ATC 200x Rebuild Compression

[Honda200x.]

I just rebuilt my 85 200x, its bored .50 over with the matching piston for the bore, all new gaskets, I had a valve job done (with new valves installed) the rings are installed correctly, valves are adjusted, timing correct, everything checks out, accept I think i'm running a tiny bit lean. It starts first kick runs amazing in every way, it seems very powerful and everything(accept I haven't really opened it up at all)I did a cold compression test and its 120 psi and then I did a warm compression test and its still 120 psi I didn't do anything performance to the motor so I don't know if this is a fine reading and I didn't do a test before I started running it so I don't know if its gone up at all. I have only been running it(slow break in) for probably an hour and twenty minutes total. So my question is, does this reading sound normal?

[Honda200x.]

Anyone? is this an ok reading?

[Jason125m]

That sounds low. Its supposed to have around 164 psi.

[4cylinders]

hey, how are you doing your compression test?

[jb2wheels]

Does it need more break in time?

If it runs fine and does not smoke, move on and ride!

[Jason125m]

Usually only need 30 minutes of runtime for an accurate reading.

[WilliamJ]

Did you do the test with the throttle fully open?
Did you do a wet test as well? Test dry then put a small squirt of oil in the plug hole which helps to seal the rings if they are faulty and the pressure jumps up. If the valves or head gasket are leaky the oil makes no difference.

If the rings are not sealing it could be that the honing was not sufficient but it could also be faulty rings or rings upside down or wrong size.

It isn’t unusual for the test gauges to read wrong so check it against another machine in good condition.
Bill

[1984 honda 200s]

Jesus, i was getting that on my stock oil burning 200s..... After .20 over wiseco raised it right up and it snaps back and nearley impossible to pull it over in -10 weather !
unsure of the comp.

[Honda200x.]

well that doesn't make me feel to good i have a harbor freight cheep compression tester and could it be that my cam is timed wrong and it's not letting enough air into the chamber to compress? my timing on my am to the rocker cover doesn't line up perfectly but its pretty close should i try one tooth over either way and see if it jumps up, also i had the valve seats cut and new valves put in professionally from g&h discount atv, they did the bore and hone too.

[Honda200x.]

And when I run I don't leak any oil out of any gaskets and yes i'm doing the test at wide open throttle, and no it doesn't smoke at all.

[1984 honda 200s]

What are your valves set at? i would check that first to make sure your clearence is correct.

[Honda200x.]

when i did the rebuild i set em to the correct clearance but would that make a 40 psi difference?

[1984 honda 200s]

I would think so, when i did my rebuild i set them wrong, they were at 0.008... made a hell of a tick... so i checked the manual again and its supposed to be at 0.002
The 200x is supposed to be .003 for both exhaust and intake..

[Honda200x.]

ok ill check it does tick a lot how tight should it be on the feeler gauge

[1984 honda 200s]

They both should have Slight resistance on the guage at .003

[Honda200x.]

did the valve clearance an wail i had it all open i tried different gaps with no compression gain, i put oil in the cylinder and it only went up 4 psi when i kick it over slow i can hear a slow slow leak from my exhaust valve but would that make up for 40 psi? and WTF is up with the exhaust valve leak i just had em done!

[Honda200x.]

Its not the valve clearance its set and bolted back up to .003 but wail it was open I tried different gaps and tested the compression and their was no change I can hear a slow leak out of my exhaust valve but what the hell I just had the professionally done by g and h discount atv.

[1984 honda 200s]

I would set them as the manual says at .003, If it isnt smoking or making any noise just run it... it may just have to be broken in still.

[1984 honda 200s]

What kind of piston are you using?
Is your decompressor functional? Maybe its being ''used'' when your kicking your engine over giving you a 120 reading !

[Honda200x.]

it was a shindy piston for a .50 bore on the 83-85 200x

[1984 honda 200s]

Im not sure on the shindy pistons... ive only done one rebuild with a Weisco..
Does your decompression lever work? Maybe its being turned on giving you that 120 reading !

[Dirtcrasher]

120 is super low, something is getting out of the combustion chamber, somewhere.

