Dong Fang DF 250 RTB Bobber Information

[Roadkill]

I'm impressed with the lathe work! I've always been interested in machine and model making. I'm fixin to retire soon and I'm gonna see if I can find a small metal fab shop and do grunt work so I can learn welding and metal work and with luck, machine work.

[axa]

I'm impressed with the lathe work! I've always been interested in machine and model making. I'm fixin to retire soon and I'm gonna see if I can find a small metal fab shop and do grunt work so I can learn welding and metal work and with luck, machine work.

Go for it, getting paid to learn can be very beneficial if u can swing it.
I thought about this when I started but you are right, you need to be otherwise retired to be able to give the time to land a decent position.

Therefore the other choice being paying a school, but living so close to NYC i could find nothing other than 15 hours of adult education welding in the evening, all the metal shop schooling has gone from this area. I didn't do it but took that money to buy my first welder.
In the end, doing is the most effective way to learn regardless, just need the will.

[DanDaMan]

its a 2 valve pushrod, everything it has is between 2500-5000 rpm , if u drag out more rpms great 4 u beating the soft springs I was givin , if u don't here your valves clicking away , either you geared to low or to tight

and tight = engine death

redline all u want , valve float from pushrod engines stops any poss damage

unless valves to tight ---

and roadkill , that "miss" sounds like u need a valve, like axa but not blown cylinder like him

adjust valves NOW

[Roadkill]

its a 2 valve pushrod, everything it has is between 2500-5000 rpm , if u drag out more rpms great 4 u beating the soft springs I was givin , if u don't here your valves clicking away , either you geared to low or to tight

and tight = engine death

redline all u want , valve float from pushrod engines stops any poss damage

unless valves to tight ---

and roadkill , that "miss" sounds like u need a valve, like axa but not blown cylinder like him

adjust valves NOW

Thanks! I started the tune over. Valves to .002 and .004, new irrudium plug gapped to .028, raised jet needle (Mikuni carb) to top position, adjusted fuel/air. She runs great now with a slight miss if I run at low rpm for a while. I think that the carb might be a tad rich. I would like to check the compression both cold and warm, but can't find any info on compression range in PSI.

Just did a quick search and found that depending on the cam setup, compression in psi should be between 15-20 times the compression ratio. Interesting for me but not much help as I still don't have a baseline to tell if a valve is causing problems or an exact compression ratio. If I go with 9.02 then I'm looking at 135-180psi on a good engine.

Maybe I'm looking at this wrong. If I have a bad valve, it will be way lower than this range or won't hold pressure very long and I can look at as a very rough leak-down test

As to gearing and RPM. I date back to when 6K was very high RPM and torque was king. I still feel like only Dremmel tools and turbines should turn 12K. Remember when the powerband for deisels was 1750 to 2150 RPM? I'm running stock front sprocket and 35T rear.

[ben2go]

Thanks! I started the tune over. Valves to .002 and .004, new irrudium plug gapped to .028, raised jet needle (Mikuni carb) to top position, adjusted fuel/air. She runs great now with a slight miss if I run at low rpm for a while. I think that the carb might be a tad rich. I would like to check the compression both cold and warm, but can't find any info on compression range in PSI.

Just did a quick search and found that depending on the cam setup, compression in psi should be between 15-20 times the compression ratio. Interesting for me but not much help as I still don't have a baseline to tell if a valve is causing problems or an exact compression ratio. If I go with 9.02 then I'm looking at 135-180psi on a good engine.

Maybe I'm looking at this wrong. If I have a bad valve, it will be way lower than this range or won't hold pressure very long and I can look at as a very rough leak-down test

As to gearing and RPM. I date back to when 6K was very high RPM and torque was king. I still feel like only Dremmel tools and turbines should turn 12K. Remember when the powerband for deisels was 1750 to 2150 RPM? I'm running stock front sprocket and 35T rear.

My GS is 9.5:1 and 175psi is what it puts out when warm.A compression check needs to be done on a warm engine.Any problems that maybe there when running, can go away when the engine cools and the metal tightens back up.

[Roadkill]

My GS is 9.5:1 and 175psi is what it puts out when warm.A compression check needs to be done on a warm engine.Any problems that maybe there when running, can go away when the engine cools and the metal tightens back up.

Thanks for the input. My career has been electronic mfg and we were required per mil spec to test over temp. Product engineer on one of the HARM missle sections and several "Death Toys" that I can't talk about.

[barnone]

Thanks for the input. My career has been electronic mfg and we were required per mil spec to test over temp. Product engineer on one of the HARM missle sections and several "Death Toys" that I can't talk about.

ENGINE COMPRESSION TESTING

http://www.dansmc.com/compression_test.htm

[bowtiewagon]

well turns ut my problem WAS the Starter clutch assembly. removal was realaively easy.Used a larger strap type oil filter tool to hold the drum, while using an impact gun to take the bolt loose. the allen head bolts were easy enough to break free. then a large puller to pull the drumm free of the shaft. once free everything else came free easily.
005.jpg
bearings were all over the place, and race was bent pretty bad.
004.jpg

located a new part online here.
http://www.motopartsmax.com/index.ph...roducts_id/666. Actually bought it off ebay, same item,looks to be from the same place.
http://www.ebay.com/itm/281265680287...84.m1497.l2649

all dimensions and toothe count added up.

Just waiting for it to show up so i can reinstall. Now I will not know if the assembly comes with a new 57 tooth gear or not, just have to wait and see. aside from that.. it is just a waiting game, and i will keep everyone posted.Thanks for everyones input. I must say, that with me having what seems like the most mileage on this bike, and for what has or has not gone wrong, i think I made a pretty sound investment thus far. Plus I hope I am asisting everyone who may have a near similar issue with their bike at one time or another.It is nothing wrong with the bike itself as far as i can see, just wear and tear. 11,000 plus miles and hopefull soon to be counting.

[barnone]

Nice riding today in the mountains of Western North Carolina.
Took a run up to the Dragon.

0622141124-01.jpg
At the Cheoah Dam (Fugitive movie)

0622141210-00.jpg
At the Cade's Cove exit.

Beautiful day.
Yesterday I rode the Ural to a Brit bike rally in Georgia.

[barnone]

well turns ut my problem WAS the Starter clutch assembly

Good news.