XR200 piston in an 85 200x???

[mayhem17]

About to order piston and rings for this 85 200x. I have a question about it. Heard of people using the xr200 piston and ring kits on them. Will this work? They are listed sooo much cheaper for basically the same thing. My question is about the compression though. There are the flat top pistons, and I see domed pistons in the xr200's that I can see. Anyone have experience with this?

http://www.ebay.com/itm/Piston-65-5mm-Rings-Wrist-Pin-Kit-Honda-XR-200-13011-446-000-80-83-86-03-/171577144546?hash=item27f2cb74e2&vxp=mtr

http://www.ebay.com/itm/Piston-65-5mm-Dome-Rings-Pin-Clip-Honda-XR-200-Compression-Height-22mm-Standar-/191411440440?hash=item2c9102cb38&vxp=mtr

[mayhem17]

Compared to the cheapest set for the 200x is around $70

[TheRealFatShady]

As far as I know, no, those are diffeent. A friend bought one for his XR200 like it said in the ad.......only the compression height on the oem piston is around 27mm or more and the eBay one is only 22mm.

[barnett468]

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the oem replacement pistons and rings from shindy are made in japan by an oem piston mfg's . . there are no better oem pistons other than possibly an nos honda piston and the kit is only $76.00 . . your not going to find a better deal, especia;lly since an orig honda piston might be around $150.00 without the rings if you can find one..

http://www.hyperparts.com/wc.dll?ctwp~getxref~1001~1002~1~probrand~1~Shindy~ 04-021

http://www.shindypro.com/piston_kits.html

[barnett468]

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you can buy higher compression pistons which will increase power and throttle response a little direct from wiseco for $128.00 or buy a complete kit.

http://www.wiseco.com/ProductSearch.aspx

[oldskool83]

185 200x xr 200 xr 185 xl 185 xl 200 atc200x pistions are all the same for 1st gen 200x.

[YTZ drew]

185 200x xr 200 xr 185 xl 185 xl 200 atc200x pistions are all the same for 1st gen 200x.
185 pistons are not the same as the 200. Also, bike pistons are different than ATC pistons.

atc185= 63mm bore, 8:1 compression
XL185= 63mm / 9:1
XR185= 63mm / 10:1
atc200 (not 200X)= 65mm / 8:1
atc200X= 65mm / 9:1
XR200= 65.5mm / 10:1

[mayhem17]

185 pistons are not the same as the 200. Also, bike pistons are different than ATC pistons.

atc185= 63mm bore, 8:1 compression
XL185= 63mm / 9:1
XR185= 63mm / 10:1
atc200 (not 200X)= 65mm / 8:1
atc200X= 65mm / 9:1
XR200= 65.5mm / 10:1


Bore size being the difference yes. Thats not my question. I'm going to have to bore my cylinder anyhow, and was looking at the xr200 piston as many state that its quite the performance increase with much less cost.

[oldskool83]

design of the pistons are all the same. there are differen compression ratios...you can stick anyone in any bike...so yes they are all the same because ived owned all of them.

ive used the same piston in a XR200 hi compression as in a 200x as in bore 185.

[mayhem17]

Found a domed xr200 piston and ring kit on ebay for $23 shipped that I talked to a few guys about, said they had great luck with them. Hell, for 23 bucks, who cares. lol

[Scootertrash]

Let us know how that piston works out.

Personally, 29.00 piston and rings scare me, and I ain't skeered of nuttin.

Wiseco makes a 10.25:1

"Trust, but verify"

Make sure to verify your piston to cylinder wall clearance and check your ring end gaps prior to install. That should go without saying, but I know guys who get stuff from the machine shop and throw it together without checking

[oldskool83]

only buy weisco.....or cast OEM.....domed just mean higher compression.

[oscarmayer]

XR200 piston will fit just fine w/o any issues. ran them many times for friends. enjoy a budget upgrade. also get the XR200 cam, open the exhaust and bigger carb and your flyin. but the best upgrade is the wiseco. much better response and performance than the XR200.

[TheRealFatShady]

I had a friend who bought that same $23 piston kit a few weeks ago when he was in the exact position as you. Piston kits were like $70 on eBay but that one was only $23 and according to the years/models listed in the ad, it should have fit.

It didn't.

The compression height is different. The top of the piston to the pin is different, it's a lot shorter. The correct ones you need all seem to have the vertical indentation around the wrist pin clips; the diagonal one is for those with a 22mm compression height. He still has that other one brand new with no intention of using it, but didn't want to bother with the hassle of contacting the seller and mailing it back over $20.