Did they test the head? If I don't want a valve job, I just squirt carb cleaner on the upside down and look for leakage.

Your spark plug is not letting anything out, is it??

[Honda200x.]

No the plug isn't letting anything out, im not stupid i will test the head gasket with soapy water tomorrow but the only thing i can hear is slight air coming out of my exhaust valve when i kick it over slowly and where is my decompressor i didn't know 200x's had decompressors

[Dirtcrasher]

No one called you stupid; I save that for other people when necessary :D

Just trying to help.

Pressure test the thing if you can't figure it out.....

EDIT - To my knowledge, no 83-85 200X motor had a decompression lever or system.....

[Honda200x.]

Thanks for the info man i'm pretty bummed I have to take the whole thing apart for a third time i'm going to call the place that did my valves and ask for my money back.

[1984 honda 200s]

I would say it might of been on the exhaust stroke when you kicked it over slowly...
It would be bad to constantly hear exhaust flow when kicking it over !
Take the cyl. head off, lay it down on a bench and put gas in the combustion chamber and let it set to see if gas if any leaks out
I had my cousin do mine not a shop, we let the head sit over night with gas in the chamber for like 14 hours and not a drop leaked out !

[Honda200x.]

I think my tester isn't making correct readings it's a harbor freight tester, I tested like three snowmobiles they all showed low compression but they all run amazing and are wicked powerful. I tested my newish stihl chainsaw and it only read 30 psi, I tested my friends trike thats never been rebuilt it is the same exact trike as mine and it gets an identical reading as my trike and mines harder to kick over than his, and his is so fast,(I don't know if mines fast cause ive never tested it)

[barrett8]

it sound like you have an 86-87 200x piston in you 83-85 motor. the 83-85 piston have a taller deck height not much only a few tho so that would do it for ya if you had the 86-87 piston

[1984 honda 200s]

Junk tester, Is there any other testers you could try?

[Honda200x.]

just exchanged it at harbor freight, and the piston box says 83-85 on it

[Honda200x.]

I actually just checked the piston box it says 83-87?????????? so does this mean thats my problem, cause I did a leak down test and its only 8% at tdc. Maybe shindys piston doesnt make more than 120 psi of compression? And if so what would you guys reccomend doing

[barrett8]

the 2 pistons are different heights so your deck high is too low the piston needs to be changed to raise the compression

[yaegerb]

I would recommend buying a wiseco piston guaranteed to fit your bike. I have no idea what the height of the piston should be. Let this be a lesson. 83-85 first gen, 86-87 second gen. Very few parts interchange and if someone is selling something 83-87 double check that the parts are interchangeable. Most sellers of general hardware don't know the differences.

[Honda200x.]

The place i bought it from says they have a 100 present satisfaction guarantee or money back so im all set should i just buy a honda one thats .50 over and also do i need to re hone?

[oscarmayer]

don;t ge a honda one. get a weisco 10.25:1. you'll be very happy you did. since your changing pisotns,t hen yes you need to have it bored/hones to the new piston, so you need the 1 size up from that. if you were .5 then you need to go 1 so you should now be at a 66mm instead of 65mm from stock. (think that is correct) This will ensure everything is right. and also make sure that pale knows the pistons do not roperly fit an 83-85 200x of any kind.

[Honda200x.]

read the rest of the post ive only run this new bore/hone for an hour no way would i go another size up all i need is a hone and i'm not going high compression i want as original as i can get it.

[4cylinders]

whoa, don't change anything.
how many times did you kick it to get that reading?
kick it until the gauge stops moving.
what does it read?

