Dong Fang DF 250 RTB Bobber Information

Quote:

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Originally Posted by DanDaMan

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

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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.

Quote:

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Originally Posted by axa

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?

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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.

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.

Quote:

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Originally Posted by axa

- 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

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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.

Quote:

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Originally Posted by axa

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??

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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.

Quote:

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Originally Posted by DanDaMan

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

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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.

Quote:

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Originally Posted by 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.

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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.

Quote:

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Originally Posted by barnone

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.

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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?

Quote:

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Originally Posted by barnone

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.

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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?

Quote:

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Originally Posted by GonzoX

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.

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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.

Quote:

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Originally Posted by GonzoX

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.

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though doesn't proper air filter media reap havoc on decent air intake.
idk, I've had dirty carbs on dirt bikes, but never one of my street bikes, I suppose I havnt ridden as long as others.
but on the road bikes, I've always noticed more junk collecting down in through the gas cap hole than collected in or around my air filter. but maybe that is not a fair scientific comparison.
bottom line if a proper filter wouldn't starve this bike I'd have one too.

that said what do you use for a gas filter

Quote:

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Originally Posted by axa

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?

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axa,
Disclaimer: DO NOT attempt this if you do not have the skill to perform this operation. DO NOT come back to me complaining after you have screwed up your muffler. Performing this will increase the noise of the DF exhaust.

Attachment 13093
Note: this drawing is not the exact same as our DF exhaust system but just a typical motorcycle exhaust system.
It is presented as an aid.
The catalytic converter is about at location 211 in the drawing above.
Do not remove the material at 209.


Take a flash light and look up the exhaust pipe and see the catalytic converter in the forward part of the muffler. That catalytic converter impedes the flow of the exhaust gas.

Attachment 13092
Above is an example of the kind of catalytic material you want to remove.

Just remove the catalytic converter material that is in the forward part of the muffler not the muffler sound suppression material. DO THIS AT YOUR OWN RISK.

Quote:

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Originally Posted by axa

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?

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The gearing change should not prevent the sputtering in the lower gears however I keep the RPM below 6k so don't care. The p trap ram will have no effect at lower speeds but the tube might improve air flow like an air box does. I don't know.

I don't run my vehicles at top RPM.

I believe the gearing is high enough in fifth gear to prevent the sputtering but still allowing a top speed of about 65 MPH indicated. I have not verified the accuracy of the speedometer but the odometer appears to be about right.

Going back and reviewing my post from my 2010 indicated I had a 68 MPH GPS top speed with a 33 tooth rear sprocket so maybe the 35 you have is just fine. I'm at 108 main, 42 slow, 2 shims under the needle (3 M washers) and at 2k to 5k altitude.

Your results will probably VARY.

I fixed the leaking carb issue but just snapping the throttle a few times. I have a 42 slow and a 108 main. It idles smooth but full throttle spudders and breaks up very very bad. I may just go back to the 105 and forget it. I cant get it rev smoothly at all. I will mess with it a bit more. I still think the slow jet is the wrong type even though I matched the serial number for the one that was listed on here as being a good replacement

Quote:

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Originally Posted by Bobthebobber

I fixed the leaking carb issue but just snapping the throttle a few times. I have a 42 slow and a 108 main. It idles smooth but full throttle spudders and breaks up very very bad. I may just go back to the 105 and forget it. I cant get it rev smoothly at all. I will mess with it a bit more. I still think the slow jet is the wrong type even though I matched the serial number for the one that was listed on here as being a good replacement

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The low speed is a newer type and works well in my 2012 DF
.

axa,
Attachment 13096
axa,
Photo of the hole saw and extension that I bought off Amazon years ago that I used it to remove the catalytic converter on my 2010 and my 2012 DFs. Worked for me but you are on your own.

GonzoX,
Also the dipstick from my 2012 DF. Plenty available on Ebay and Amazon if you search for atv , dirtbike, motorcycle etc dipstick. Match up the length.

Here is one that looks right but YOU NEED to make sure.
http://www.ebay.com/itm/OIL-DIPSTICK...3e19a6&vxp=mtr

Thanks for all your help Barnone!

My bike starts instantly, runs great, hits 67 mph, 60 to 75 mpg. Should I try to mods like everyone or just leave it? I'm afraid to mess with anything except the idle. It has almost 2K. I bought it locally. They let me test drive it. Only driven a bike once 20 years ago I instantly was hooked!! I also run 100% gasoline (no ethanol) high octane.