[barnett468]

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xlnt point shady

yes, you might ask someone what the compression height is for your piston then ask the seller what the compression height is on his . . the piston they are selling is NOT for your bike . . it is for a chinese made bike and quite possibly a longshen engine . . there are several pistons with the same or similar bore and same pin size, but due to the stroke and rod length etc, they will have a different compression height . . if the compression height of the replacement piston is less, and has the same top as yours, it will have less compression.

Also, its a chinese made piston . . if i have some chinese made sunglasses or watch etc, and they break, they wont destroy my engine.

do it right and you'll only do it once

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[YTZ drew]

Sorry if you all misunderstood my post. I wasn't trying to say that XR pistons would not fit, only that they are not identical to a stock 200X piston. FWIW, I have a stock 10:1 XR185 jug and piston on my 200X. It works just fine. As far as the cheapo aftermarket piston kits, its common to find lower compression height than stock. Its also a common issue with cheap automotive piston kits. Sometimes the aftermarket slugs end up 0.040+ down the hole at tdc!

[mayhem17]

I had spoke to two guys I know on the Honda ATC facebook site that had used the piston I ordered and said that it worked great for them. They used the domed piston which is the one I ordered. I'll check it out once I get it. I figured for that price, and 2 others using it with no issues to date, it couldn't hurt. I will get it and compare to my original first also.

I was wondering if with the lower compression height, but being domed... if maybe being domed which would give it more height, but then being a lower compression height.. if it would somewhat cancel each other out maybe? I'm by far an expert on this. Will be the first time doing it myself.

[barnett468]

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i would have just bought the correct piston . . do it right and you will only do it once.

a compression estimate in your case would be this . . if you have a 10.0 compression piston and you raise the pin by .015", your compression will be 9.5, if you raise it .030", your compression will 9.0 . . if you raise it by .045" it will be 8.5.

[mayhem17]

As stated, was told this was a good option from a few fellow trike riders. Also stated it was a good bang for the buck upgrade. Figured for that small amount of money, its worth finding out myself, and if it doesn't work out, it't only $20 for a good lesson learned.

[barnett468]

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As stated, was told this was a good option from a few fellow trike riders. Also stated it was a good bang for the buck upgrade. Figured for that small amount of money, its worth finding out myself, and if it doesn't work out, it's only $20 for a good lesson learned.

As stated, wrong parts are never a "good" option . . Also since no one has the actual data or has posted compression tests, there is no hard data as to what it will do, however, if shadys info is correct, it will most likely have less compression than a stock piston . . Even if it actually does increase the compression by 1/4 point it’s a totally useless "upgrade" . . The only way to know for sure is to do the math and do a compression test.

According to Honda, the stock compression on that engine is around 163.6 psi . . If you are at 170 or less with the new piston after it is broken in, you have not gained anything relevant other than restoring compression back to factory spec . . If your compression is around 176 or more, then you have made a difference.

One of the problems with the claims of big power improvements from this piston is that their old piston and rings are so worn out that instead of having the factory 164 compression, they might only have around 135 or even less, therefore, even if this piston only increases compression to 150, it is still a big improvement to them even though t is still below the factory 164 psi level.





From post 3.


As far as I know, no, those are different. A friend bought one for his XR200 like it said in the ad.......only the compression height on the oem piston is around 27mm or more and the eBay one is only 22mm.

Using a compression height difference of a whopping 5 mm as shady has stated it is, if it was a 10.0 piston with the correct pin height and you raised the pin 5 mm . . the compression would then be around 5.22, if it was 13.0 with the correct pin height, it would be around 5.76 if you raised the pin 5 mm.




Bore size being the difference yes. That’s not my question. I'm going to have to bore my cylinder anyhow, and was looking at the xr200 piston as many state that its quite the performance increase with much less cost.

Not all pistons measure the exact same size even if they say 50 mm or 48 mm etc . . if you bore your cylinder and do a compression test and find that it is around 140 or less, you need to get another piston and pray that it is the same size or bigger so you can hone the cylinder to size because if it is smaller than the other one, it will still work but it will be loose which is not the best option.

[mayhem17]

Got the piston in yesterday. Spoke with the guy that had used the same piston last night also. Just finished his break in period and is right at 170 psi. Not bad for under $30. So I went ahead and took it and my cylinder to a machine shop out of town today to get them matched up. Said should have it done tomorrow, so hopefully have this thing back together this weekend and I'll let you know what I find. I don't mind learning the hard way at times I guess. As stated, I have a few more cylinders, and this was just a budget build plan for me. I did compare the pistons also. There is a difference in the compression height for sure. Stock is a dished piston, and this one is domed. I'm guessing that the difference there is roughly making up for the difference in compression height. At least a guess from speaking with the other two that have used it. This will be a good learning experience for me either way. Hopefully can put a few hours on it this weekend and I'll get back to you.

