200 bored to 220 ????

Got questions? We got answers....
WesKDX
Member
Posts: 8
Joined: 12:02 am Apr 05 2007
Country:
Location: San Jose, CA

200 bored to 220 ????

Post by WesKDX »

So I recently bought a well used 96 KDX and was told that it supposedly had a 220 motor and a lightened flywheel. I say supposedly because the guy I got it from had not been the owner very long and said this is what the previous owner told him. From the exterior, I didn't see anything to indicate it was a 220 (cylinder is stamped with the 200cc mark).

So after I got the top end torn down I took the piston to a local shop which helped me measure the old one and suggested that I had a +2 overbore. While I was fitting the new piston I realized that it wasn't the right size. After measuring the old piston many times, it appears that it is a stock 220 piston with the cracks on the crown and all.

So now, I am considering WTH I am going to do. My first thought was to just purchase a new 200 cylinder and piston, but then I started thinking that I may need a head as well.

I never did notice any overheating.
I could only guess that it may have been done as a cheater motor (racing???)

Has any one heard of a 200 cylinder bored out to 69mm?
Suggestions?
User avatar
canyncarvr
Gold Member
Gold Member
Posts: 6943
Joined: 01:07 pm Nov 05 2004
Country: US
Location: The Mythical State of Jefferson

Post by canyncarvr »

There being considerable difference between the two bore sizes, I'm curious about the 'suggestion' that you had something other than an OEM 200 bore.

The more common 'overbore' on the 200 is to 225. E. Gorr does those. Nothing wrong with the idea (overbore) as long as it is done correctly. The KIPS valve needs to be correctly fit to the new boresize for example..and, as you note..the head had better be changed to suit the new swept area, too. Maybe 'they' put a 220 head on it? If that is the case, it STILL needs to be 'fixed', as the 220 heads are known to be widely variable volume-wise.

At least one thing for sure...if you modify the head, you HAVE to know what the cylinder is doing volume/size-wise.

The primary drawback to the 'overbore' idea is the usual considerable reduction in fuel economy. Yes, such an overbore commonly is part of a porting attempt, too...and it's the two that lower your range.

Don't know where you ride, but I've needed 70+ miles out of a tank more than a couple of times. It's a big enough deal to completely nix any idea of such for me. 40-some miles out of a tank of fuel (for example) is simply not acceptable...and I don't want to go the 'Clarke' (or any other aftermarket tank) route.

I have no idea why anyone would do such a thing. As noted, using an OEM Pro-X 220 piston is simple brain-death in action...a foolish, uninformed, serious mistake.

Take your pick as far as which way to go. How the cylinder was prepped/ported to accept the larger piston is important..and you won't likely know how well it works until you put it back together and tune the thing. Certainly it didn't come from Gorr. He wouldn't do anything as stupid as that (put an OEM 220 piston into a 200 overbore).

Consider the source
Using a perceived level of knowledge to boost my self worth.
Non impediti ratione cogitationis

bike profile: !clicky!
GS
Member
Posts: 644
Joined: 11:33 pm Feb 17 2005
Country:
Location: Vancouver area, Canada

Post by GS »

What did the cylinder actually measure?

Is it plated? Sleeved?

What did the piston actually measure?
WesKDX
Member
Posts: 8
Joined: 12:02 am Apr 05 2007
Country:
Location: San Jose, CA

Post by WesKDX »

>|<>QBB<
GS wrote:What did the cylinder actually measure?

Is it plated? Sleeved?

What did the piston actually measure?
Measuring the piston the way the manual states, I get 69mm.

My micrometer is not that good and only has mm increments :(
That is why I took it to the shop instead.

The cylinder does not appear to have a sleeve in it. I don't have an accurate measurement on it.

I actually put the 68mm piston that I had ordered into the cylinder and it is obviously too small.

