EC 250 to 300

[dimtsam]

Hello everyone
I got an EC 250 2011 and I must replace the cylinder. I'm thinking to use a 300 cc kit, but the cylinder head comes without support for the brackets. Do you think that I will have problem?

Thanks a lot

 

[Jakobi]

The 250 and 300 heads use the same support brackets.
The cylinders use the same powervalve assembly.

 

[dimtsam]

The cylinder head that I found is without support.I think that is from 2014 or later. Do you think that this will be a problem?

 

[Doc Brown]

Get the right cylinder head. The support brackets are there for a reason...

 

[Zman]

A couple more options: 1) rechrome your cylinder and keep it a 250. 2) Have your cylinder bored to a 265cc (they will weld and cut your head to match the larger bore. 3) Get the 300 cylinder and have your head welded and cut to match the 300 cylinder.

 

[StuJohnson]

A couple more options: 1) rechrome your cylinder and keep it a 250. 2) Have your cylinder bored to a 265cc (they will weld and cut your head to match the larger bore. 3) Get the 300 cylinder and have your head welded and cut to match the 300 cylinder.

Where have you had your cylinder rechromed? Thanks

 

[Zman]

https://www.millennium-tech.net/

or

https://www.usnicom.com/DirtBike/CylinderPlating

 

[Zman]

https://www.millennium-tech.net/

or

https://www.usnicom.com/DirtBike/CylinderPlating

You should double check to see if either of those two places can weld and cut your original 250 cylinder head to work with the 300 cylinder. That is a common service for big bore kits.

 

[StuJohnson]

https://www.millennium-tech.net/

or

https://www.usnicom.com/DirtBike/CylinderPlating

You should double check to see if either of those two places can weld and cut your original 250 cylinder head to work with the 300 cylinder. That is a common service for big bore kits.

Thank you. Sorry for confusion. I doing opposite here. Going from a 300 to a 250 since my 300 overheated. See pics below.

I’m actually thinking I’ll install the brand new 250 cylinder on my 300. This way I can ride for the summer. And I’ll send my 300 cylinder in to see if fixable.

Since I have a 250 “A” cylinder.
I need: ? Anything I’m missing?

250 head
250 “A” piston
Gaskets

You think my Lectron will still work on the 250?

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[SS109]

Lectron should work fine. Just will probably have to retune it richer for the 250. That cylinder can be fixed by Millennium. I've seen them fix worse.

 

[Zman]

I agree that can be easily fixed by either company.

 

[StuJohnson]

Lectron should work fine. Just will probably have to retune it richer for the 250. That cylinder can be fixed by Millennium. I've seen them fix worse.

Thank you. And to other responses.


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