[mayhem17]

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i would have just bought the correct piston . . do it right and you will only do it once.

a compression estimate in your case would be this . . if you have a 10.0 compression piston and you raise the pin by .015", your compression will be 9.5, if you raise it .030", your compression will 9.0 . . if you raise it by .045" it will be 8.5.

These measurements in inches I take it?

[barnett468]

These measurements in inches I take it?

yes, those are in inches and they are not guesses, they are exact mathematical calculations, and i would be happy to calculate what your piston should have if you want but ultimately the compression test is the final say . . even if you have a 12.0 piston with the proper pin height, it might only provide the compression of a 10.0 or 9.0 piston etc if your rings leak.

[mayhem17]

So what is the stock compression height for the 85 200x? I'm not finding it anywhere. I believe this one was listed as a 22mm, but domed. Having my cylinder done at a shop I finally found. So all that should be good.

[barnett468]

So what is the stock compression height for the 85 200x? I'm not finding it anywhere. I believe this one was listed as a 22mm, but domed.

I don't know right now but shady said it is 27 mm which is a whopping 5 mm difference.

[mayhem17]

Thats for the xr200 he did say. Wonder if there is a difference.

[barnett468]

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the atc200x piston is purportedly 18.5 mm from the top of the pin to the top outer edge of the piston

[YTZ drew]

I just dug out my worn out original 1984 atc200X oem piston. Has honda cast into it and 965 stamped on top (OEM code for 200X), a flat top and 2 valve reliefs. It measures 17.57mm from the top of the pin hole to the top of the piston. Add 7.5mm for a 15mm wrist pin centerline and you've got a 25.07mm compression height.

[Scootertrash]

So what will the theoretical compression be with the shorter compression height?

[barnett468]

So what will the theoretical compression be with the shorter compression height?

i still need to know the exact pin/compression height and rated compression of the xr200 piston to determine it.

[barnett468]

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without the rated compression i would need the dome volume.

[barnett468]

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having the dome volume would be easier because i have to work backwards to calculate it with just the compression rating but no big deal either way.

[mayhem17]

It didn't list the compression it was supposed to be rated at sadly. Just stated mm compression height.

[oscarmayer]

ok guys look here is the dummy version.
stock 200x is 9.2:1
stock 200s is 9.0:1
stock xr200 is 10:1.
drop in a xr200 into a 200x or s and you get 10.1:1 due to volume chamber differences and smaller squish because it is .5mm larger.

in a nut shell, about 1 hp gain on a stock trike.

[barnett468]

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So what will the theoretical compression be with the shorter compression height?

Ok, Scootertrash, here's the answer . . Sorry it took me so long.

Since the compression of the XR200 piston is not mentioned, based on photos of a 10.25 compression piston for the arc200x, I guestimated that the xr piston with the raised dome is 1.3 cc which would give the atc200x 10.50 compression IF the piston pin was in the correct location . . I have verified two different ways that the XR200 pin on the piston in question is 3 mm lower than the ATC200X pin.

Anyway, long story short, accounting for the guestimated dome size, pin location and .5 mm bigger bore of that XR piston, it will in fact LOWER the compression of the atc200x from the factory number of 9.6, all the way down to 7.4, lol.

Now, even if when I gave the XR200 piston a dome that would provide 11.0 compression in the ATC200X if the pin height were correct, it would still only provide 7.66 compression with its shorter compression height and .5 mm bigger diameter.


SUMMATION

Installing the XR200 raised dome piston in question, will in fact, lower the compression of a stock ATC200X by basically 2 points, which will result in significantly lower power, however, on the positive side, it costs around $100.00 less than the correct piston, the bike will no longer smoke from ring blowby, you will easily be able to start it with your hand if your leg is too tired, it will be safer to ride due to the greatly reduced power level, AND you can run kerosene in it instead of expensive gasoline.
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[Scootertrash]

No prob on the time.....

I ain't got the smarts to figure it out so I defer to those who can. I know that the head work that will be done on my Harley has chamber cc, cylinder height, piston dome, milling the heads, base gasket thickness and head gasket thickness figgered in to come to a targeted corrected compression. Waaayyy over my head. That's why it's going to someone with 30 years experience. ;)

[barnett468]

No prob on the time.....

