Dong Fang DF 250 RTB Bobber Information

**ghost1133** · 07-30-2012, 09:10 PM

I've done just about every mod posted on this forum and have been happy with the results. I have been running a 38 tooth sprocket for about 700 miles now and been good with that, but today I put on a 35 tooth sprocket and I really like the way it cruises now. But my top end is about 70 mph. It runs really great at that speed but somehow I lost 5 mph on the top end. But I am going to keep it for awhile, 65 is fast enough and it just purrs along the highway. In town between redlights is awsome. I like it. As long as I do not feel the need to do 70 plus. It is a keeper setup. Enough is enough. It has exceeded my expectations. But I cannot stop somewhere for more than a minute without drawing a crowd. What bike is that? Who makes it? Did you build that? Is that an old bobber frame? A couple have reconized it as the Honda 185 and even as a Honda 250. But only a couple have.
Another thing, since I stopped the inner pipe in the exhaust from being loose. it no longer pops and backfires upon deceleration ? ?
Another great find from this forum. The idea of a chain tensioner from rollenrock rocked. I love it. So much smoother now. Will work with the headlight when it gets colder out. The "Df250RTB", I'm lovin it, with all of you and your help. The leather seat is next, but only when it gets cold out.

donedid.jpg

**bowtiewagon** · 07-30-2012, 09:44 PM

Originally Posted by ghost1133

I've done just about every mod posted on this forum and have been happy with the results. I have been running a 38 tooth sprocket for about 700 miles now and been good with that, but today I put on a 35 tooth sprocket and I really like the way it cruises now. But my top end is about 70 mph. It runs really great at that speed but somehow I lost 5 mph on the top end. But I am going to keep it for awhile, 65 is fast enough and it just purrs along the highway. In town between redlights is awsome. I like it. As long as I do not feel the need to do 70 plus. It is a keeper setup. Enough is enough. It has exceeded my expectations. But I cannot stop somewhere for more than a minute without drawing a crowd. What bike is that? Who makes it? Did you build that? Is that an old bobber frame? A couple have reconized it as the Honda 185 and even as a Honda 250. But only a couple have. Another thing, since I stopped the inner pipe in the exhaust from being loose. it no longer pops and backfires upon deceleration ? ?Another great find from this forum. The idea of a chain tensioner from rollenrock rocked. I love it. So much smoother now. Will work with the headlight when it gets colder out. The "Df250RTB", I'm lovin it, with all of you and your help. The leather seat is next, but only when it gets cold out.donedid.jpg

I know exactly what your sayin.. I have done some mods, and am pleased beyand anything I have done before, and i love this bike. I too get all kinds of crowds wehn i stop. I even had a cop pull over just to take a picture of it..he thought it was awesome.happy riding..keep the rubber to the road.

**DanDaMan** · 07-31-2012, 04:28 PM

get that U pipe onto the air cleaner to get it into the airstream and act as an air ram , it'll improve topend

gunrod did u have the air ram when u cut out with 120 main ?

stock air cleaner is open topped and works better as a ram then the "crome topped" cleaners

**GUN ROD** · 07-31-2012, 09:14 PM

Originally Posted by DanDaMan

get that U pipe onto the air cleaner to get it into the airstream and act as an air ram , it'll improve topend

gunrod did u have the air ram when u cut out with 120 main ?

stock air cleaner is open topped and works better as a ram then the "crome topped" cleaners

I have read about some of you using a 'ram air' intake but not seeing the set up, I have not experimented with my own version. Could one of you share a picture & where parts are available.

**bowtiewagon** · 07-31-2012, 09:51 PM

Originally Posted by GUN ROD

I have read about some of you using a 'ram air' intake but not seeing the set up, I have not experimented with my own version. Could one of you share a picture & where parts are available.

I second that request.. sound very interesting and I am just not seeing how it would be set up. Thanks.

**DanDaMan** · 08-01-2012, 03:02 AM

dunno how link pic : \

I went to auto parts store and bought a radiator hose (carried in the air filter for sizing) with a 180 degree bend in it , for about $10
I searched the racks of hoses myself not the clerk
I found a 20" U bend hose that fit (same size piping as airfilter) with some other kinks and straight runs that would need to be trimmed off
cut it to 8" to only have the U shape
I bolted it to the carb the other end to the air filter with an exhaust joint (purchased at same time as radiator hose) that fit into both airfilter and hose , now I have a forward facing air intake out in the air stream - aka poormans air ram/cold air intake ( no real effect untill past 55-60 indicated )

ends up looking something like this , but the full 180 instead of only a 90 degree bend , and I sloped mine slightly down
http://www.latus-harley-davidson.com...Kit-Chrome.htm

its performance "boost" is modest at best , perhaps 1/4 of a horse power @ 65mph , guessing here at around .15 to .25 psi boost
this mod alone gave me about 5 more MPH wide open on the highway from the previous months riding (but caused me to begin running a bit lean , 110 main)
I do Mods 1 at a time and use it for a while then do another

who's to say , this may only be helping because its a cold air intake and the ram is having no effect at all , either way it helped , a tiny bit at 60+ mph

Warning - this will drown your motor if u get caught in anything more than a sprinkle (but ive found pinching my leg to tank over it allows me to keep riding , albeit uncomfortably)

**rollenrock** · 08-01-2012, 04:37 AM

Good job, Ghost. Looks awesome. I love my chain tensioner and it runs smooth, but I like how you set yours up. My garage is in storage while I am in college, so I have very few tools. Wish I had my welder to make changes. I'd like to take off my rubber seat but I worry about fabricating a mount. I actually found a wood one that I have my eye on. I haven't done the ram air intake, but I am sure I will. With the heat here, air seems to be my biggest challenge. I just hit 500 miles on mine, and I'm still falling in love on every ride.