BGF Hongdu/Solex

[wayne z]

OK, I think I found the cause of my low performance.
After trying the 5.5 muffler hole, the extended spark plug, and drilling the air inlet holes to 8mm, with no change in performance, I had to pull the jug for a looksee.
I pulled the cylinder off today and found all 3 ring gaps in line, over the wristpin hole.
The top ring looks like it is seating pretty well. The second and third ring only show abouy 50% contact, no contact 1/4" each side of the gap. Might be inferior rings.The bore has crosshatch but not much and very ( mebbe too) smooth. Mebbe I shoulda honed it again.
I spaced the ring gaps and put it back together.It runs a lot better now, but mebbe still not right wit these crappy lookin rings.
Ran better after about 1 hr more time though. Might try a set of Solex rings if it don't get better with some more run time.

 

[cannonball2]

OK, just to to prove my sanity is just questionable as my kids tell me, I am going to build a Velosolex out of this! Now I know what mopedjay(I believe it was him) indicated about the French. This thing is weird! Not a Threaded bolt hole on the whole thing. They must have had Professor Eiffel help with the engineering, becaues you can bend any of the stamped metal parts around your knee, but as a unit its very strong. I love a challenge!?! There is an original engine, or most of one in bound, so we will have something to compare the Hongdu to.

 

[Colony Five]

my main concern with the chinese solex is longevity. but if i can get at least a year of reliable service out of mine, i'd say it was worth it. and i would get another. but who knows how long BGF will sell these at such a discounted rate? especially with the cost of gasoline on the rise. anyway here is mine, total cost of build well under $300. that includes the used bike, paint, a new cargo rack, and nickel and dime items like hardware and new brake pads.

 

[camlifter]

i see you found somewhere to bolt up the exhaust support bar, do you have a better pic of that.

 

[cannonball2]

GREAT looking job and bike! I think the Hongdu in therory should last. If its not plauged with electrical issues like ignition failure. As far as I have torn mine down it looks pretty tough for the power it makes. Got a cast iron cylinder, a pretty big crank, 3 ring piston and the rod runs in needle rollers in a sleeve that bolts to the crank pin (cool design), so the crank is really never wearing anywhere. At .8hp and < 4K rpm its not stressed too much . The BlacknRoll folks got a lot invested to sell these world wide, they better have em worked out! I guess time will tell, the originals were noted for running "forever".

 

[mopedjay]

well i was looking on alibaba.com and i found a company that has these in 48cc 66cc and 80cc it says minimum order 50 so im gonna find out how much a pallet of 50 will be

 

[cannonball2]

Those gotta be 2 strokes, they must have listed them wrong. BTW the seller on ebay from Canada is underselling BGF, but the shipping kills it.

 

[Colony Five]

i see you found somewhere to bolt up the exhaust support bar, do you have a better pic of that.

go back in the thread, there is a close up of it. the threaded end of the bar goes in the flange at the end of the exhaust, and the other end of the bar has enough room either way where you should be able to line it up with one of the clamp bolts, or you can even attach it to the fork on its own.

 

[camlifter]

mines to short to mount anywhere that will let it pivot with the motor. i don't want to mount it in a way that it will pull apart when you lift the motor. i'll have to make a new one that lets it pivot with the motor.

 

[wayne z]

Hey Cannonball, where did you find solex(or black n roll) gaskets?
So far, i've been unsuccesful at finding parts vendors. Still can't cruise over 10mph. I want to try new rings and a good crosshatch honing job.

Could I possibly get better quality rings that arent made by Hongdu?

 

[camlifter]

wayne. i found my fuel tank full of rusty scale, when i took it off to clean it, the outlet hole where the fuel line connects was almost cloged shut, very little fuel would have been able to flow out, might want to check that.

 

[wayne z]

Thanks Cam, My tank was full of rust too. I rattled pea gravel in it, rinsed it out and treated it with phosphoric acid, and checked flow from outlet.
I don't think I have a fuel problem, it 4 strokes just a a little while cruising at 10mph.
Supposed to make 95psi cranking compression. Gonna check thst today.
I suspect that the rings aren't right. 2 of them aren't making good contact with the cyl wall,at the ring gaps.