[1984 honda 200s]

I wouldnt go with a stock piston, shindy obviously isnt any good either...
I went Wiseco for my 200s and it works well !
For the wiseco since there forged pistons, you will need another bore over since theres supposed to be more clearence to the cyl. wall since that piston expands more...
Id go Wiseco and forget about it,, problems solved

[WilliamJ]

I believe the Wiseco forged piston requires an additional 1 thou clearance, which will be achieved with a hone by a machine shop (assuming your bore is in good condition).
Bill

[oscarmayer]

read the rest of the post ive only run this new bore/hone for an hour no way would i go another size up all i need is a hone and i'm not going high compression i want as original as i can get it.

that does NOT matter... These are different pisotns, different specs. even the same manufacturer you cannot stuff 1 pisotn into a hole measured for anotehr pisotn they must match. that is the very basic of mechanical knowledge. Everything has a specific spec. each piston coudl eb as much as .0012 diffeent in size over the other piston, but it's enough to require a new bore/home if chaning. i udnerstand your thought,b ut it's wrong nad it will cost you. what WILL happen is your piston will get hot, swell, grab the sidewalls of the yclinder and either get jamed stopped breaking rod and crank or ruin a $120 pisotn and jug and head assembly. i don;t k now about you but that $45 is not worth $300+ in repairs.

do ewhat ever you feel, but just remember, the only words you will hear form me if you don't do it right and WHEN ir breaks is "I told you so...." (sorry, but when you ask a quesiton and you egt a correct answer then defend the wrong one, why even ask it? pretty much a waste of our time trying ot help if your goig to ignore correct answers...)

[Scootertrash]

First, Verify that you have the proper piston
Then, I would try another compression tester or 2. Is your compression tester possibly missing an o-ring?
Then, if it's still not reading right we'll go from there.

If your machine shop was any good they honed/bored the cylinder to fit the piston, which is the proper way to do it.

ETA: After looking at the Shindy pistons, they do in fact list the 200X piston as 83-87. Your piston should be the same as the OTHER Honda 200 motors in the 81-85 range (200S, 200M, 200ES, etc).

The part number for the other Honda 200 motors is different than the part number for the piston you have. These are the Shindy +.50 numbers:
200X part #04-023 (86-88 TRX200SX is also included in this part number)
Other 200 models part #04-013

It is very possible you have the wrong piston. I'm going to go out and a limb here and say that you do have the wrong piston, just going from the part numbers


I do not know the difference between the 83-85 200X piston and the 86-87 200X piston, but it seems to me that in another thread someone stated that the 86-87 has a higher dome on the piston. If in fact that is true, this could potentially be a problem if it's high enough to contact the exhaust valve on the exhaust stroke when the exhaust valve is open, as in possibly bending the valve if they hit.

This in turn could cause a pressure leaking sound at the exhaust port on the compression stroke if the valve got bent.

So first you need to verify you have the correct piston.

FWIW, I only use Wiseco pistons and have for years, in everything from a Honda XR80 up to my 1340cc Harley, and I've never had a problem.

[Honda200x.]

Im sorry oscermayer I should have listened, the piston box says 83-87 ATC 200x on it and .50 over on it, I measured my bore and its 65.5 mm and stock is 65. I don't want to get a wiseco high compression piston, and they don't sell one thats the stock compression as most of you guys probably know, if I were to buy a Honda .50 over piston wouldn't it fit correctly, I guess I don't understand, I just want the thing to be as reliable and as stock as possible, if I only have an 8%ish leak down than my valves are fine right?

http://www.shspowersports.com/fiche_section_detail.asp?section=117496&category=ATVs&make=HONDA&year=1985&fveh=2806

couldn't I get number three that says .50 (and the rings that match it) and call it a day?

[Honda200x.]

The label on the box says all this

04-023 PISTON KIT
0.50 ATC200x (83-87)
OVER TRX200SX (86-88)

Shindy Products. Inc.
Made In Japan

Thats what the label on the box looks like and states.

[oscarmayer]

here's why. when they cut a piston the meachine is enver 100% exact for every piston. each batch can very in diamater. so because of this reason, this is why you would to at minimum get qa re-hone but best to do a new bore/hone to confirm it's dead perfect. you can try the poor man's way but i didn't post what will happen out of guessing. I've done it. thatw as expirene talking. LOL yea i was young once too and thougth better than the guy that told me that exact same thing I typed to you. I was actually laughing when I said it soorry if it came off bad, I was really laughing. honestly, I'd hate for you too spend the $ on the same sized piston only to discover the bore for the other is too big. if that happens then you have to get another piston that is .5mm larger than that (66mm total) and your back to bore and hone. that is why I ercommended you get a 66mm and be doen with it. you know it will be 100% dead nuts on and work perfect.
I always use weisco pisotns. they outlast stockers and offer little better peformance on a stock bike. the 10.25:1 is perfect for a st9ocker, but that's a personal preference. the honda XR200 has a .5:1 bump from the stocker 200x so that would work (of same year), or as you mented a stocker style 200x is fine, it's all personal preference. either way, good luck and enjoy the bike. ocen your over this hump, you'll be fine.

