Piston Size EC300

Moto7man said:
Did you look under the intake for the letter?
Click to expand...

The cylinder is marked E on the intake side, 2cm from bottom. Clearly, piston size is marked A-D, so cylinder is unmarked.

Using a bore-gauge tomorow. Typical that im in a hurry and get and unmarked cyl.

Still have not answered my question thought. I still doesnt know what size A, B or D is. If I measure XX,96, still doesnt know what piston I need.

Please clearify what size for example A piston or D piston are.
 
The clearance between the cylinder and the piston should be around 0,06mm!
Means, when measuring 72,00 on the cylinder the piston is 71,94!
 
stian said:
Please clearify what size for example A piston or D piston are.
Click to expand...

If you take a look at Wossner's home page and select your engine size and year, they will show you what bore size pistons A B C will fit.
 
Since I was bored here's the sizes.
std bore - 72.00mm
A piston 71.93mm
B piston 71.94mm
C piston 71.95mm
D piston 71.96mm
0.07mm piston clearance
as per Vertex
 
Last edited:
hamilton said:
Since I was bored here's the sizes.
std bore - 72.00mm
A piston 71.93mm
B piston 71.94mm
C piston 71.95mm
D piston 71.96mm
0.07mm piston clearance
as per Vertex
Click to expand...


My cylinder is 72,01mm. Makes my piston with 0,07 in clearence a B piston.
isnt 0,07 too much? Ive heard more 0,05-0,06 (making my piston A)
 
stian said:
My cylinder is 72,01mm. Makes my piston with 0,07 in clearence a B piston.
isnt 0,07 too much? Ive heard more 0,05-0,06 (making my piston A)
Click to expand...

Thats backwards. An A piston will give you more clearance again. Based on what you specced your cylinder at Wossner suggest a B which gives 0.07mm clearance. Thats a forged piston, so you may wish to run a bit more than a cast. I'm sure you could drop a C piston in and still be fine, but what if..?

What was the size of the piston you just pulled out?
 
Jakobi said:
Thats backwards. An A piston will give you more clearance again. Based on what you specced your cylinder at Wossner suggest a B which gives 0.07mm clearance. Thats a forged piston, so you may wish to run a bit more than a cast. I'm sure you could drop a C piston in and still be fine, but what if..?

What was the size of the piston you just pulled out?
Click to expand...

Yeah, was in a hurry there.

Wossner is forged, but looking at standard GG piston, and I presume thats cast.

Forged= 0,07
Cast = 0,07 or if I dare; 0,06 (making B to a C in this case.)
 
Hey All,
I'm a bit confused and hoping to learn something. Aren't these cylinders plated? Are the different piston sizes to accomodate cylinder wear or manufacturing variances (pistons matched to cylinders)? I'm probably missing something very basic so don't beat me up too bad.:)

Thanks,
Chuck
 
Chaz955i said:
Aren't these cylinders plated? Are the different piston sizes to accomodate cylinder wear or manufacturing variances (pistons matched to cylinders)?
Click to expand...

Yes the cylinders are plated. The size differences are from manufacturing and each cylinder is marked with a letter A, B, C from the factory. The letter indicates the bore size and should be matched to a piston with the same letter when new. After some wear one could measure the bore and match it up with a piston according to the table given above.
 
Anders said:
Yes the cylinders are plated. The size differences are from manufacturing and each cylinder is marked with a letter A, B, C from the factory. The letter indicates the bore size and should be matched to a piston with the same letter when new. After some wear one could measure the bore and match it up with a piston according to the table given above.
Click to expand...

Thank you for the explanation. :)
 
The pistons from GG are EXPENSIVE! The price goes up roughly 30% when they put a GG part number on it. I would buy an aftermarket one.
 
Zman said:
The pistons from GG are EXPENSIVE! The price goes up roughly 30% when they put a GG part number on it. I would buy an aftermarket one.
Click to expand...

Now, Since motocrosscenter doesent resepond to well on emails, Im open for suggestions for other online shops who also will send to scandinavia.

Motocrosscenter retails the GG piston for 300ccm to 133 euro. In my eyes, thats decent. Vertex is to pricey for my part, and my use.
 
stian said:
Now, Since motocrosscenter doesent resepond to well on emails, Im open for suggestions for other online shops who also will send to scandinavia.

Motocrosscenter retails the GG piston for 300ccm to 133 euro. In my eyes, thats decent. Vertex is to pricey for my part, and my use.
Click to expand...
You could always try our "local" web shop 24mx.no.
I think my son got a piston there some time ago. I checked now, but did only find some horribly expensive ones. I think the have some more normally priced ProX as well.

Last time I bought a piston for my 200, I used trialendurodirect.co.uk

They are approx £100 if memory serves me correctly.
 
Anders said:
You could always try our "local" web shop 24mx.no.
I think my son got a piston there some time ago. I checked now, but did only find some horribly expensive ones. I think the have some more normally priced ProX as well.

Last time I bought a piston for my 200, I used trialendurodirect.co.uk

They are approx £100 if memory serves me correctly.
Click to expand...

Going to check it out, but I am in need of some other parts as well. Licenceplate-holder with light due to registration and some small other parts.

Kinda funny to have a business, and not answer order-mails thought.
 
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