Quote:

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Originally Posted by axa

though doesn't proper air filter media reap havoc on decent air intake.
idk, I've had dirty carbs on dirt bikes, but never one of my street bikes, I suppose I havnt ridden as long as others.
but on the road bikes, I've always noticed more junk collecting down in through the gas cap hole than collected in or around my air filter. but maybe that is not a fair scientific comparison.
bottom line if a proper filter wouldn't starve this bike I'd have one too.

that said what do you use for a gas filter

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Stock filter that came with it but that will also be replaced soon. This bike is a work in progress.

Quote:

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Originally Posted by barnone

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.

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Thanks barnone, Im good.

I did a search using the DF250 parts number list and found the correct stick (oil ruler assy) at rocketa.com. Or at least it says it's the correct part. Guess Ill find out.

M

Quote:

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Originally Posted by Tedub

y bike starts instantly, runs great, hits 67 mph, 60 to 75 mpg. Should I try to mods like everyone or just leave it? I'm afraid to mess with anything except the idle. It has almost 2K. I bought it locally. They let me test drive it. Only driven a bike once 20 years ago I instantly was hooked!! I also run 100% gasoline (no ethanol) high octane.

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I wouldn't do a thing except regular maintenance. I have stock gearing and jets, changed the plug, fuel and air filter, added a crank breather, got rid of the air pump. Going on 500 mi and the bike just runs better and better. I do 55 in 5th and get 60 mpg and it purrs. Decided I'd like a highway bike so I picked up a Honda 1300 vtx last week 2004 5100 mi $3800. I love my DF for what it is and use it as a nice in town go bike. It is the nicest town bike in town.

Attachment 13098

[QUOTE=Tedub;61118]My bike starts instantly, runs great, hits 67 mph, 60 to 75 mpg. Should I try to mods like everyone or just leave it? I'm afraid to mess with anything except the idle. It has almost 2K. I bought it locally. They let me test drive it. Only driven a bike once 20 years ago I instantly was hooked!! I also run 100% gasoline (no ethanol) high octane.[/QUOTE
Your DF is good to go. Runs and looks good, I'd say leave it be. Like that silver.

[QUOTE=Bob form NV;61123]M
I picked up a Honda 1300 vtx last week 2004 5100 mi $3800. I love my DF for what it is and use it as a nice in town go bike. It is the nicest town bike in town.

[/QUOTE
Bob,
Nice looking Honda and a good buy. I've had several Honda Shadows over the years and they were bullet proof.

Quote:

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Originally Posted by Tedub

My bike starts instantly, runs great, hits 67 mph, 60 to 75 mpg. Should I try to mods like everyone or just leave it? I'm afraid to mess with anything except the idle. It has almost 2K. I bought it locally. They let me test drive it. Only driven a bike once 20 years ago I instantly was hooked!! I also run 100% gasoline (no ethanol) high octane.

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Looks just like mine.

I would not mess with it if it's running good. My own major mistake was to leave it in the elements so I suggest you either garage it or keep it covered unless you want to deal with rust later as the metal isnt that great on these. I would also order a spare shift rod as sooner or later you will need one.

Quote:

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Originally Posted by barnone

axa,
Disclaimer: DO NOT attempt this if you do not have the skill to perform this operation. DO NOT come back to me complaining after you have screwed up your muffler. Performing this will increase the noise of the DF exhaust.

. DO THIS AT YOUR OWN RISK.

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I spoke to my lawyer and he ensured me that an internet forum disclaimer does not constitute immunity from negligence and prosecution.

so in following your advise, I blew it up in to 1,247,154 pieces, now I have emotional issues including post traumatic stress disorder.

Therefore i have no choice but sue, so consider yourself served!



Now on to more more serious business... my initial concern about my shallow depth hole saws were correct, with out the depth that barones bit there has, you wont be able to dig deep and break up the catalyst and make it fall out very easily.
I was forced to use my prized precision Silver & Deming bits and fabricate an extension to hold the their 1/2" shanks... my lathe and mill tools never leave the shop but i had to do what i had to do.