When the guy at the shop measured the piston he said to him self that it was an ART piston and I asked him "what does that mean?" and he just said nothing. But, now I realize that ART makes factory pistons and that is why it was weird to him since this appeared to be an "overbore".
WesKDX
Member
Posts: 8
Joined: 12:02 am Apr 05 2007
Country:
Location: San Jose, CA

Post by WesKDX »

Yeah, It definitely looks to be ported.
Great, I have modified kips as well.

I knew I should have ran when I heard "modifications".

I was hoping he was just attempting to upsell the bike.

The bike definitely seems to guzzle the gas.

>|<>QBB<
canyncarvr wrote:There being considerable difference between the two bore sizes, I'm curious about the 'suggestion' that you had something other than an OEM 200 bore.

The more common 'overbore' on the 200 is to 225. E. Gorr does those. Nothing wrong with the idea (overbore) as long as it is done correctly. The KIPS valve needs to be correctly fit to the new boresize for example..and, as you note..the head had better be changed to suit the new swept area, too. Maybe 'they' put a 220 head on it? If that is the case, it STILL needs to be 'fixed', as the 220 heads are known to be widely variable volume-wise.

At least one thing for sure...if you modify the head, you HAVE to know what the cylinder is doing volume/size-wise.

The primary drawback to the 'overbore' idea is the usual considerable reduction in fuel economy. Yes, such an overbore commonly is part of a porting attempt, too...and it's the two that lower your range.

Don't know where you ride, but I've needed 70+ miles out of a tank more than a couple of times. It's a big enough deal to completely nix any idea of such for me. 40-some miles out of a tank of fuel (for example) is simply not acceptable...and I don't want to go the 'Clarke' (or any other aftermarket tank) route.

I have no idea why anyone would do such a thing. As noted, using an OEM Pro-X 220 piston is simple brain-death in action...a foolish, uninformed, serious mistake.

Take your pick as far as which way to go. How the cylinder was prepped/ported to accept the larger piston is important..and you won't likely know how well it works until you put it back together and tune the thing. Certainly it didn't come from Gorr. He wouldn't do anything as stupid as that (put an OEM 220 piston into a 200 overbore).
User avatar
Indawoods
Creator and Founder
Creator and Founder
Posts: 9951
Joined: 09:59 am Jun 12 2003
Country:
Location: Midwest

Post by Indawoods »

Don't sweat it... order a Wiseco 220 piston and call it good!
*** Administrator //***
****'95 KDX 200/****

"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
User avatar
canyncarvr
Gold Member
Gold Member
Posts: 6943
Joined: 01:07 pm Nov 05 2004
Country: US
Location: The Mythical State of Jefferson

Post by canyncarvr »

DO get the head sorted out!! Check the link noted below for at least one good reason why.

There was a pic posted awhile back..head off a 220. They have a process 'hole' in them that the 200 head does not. At least, that was my understanding. I don't know that EVERY 220 head has that mark.

Any unusual marks in the dome (chamber) of your head?

I don't recall the volume diffs between 200/220....I knew once.

RB-Designs makes the 220 head sing. BUT...it's a crap shoot if the other 'modifications' are involved. Porting makes a difference in static compression. Like..how far 'up' has the exhaust port been moved? Talk to Ron first if you're going to send it to him. He may well NOT want to deal with the way too many variables situation you have....he may want to see the cylinder with the head...I have no idea.

About the time someone modifies the head to 'fit' with an OEM heighth exhaust port..and the port turns out being a few mm high..and the bike runs fer crap..that 'someone' is going to get the blame for the result.

Good luck! Please do look into getting the head configured for SURE with the already done mods you have cylinder-wise. It's a huge part of the overall picture.

HERE! it is. Take a look (click on the HERE! part).

Consider the source
Using a perceived level of knowledge to boost my self worth.
Non impediti ratione cogitationis

bike profile: !clicky!
muddertrucker
Member
Posts: 230
Joined: 08:40 pm Dec 04 2006
Country:
Location: Chicoutimi, Canada

Post by muddertrucker »

>|<>QBB<
WesKDX wrote:>|<>QBB<
GS wrote:What did the cylinder actually measure?

