BGF Hongdu/Solex
- Thread starter cannonball2
- Start date
my clutch works, i just don't use it/need it, especially now that i nixed the throttle control. i was just wondering if i could get rid of the internal clutch parts with no drawbacks, even if it's just for the sake of simplicity or eliminating possible future failures relating to it. do these clutches go bad often, and what kind of symptoms do they cause if they do?
I dont think the clutches are an issue. The original one in the ancient Velo Im redoing is in fine shape after years of use. To remove it would require some how locking the crankshaft to the clutch drum. I just think its more trouble than its worth. The Hd clutch looks to be made as well as the Velo clutch, so I dont think you really need to worry too much about failure.
I've enjoyed this thread, not because I've had a Solex, because in 1956 I bought an engine drive kit out of the back of Popular Science. The engine was a 2 stroke Power Product's single, 1 1/2 HP, compression release for starting, and drove the front wheel by friction using a grinding wheel like stone. I think they called it the Travis. In stock, new condition it went 25mph on the level. As it broke in it got a bit faster. The exhaust came out the front and I took a piece of 1/2" water pipe and bent it so it went out the front and down past the lower part of the front fork. It was very loud and my Dad said it he could tell where I was, and was going, by listening. I blew it up one day after winding it up going down a pretty good hill. It didn't blow from the RPM, it blew because I closed the throttle. In the 2 stroke you get lubrication from the fuel mixture, and when I closed the throttle at full RPM I shut off the lube and it didn't go but a few hundred feet before it spit parts through the crankcase. I'm sure many of the China Girl's failures come from the same reason. As I learned as a 13 year old, the off throttle at speed down hill is a killer with a 2-stroke.
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Great story Greybeard. Reminds me of my Cyclops mini bike. Had a portion of a sink S trap for an exhaust, mainly because it was chrome. Talk about loud! My Dad kept up with me the same way in our small Fla. town. If he couldnt hear me real well meant I was out of my local area and I caught it big time when I got home. No GPS tracking needed for him!
Well, Engine #2 has been running pretty good, but not good enough, So I decided to pull the head and investigate.
First thing I noticed was that there was hardly any honing marks at all. The bore was mostly shiny and glazed. Can't wear the rings in against that!
I did a shortutcut hone job without pulling the cylinder, just the exposed bore from bdc positon. Didn't want to deal with further dissasenbly. After working the med. grit hone about 45 seconds with a vari-speed drill, all glaze was gone and had a good crosshatch pattern.
After I buttoned it up, I ran it for about 10 miles. It got stronger with each mile. I think the rings are finaly starting to seat.
Very dramatic increase in power. This mod has made more difference than anything I have done so far. The honing has to be right and sorta rough or the rings won't seat.
Gonna do another 10 miles and check the compression again. Hoping that it will be up from that measly 75 psi.
So, if yer new Hongdu is runnin kinda weak , pull the head, at least, and hone the sheet out of it!
First thing I noticed was that there was hardly any honing marks at all. The bore was mostly shiny and glazed. Can't wear the rings in against that!
I did a shortutcut hone job without pulling the cylinder, just the exposed bore from bdc positon. Didn't want to deal with further dissasenbly. After working the med. grit hone about 45 seconds with a vari-speed drill, all glaze was gone and had a good crosshatch pattern.
After I buttoned it up, I ran it for about 10 miles. It got stronger with each mile. I think the rings are finaly starting to seat.
Very dramatic increase in power. This mod has made more difference than anything I have done so far. The honing has to be right and sorta rough or the rings won't seat.
Gonna do another 10 miles and check the compression again. Hoping that it will be up from that measly 75 psi.
So, if yer new Hongdu is runnin kinda weak , pull the head, at least, and hone the sheet out of it!
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Just got my micro drills and checked the main jets I have. I have one original Solex, and two Hongdu. The Hongdu jets are smaller than the Solex. The #76 drill measures .0195and fits snugly into the Solex jet, the Solex jet is supposed to be .5mm or .197 so this jives.. The Hongdu jets are smaller reading around .0175 with the #77 drill. This explains why mine ran better with the Solex jet and the choke could be fully off. I had to have the choke slightly on to run well with the Hd jets. Seems that the Hd jets might actually need drilling to the #76 size.
my stock hd jet was .024, was running really rich. runs great now that i've leaned it out to .019
These things must be all over the place size wise. I drilled the Hongdu jets to .019, from .017, and they run the same as the Solex jet, great. Probably a good idea for those that havent checked their jets to have a look at em.
we maybe over looking something here. my drills didn't come with a chart so i had to mic them to get there size.
these china micro bits might not conform to any set stanard.
Mine didnt have a chart I googled one. My bits have measured right on/close enough to the chart. Mine are Chinese also. Given the sporadic quality of these engines it seems possible the jets are questionable too. You Im sure are correct in your measurements, just proves how stuff slides by/out of these little factories. This is pretty much verified since your Hd is running well now, the .019 jet is what they require, at least stock.
My engine #1 had a .024 jet. Engine #2 has a .019 jet and runs good now, after I did a re-hone.
I put new rings from Steve's in engine #1 Sunday.
I found that the original rings were fitted too tight, no gap at all!
I believe this may have worn the bore out of round some. If the rings expanded , something had to give.
When I honed this cylinder, there was a couple of large, very obvious low spots in the honing finish, Took several munites work to remove them. One spot was at the very top of the bore and about 1/2" wide at first.
Steve's rings come pre-fitted. They all had the same gap of about .003-.004 by my callibrated eyeball.
I soldered up the jet and drilled it to .018, and after about 5 miles of break-in, it's running slightly stronger than weak.
It is 4 cycling a lot. I'm gonna have to try smaller jet.
I may try to modify the stock jet by removing the ball plug and adding an adjustable screw needle.
I put new rings from Steve's in engine #1 Sunday.
I found that the original rings were fitted too tight, no gap at all!
I believe this may have worn the bore out of round some. If the rings expanded , something had to give.
When I honed this cylinder, there was a couple of large, very obvious low spots in the honing finish, Took several munites work to remove them. One spot was at the very top of the bore and about 1/2" wide at first.
Steve's rings come pre-fitted. They all had the same gap of about .003-.004 by my callibrated eyeball.
I soldered up the jet and drilled it to .018, and after about 5 miles of break-in, it's running slightly stronger than weak.
It is 4 cycling a lot. I'm gonna have to try smaller jet.
I may try to modify the stock jet by removing the ball plug and adding an adjustable screw needle.
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The jet mod sounds like a great idea Wayne, gonna check around for some needles in my junk carbs.
these motor kits will soon be here in the uk, as i mentioned on another section of this forum. I have no connection with this company, but if you go on youtube search velosolex, you will know a lot more than you do now, made in europe i believe, and upgraded to pass british specs, so should easily get any parts you want, I think they said there is 8 million of them around the world. enjoy.
From what I have read from many sources, the only engines of this type currently being produced today are the ones made by Hongdu. The last ones made in Europe were the Hungarian made ones, which are supposed to be out of production. The French assembled Black and Roll and the Velosolex currently sold in the US are using these engines. Parts are slow to get from Velosolex USA I have been waiting over 6 wks for some. Not all of the original Velosolex engine parts interchange, so you have to be careful on assuming everthing fits.
HI, cannonball, i had difficulty finding the site i mentioned, it was not on youtube, i used the search engine, here it is, I don,t make a penny out of this, mr moderator, just trying to help. try VeloSolex is back later this year, they should be available they say. yes they are still made in hungary, being imported.
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