Dong Fang DF 250 RTB Bobber Information

[axa]

I did see a post where someone had switched to larger front sprocket and 35T rear. They did the chain swap because of clearance problems with the larger sprocket. There is a kit being sold for Tha Heist. I think it's about $100.

Right, it was Dan.
But you can get the same parts far less $ than that. Everything on that site is way over priced.
They sell decked cylinder heads for $550 for xst sake ...

[Roadkill]

Yes the lower ratio would in theory allow a higher speed of travel, by moving ceiling created by float at around 7.5k
But one needs the engine power to overcome all resistances (primarily wind at highway speeds) to attain these higher speeds.
And if one considers a flat road with windless conditions as a benchmark, none of us other 167fmm riders have seen enough power to "cruise" at the speeds that you claim to...

Thus the search for what is so special about your bike goes on...

Little confusion here. I'm roadkill and I've never had mine over 55 mph.

[DanDaMan]

I didn't change chains , I drive a different model , with diff chain

and I think y the higher attainable speed , is simply because no one else has DARED/or botherd to gear for 90, and accepted just the 35 tooth rear as max , which is 60ish with motor screaming , like wants to explode (might varv wih your larger tire)

u need a additional 10-20% (front sprocket) depending on lbs. , im 165

[axa]

Little confusion here. I'm roadkill and I've never had mine over 55 mph.

That's exactly my point... Dan claims he can attain up to 75.
Truthfully i can't see that, but I'm in pursuit for the most powerful 167fmm possible

[DanDaMan]

even barnones 45 to 30 swap (right?) was/is only a 30% boost to stock

mine has been faster than 60 , since 8 days after it arrived and I maxed front sprocket

yes up an incline or stiff headwind and nothing to draft 60 still my max ,,, in 4TH gear


IMO , you cannot possibly attain that which u have already givin up be4 u started , by gearing so low

if you've geared for 75 even down hill you will never pass that speed as valve float will actually engine brake u preventing more speed EVER from being attainable

gearing really high has drawback being really hard on valve train

[axa]

I think y the higher attainable speed , is simply because no one else has DARED/or botherd to gear for 90, and accepted just the 35 tooth rear as max , which is 60ish with motor screaming , like wants to explode

u need a additional 10-20% (front sprocket) depending on lbs. , im 165

Barnone used a 2.30769231 ratio and I believe went back to 2.69 for the same lack of power reason I just posted.

Dan, I'm going to give you the benefit of the doubt on both the higher ratio and smaller chain...
But do u realize you are claiming such a massive amount of better performance than absolutely everyone else gets that it is just hard to believe.
Really I'm not looking into getting into a pissing match about this but that GARDO creep spread allot of bull shit about this bike that helped influance me to buy it. I may not have otherwise...
and I just think the true potential should be clear, not subliminal wishes...

[barnone]

I didnr realize there was proof to smaller chain - better hp+torq , I thought it mearly the fact I was gearing 20% higher that any o u could was the issue :p

About a one percent improvement in that test the axa showed us. That is not going to make much of an improvement in speed.

[Roadkill]

Barnone used a 2.30769231 ratio and I believe went back to 2.69 for the same lack of power reason I just posted.

Dan, I'm going to give you the benefit of the doubt on both the higher ratio and smaller chain...
But do u realize you are claiming such a massive amount of better performance than absolutely everyone else gets that it is just hard to believe.
Really I'm not looking into getting into a pissing match about this but that GARDO creep spread allot of bull shit about this bike that helped influance me to buy it. I may not have otherwise...
and I just think the true potential should be clear, not subliminal wishes...

I just assumed that Dan was talking about the bobber, but his recent post says that he drives a different bike. Maybe it's lighter, or has a different transmission. Might be his will do what he says. Don't they make s streetbike version with the same motor?

[axa]

yes up an incline or stiff headwind and nothing to draft 60 still my max ,,, in 4TH gear

This is what I'm talking about...
If my heavy head work achieve 60 on just a flat.... Ill die happy.
Ur extremely lucky. Apparently no one else comes close.

[DanDaMan]

I agree axa a fat man buying this isn't gunna race the highways at 70 , I am 165 and its not usual to get perfect circumstances , but 60 attainable and sustainable , with bursts +15 depending on heavy driver and conditions

same carb , engine , tranny , electronics , brakes = neck angle , diff chain and sprockets the only real diff

who lives close to Austin ill ride to u, I was even thinking about riding to SCarolina , visit my bro/family