Dong Fang DF 250 RTB Bobber Information

[bowtiewagon]

I am gonna do the next step and clean the carb out. I think my issues lay beneath its cover. Just out of curiaosity, I may want to replace the carb.. what are the spec on the factory one? Or anyone else change theirs out and where di you get it.

[birdmove]

The pilot jets, on the motorcycles and scooters I've worked on, seem to plug the easiest. Let us know what you find in there.

[axa]

I am gonna do the next step and clean the carb out. I think my issues lay beneath its cover. Just out of curiaosity, I may want to replace the carb.. what are the spec on the factory one? Or anyone else change theirs out and where di you get it.

slow down.
Dont believe the hype you might read on the ccw thread, there are NO direct swap replacement carbs for this engine. and as far as ive found, the pz30 is not the bottle neck in the system and Ive not yet found evidence that this engine would benefit from more delivery.

Also, I dont know what you like to do with the money, but you are not likely in need of a new carb.
Remove it, dismantle it, clean it well, or at least the jets, and you will be fine unless you find something damaged or broken.... then even a rebuild kit can be had.

this engine is simple, and just be glad this one below is my engine, and not yours.

blown piston.jpg

[axa]

Finally I have just confirmed our motor in the dong fang RTB is a LONCIN and not Zongshen as i thought.
I did this by finding the parts diagram on the DongFang site finding the part number of the push rods im looking for and googling lead me to the Loncin site....


check out this new DongFang offering:
http://www.df-motor.com/product_show.asp?id=702

something tells me I could bob the hell out of that...

[bowtiewagon]

slow down.
Dont believe the hype you might read on the ccw thread, there are NO direct swap replacement carbs for this engine. and as far as ive found, the pz30 is not the bottle neck in the system and Ive not yet found evidence that this engine would benefit from more delivery.

Also, I dont know what you like to do with the money, but you are not likely in need of a new carb.
Remove it, dismantle it, clean it well, or at least the jets, and you will be fine unless you find something damaged or broken.... then even a rebuild kit can be had.

this engine is simple, and just be glad this one below is my engine, and not yours.

blown piston.jpg

AXA I am a budget rider, if I do not need to spend the money I will not, so yeah you are correct.gonna hold off on buying anything until I figure this one out.I already made the mistake of purchasing a new starter for no appernt reason. Just jumped the gun a bit I guess. Gonna clean the carb, check for fuel intake, and go from there.

[barnone]

DF250RTB parts manual that axa referred to is at
http://www.df-motor.com/MLC/Parts%20...0RTB(2014).pdf

[axa]

Pulled out the engine and began to split the case in order to fish out the rest of the blown pieces.
I really didn't want to split the case open as I can't bear to have yet a third vehicle entirely down for long...
So I got the bright idea to turn the crankcase upside down and manually work it back and forth; sure enough the first bits of piston fell out.
Flip, check, still locking up, repeat, larger bits of piston.
And again, low and behold on the third cycle, out comes the missing exhaust valve!
Finally the engine turns free as i ran it counter clockwise connected to a hand drill...

No lock, no more bits, slapped it back together and put it back in the bike...


When I was in there i noticed 2 things, chain driving the oil pump is way loose only after 1000 miles (if it were ever tight to begin with). Lose chains wear way faster than they otherwise should. This is a shame on an otherwise tight engine.

Second the part marked "Rotor assy of filter" in that manual linked just prior, on my bike had extreme run out.
It is a cast part. It would take a special tool to get at the retaining nut deep inside its bell hosing, and if were not soooo out of true and had such thin walls, i would at least have tried to get it off to true it on the lathe...

This is the only part i found in the clultch case out of balance, there may be more inside the crank case, but all machined parts I found were pretty well made.

[axa]

DF250RTB parts manual that axa referred to is at
http://www.df-motor.com/MLC/Parts%20...0RTB(2014).pdf

ya thats it. riddled with errors... they should just take a copy of the Loncin version.

[axa]

put the Dong Fang shipping cage to use...

https://drive.google.com/file/d/0B-M...it?usp=sharing

welded an engine hoist!

[barnone]

My DF is a better here in Western North Carolina on the two lane roads than in flat Florida with the higher speed roads. Think I will leave her here in WNC and be happy with her stock performance.