Is it plated? Sleeved?

What did the piston actually measure?
Measuring the piston the way the manual states, I get 69mm.

My micrometer is not that good and only has mm increments :(
That is why I took it to the shop instead.

The cylinder does not appear to have a sleeve in it. I don't have an accurate measurement on it.

I actually put the 68mm piston that I had ordered into the cylinder and it is obviously too small.

When the guy at the shop measured the piston he said to him self that it was an ART piston and I asked him "what does that mean?" and he just said nothing. But, now I realize that ART makes factory pistons and that is why it was weird to him since this appeared to be an "overbore".
69 mm isn't that the size of a stock 220 piston. Its been a little while but I seem to remember those number on the box of my wiseco piston.
4 wheels move the body 2 wheels move the soul
Gallery!
KarlP
Supporting Member III
Supporting Member III
Posts: 1484
Joined: 02:26 pm Jun 29 2005
Country:
Location: Alabama

Post by KarlP »

If it were me....

It sounds like you've got this combo running? how well does it work?

I'd find a 200 or 220 cylinder and head and put them on.($money$)
I'd then send the modified cylinder and head and piston off to RBD or Eric with your impressions of how well it works and ask them to take action, if any needs to be done ($$more money$$)

Or you could just run it the way it is. It may work pretty good.

I know a guy that has a KDX motor in a KX125 frame. Supposedly ran it for one Enduro series back in '98 and then took it apart to do a 225 job on it. Got divorced and never finished the job so the bike and motor are in baskets. (We used to call those Basket Cases :lol:) He offered it for sale for pretty short money but I can't see doing it because of all the unknowns.
'08 KTM200xc
'99 CR/KDX Hybrid with that RB stuff done to it
KX100 for the boy
User avatar
canyncarvr
Gold Member
Gold Member
Posts: 6943
Joined: 01:07 pm Nov 05 2004
Country: US
Location: The Mythical State of Jefferson

Post by canyncarvr »

FFR..original bores:
KDX200: 66mm
KDX220: 69mm

Wiseco makes pistons for the KDX in +.5mm increments...up to 68mm for the 200, up to 70mm for the 220.

Both have 58mm strokes.

Consider the source
Using a perceived level of knowledge to boost my self worth.
Non impediti ratione cogitationis

bike profile: !clicky!
muddertrucker
Member
Posts: 230
Joined: 08:40 pm Dec 04 2006
Country:
Location: Chicoutimi, Canada

Post by muddertrucker »

>|<>QBB<
canyncarvr wrote:FFR..original bores:
KDX200: 66mm
KDX220: 69mm

Wiseco makes pistons for the KDX in +.5mm increments...up to 68mm for the 200, up to 70mm for the 220.

Both have 58mm strokes.

So I guess that means I'm not going crazy :supz:
4 wheels move the body 2 wheels move the soul
Gallery!
User avatar
canyncarvr
Gold Member
Gold Member
Posts: 6943
Joined: 01:07 pm Nov 05 2004
Country: US
Location: The Mythical State of Jefferson

Post by canyncarvr »

Like they say...just 'cuz you're paranoid doesn't mean they aren't out to get you.

:wink:

Consider the source
Using a perceived level of knowledge to boost my self worth.
Non impediti ratione cogitationis

bike profile: !clicky!
User avatar
fuzzy
KDXRider.net
KDXRider.net
Posts: 3437
Joined: 01:29 pm Jun 18 2003
Country:
Location: Fredneck, MD

Post by fuzzy »

