Dong Fang DF 250 RTB Bobber Information

[barnone]

Nick, I don't know but you need to tell us what model you have.
2010 DF250RTB, 2012 DF250RTB_A, or 2012 DF250RTB_B, it might make a difference.
I'm guessing under the tank but that is just a guess.

[Nick Papageorgio]

Thanks Barnone. It's a 2010 DF250RTB.

[axa]

Stock is 45, I'm currently running a 35 with 6k RPM approximately 60 MPH.
35/30 x 60 MPH approximately = 70 MPH if she will pull it and I will be happy.

if my tach is accurate, slight downhill yesterday, i got just a hair below 60 indicated at just a hair below 7k, and it wouldn't do any better.
Please do tell how the 30 tooth works out.
I must say im going to be a bit tweaked if i have to dump $ on another sprocket.
Against my better judgment, i took the advise of the collective which claimed your weight should determine the size sprocket you can go with... which appear to be a load of crap.

The bike is rev limited like none other ive ever ridden.
I had a 50cc (49cc) 2 stroke way back when that had a normal operating rpm from 5k up to 13k if you pushed it, and would easily achieve 65 no problem cuz apparently it was geared correctly.

On this bike I will top out about 6.5k when it begins to spudder, then shifting at that point brings me no lower than 4k
there is just no range...

[DanDaMan]

I went thru about 5 sprockets , until I figured out the only way I could get speed that wasn't RPM valve float capped (engine sputter @ WOThrottle) was to go with the 17 35 , which is stretching gears from 3 to 2 , id need a diff rear rim to make it geared any lower , Maxed front and rear both at the moment

I stretched front 2 teeth 20% faster , and Rear 10 teeth 33% faster than stock

and when cold . down hill . the wind with me and drafting Im still RPM limited at about 82 indicated (about 73-75 mph)

but my valves are VERY loose , like I set my 38 HPower 1974 VW beetle's valves IMG_2189.jpg , if I tighten em down I may drag a bit more from her just pics 053.jpg

[DanDaMan]

Aboshi,
Funny you should ask about sprockets because I just changed out the rear and went with the 33 tooth below. Had to remove three links from the 520 chain but kept the stock 13 front tooth because I decided to not modify the front sprocket cover.

Front Sprocket JTF270.14 14 tooth
Rear Sprocket JTR279.33 33 tooth
They are the ones you gave me in post 185. I got mine from Old Bike Barn but anyone that handles JT sprockets should be able to get them. Rear fit just fine but you need a big pair of o-ring pliers or fight it like I did with a couple of screw drivers.

33/13 = 2.53 my current ratio
45/13 = 3.46 stock DF
38/13 = 2.92
41/15 = 2.73 Heist stock

I only had time for a short ride but it sure was nice to be able to get up to 20 MPH indicated in first gear. It might be too high a ratio but I'm going to try it for a while and report my finding later. Your ratio of 13/38 might be better.

Actually the seat is pretty nice. I adjusted the preload to the max on the spring under the seat to get me sitting up straight with my new bars. The sheep skin or a leather cover like you suggested will help.

EDIT: Stock DF rear sprocket is 45 teeth not 40.!!!!!!!!!

/cough , 13/45 that's a snowplow gear that gets about 6 mph ..... and I run a 17 35 :p and think 1st is now "just" short enough (73% shorter) shorter = higher speed , of all vehicles u want 1 that 1st gear is perfect for how u drive is the 1 u get , bikes 1 the only things u can do it yourself with ratio's , do I want a 1/4 mile bike or a cruiser

cruiser tan idler , tan main
racer - tan to black idle , slightly lean very tan 3/4 throttle

[GonzoX]

how many of you have had to replace the stock horn , and how many times. My issue Is not that the horn fails to work, it is that the bracket it is attached to keeps breaking. I have had to replace it twice now. seems that it rattles so bad that it eventually just breaks. I am in the market for replacements and was thinking of going with a louder style horn set.

By the way.. I am up to 9907 miles as of last nights ride. Gonna do the Chinese fire drill when it hits 10,000. Plus take pictures.

I have replaced my horn after 6 months. Had it a year now. And yes it was the horn. Got a french made quality replacement that is adjustable for tone. Didnt want a big ass horn on there as im of the old scholld K.I.S.S. class.

Picture 2557.jpg

[GonzoX]

that's INDICATED , and at 70 indicated , im actually goin 63 , 10% off

and as I said be4 , believe its about 6k rpms then it valve floats

gearing for 85 like I did , might be pushing it because 5th has no umph when its HOT out , ill shift to 5th at 65 or so and cruise at 70-75 indicated

its funny with everyone saying its not made for it/don't try it , but I got this bike PURELY for use as a highway bike

Well no offense Dan and maybe you are the exception. But here in TX the speed limit is 75mhp and most do 80+. And I live in the hill country so I have inclines to deal with. And every biker I talked to thinks I was crazzy to take a 250 on the hwy. IMHO they have a valid point.

[barnone]

45/13 = 3.46 DF stock
​41/15 = 2.73 Heist stock
30/13 = 2.31
33/13 = 2.53 my previous 2010
35/13 = 2.69 my current 2012
38/13 = 2.92

I'm going to try 30/13.

I would like to cruise at 55 - 60 MPH on level pavement at 4000 or so RPM.
Don't mind down shifting to 4th to accelerate or go up a grade.

[bowtiewagon]

I have replaced my horn after 6 months. Had it a year now. And yes it was the horn. Got a french made quality replacement that is adjustable for tone. Didnt want a big ass horn on there as im of the old scholld K.I.S.S. class.


Picture 2557.jpg

Trouble isn't the horn itself, it is that little bracket that hold it to the bike, right where yours is.See it moves back and forth so much that it eventually just breaks off. I am going for a set of horns and looking at the car horns like Dan said. Louder is better, and hopefully can mount them on a bracket that will not move and break off.

[jeperezjr1371]

Barnone was it easy getting your 2012 DF250 legal to ride in North Carolina? Just wondering cause I'm interested in getting the DF250RTB_A in a couple of months! I found a shop here in Wilmington, NC that can order it for me!