Dong Fang DF 250 RTB Bobber Information

[ProDigit]

How much different are the Dongfang RTB and RTC engine and transmission wise, and/or gear/sprocket wise?

And what about performance comparisons?

[axa]

well i pulled the trigger on the cush bushings ,lets hope they are correct. i purchased 41241-307-010. will keep you posted.

Think you mentioned visiting a honda dealer...
Would they not pull the honda part so you could measure it against yours?
Did they not have it in stock?

Only trouble is ur the first to 10k and and i bet the first to need a drive bushing swap

Don't forget to post the winning part #...

[ben2go]

How much different are the Dongfang RTB and RTC engine and transmission wise, and/or gear/sprocket wise?

And what about performance comparisons?

They are the same.All the mod info is in this thread.

[Bobthebobber]

I drilled out the cat tonight..it looked to be more of an aluminum baffle than catalyst material.

I went to lowes and bought a 1 inch bi-carb hole saw.. the deepest one i could find.. and two 10 inch extensions and attached them together..

It took me about an hour.. because the drill bit fell off the extension and got stuck in the pipe... (silly me for not tightening down the set screw enough)

It was pretty diffiuclt because the holesaw bit was not deep enough.. even though it was the longest one.. so you really have to keep working at it from different angles until you can grind it all out. It seems where the exhaust comes in from the inside of the pipe... it runs out of a tiny 1 inch pipe as you can see way down at the end in the picture... the outside of this pipe is quite deceiving..

Anyway the sound is the same.. no real changes.. seems to pop a little more... which I like anyway.. but I didnt ride it much.. ill keep you updated.

I have not attached my ram air pipe yet.

[axa]

I drilled out the cat tonight..it looked to be more of an aluminum baffle than catalyst material.

I went to lowes and bought a 1 inch bi-carb hole saw.. the deepest one i could find.. and two 10 inch extensions and attached them together..

It took me about an hour.. because the drill bit fell off the extension and got stuck in the pipe... (silly me for not tightening down the set screw enough)

It was pretty diffiuclt because the holesaw bit was not deep enough.. even though it was the longest one.. so you really have to keep working at it from different angles until you can grind it all out. It seems where the exhaust comes in from the inside of the pipe... it runs out of a tiny 1 inch pipe as you can see way down at the end in the picture... the outside of this pipe is quite deceiving..

Anyway the sound is the same.. no real changes.. seems to pop a little more... which I like anyway.. but I didnt ride it much.. ill keep you updated.

I have not attached my ram air pipe yet.

I too had a hell of a time drilling out the cat for similar reasons.

Also I didn't notice a hell of alot after drilling out the cat, but that might be because just the day before i installed the reverse ram which solved the top end WOT sputter by itself.

Since you didn't install the reverse ram yet, it would be interesting to know if just drilling out the cat by itself will allow enough airflow to stop the top end WOT sputter.
Or did you deal with that issue already?

And I didn't really notice the exhaust being any hotter before, or cooler after...

[ProDigit]

Are there true 250cc BBK kits for this 229cc engine? Or is the engine on itself a 200cc engine with 229cc BBK?

[Bobthebobber]

I too had a hell of a time drilling out the cat for similar reasons.

Also I didn't notice a hell of alot after drilling out the cat, but that might be because just the day before i installed the reverse ram which solved the top end WOT sputter by itself.

Since you didn't install the reverse ram yet, it would be interesting to know if just drilling out the cat by itself will allow enough airflow to stop the top end WOT sputter.
Or did you deal with that issue already?

And I didn't really notice the exhaust being any hotter before, or cooler after...

My top end sputter already sorted itself out prior to the exhaust. With a motor this small though.. every little thing helps

I waxed my exhaust to make it shine. The spot on the pipe where the "cat" was would always just turn dull again.. Ill rewax it tomorrow and see if it keeps a shine now.. that will be a good indicator if that "hot spot/shoe melter" is gone

[barnone]

I did test the exhaust pipe with my infrared thermometer and the area where the catalytic converter was definitely hotter. That is why your auto's cat has a heat shield.

All these mods we make to our 229cc motors probably help some but none are that big of an improvement.
The best I got out of my 2010 DF was 68 MPH GPS. I'm at 65 MPH indicated with my 2012 DF now.

"Change your CG250 67mm air cooled engine (167FMM)to 70mm bore,Kit include piston kit and gasket" at
http://www.chinese-parts-canada.com/...bore_kits.html
might help some but I don't know if it is worth the money.

[DanDaMan]

Are there true 250cc BBK kits for this 229cc engine? Or is the engine on itself a 200cc engine with 229cc BBK?

its a Honda clone CG 125 big bore kitted to the 229 , U might try measuring a Honda 250 motor to see if a direct swap is doable , ive been meaning to but every time I start to get to that point life punches me squarely in the wallet

[ProDigit]

From a 125 to a 229??? Are you sure that's right?
That'll be 80+% more displacement; those engines will be worn out in no time, and no wonder they vibrate so much!
I doubt that the counter balance is made to handle those extra cc's !

Is there something simple that can be done to reduce vibrations?

I rather have a 250cc with a 229cc small bore kit (if that existed), than having a 125cc engine with a 229cc bbk.

The MC-05-127 I have now, with a step through semi-manual gearbox, is a 110cc engine with an extra 17cc's, and it's pulling the clutch to where it slips.