as mentioned, before you do anything, get it professionally checked out. the $45 a shop may charge to run a test and check is well worth it. if you were close, I'd check it out. see if any of the mn guys are willing to help ya out. i bet for soem pizza and beer you'd get soe help. :) beer and food always works for me! :D

btw, on the parts list, if you go with oem honda, you will need the piston, the pin, the pin clips, and the piston ring set so as follows:
1 of numbers 2, 3, 4 and 2 of number 15 (may consider geting 1 extra of #15, there's always a chance of loosing 1 when isntalling and it's a pitta tearing up the garage trying to find it after it flinged itself across the garage. ;) )

[WilliamJ]

The stock Honda item should be fine. There are still quite a few running around perfectly happy. Its just that if you want to use more revs than stock or just lots of revs all the time then, generally speaking, a forged piston will cope with higher piston speeds than a cast piston. You need to check that your bore matches the piston properly and has the correct clearance, and a cylinder needs a proper bore gauge to measure it accurately. Piston will be the size that Honda say it is but always check in case the box has been labelled wrong. You should have between 1 and 2 thou clearance at the fattest point of the piston skirt when new and 4 thou is the service limit quoted.
Bill

[Scootertrash]

Stock compression ratio is 9.6:1, the Wiseco bumps it up to 10.25:1 (not something I would call high compression in this case), unless you went with the 12:1 high compression piston

[Honda200x.]

Thanks for the info guys i really appreciate it, isn't the next size up for me .75?, and honda doesn't sell a piston for that i belive, my only concern is my kick starter slips just a little probably once every 20 kicks and wouldn't the high compression piston accelerate the process, also don't you need to run 93 with the 10.5 to 1 and would I need high compression gaskets?

[Scootertrash]

Thanks for the info guys i really appreciate it, isn't the next size up for me .75?, and honda doesn't sell a piston for that i belive, my only concern is my kick starter slips just a little probably once every 20 kicks and wouldn't the high compression piston accelerate the process, also don't you need to run 93 with the 10.5 to 1 and would I need high compression gaskets?

Nope.

I Just put the 10.25:1 in my 200S and used a regular gasket set, Vesrah gaskets if I remember correctly. I just run regular gas and it runs great.

You are correct on Honda not selling a .75 over piston. I'm not sure if you get your pistons at the same place that does your machine work, but it is possible that you will not have to bore another size over. If you could get the bore dimension, you could call Wiseco and see if your bore falls into their tolerances for their .50 over piston. It could save you the cost of another bore job. ;)

As far as the kicker slipping, there is a fix for those gears, an upgraded spring for the kicker or you could shim it with very thin shim washers. The fix for the gears is back cutting them slightly so they lock together better.

Here is a link to the 200X kicker slippage thread. The gear mod starts close to the bottom of the 2nd page and there are some good instructions:
http://www.3wheelerworld.com/showthread.php/57972-What-makes-200x-kick-starters-slip-Several-soloutions-inside!

[Honda200x.]

That makes me feel much better about it so like 87-89 is fine? And do you think I will have any overheating problems with a 1.00 bore and a high compression piston?

[yaegerb]

I don't know what you are looking to spend but for 210.00 you can go with a 10.5:1 piston from Powroll. It comes with the necessary gaskets, pin, everything you need. Just got done doing the kicker mod. You can mess with the shims but the only way to fix is to back cut the gears. Also you wont need to run high octane with a 10.5:1 piston. So, 210 + 50.00 for a new bore + 10 bucks to re-jet. With tax you are going to spend approx 290.00 for a reliable motor with great components.

