EC250 to 300 Questions

[dave948]

I have a few questions about converting my 06 DE 250 to a 300.

I spent about an hour searching the threads but most posts are about cylinder and head questions or about older bikes with different CDI box's.

I have the jug with PV in it, the head and the piston & rings as well as gaskets, cir clips, o rings etc.

What I'm looking for is the overlooked items or unseen problems. From what I understand the 06 CDI is the same for both bikes but is the timing? Will the 300 run hotter than the 250 at low speeds?

I'll look at the jetting posts when that time comes and gearing by feel.

So if you've done it please drop in and let me know how it went.

 

[MattR]

I considered the conversion before, but have never done it. It sounds like you got all of the right parts. If I recall correctly, the 300 may have a different thickness spacer under the VForce intake manifold.

Sorry I can't help on the timing, etc.. I'm interested in hearing the responses too.

 

[seitz64]

did this swap a year ago! 3 years ago bought 03 mc 250 6 speed small flywheel ! was really fast !had to change gearing 12 -50 Big fly wheel weight ltr carb kit auto clutch i only 2 finger on my left hand after a year got to 13-50 med flywheel weight loved the bike last year had a chance to buy a new 300 kit at a good price !! i did a rb carb at the same time what a ride anyone could ride this bike still have med flywheel weight but back to 13-48 i think its about perfect !! it grunts and the top end is crazy at 1000 to 1500 feet 20f to 80 f i use 42 pilot needle clip at 3 or 4 , main 180 ,air screw 1 to 2 youre going to love it doing the same swap on my 2 sons bikes 05 ec & 06 ec gathering parts now ,should have done by spring,hope i was helpfull ,good luck !!

 

[widebear]

I have a few questions about converting my 06 DE 250 to a 300.

I spent about an hour searching the threads but most posts are about cylinder and head questions or about older bikes with different CDI box's.

I have the jug with PV in it, the head and the piston & rings as well as gaskets, cir clips, o rings etc.

What I'm looking for is the overlooked items or unseen problems. From what I understand the 06 CDI is the same for both bikes but is the timing? Will the 300 run hotter than the 250 at low speeds?

I'll look at the jetting posts when that time comes and gearing by feel.

So if you've done it please drop in and let me know how it went.

Dave. tearing into my mc-250 I realized that I had swapped the cdi's from bike to bike and subsequently had been using a mc cdi in the 300 and vice versa, no problems , no differance. Hope this helps. Rick

 

[dave948]

Thanks for the responses so far, I was hoping to get a few more.

I knew you would post Widebear, after all they are your parts.

My gearing right now for the 250 is 13/50, I had 12/48 on it and have a 52 for it as well. (helps that it's the same rear as my husky).

I never got the jetting on the 250 were I wanted it. I picked the bike up in Sept. and only got 5 or 6 rides in before bad weather hit. Didn't help the temperature was drastically different every time I went out.