Dong Fang DF 250 RTB Bobber Information

[GonzoX]

I admit that p trap looks a lot sharper than my U bend radiator hose :p

and the faster u go the better it works 50-55 negligible , near 70 noticeable improvement

but to get that kinda speed youd need bigger front sprocket , meaning a chain change

u can fit a 17 tooth front with 428 HD chain

and remember , a bit lean provides better power

I agree, the p trap looks a lot better and doesnt look like it will get in your way while riding. And with the stock filter with no filter media on the tip end I think it will get the air ram effect at speed.

But Im a type A personality myself and hate the stock filter. To me a filter should do just that, filter the air and keep the crap out of the carb. Dirty carbs are a royal PITA to fix and are hard to diagnose when they cause a problem so Im the kind of guy who wants absolutely clean air going into the carb. That's two things I dont skimp on with any of my vehicles, oil and filter media. One ouce of prevention prevents a pound of pain later.

[GonzoX]

Yikes, I'm going to go home today and cut off that dipstick.
Which leads me to ask, why do you really even need a dipstick.
You can visually view the oil window and learn to get the same idea on the level just as you would a dipstick, cant you?

That's a good question. I guess I can say that the oil window is below where the level needs to be but nobody really knows this for sure. It's not in the owners manual. I am paranoid about not having enough oil so I want a dipstick. Ask anyone that has ever burned up an engine because of not enough oil. I did this. Dipsticks are cheap, new engines arent. But I would like more input on this if anyone has some facts on the matter. Im still a newb.

[GonzoX]

Good Lord Im having a hell of a time finding the right oil dipstick on ebay or amazon. I measured mine and since the tip is missing I have to guess I need at least an 11cm length and the threading is either 1.9 or 2.0cm. Has anyone had to replace one of these? Didnt think it would be this hard to find a replacement.

I guess I might have to go to a bike shop and see what they would recommend. Almost tempted to just plug the damn thing up and use the sight glass.

[barnone]

- this 1-½" Chrome P trap
- this 1-¼" flexible pipe coupling
its the BOM, pun intended.

dont freak out, that pic isnt the exact one, and those links may contain parameters for my local store but the part numbers are exact.

Needed to trim about an inch off one end of the p trap.
And only needed a fraction of that couple, wish it wasn't so cost prohibitive to send you the rest.

Now that it hints our top end sputter night be a lack of air on these 2012 bikes, it would be interesting if you have better luck with this mod and your 120 main jet.
dan uses a 112 anyway. i may start at 114-115

Thanks. Sounds good. BTW, with my 108 main and 30 tooth rear sprocket I am not getting the sputter so will hold off on the p trap.

[barnone]

barone , you mentioned how you drilled out the cat, and it helped out your top end a bit, i want to do it...

might you confirm for me how deep a hole saw bit is needed to make sure i cut through that ring of weld?
my hold saws are kind of shallow maybe only an inch or so deep.
Also, dying to know how is that 30 tooth doing??

I used a bi metal 1" hole saw with a 12" extension. Drill then clean out the cup, then drill and clean out the cup, etc.

I like the way my DF drives with the 30 tooth rear tooth sprocket. You can stay in each gear much longer because of the higher gearing.

Down shifting is a necessity here in the mountains regardless of the gearing. I don't mind.

[barnone]

I admit that p trap looks a lot sharper than my U bend radiator hose :p

and the faster u go the better it works 50-55 negligible , near 70 noticeable improvement

but to get that kinda speed youd need bigger front sprocket , meaning a chain change

u can fit a 17 tooth front with 428 HD chain

and remember , a bit lean provides better power

If you don't get any performance improvement until you get to 70 MPH then I gonna forget the ram p trap ideal.

Remember DanDaMan has a different bike than the DF250RTB so take his suggestions with a grain of salt.
You don't need to replace the chain to get a higher gear on the DF250RTB, get a 30 tooth rear which fits the DF250RTB just fine.

Disclaimer: However that high a gearing might not be your cup of tea if you don't like to shift gears.

The best I ever got out of my 2010 DF was 68 MPH GPS which was fine with me. I am approaching that with my 2012 model so am happy for now.

Dan, I don't agree that a bit lean increases power.

[barnone]

Good Lord Im having a hell of a time finding the right oil dipstick on ebay or amazon. I measured mine and since the tip is missing I have to guess I need at least an 11cm length and the threading is either 1.9 or 2.0cm. Has anyone had to replace one of these? Didnt think it would be this hard to find a replacement.

I guess I might have to go to a bike shop and see what they would recommend. Almost tempted to just plug the damn thing up and use the sight glass.

When I change my oil on the DF I use about 1.2 liters (1200 ccs) of oil and the dip stick and the sight window both show full. Remember to stand the bike upright when you are using the site window. (Also don't screw the dipstick in when checking the oil.)
And I don't know what you mean about "just plug the damn thing up and use the sight glass". You still need to unscrew the cap to put oil in it.
I've had many bikes with just site windows and never blew an engine.

BTW, again for those who have a intact dipstick, don't screw the dipstick in when checking the oil.

I'll measure the dipstick length on my 2012 DF and get back to you.

[axa]

Thanks. Sounds good. BTW, with my 108 main and 30 tooth rear sprocket I am not getting the sputter so will hold off on the p trap.

you mean you don't wind out each gear so not chance to sputter? or just somehow the condition has gone with the new gearing?

[axa]

I used a bi metal 1" hole saw with a 12" extension. Drill then clean out the cup, then drill and clean out the cup, etc.

I like the way my DF drives with the 30 tooth rear tooth sprocket. You can stay in each gear much longer because of the higher gearing.

Down shifting is a necessity here in the mountains regardless of the gearing. I don't mind.

so 1" to not bore out the innards cleanly parrallel to the exhaust inner wall, but rather mutilate the innards with a smaller 1" diameter drill and have at least that large a passage.
would you say that is accurate?

[axa]

That's a good question. I guess I can say that the oil window is below where the level needs to be but nobody really knows this for sure. It's not in the owners manual. I am paranoid about not having enough oil so I want a dipstick. Ask anyone that has ever burned up an engine because of not enough oil. I did this. Dipsticks are cheap, new engines arent. But I would like more input on this if anyone has some facts on the matter. Im still a newb.

I don't get it. with the proper amount of oil, 1.2L, and standing the bike upright, the oil window displays the oil level. it even has a high and low mark I believe. I've even used too little oil when I just had a Quart and it falls in the window, be it lower.
I for one never use the dip stick. I don't see the need.