Dong Fang DF 250 RTB Bobber Information

[barnone]

DF250.jpg

[birdmove]

Here is a website that has this model for the lowest price. They call it the MC-G46 : http://www.powersportsmax.com/produc...ducts_id/16997 I like the bars much better. The tank also, and there were far too many leaks with the old tank. It was lucky that some owner didn't become a fireball. I would assume the sellers of these bikes complained about the high numbers of gas leaks from the tanks. I didn't care for the shape of the old tank or the bars. And someone said this new one has a different seat? I'm still working my way through this thread. Heist owners are also having problems shearing rear sprocket bolts, and I believe I read on the Facebook page that Gardo may be selling his Heist. That surprised me as I thought he really loved that thing. Many are selling their DF's and Heists because it was their first bike and they want something with more power. I've been all through that years ago, and I am back to where I have fun riding any bike, big or small. My idea of a good time is NOT trying to herd an 800 pound Harley around. This bike is just a basic no frills motorcycle. Looks like it would be easy to work on. But I really didn't want to buy on and risk becoming the human torch on a ride. There is no excuse for the way they slapped those tanks on. Obviously no quality control there. There is a thread on advrider.com about a guy that bought one of those BMS Bi-Metros, which I believe is the old Fly copy of a Honda CT-70. The production line that thing came off of I wouldn't trust to assemble a barstool. It's plain that, with Chinese motorcycles, if there is someone who cares in a QC position (ZhongChen, maybe TMEC, and certainly others), or the parent company that is having the bikes built is in control of quality (SYM, Kymco, BMW, our the Japanese companies), that one can get a decent motorcycle or scooter. Look at Spudrider, now with over 50,000 miles on his Zong dual sport. I've heard good things about the Qlink dual sport bikes too. I'm sure Qlink is deeply involved in keeping there bikes safe and solid. The people that make this bobber should have their suppliers go with decent grade 8 sprocket bolts. In over 50 years of riding, I have never broken a sprocket mount bolt on any Japanese, English, Spanish, or Indian made motorcycle I've owned. These issues are why this thread is so important. Everyone will know the weak points on these bikes and can act accordingly. Watch those rear sprocket bolts. Someone here shows the equivalent Honda bolts, and if get one of these, I thin I would order a set, and when I replaced the rear sprocket I'd use those Honda bolts. The other side of the coin is, you can't expect perfection for $2069.00. I just priced a 2013 Suzuki DR200 at a dealer here in Hawaii. $5300 out the door. I can get a new TMEC delivered for about $2050. Is the Suzuki a better bike? I'm pretty sure it is. Is it two and a half times better than the TMEC?

[skullworkz]

So, on this valve situation I have found this. .004/.006 is NOT a good choice. The owners manual states it should be .006/.008. I also saw the CCW video and in that video you also heard him say between 1:40 and 2:20 is what the issue is. Also, I think that these two engines are different manufactureres yet the same engine with different specs. I think I read this somewhere in this HUGE FREAKING thread!!!! I did indeed set my valves according to this video and the bike sounded pretty quiet. BUT, I did get some clanking sound from the engine when it got warm! This engine is based on an old design and should be kinda free in the AK-47 kinda way. It's gonna get hot and the cheap chinese metal is going to swell so give it room. Scared the $hit outta me when I heard a sound like someone threw a bolt in my motor. I opened it up and there wasn't any valve or piston damage, but run your bike till it's warm and do a PROPER valve adjustment at the suggested specs. After i adjusted my valves to the owners manual specs I haven't had ANY issues with my bike. And, again I have to plan to wait ANYWHERE I go for an additional 10mins for questions and drool.

[ben2go]

birdmove,
I know you from ADVrider before you moved to HI.
I started this thread but sold my DF after several years of ownership but am now interested in getting one of the new non springer models. Looks to me that quite a few improvements are included in the new one especially the fuel tank.
I never had any problems with the wheels leaking air but some did and put a tube in to solve the leak.

I am interested in hearing from owners of the new "non springer" models. BTW, what model number is it?DF250.jpg

Good to see you are still around and thinking of buying another DF.I am so glad you started this thread.I held off on buying a DF due to the problems.I was considering it for my oldest boy's first bike.Now that the DF has been improved,it's back in the running.

[barnone]

According to this site (http://www.df-motor.com/ProductShow.asp?ID=16) which appears to be the USA DF site, the number for the telescopic fork model is DF250RTB-A while the springer model is DF250RTB-B.

