Dong Fang DF 250 RTB Bobber Information

[axa]

so do you have a hiest or a DF?

I need new sprockets( suggestions for good torque and speed? I am thinking 13/35).

im about 160 and IMHO I would get (and have) the lowest ratio available (without replacing both sprockets and possibly grinding the front sprocket cover), 2.3. DF stock front 13, 30 rear which is the smallest available.
The bike doesn't have much power , but it is certainly possible to get on a long strait or decline where even perhaps with both you and ur chick on the bike might be be held back by anything less.
I bought a 35 because everyone and their mother said that was the best, put a few hundred miles on it, consistently riding at the 7-7500rpm redline, which if i recall is a modest 55 - 60 mph at that ratio (real not 10% overzealous stock DF speedometer) and then went to 30 and glad i did.

At my weight with a full backpack, full face helmet and some leather, Im still constantly near the red line.

The only argument i hear against a lower ratio is that it takes longer to get through (each/all) gear(s).
And if your heavy its arguable that you will have less of top possible speed so a higher ratio will better distribute through the range, but i just dont put much stock in that argument.
At top speeds the wind resistance is 50% of your engine output, an actual greater factor than say a 30% heaver load.
A higher ratio just gets you to a lower speed faster, so it makes no sense to me.

Now if your on the F1 circuit and it matters exactly where your shift points are then by all means limit your top speed with a higher ratio.

-I need new jets

You don't state which jets and for what purpose.
Pilots?
if replacing a clogged one, you need a new 40, you could get away with 42 or perhaps 45.
If you have reason to think you need a different size, here is everything you'll ever need
http://www.ebay.com/itm/401030124735...%3AMEBIDX%3AIT

you wont use most of them but look at the price, most people pay more for a single jet.
These are shipped from one of the most famous counterfeiting locations in china, but i measured these with a pin gauge set and they were remarkably accurate, I cant speak for hole roundness but overall throughput are accurate. I don think it matters in our use.

main?
m5-.08 is what you want.
105 is stock, if replacing a clog.
http://www.ebay.com/itm/Carburetor-M...5WX~so&vxp=mtr

again more than you need, and i cant vouch for this seller but you get the idea.


Id be careful about re-jetting a nicely running engine if you have no fair reason to.