So because my muffler baffling was not nice and evenly installed, it kept catching and binding and raking up my poor poor bits... This is why a 30 min job took me most of the morning.
That said, got the cat out, it must have been 3 maybe 4 inches long.

- So plan your cutting tool accordingly. Something that can work with deeper holes, shallow hole saws are out! And watch for an unruly baffling, catch an edge and it will make this easy job a pita!

Quote:

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Originally Posted by GonzoX

Looks just like mine.

I would not mess with it if it's running good. My own major mistake was to leave it in the elements so I suggest you either garage it or keep it covered unless you want to deal with rust later as the metal isnt that great on these. I would also order a spare shift rod as sooner or later you will need one.

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If you need to ask I think your question is answered, leave it be.
But some of us get this bike because they enjoy not only riding , but working on it.
I bought this bike expecting to work on it, which i do more than ride it...

I for one like finding things that are broken or unoptimal, and then the challenge to fix it correctly.

Quote:

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Originally Posted by axa

I spoke to my lawyer and he ensured me that an internet forum disclaimer does not constitute immunity from negligence and prosecution.

so in following your advise, I blew it up in to 1,247,154 pieces, now I have emotional issues including post traumatic stress disorder.

Therefore i have no choice but sue, so consider yourself served!



Now on to more more serious business... my initial concern about my shallow depth hole saws were correct, with out the depth that barones bit there has, you wont be able to dig deep and break up the catalyst and make it fall out very easily.
I was forced to use my prized precision Silver & Deming bits and fabricate an extension to hold the their 1/2" shanks... my lathe and mill tools never leave the shop but i had to do what i had to do.

So because my muffler baffling was not nice and evenly installed, it kept catching and binding and raking up my poor poor bits... This is why a 30 min job took me most of the morning.
That said, got the cat out, it must have been 3 maybe 4 inches long.

- So plan your cutting tool accordingly. Something that can work with deeper holes, shallow hole saws are out! And watch for an unruly baffling, catch an edge and it will make this easy job a pita!

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axa,
Are you saying that I did not remove catalytic converters from my DFs with my hole saw?

I gave up with my 42 slow and 108 main. I tried every combo... stock main with 42 slow.. and stock slow with 108 main... shimming the needle... adjusting the mixture.. I could not get the thing to rev without breaking up.. so I just threw the stocks back in and it revs perfectly in neutral now. Anyway if anyone wants the 108 main and 42 slow that I bought I would be happy to send them out to you for a little less than I paid.

Barnone and other confirmed these jets work for them.. I think I may have just gotten a poorly tuned biked to start with :(

Quote:

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Originally Posted by axa

I spoke to my lawyer and he ensured me that an internet forum disclaimer does not constitute immunity from negligence and prosecution.

so in following your advise, I blew it up in to 1,247,154 pieces, now I have emotional issues including post traumatic stress disorder.

Therefore i have no choice but sue, so consider yourself served!



Now on to more more serious business... my initial concern about my shallow depth hole saws were correct, with out the depth that barones bit there has, you wont be able to dig deep and break up the catalyst and make it fall out very easily.
I was forced to use my prized precision Silver & Deming bits and fabricate an extension to hold the their 1/2" shanks... my lathe and mill tools never leave the shop but i had to do what i had to do.

So because my muffler baffling was not nice and evenly installed, it kept catching and binding and raking up my poor poor bits... This is why a 30 min job took me most of the morning.
That said, got the cat out, it must have been 3 maybe 4 inches long.

- So plan your cutting tool accordingly. Something that can work with deeper holes, shallow hole saws are out! And watch for an unruly baffling, catch an edge and it will make this easy job a pita!

---

How does she sound and ride now ?

Quote:

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Originally Posted by Bobthebobber

I gave up with my 42 slow and 108 main. I tried every combo... stock main with 42 slow.. and stock slow with 108 main... shimming the needle... adjusting the mixture.. I could not get the thing to rev without breaking up.. so I just threw the stocks back in and it revs perfectly in neutral now. Anyway if anyone wants the 108 main and 42 slow that I bought I would be happy to send them out to you for a little less than I paid.

Barnone and other confirmed these jets work for them.. I think I may have just gotten a poorly tuned biked to start with :(

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I did mention that I removed the catalytic converter which reduces the back pressure in the exhaust and that should allow more air/fuel to flow through the system therefore needing the larger jets.

Anyway, whatever works for you is good.