Dong Fang DF 250 RTB Bobber Information

[axa]

that manual is riddled with errors, I've ceased to reference it

anyway pulled the r/r on my bike and found it was allowing way too high voltages. ordered a new one.

[axa]

Barnone, AXa ,,, I have just got a problem agin hope you guys can help with,,, just had the bike pass the registration test went to ride it to the MOT center to finalise all documentation and lost Left side indicators ???? checked lamps and then basic wiring plugs etc,,, all seem sound right was working now lost all indicator's...... can you pass any wiring drawings for these bikes or parts list for a new flasher box ?? were can I order etc ??? or even if I have missed looking for something ,,,, all your help is much appreciated... don't forget mines the 125 RTB if that makes any difference.

if both left side indicators, might be related to the switch. just a single light may indicate a bulb.
check each connector is clean and secure.

I just found worn wire insulation that got pinched between the tank and frame.
it could be many things.

[axa]

Im at a loss....

Leaving the battery in.

Disconnecting the stator output from the R/R, measuring consistent AC voltage (about 16VAC RMS) through each coil, which only increased with increased rpm, and that there are no shorts from each of the 3 nodes to ground, i judged the stator good.

Reconnecting the stator output to the rectifier input stator, measuring the disconnected R/R output, i measuring a reduced DC voltage that only decrease as RPM increased, so i could only judge the R/R must be bad...

So i purchased and installed a new R/R but I_have basically the same situation....

I cant fathom why the old and new do not give a consistent 12-15 dcv.
What am i missing?
Out of ideas, and seeking advice from the experienced in the hoard...

[axa]

barnone. your big bore is finally here...
brought to you by the highly skilled R&D team at ccw:
http://cleveland-cyclewerks.theshopp...ry/performance

300cc of raw screaming and illegal power...
so be sure to read the disclaimer and note these modification are to be limited to the 'closed course race track only',where this explosive power can be safely unleashed...

so where do I begin...
first of all that is a 69.5 mm piston, which equates to a 246.6cc engine... that's quite a stretch don't u think... don't even call it a 'true 250' just jump right to 300..
why stop there, a 333 has a nice ring to it...

now i haven't done any research in to this but if you were to bore the original cylinder you would end up with only a 1.75mm cylinder wall at best.
Boretech refuses to bore to anything less than to 3mm so I doubt this is happening...

then if you take a look at the sticker placed on the wiseco piston box, you can see "11.1 CR", more horse shit.
I ran the numbers and the larger bore will only yield a 9.39:1 ratio. that is allowing the benefit that the original 67mm head is used in the calculations. for if u calculate with a proper 69/70mm dome, that number drops back near 9:1
The original piston is domed to begin with, and no where does this kit suggest anything in regards to a decked head, so the suggested higher compression is simply not possible without further machine work of decking the cylinder mating surface.

next scroll on over to the pic of the cylinder itself, there u see a virgin UNMACHINED part complete with a messed up mating surface with genuine scratches due to poor packing on the long boat trip from China... every head and cylinder I've seen had these... then look at my profile to see what an actual decked surface looks like.

now on to the over head pic of the cylinder and you can see the virgin unmachined fully think cylinder sleeve walls, this head wasn't bored either.. so niether the required bore nor decking has been displayed...

maybe they just ran out of inventory on this hot item and had none to take photos of...
but at 420$ plus shipping, nearly the cost of a fully assembled, ready to go, true 169fmm entire engine, let's just say I have my doubts.

at best they found, and found a way to squeeze an off the shelf cg169fmm cylinder kit into the transmission... but I also have reservations about this as i needed to slightly grind some of the transmission case away in order to fit the slightly thicker cylinder sleeve on my replacement 67mm cylinder..


I'm not buying any of this quite yet, but I will look into seeing if a cg169fmm cylinder kit really does exists, and then I'll really deck it to an 11:1 CR !

[barnone]

Well I guess that CCW could not call it a 250cc big bore kit since they use to claim that the stock engine is 250cc.


These guys are still advertising "Change your CG250 67mm air cooled engine (167FMM)to 70mm bore,Kit include piston kit and gasket".
http://www.chinese-parts-canada.com/4_stroke_big_bore_kits.html
I never have gotten an answer from them.

Anyway, I'm happy with my DFs performance for now.

Maybe DF will put the overhead cam engine in the Df250RTB's next generation.

[axa]

Well I guess that CCW could not call it a 250cc big bore kit since they use to claim that the stock engine is 250cc.


These guys are still advertising "Change your CG250 67mm air cooled engine (167FMM)to 70mm bore,Kit include piston kit and gasket".
http://www.chinese-parts-canada.com/4_stroke_big_bore_kits.html
I never have gotten an answer from them.

Anyway, I'm happy with my DFs performance for now.

Maybe DF will put the overhead cam engine in the Df250RTB's next generation.

if DF goes to an ohc, I'd likely sell the 2012 and get one.

so I searched all night for a 169 or 170 fmm...
several proved to be 167, many had no info at all, and a few weren't even a cg clones...
Of all I only found one with a considerable possibility of being true...

I'm still not convinced a larger cylinder will fit, nor is it a good idea to shave the outside of a cylinder sleeve so it will fit the crack case.

[SR.MAILMAN]

Generally, when a "big bore" kit is installed,the crankcase has to be bored larger to fit the increased diameter of the new cylinder/jugs.

(on a Yamaha 250/249cc ,it can be increased to 334cc- $599.95 and one owner said it made a BIG difference in grunt).

personally, I just use a bigger bike,if I need that much more power...

[ben2go]

The wiseco piston and rings are US made.The piston pin boss is machined a tad bit lower than stock which allows the piston to rise further up in the bore,more compression.It's one of the tricks they used and I figured it out after installing quite a few in my bikes over the years.I had to raise the cylinder block on my GS 569 project by shimming to keep pistons from hitting the valves.They didn't know I was using Megacycle high lift long duration cams in my build.I bought them before the cams.

[axa]

no doubt it's s a good piston, i confirmed wiseco made it in a custom run of 'at least 4 parts'. it's quite reasonable they reposition the gudgeon pin to meet their claimed CR.

and no boring of the crank case, confirmed they bore the original cylinder. I always wondered how thin it could go.
the stock cylinder sleeve is 3mm thick, a 69.5 bore leaves the walls at 1.75mm.
I always wondered how thin u could go, surely no long term endurance testing could yet be done but I'm all for trying...
just personally wouldn't want to be a guinea pig at ~450$ a pop, with no warranty.

it's a hard sale when you could get a true 170fmm entire engine with greater displacement for not too much more.
or better yet a CB type OHC with significantly more power, both I believe drop in replacements.

anyway I must admit I expected this was just a 169fmm cylinder kit strait off eBay.
But it's warranted criticism, 300cc is far from the actual 246. and the claimed gain of "4-6 HP" with their decked head on a 10 -12 HP engine is undisputed BS as well.
so really couldn't believe they did any of the actual leg work on this.

[axa]

so I hit 68 mph indicated for the first time yesterday. and that was with a partially closed choke, I haven't yet the time to rejet after all the head work. I'm running 110 main now, so i do get the hint there is some gain left to squeeze out.
but I'm a bit cautious to push things for another couple hundred miles after the first oil change. I wouldn't be surprised to find some of my exploded piston or exhaust valve in the oil screen.

but the head work has proved effective for me, I'm going to continue with it to an 11 or 11.5 CR this winter...