Dong Fang DF 250 RTB Bobber Information

[axa]

your right rich is safer , and even though having it start to lean out near max speed because of air ram does "slightly" increase power , its almost pointless because it only has 9-11 horsepower to begin with :p so another .2 hp isn't much , with the added danger of added heat

but doing a chop plug check at 50 I'm dark brown , chop plug check at 73 its light brown

i hear ya

[axa]

Got the 30 tooth rear sprocket installed and tested a little. I don't have a long straight away here in the mountains close to our cabin so will have to try a high speed run tomorrow when I have more time. I did get close to 30 MPH in first gear which is nice and did not have any problem going up my steep gravel driveway.
Attachment 13067
The sprocket sure looks small. So I am now running a 30/13 vs the stock 45/13. Big difference and I believe a keeper but will do more testing before recommending it. I think the drive ability is improved.

hows testing going?

[Bobthebobber]

I have to second that, I think our 2012 bikes are bordering on a rich condition to begin with.

As ive said now a bunch and dont mean to repeat, but just adding the air ram eliminated the sputter and allowed me to REV as high as 7k resulting in a slightly higher top end (slightly downhill be it)
Before that I tried applied a bit of choke to test a lean condition, and had immediate engine trouble.

Doing this now has little effect, so thats my first piece of rich evidence.
Second is even with both air modifications, -cat and +ram, it seems to have a very limited amount effect when closing the fuel/air mix screw. that i believe would close off the slow pilot jet, so reducing the fuel at idle (as little as one turn from seated) and it will still idle smooth. That said it also seems to idle well all the way to 4 turns... (so im still probably doing something wrong here. I do adjust a half turn at a time and wait about 15 seconds for a response...)

I'm going to ride around for a while with choke full open, and as soon as i remember pull the plug, i expect to see a slight to moderate lean condition... but if i dont, then that will be the third peice of evidence for me to judge these bikes come at least a bit rich.

While even though dan may protest, rich afaik is a safer condition. A bike might seem to run well a bit lean, but i haven't yet found evidence that it adds power, the added heat i don't imagine helps anything. but we'll see

YES YOU AGREE!!!!! The 2012 does seem to run rich!!!! I swapped back to my stock jets, and my after market filter. The engine was breaking up with the stock filter.. I changed to my after market filter.. which actually has real filter material under the mesh, and a closed end. Man she runs like a freaking dream now.. I messed with the air/fuel mix.. and tossed in a new plug.. On flat ground I can cruise 55 no with no engine break up... still on hill i have to have her wide open to hold 45.. Im going to try on a nice straight flat road to try and do over 55.., maybe I can hit 60 now. I checked the new plug after riding about 10 miles.. and it looks exactly the same as when I put it in... so maybe I just need to put more miles to get a good reading.

I also cut off the tabs that held on the air injection... with nothing but a hacksaw blade in my bare hand.. and then a metal file. .. and a quick touch of with the satin paint I mixed previously for the tank and fenders. I know there is still a little stub of weld.. but after 45 min .. my hands were really tired.. so maybe I'll just use a dremel later and grind it down flat... but something about this bike makes me want to do everything by hand instead.. makes me feel like I really worked hard to do something.. lol




Oh that metal stuff behind the bike is a weight bench i was building (its not something hanging off the motor)

[Bobthebobber]

Hey guys. I know there were some new members to our DF posts asking questions about the bike. I just wanted to give an example of how the new 2012 looks with the basic modifications to make her ride better, and look pretty. I would invite you to compare to stock photo's to get an idea of how a few easy cosmetic changes can make this bike unique

2012 RTB_A

Current mods

1. Changed to a 35 tooth rear sprocket

2. Removed stripes and repainted the tank and fenders satin black.

3. Removed side mirrors (this is purely cosmetic and I would NOT recommend this because it effects safety)

4. Removed orange reflectors mounted to the sides of the forks (again this effects your safety and is just cosmetic)

5. Custom Rear fender to prevent the tire from rubbing (You can just shim the stock fender to prevent this issue)

6. Removed stock air filter and replaced with a better filtration cone and put mini filter on crank case hose.

7. Removed Air Injection unit and all components and removed mounting tabs.

8. Performance Plug slightly gaped over recommended specs for easy cold starts.

9. Replaced brake pads with genuine honda.

My next plans are to find some smoked lenses for the turn signals, and find some lower handle bar risers to make the bars sit lower.