So I guess that means I'm not going crazy
Very valid question though....w/ the cyl reading 200cc. This means it's been bored....and a bore job isn't that simple. Porting MUST occur w/ a 3mm bore change. That being said someone could've come up with a 'better' 220 as Kawi's 220 porting is repudedely not that great....Which is why E Gorr does a 225 (starting w/ a 200). At the same time they could've come up w/ some crappy porting, or none at all. You won't know until you get her running how you like the power delivery.
'91 KDX 200 Project $300 KDX
'95 KDX 200 Project $600 KDX
'94 WR 250 Always a project
User avatar
canyncarvr
Gold Member
Gold Member
Posts: 6943
Joined: 01:07 pm Nov 05 2004
Country: US
Location: The Mythical State of Jefferson

Post by canyncarvr »

I wondered about this at first: 'cylinder is stamped with the 200cc mark'

Seeing as a 200 cylinder does not have '200' stamped on it anywhere (and just to cover a base)..what DOES your cylinder in fact have stamped on it?

Consider the source
Using a perceived level of knowledge to boost my self worth.
Non impediti ratione cogitationis

bike profile: !clicky!
WesKDX
Member
Posts: 8
Joined: 12:02 am Apr 05 2007
Country:
Location: San Jose, CA

Post by WesKDX »

>|<>QBB<
canyncarvr wrote:I wondered about this at first: 'cylinder is stamped with the 200cc mark'

Seeing as a 200 cylinder does not have '200' stamped on it anywhere (and just to cover a base)..what DOES your cylinder in fact have stamped on it?
0.198 and like a cursive L

I'll pull it apart this weekend when I have some time and take some pics if any one cares.
User avatar
skipro3
Gold Member
Gold Member
Posts: 4329
Joined: 11:58 pm Nov 04 2004
Country:
Location: BANNED FOR LIFE!!
Contact:

Post by skipro3 »

I care. I'd like to see pictures. What part of the country are you located BTW. Oh, and welcome to the site!!
Jerry

I'd rather be a smartass like carvr, than a dumbass like.... well, you fill in the blank!
WesKDX
Member
Posts: 8
Joined: 12:02 am Apr 05 2007
Country:
Location: San Jose, CA

Post by WesKDX »

>|<>QBB<
skipro3 wrote:I care. I'd like to see pictures. What part of the country are you located BTW. Oh, and welcome to the site!!
Thanks for the welcome, the forum is a great resource. :supz:
I am in San Jose, CA.
User avatar
KDX Butterfly
Queen B
Queen B
Posts: 2063
Joined: 05:12 am Aug 04 2007
Country:
Location: Cedar Grove, Tennessee

Educational moment here....

Post by KDX Butterfly »

>|<>QBB<
GS wrote:What did the cylinder actually measure?

Is it plated? Sleeved?

What did the piston actually measure?

Sleeve?
Plated?
Piston measurement?
"If I were just two inches taller, I wouldn't be me." ~KDX Butterfly
User avatar
skipro3
Gold Member
Gold Member
Posts: 4329
Joined: 11:58 pm Nov 04 2004
Country:
Location: BANNED FOR LIFE!!
Contact:

Post by skipro3 »

San Jose? Great! Then let me know when you get that bike running. I've got tons of awesome riding areas up in my area; Placerville. It's about an hour from Sacramento.
Jerry

I'd rather be a smartass like carvr, than a dumbass like.... well, you fill in the blank!
UFS207
Member
Posts: 61
Joined: 03:17 am Mar 19 2006
Country:

Post by UFS207 »

KarlP wrote:I know a guy that has a KDX motor in a KX125 frame. Supposedly ran it for one Enduro series back in '98 and then took it apart to do a 225 job on it. Got divorced and never finished the job so the bike and motor are in baskets.

(We used to call those Basket Cases Laugh) He offered it for sale for pretty short money but I can't see doing it because of all the unknowns.
KarlP, is that still up for grabs? Is this guy near you? I'm in Alabama too (Tuscaloosa) and I would love something like that to tinker with.

WesKDX, there is a 220 cylinder on ebay right now if you decide to start fresh:

here
Post Reply