess a piston manufacturer (OK, I guess I am :D) But all you'd have to do is take a simple CC measurement of the combustion chamber with the valves closed and the piston at TDC. Determine the compression ratio then (Which should be very close to the advertised amount) and then play with the numbers of additional combustion chamber cc size until you get the amount your desiring. You'll have a more accurate idea too because of varying gasket thicknesses too. I can't remember the exact formula for calculating the compression ratio off the top of my head but if your interested I'll dig it out of one of my books and post it. Thats what I'd do if I were in your position.

Well, you obviously have no fear of taking a few thousandths off of a piston :lol:

Yes, please dig that out Billy. Then I can grab a 12:1 and go down to 11:1 from there, hopefully..... Guys the only goal is to get away with running 93 octane, maybe 12:1 can be built to run that but I don't want to chance it.....

[The Goat]

didn't like the 2001 400ex come stock at 11:1...maybe i'm an idiot.

idk, i was just thinking that they didn't ping however high their compression ratio was.

[SWIGIN]

Well, you obviously have no fear of taking a few thousandths off of a piston :lol:

Yes, please dig that out Billy. Then I can grab a 12:1 and go down to 11:1 from there, hopefully..... Guys the only goal is to get away with running 93 octane, maybe 12:1 can be built to run that but I don't want to chance it.....


i turn down 12-1 pistons all the time....and they all have ran on pump gas when im done.

its no big deal....i just never bothered to check the new compression

i just know its between 10.25 and 12-1

[Billy Golightly]

OK, here we go.



CR = (CV+CCV) / CCV


Formula key:

CR= Compression Ratio
CV= Cylinder Volume
CCV= combustion chamber volume.


Cylinder volume must be calculated, luckily its pretty easy.


CV= (3.1416xD²xS) / 4000


Formula Key:

CV=Cylinder Volume
D² (Which is to the second power)=bore in mm
S=stroke in mm


Combustion chamber volume usually must be measured manually via oil in a syringe or a burette of some sort.



So now that we have the mechanics of the forumlas and they've been roughly explained by a mathematical genius like myself :rolleyes::lol: We will continue on to actually executing and USING them.

First lets find your cylinder volume. Obviously the 86-87 200xs are advertised as 199cc. You could use that for a quick and dirty measurement but thats exactly what is if you do not account for cylinder over bores. For ease of calculating, you can figure every .040 thousandths of overbore is equal to 1mm. Its not exact but its close enough for what we're doing. I don't know the stock bore of the x off hand, but if its 64mm and you've got a .080 over cylinder the bore is actually 66mm.

I'm gonna whip out a calculator (the one that comes with windowsXP works fine for me). First I'm going to multiply pi (3.1416) by 66² (which came out to 4356) multiply again by 60mm stroke and I came up with 821086. Now divide that by 4000 and I've got a 205cc cylinder volumed engine.


So now that we for sure know our cylinder volume, I'm going to start working out the compression ratio formula.

CV(205) + CCV(16) (I don't know this #, but I'm gonna take a guess and use 16cc as a number) Those two numbers make 221. Now divide 221 by your same # you used for the CCV (16) and you arrive at a 13.8125 compression ratio. This is pretty high, so lets try it again with an 24cc volume instead.

205+24=229

229/24=9.541

So CR=9.5

This gives us a 9.5:1 compression ratio from the parameters we've used which is very close to the factory advertised compression ratio.




If you want to bump up Compression ratio (CR) play with the combustion chamber volume (CCV) numbers. There is a way I'm sure of calculating and figuring exactly how much volume would be removed from the top of a piston by converting the area and depth of a cut int a cc volume, but I don't know that off hand either and it would take some more research to find it. It should be a pretty straight forward deal (lengthXwidthXheight for cubes, you'd have to use pi in there somewhere since we're doing round cuts) but like I said I don't know it off hand. Some of the other infinitely more informed math gurus here can answer that one for us :)

[Dirtcrasher]

Ooooooooooooooooooh K......................

So, I guess I'll just throw it in the lathe and wing it like you did :lol: :lol:

J/K, gee, what a shame geek isn't here to help :naughty:

Anyhow, thats some crazy math but easy nonetheless. Thanks for taking the time to post that :beer

The dome of the piston is curved so each lathe pass removes even more material. There must be a way to measure it with liquid?

Friggin lack of parts for the 86!! :mad:

Oh well, we gotta figure it out sooner or later :wondering

[Billy Golightly]

Yeah the high compression 4 stroke pistons normally have the domes with the valve cut outs. Hell put some water in a small plastic container with some scaling on it like a 1/8in deep and see how much it rises with that much of the piston sticking down in it? More then one way to skin a cat :)

[Dirtcrasher]

More then one way to skin a cat :)

LMFAO.......:lol:

[honda250sx]

Steve-o how about a nice plastic syringe. They can be bought in most cooking aisle's and pet stores and measure in CC's. Come in thru the spark plug maybe? I was thinking oil instead of water?

[OldSchoolin86]

didn't like the 2001 400ex come stock at 11:1...maybe i'm an idiot.More like 9:1 compression.

11:1 is the most you want to run in an air cooled bike on pump gas but even that can ping depending on your total set-up. If you have E85 available you can run 12:1 all day without pinging but then you have to find it when riding out of your area. As far as getting 11:1 SWIGIN has the right idea. Just get the 12:1 and have a shop turn it down. Any competent motor shop should be able to do it fairly cheap. Even if they're a little off you'll never notice a difference between plus or minus .1

[Dirtcrasher]

Steve-o how about a nice plastic syringe. They can be bought in most cooking aisle's and pet stores and measure in CC's. Come in thru the spark plug maybe? I was thinking oil instead of water?

Hey bud, thats an idea, I already have a few of those for bleeding brakes and injecting grease etc etc. I have a huge one I use to put SLIME in tires with :lol: .

Brings about more thoughts.......

I was thinking about another way that may be a fair way of getting about 11:1.

What if I bought both an 10.25:1 and 12:1 from Wiseco. Then I measure out say 1000cc in a container, insert the piston dome side down and measure the amount it rises. Then, do the same with the other piston. Each piston would be inserted to exactly the same position using the wrist pin hole as a guide.

Then I can toss the piston in my SouthBend Lathe and turn it down a bit, toss it back in the liquid and continue this until I am between the initial 2 numbers. That would bring me about 11:1.

Any thoughts on this?? :D

[SWIGIN]

or just measure the highth of both and go in between

just dont make the top any thiner then a stock piston

[Billy Golightly]

Thats similar to what I had suggested DirtCrasher. I don't see any reason at all why it wouldn't work.

[Dirtcrasher]

OK, so I'm gonna go 12:1 and maybe turn it down based on all the above info.

Then I'll break it in and run it. I have numerous motors so I can expirement a bit anyhow, I just can't ruin this head I have.....

Anybody got an overbore 12:1 WISECO piston kit for this??