[Scootertrash]

[QUOTE=Honda200x.;1104314]That makes me feel much better about it so like 87-89 is fine? And do you think I will have any overheating problems with a 1.00 bore and a high compression piston?[/QUOTE

87-89 octane? Yes you will be fine, and you can run 93 or whatever it is if you want.

And, if you have to go to 1.00 over, you shouldn't have any problems with overheating.

Nothing against yaegerb or Poweroll, but:

Don't assume that you have to do another bore job. Pull the cylinder and have it measured like I said in my previous post. It doesn't make sense to spend an extra 50.00 if you don't need to.

You can get a Wiseco piston on ebay for less than 120.00 (or close) Both Wiseco and Poweroll are forged pistons. (I wonder who makes the pistons for Poweroll?)
Base gasket from Honda is around 6.00
Head gasket from Honda is around 15.00

or you could go with a Cometic or other top end gasket set for around 20.00-25.00 and have a spare exhaust gasket and a few other spare gaskets/seals just in case. ;)

You already have the jets for .50 over, so if it works out in your favor you won't have to buy more jets.

So for around 150.00-160.00 (with quick touch up hone job if you so desire) you can still have a reliable motor with great components, and over 100.00 left over to buy gas, beer and take your favorite girl out for a nice dinner.

[Honda200x.]

Im going to pull the whole thing apart tomorrow then bring the cylinder to the machine shop down my road(literally down my road) and have them measure It, so if it's exactly 65.5 mm then I can just buy the 65.5 mm 10.25 to 1 piston wiseco offers(and rings, pin and clips) and be done with it right? Cause if my bore is 65.5 mm then doesn't that mean the piston that wiseco says is for 65.5 mm is all set to fit in there with the right clearances? Then if it is exact then i'll have them do a quick hone and call it a day, and with that piston will the Honda gaskets work just fine? And i'm not going to open my bottom end and fix the slipping gears cause I cant back cut them, do you think ill be fine if it almost never slips. I've rebuilt many motors and know a lot about them but I have never done a bore on a motor just bought new cylinders, thats the reason for all the question's, by the way i'm 15.

[Scootertrash]

Have your shop give you the dimensions of the cylinder and the piston, then call Wiseco and see if their piston falls into the specs for the cylinder.

Here is a Wiseco piston kit for 104.22. Piston, rings, clips and pin.:

http://www.ebay.com/itm/Wiseco-Piston-Kit-Honda-ATC200S-81-86-65-5mm-/330439846045?pt=Motors_ATV_Parts_Accessories&hash=item4cefbfe89d&vxp=mtr

Or, if you want to save ordering the gaskets from Honda, here is a Wiseco top end kit for 136.74. I know it says 200S, but it's the same kit for the 83-85 200X. Same as above, but has all the gaskets included:

http://www.ebay.com/itm/Wiseco-Top-End-Piston-Kit-ATC200S-81-86-65-5mm-/220616496104?hash=item335dc493e8&item=220616496104&pt=Motors_ATV_Parts_Accessories&vxp=mtr

Don't order your kit until you verify the dimensions. ;)

[Dirtcrasher]

Im going to pull the whole thing apart tomorrow then bring the cylinder to the machine shop down my road(literally down my road) and have them measure It, so if it's exactly 65.5 mm then I can just buy the 65.5 mm 10.25 to 1 piston wiseco offers(and rings, pin and clips) and be done with it right? Cause if my bore is 65.5 mm then doesn't that mean the piston that wiseco says is for 65.5 mm is all set to fit in there with the right clearances? Then if it is exact then i'll have them do a quick hone and call it a day, and with that piston will the Honda gaskets work just fine? And i'm not going to open my bottom end and fix the slipping gears cause I cant back cut them, do you think ill be fine if it almost never slips. I've rebuilt many motors and know a lot about them but I have never done a bore on a motor just bought new cylinders, thats the reason for all the question's, by the way i'm 15.

That would be in a perfect world,but; a Wiseco 65.5 could be 65.503. I don't know what their tolerance are.

I know you just trying to figure it and probably broke. We've all been there. I would bring the new piston and jug and let them check the fit.

In all honesty, I just tossed in a 10.25 into my 350X crate motor and hoped for the best :D but honestly, it's better check it now than later........