Special thanks to everyone here for providing the information required to improve this bike, and special thanks to Barnone for going an extra mile to assist me with issues.

[GonzoX]

Bob, you said you replace the brake pads with Honda pads. You got a part number? Only ref I remember reading on here was somebody using Yamaha pads that worked.

[ben2go]

Bob, you said you replace the brake pads with Honda pads. You got a part number? Only ref I remember reading on here was somebody using Yamaha pads that worked.

For even better braking cross reference the honda pads with EBC and see if HH pads are available.I have had the best luck with those on all my bikes.

[GonzoX]

I hear ya, i too bought into this cuz the low buy in cost.
but its all a personal preference and how you prioritize your time and money.
that said, you can always work on the looks if dont feel confident to work on the performance.
its not like all these tune ups will buy you much at all...
The sprocket change is like 90%, all the rest is quite marginal.

Well I accept my bike for what it is. An around town bike. With that I have no desire to spend money and time trying to make it into a highway capable machine. It's still a 250 no matter what you do and unlike many other states the hwy speed limit here is 75 and 80mhp and most cars do faster than that so there is no way in hell I will get on the hwy with this thing again. It would be suicide in my area.

But for around town driving I find the stock engine and gearing just fine. If I can get a few more HP out of it with a simple and cheap upgrade though, Im not above that. To me, realiability is more important.

[van_tri]

Greetings! I'm in Arizona and have been researching Bobber conversions of Kaws and Suzukis for several weeks and finally decided I am not interested in a big bike and my wife is not happy with the idea of me doing highway riding.

I really like the DF and want to know the best method of buying one in Arizona. Is Scooter Depot my only/best means of getting a DF250?

Next, would someone please tell me what the difference is between the D250_RTB, and the "A" and "B" models?? I see scooter depot has the basic (blue) D250_RTB on sale but I do not want to get an old or stripped version and miss out on an improvement/upgrade everyone recommends which comes on the "A" or "B"

THANKS!!!

[GonzoX]

Greetings! I'm in Arizona and have been researching Bobber conversions of Kaws and Suzukis for several weeks and finally decided I am not interested in a big bike and my wife is not happy with the idea of me doing highway riding.

I really like the DF and want to know the best method of buying one in Arizona. Is Scooter Depot my only/best means of getting a DF250?

Next, would someone please tell me what the difference is between the D250_RTB, and the "A" and "B" models?? I see scooter depot has the basic (blue) D250_RTB on sale but I do not want to get an old or stripped version and miss out on an improvement/upgrade everyone recommends which comes on the "A" or "B"

THANKS!!!

van, is this your first bike? Im still a bike newb but I can tell you that a light bike is your best choice as a new bike.

I remember my brother letting me get on his big ass Harley and it weighed a ton to manhandle. I prefer something lighter and more forgiving so yes I think it's a good first choice. I payed $2500 or so for mine with TTL and it was the cheapest bike I could afford this side of a Royal Enfield (my second and next choice I think $6-7k). Others paid less for their DF.

The newer model has a better gas tank which is good. There are more than one model though, one with a front fender and one without and one with shocks in front and one with a springer front end. Wish I had the B model with the springer front end but I dont regret my2010 model at all.

No expert but with any vehicle I think a later model fixes many of the issues in the first model. Think "Ford Pinto" here LOL. But I could be wrong. Im sure others will chime in.

[barnone]

Bobthebobber,
Good post with all your mods.

2. Removed stripes and repainted the tank and fenders satin black.

I want to do your #4. How did you remove the stripes?
Thanks