Two different Heads & Bolt Patterns for the ec200.

[Zrt1200]

I just picked up a spare top end that needs plating and after i opened the box I soon realized this top end does not have the same head bolt pattern as my 05 ec 200. My stock 05 Cylinder & head is a B cylinder. The top end I just picked up is a A cylinder. The Part Numbers on the heads are different and so are the bolt hole pattern in the cylinder & head. I will show Head PN's VS dimensions so you can see the difference. I will also show the bolt Center to Center in the pics.

So if you decide you want another head or cylinder for your 200 make sure the bolt pattern is the same. I am not sure if all the A's are one way and all the B's are the other but here is a link to another member who found there is a difference as well.

http://www.gasgasrider.org/forum/showthread.php?t=20846

Here are the pics from my 05 ec200 (B) cylinder head...

[Zrt1200]

Now here are the Pics from the (A) cylinder head...

[(F5)]

Huh. Would have caught me out with that one.

There'll be a reason.

Not necessarily a good one, but.

[RBrider]

Good info. Thanks for posting.

RB

[Zrt1200]

F5, I would like to know the reason if any one has any info?? Save weight?? Left over parts from a 250 and they made them work??

My (B) cylinder match's the OD of the (B) head. The (A) cylinder match's the OD of the (A) Head. So to me it seems like it was planned like that.

I will check the outer O-ring location to see if its in the same location the next time I have the (B) head off my bike. I don't think it will be in the same location because the water jacket slots follows the bolt pattern.

Originally Posted by RBrider

Good info. Thanks for posting.

RB

You are welcome.

[Zrt1200]

I Just checked some Part Numbers from a 01 ec200 compared to my 05 ec200.

They are different Part numbers.

-----------------01 ec200 PN---------------------05 ec200 PN

Head-----------ME20916040--------------------ME200216000

Outer O-rings ME25616060---------------------M01619135

The Cylinder PN's are the Same Though ME20916022

Inner O-rings PN's are the same

[RBrider]

The A vs B markings are for slight difference in finished bore size. There's only about .0005 (of an inch) difference between the A, B or C cyl.

My 2001 cyl is near the end of it's usable limits, it's a B cyl, I found & installed a C piston to make up for some of the cyl wear. As I said, there's only about 1/2 of one thousand of an inch difference between each size. The A, B or C has nothing to do with the year of manufacture.

Since my '01 cyl was getting ready for a re-plate, When I found what I thought was a good buy for a new cyl with piston kit, I ordered it, thinking I'd put together the parts, in advance, for my next top end job.

The new cyl turned out to be the later model that requires the later model head.
It's an A cyl, which, again, just indicates finished bore size. The kit included a A piston kit to match the A cyl.

So, my 01 200 has the head with the smaller measurement as shown in your photos, but my new replacement cyl will require the head with the wider measurements . An '05 or later, it seems.

It appears to me that later model cyl & head was made bigger to improve cooling by increasing the amount of coolant in the upper cyl & head. Not a bad thing.

Thanks again for posting the photos and measurements. Very helpful.

RB

[RBrider]

Originally Posted by Zrt1200

I Just checked some Part Numbers from a 01 ec200 compared to my 05 ec200.

They are different Part numbers.

-----------------01 ec200 PN---------------------05 ec200 PN

Head-----------ME20916040--------------------ME200216000

Outer O-rings ME25616060---------------------M01619135

The Cylinder PN's are the Same Though ME20916022

Inner O-rings PN's are the same

This caught me out, too. The cylinders for the two different heads are not the same, not even close, in spite of what the part number indicates.

The inner o rings are different sizes too. The Cometic top end gasket set comes with both sets of o rings to fit both the smaller and larger head/cyl.

Thanks for listing those cyl head part numbers. I think you just confirmed the part number for the new head that I need. (ME200216000)

RB

[Zrt1200]

FYI guys. I picked up another ME25-30916000 head casting number assuming it was a 200 head. After I received it I found out it is a 250 head. It has the same bolt pattern and outside diameter as my 05 200 head but the bore is bigger. If you look at the pics you can see where it say's 25E on the head stay. My 200's show 20E on the head stay so the factory must be calling out what size the engine is on the head stay as well.

I may be able to machine this head down to fit the 200. It will depend on squish width and CC volume if I can use it.

I think RB called it out with the newer cylinders having more cooling capacity.

[RBrider]

Thanks for posting that info,Zrt.

I saw the 20 stamp on the head stay of my '01 cyl head, but didn't consider that it's a good way to verify that a future purchase is , in fact, a 200 head.

Good info.

RB