2001 EC250 Cylinder specs.

[bobr]

Good afternoon folks.
I haven't been in here in a looooooooooong time.
I'm currently freshening the top end on an 2001 EC250.
Could any of you assist me in finding the cyl. wear specs. and what piston cross references to fit this bike?

Thanks in advance from an old Gas-Gas enthusiast.

Bob R.

(Is Ed Fox still snooping around here?)

 

[(F5)]

from the manwell:

ring gap:
Opening at the end of
250 cc: STD: 0.4 mm
Limit: 0.7 mm


Cylinder diameter
250 cc: STD: 66.38 mm
Limit: 66.50 mm

Woosner seem good piston & are cheap as a bonus. Just put one in my 300. Wiseco are good too. Vertex std but more $

 

[bobr]

Thanks for the info. I'm currently still in the motorcycle industry as a parts guy and appreciate the help. The pistons you mentioned I can't find in any of my vendor's catalogs.

I remember from 'back-in-the-day' when I was selling Gas-Gas's there was a Honda CR piston from Wiseco that would work?

 

[eff]

Hey Bob, great to see you back here. Most distributors do not seem to carry GasGas specific pistons, except maybe the Wiseco. You may have to contact GoFasters.

 

[bobr]

Wasn't there a cross reference with a CR Piston from Wiseco?

 

[jostby]

Wasn't there a cross reference with a CR Piston from Wiseco?

I remember the rod crossing but don't remember about a CR piston interchange. The piston is the same as used in TM 250 of '99 era if that helps. I just ran across an old piston part number that I used a few years ago, I think it was a Vertex and it was labelled for a '99 TM250

 

[bobr]

I remember the rod crossing but don't remember about a CR piston interchange. The piston is the same as used in TM 250 of '99 era if that helps. I just ran across an old piston part number that I used a few years ago, I think it was a Vertex and it was labelled for a '99 TM250

Do you have that #?

 

[bobr]

I'll be freaking dammed!

I just rechecked the P.U. book and wadda ya know?

Vertex lists a piston for the EC250 02-07 66.34 M.M.

Does anyone know if this will work in the 01?

Someone posted the bore for the 01 as 66.38 M.M.

 

[jostby]

At home so I'll have to send tonight. I'll send you the part number and I think the size is on it too. Don't remember if it's an "A" or "B".

 

[bobr]

I just had a thought. The Vertex is smaller then the 66.38 M.M. posted earlier.
What's stopping me from just have the cylinder plated to the size of the 66.34
Vertex?

If the piston is the same design and shape it shouldn't be an issue.

 

[bobr]

At home so I'll have to send tonight. I'll send you the part number and I think the size is on it too. Don't remember if it's an "A" or "B".

Thanks man.

 

[(F5)]

hey must put my hand up the specs were from the 06 manual, assumed they would be the same. If you are replating just send them the piston & they will match it perfectly.

 

[bobr]

hey must put my hand up the specs were from the 06 manual, assumed they would be the same. If you are replating just send them the piston & they will match it perfectly.

Thanks and I thought as much.....Now i just need to know if the 01 and 02 share the same piston design.

 

[bobr]

I asked the boys over @ GoFasters about the piston compatibility between years and this is their reply: Yes, same piston from 1996 to current

 

[GMP]

bob,

Its the same piston. Just look on your cyl for the letter code, and order one up. If your an "A" cyl just get a "B" piston. If your plating is in good shape you will be fine. You will never be able to measure the cylinder to .01mm accurately without some very expensive calibrated tools and technique. It will be fine, been doing it this way for years now.

 

[bobr]

bob,

Its the same piston. Just look on your cyl for the letter code, and order one up. If your an "A" cyl just get a "B" piston. If your plating is in good shape you will be fine. You will never be able to measure the cylinder to .01mm accurately without some very expensive calibrated tools and technique. It will be fine, been doing it this way for years now.

The Techs. here have the tools. I'm sure the cylinder's fine. They're tough as hell.

 

[jostby]

vertex number is 22292A. The GasGas "A" piston is 66.33mm. I think the size increases .01 for each letter designation (B,C,D)
When I did my bike the cylinder is stamped "A" and I put in a "B" piston. The part number I gave is for an "A" that we put in my kids bike (we had it replated by Millenium because of damage)

 

[Eric]

I have a 86-96 honda cr250 prox size b piston (the wiseco for that bike works too) in my 03 gasgas 250 the honda piston will work but its .01 or so of a mm bigger, I forget the exact amount a quick look at an online catalog will tell you its exact size, you will have to check your clearances to run this piston.
I needed a replate, the extra .01mm or so wasnt an issue for me so I went with the cheap super easy to get (im in canada I get screwed getting parts out of the us) honda piston. The honda piston looks a little different it has a small notch cut out of it on the bottom of the intake skirt but this has no effect on anything.
I dug through a lot of old threads on here last year to find out that piston works, years ago when it was harder to get gasgas pistons this was common.