Dong Fang DF 250 RTB Bobber Information

**mrphrancis013** · 06-24-2011, 02:41 AM

I can handle the bumps with my back. But for some odd reason sitting on uncomfortable seats hurts my back.

They get over 75 from the 130lb Chinese test rider and the downhill ride for them. Lol. Honestly I have no clue, but either of those do seem plausible.

**AKAsam** · 06-24-2011, 02:45 AM

the speedo said 73 but the gps said 63.

**lanzen114** · 06-24-2011, 02:46 AM

AKAsam, did you put on a 35t? Anything on the front? I was just getting ready to order a sprocket for mine if it ever ships, but didn't know if I should go with a 35 or 38. Do you lose a lot of bottom end?

**AKAsam** · 06-24-2011, 02:55 AM

no change up front, just the 35 in the back. I didn't loose anything on the bottom end. It actually rides better now, smother, less vibrations. This bike should have come with that sprocket. Before 5th felt like the main gear, but now 4th is and then you are surprised you still have another. Best buy for this bike so far. The Link Barnone posted was were i got it and it fit just right.

I do have a problem now with the spacing of the tire thought. I will have to add spacers so that my chain does not hit the frame and the brake bracket does it the rear rotor.

**barnone** · 06-24-2011, 03:05 AM

Originally Posted by AKAsam

After sprocket Change to a 35bike will do 63mph gps. Where did they get over 75? Hope to get a little more after carb work.

You need to change the main jet to at least a 100 and add a least one washer under the needle to improve the top speed. The stock jetting is very EPA lean.

**AKAsam** · 06-24-2011, 03:16 AM

Yea, I have the jet I am just waiting for a min to change it.

**Babyswiss** · 06-24-2011, 03:23 AM

Barnone: Did you have any spacing or chain hitting the frame issues when you changed the rear sprocket?

**barnone** · 06-24-2011, 03:35 AM

Originally Posted by Babyswiss

Barnone: Did you have any spacing or chain hitting the frame issues when you changed the rear sprocket?

Babyswiss,
No problem with the chain hitting the frame. Changing the rear sprocket should not cause a problem. I've got over a thousand miles with the new rear sprocket.
You can't change the front sprocket without doing some grinding to get clearance for a bigger front sprocket. The chain is a 520 and I guess you could go to a smaller 428 chain like the Heist has and then a larger front would fit but why go to the trouble.

AKAsam,
You must have put the wheel spacers or the sprocket on wrong. Did you leave off a spacer or get them mixed up? The sprocket has to go on the same way as the one you removed.
Post a photo of your rear wheel as it is now installed and I will compare it to mine.

**AKAsam** · 06-24-2011, 07:08 AM

I got the sprocket changed at my local motorcycle shop. I don't have a chain tool and it only cost $20 to get it done there. After taking everything apart i realized that he did not put the sprocket back in the rim all the way and he also got the two washers mixed up. It is all good now. While i was dirty i went ahead and took the carb apart and to my surprise i already had a 105 main jet in there. I bought a 100 so it didn't make any sense to change it. I did put a small spacer on the throttle needle though. Will see how it runs tomorrow.

**barnone** · 06-24-2011, 12:53 PM

Originally Posted by AKAsam

I got the sprocket changed at my local motorcycle shop. I don't have a chain tool and it only cost $20 to get it done there. After taking everything apart i realized that he did not put the sprocket back in the rim all the way and he also got the two washers mixed up. It is all good now. While i was dirty i went ahead and took the carb apart and to my surprise i already had a 105 main jet in there. I bought a 100 so it didn't make any sense to change it. I did put a small spacer on the throttle needle though. Will see how it runs tomorrow.

AKA,
Glad you got the sprocket problem sorted out. I don't take my bikes to a shop to be worked on by a so called mechanic. I can screw it up myself.

I have a chain breaker from Harbor Freight which I have used for years. On sale for $10. Good for my needs.
http://www.harborfreight.com/catalog...CategoryExpand

Don't understand how your DF could have a 105 main jet. Did you buy your bike used? My DF came with a 88 and I put in a 100. I think the 105 is too big and the engine is not going to rev out properly being overly rich.

You might try the 100 if you still can only get GPS 63 MPH. I'm not sure what my GPS top speed is but I would guess maybe 70 MPH.