I ain't got the smarts to figure it out so I defer to those who can. I know that the head work that will be done on my Harley has chamber cc, cylinder height, piston dome, milling the heads, base gasket thickness and head gasket thickness figgered in to come to a targeted corrected compression. Waaayyy over my head. That's why it's going to someone with 30 years experience. ;)

There are compression calculators that are helpful too . . You can change the different numbers to see the effects . . The complicated thing is determining actual running or dynamic compression.

Here’s a calculator you can mess with.

http://wallaceracing.com/cr_test2.php


So, a Harley huh…very cool . . What kind is it?

I had a 1974 full dresser AMF FLH and it was fun . . I bought it because my girlfriend liked Harley’s, plus it kept me from going fast on the street, lol . . A friend of mine at Kawi was a friend of Jerry branch of Harley fame so he had him port the head on our 250 Mojave that I tried to race . . He actually worked on Elvis's 125 when Elvis was young, lol.

[Scootertrash]

85 Low Rider. First year of the evo motor in the Low Rider, still a 4 speed tranny, but belt drive. I bought it new, she's my baby. Planning on a Geezer Glide in the next 5 years, this is/will be my hot rod. ;)

[oscarmayer]

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Ok, Scootertrash, here's the answer . . Sorry it took me so long.

Since the compression of the XR200 piston is not mentioned, based on photos of a 10.25 compression piston for the arc200x, I guestimated that the xr piston with the raised dome is 1.3 cc which would give the atc200x 10.50 compression IF the piston pin was in the correct location . . I have verified two different ways that the XR200 pin on the piston in question is 3 mm lower than the ATC200X pin.

Anyway, long story short, accounting for the guestimated dome size, pin location and .5 mm bigger bore of that XR piston, it will in fact LOWER the compression of the atc200x from the factory number of 9.6, all the way down to 7.4, lol.

Now, even if when I gave the XR200 piston a dome that would provide 11.0 compression in the ATC200X if the pin height were correct, it would still only provide 7.66 compression with its shorter compression height and .5 mm bigger diameter.


SUMMATION

Installing the XR200 raised dome piston in question, will in fact, lower the compression of a stock ATC200X by basically 2 points, which will result in significantly lower power, however, on the positive side, it costs around $100.00 less than the correct piston, the bike will no longer smoke from ring blowby, you will easily be able to start it with your hand if your leg is too tired, it will be safer to ride due to the greatly reduced power level, AND you can run kerosene in it instead of expensive gasoline.
.

The XR200 is slightly larger cc head due to the stock piston being .5mm larger than stock 200x. It also has higher compression piston to deck height is exactly the same. So you will gain a tiny bit of performance over 200x piston setup not to mention the cc of the head on the 200x is again slightly smaller resulting in a tiny bi more compression. The gains are minor. Only about 1 hp or so on a stock 200x.
Bigger gains can be had by dropping in a Better cam, larger carb and better exhaust. Do that with the xr200 piston and you can expect 3-4 hp gain over all as it allows the motor to breath better and run more solid. It will also give more torque and a better mid range.


Sent from my iPhone using Tapatalk

[barnett468]

The XR200 is slightly larger cc head due to the stock piston being .5mm larger than stock 200x. It also has higher compression piston to deck height is exactly the same. So you will gain a tiny bit of performance over 200x piston setup not to mention the cc of the head on the 200x is again slightly smaller resulting in a tiny bi more compression. The gains are minor. Only about 1 hp or so on a stock 200x.
Bigger gains can be had by dropping in a Better cam, larger carb and better exhaust. Do that with the xr200 piston and you can expect 3-4 hp gain over all as it allows the motor to breath better and run more solid. It will also give more torque and a better mid range.

oscarmayer, thanks for the info, however, unfortunately, according to the actual numbers, your info is somehow inaccurate as far as what amount of compression the piston in question will provide in an ATC200X, so my guess is that you probably just had a number wrong somewhere . . It’s easy to do, I have done it before more than once, but fortunately, I have always caught it because I always double check my numbers and sometimes even triple check them.

When using all the correct data, your numbers will come out similar to mine . . They have no choice . . The math is simple and the math has never lied to me before and I have been using the same math when building engines etc for the last 40 years . . If it had, “The Tecate . . The Most Powerful 3 Wheeler On Earth.” Would not have been the most powerful 3 wheeler on earth, plus my race bike would not have hole shot Jimmy White and several other pros at a couple of races, and I certainly would not have beaten him and the rest of the competition at Saddleback like I did etc . . Also,our Kawi 165 mph Road Race bikes would not have gone 165 mph if the numbers lied.

If you do check the numbers and find an error in my calculation, please feel free to post all the numbers you used so I can see where my error was, however I actually checked the numbers and did the calcs 4 times from scratch to insure it was correct in case there were any questions about the results.
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