[DanDaMan]

dont do as suggested , never do valve timing on hot motor

as stated its a copy of a 40 yr oldish motor , its ment to be a lil loose and chattery

stone cold adjustments , if to tight they will snap off and fall on top of moving piston

Id much rather have a chattery motor , than an exploding one , when its between my legs

[Bob form NV]

Aboshi,
Here is one by our own ChinaV, different bike but same procedure with a few differences.
http://www.mychinamoto.com/forums/sh...justing+valves
Pretty much the same as our bobber. I had to use an impact screw driver to remove the four screws that holds the plate covering the nut that you can use to turn the engine to get to the TDC mark. Another difference is you remove the three bolts to remove the valve cover instead of removing the two round valve covers.
Edit: Manual and sticker on frame both say .06mm intake and .08mm exhaust.

Found this while searching for proper valve ajustment values

[axa]

So, on this valve situation I have found this. .004/.006 is NOT a good choice. The owners manual states it should be .006/.008. I also saw the CCW video and in that video you also heard him say between 1:40 and 2:20 is what the issue is. Also, I think that these two engines are different manufacturer's yet the same engine with different specs. I think I read this somewhere in this HUGE FREAKING thread!!!! I did indeed set my valves according to this video and the bike sounded pretty quiet. BUT, I did get some clanking sound from the engine when it got warm! This engine is based on an old design and should be kinda free in the AK-47 kinda way. It's gonna get hot and the cheap Chinese metal is going to swell so give it room. Scared the $hit outta me when I heard a sound like someone threw a bolt in my motor. I opened it up and there wasn't any valve or piston damage, but run your bike till it's warm and do a PROPER valve adjustment at the suggested specs. After i adjusted my valves to the owners manual specs I haven't had ANY issues with my bike. And, again I have to plan to wait ANYWHERE I go for an additional 10mins for questions and drool.

ok so there is seemingly some evidence here suggesting a .006 IN .008 OUT valve setting.
But the reason to adjust valves is to give clearance for expansion when the engine heats, so the goal is to have perfect mating. That is no clearance and the inverse, no stress. Buy why would one want to be making adjustments for extra clearance once the engine is hot. Thats seems counter productive, cuz if you keep more than needed clearance on a warm engine, you will just be loosing efficiency in power and mileage.

But I suppose one might argue in doing that, they are providing extra protection from further expansion .

I think the AK analogy has some merits but, in the case of a gun, you will live with the lost in power and accuracy loose tolerances buys, because when making the decision to shoot someone you want to be sure that last roll in the dirt won't end up being the reason your weapon ceased.
It also allows you to fit your weapon with poorly machined parts and ammo.
But as for our df250s engines, we are only concerned with the expansion. There isn't too much else.
You change your oil, clean the filter, nothing to swap in or out. So why not shoot for the ideal adjustment when warm rather than a continued loose one.

for me its just so strange that my bike not only didn't have any clearance, but actually had stress on the rods.

[GonzoX]

The RE can be lowered or the suspension preload soften to allow it to squish down a little more when you set on it.

Thats good news and I will inquire about this with them. Thx.

[birdmove]

My 2007 Royal Enfield, and the newer fuel injected ones, are an old style pushrod engine. I could check the valve adjustment in about 3 minutes. On those, you first located TDC. Then removed a small cover on the r/side of the engine accessing the pushrods. One would grab the pushrods with thumb and pointing finger and rotate them (spin them a little). If one wouldn't spin, then the engine was most likely not on TDC on the compression stroke. Rotate engine 180 degrees and check again. If both pushrods could now be turned, then you were on the compression stroke. Valve clearance adjustment was correct when you could spin the pushrods pretty easily, but they had no up and down play. This was done with engine cold. No actual measuring devices (feelers) were needed. On these bobbers, once you get the adjustment correct per feeler gauge, grab that pushrod and try spinning it. Then see if it has any up and down play. Remember your results. That's a good way to check if you are at TDC on compression stroke too. If one pushrod will not spin, then that valve is at least, partly open. Turn the engine over 180 degrees and try again. If both spin, then you are at TDC on compression stroke. A four stroke has two TDC's. One on compression stroke, where you can now adjust the valves, and one on the exhaust stroke, where that valve is open and the pushrod for that valve is tight and won't spin easily. There are a lot of mistakes made doing valve adjustments due to the engine being at TDC, but on the exhaust stroke, and not the compression stroke. The reults will be a bad top end clatter, if the engine will even run. Worst case, the rocker arm could spit the pushrod out and maybe do some damage.