 

[cannonball2]

Hey Cannonball, where did you find solex(or black n roll) gaskets?
So far, i've been unsuccesful at finding parts vendors. Still can't cruise over 10mph. I want to try new rings and a good crosshatch honing job.

Could I possibly get better quality rings that arent made by Hongdu?

Goggle Steves Mopeds NJ I dont know what the have in stock, but thay have listed almost all of the new generation Velosolex parts, the gaskets and rings are listed. The Rings are confusing, I believe they are listed x1 not a set. Not cheap 8 bucks ea as I remember. Gaskets arent too bad.

 

[cannonball2]

Here is another thought, Goggle Frank Bowman rings. He makes custom rings for just about anything. Mostly R/C aircraft engine conversions. I have used his rings in the past in my conversions, Best rings I have ever seen! I believe he states If you send him a piston he will send it back ringed. The size of the HD piston is right in the R/C range and shouldnt be a problem. I have never gone the sent piston route but his off the shelf rings are less than the Velo rings if 8 bucks a pop. If you go this route, let us all know maybe we can save us all some $$$ in bulk.

 

[wayne z]

OK, I found the Velocruz website, The rings are around 6 bux each there. His webstore wouldn't process my card. I'll call him later today

 

[wayne z]

OK, I ordered rings and stuff from Steve's Mopeds. Does anyone know the ring end gap specs for this engine?
Thakls, Wayne

 

[Colony Five]

OK, I ordered rings and stuff from Steve's Mopeds. Does anyone know the ring end gap specs for this engine?
Thakls, Wayne

VeloSoleX S 3800 Engine Data

should be the same for the hongdu

 

[Colony Five]

mines to short to mount anywhere that will let it pivot with the motor. i don't want to mount it in a way that it will pull apart when you lift the motor. i'll have to make a new one that lets it pivot with the motor.

well yeah, you aren't using the kit bracket to mount yours so you might as well rig yours up to pivot. that's my only complaint about these. the kit bracket doesn't let the exhaust pivot and that joint where it connects makes a real mess. the cut innertube i wrapped on mine didn't hold up so i will have to try the 5/8" heater hose as per cannonball2's suggestion. hopefully that will work well enough for me.

can anyone tell me how a real solex addressed this? does the exhaust pivot on one of those?

 

[cannonball2]

I believe the HD works like the Solex. The muffler is attatched to the front fender on the Solex as it is on mine, as well as the fixed engine bracket, so it is immoveable. The joint has a sloppy enough fit to allow for the limited movement of lifting the engine. I believe to get it to optimum, the muffler needs to be attatched with the joint in the middle of the engine travel so it not all one way, particuarly when the engine is down allowing the widest gap while running. The Solex had "protector" plate(shield) to protect the rider behind the exhaust. The front wheel on my basket case had years of oil residue on the rim and spokes, sure leaked somewhere! The hose trick works well on mine.

 

[Colony Five]

I believe the HD works like the Solex. The muffler is attatched to the front fender on the Solex as it is on mine, as well as the fixed engine bracket, so it is immoveable. The joint has a sloppy enough fit to allow for the limited movement of lifting the engine. I believe to get it to optimum, the muffler needs to be attatched with the joint in the middle of the engine travel so it not all one way, particuarly when the engine is down allowing the widest gap while running. The Solex had "protector" plate(shield) to protect the rider behind the exhaust. The front wheel on my basket case had years of oil residue on the rim and spokes, sure leaked somewhere! The hose trick works well on mine.

now there's an idea...maybe i can put some kind of shield on mine along with the hose to help even more. or maybe it won't be as messy after i break it in and thin the oil ratio.

i also noticed that if i don't mind to put my right pedal behind me while i am riding, my foot is right under the little pipe that sticks out of the muffler, covering my shoe with oily exhaust!