BGF Hongdu/Solex

[wayne z]

How did you shave the head?

I Have a lathe with a 6" 3 jaw chuck. I chucked the head with the combuston chamber towards the headstock,tightly seated flat on the jaws.

I then made a light cut to insure that the top was parallel to the bottom of the head.

I then reversed the head in the jaws, and checked runout to the the head surface.
Note: the chamber is not centered with a 3 jaw. Don't matter as long as only the head surface only, is cut.
Had no runout, so I proceeded to take small cuts and measure depth with depth guage on my dial caliper, until I sneaked up on .045 depth.

Lightly deburr holes and chamber edge, clean and assemble.

 

[Mike B]

Cool. It didn't sound like a good sandpaper project.

Yeah, I'll just take it to a machine shop and have them do it.

 

[wayne z]

Hey Wayne, if you want to fool around with timing, lap the flywheel to the crank with valve grind compound for a lock on fit, then advance it 1/2 the key way to start, I bet that will really wale it up!

Hey CB, thanks for the good tip. Prolly won't fool with the timing right now though. I don't wanna stress the overhung crank and Brand x bearings for now.

 

[cannonball2]

Im waiting for a flywheel puller from Velocruz. When I get it I will experiment with timing. I have 4 flywheels to mess around with. As far as drilling your jet to a larger size be careful, I had the original Solex carb on my hybrid engine, and it had to run with the enricher nearly full on. I measured the jet @.020, my next drill bit was .024. Close enough I figured, was so rich it wouldnt even run. Went back to the original jet in the HD carb and all was well. I believe the original carb leaks air at the base. The manifold fits it loosley. The original parts have really powered up my engine, what you hve done with the head is Im sure is what has worked on mine also as the Solex head is higher compression than the HD. They must have detuned the HD for poor fuel, which I have heard is common in China.

 

[MB Dave]

I suspect this is the same motor as used in Mopex Black n Roll bike.
SOCIETE MOPEX
In this news clip they mention the majority of parts come from Asia and are assembled in France.
http://www.blacknroll.com/press book/MOPEX_bbcnews.wmv
If you look at the lettering above the headlamp it is identical.
Somewhere in the specs it mentions use of CDI. I believe the earlier models used points.
Food for Thought.

 

[MB Dave]

Just got me one of these critters.
Couldn't wait for a bicycle to test it on. So put it on my daily ride.
Twin engine Indian hahaha
Anyway, goes pretty good.
I've got the covers off in the photos , so as to try and get the lights working,
any tips?

 

[cannonball2]

Unless you want to try to use the unreliable little switch, just wire the lights direct from the pointed insulated post on the flywheel side, and ground the other wire. There is enough output to run a tail light also. Yours has the Velosolex front fender tip. Most of the ones I have seen have a different tip, seems no two of the are the same, kinda like Blue Heelers!

 

[wayne z]

the engine/light cover doesnt fit right so im gonna make a new one and put a different light on it

im not gonna ride it at night too much so this little 12 volt 1.5 ah battery should work fine plus the lights will be really bright

Hey MPJay, Would you likt to sell or barter for that original light? mine fell out and dissapeared down a ravine on the maiden voyage.

If you want, I'll shave your head to the Solex specs for it.

Wayne Z

 

[MB Dave]

Thanks Cannonball for the tip on the lighting. All good now.
Here is some pictures of the pointed insulated post that supplies power to the lights. Also a pic of new power switch.

 

[cannonball2]

Wow, different still. The engines we got have a very crude lever switch that contacts the power post. Mine would never stay contacted very long. You switch looks useable. Im thinking you may have more of a Black n Roll engine, maybe a little better quality. Where did you get it?

 

[cannonball2]

Sorry too early! Now I get it, you installed a switch, good move!

 

[MB Dave]

Got the engine from Ebay. Local pick-up. New still in box. Solex Made in China.
He has a local business selling HT kits, parts etc..
Blue Icon
Said he was testing the waters with the Solex.
Got it for $225. He still has 14 of them in stock.
He is not willing to sell them at that low price however.

Surely there must be a better way to seal the exhaust flange.
The rubber starts to smoke and smell, then hardens and just doesn't work very well.
Will have a look in the plumbing section of hardware store for some ideas.

 

[wayne z]

I use 3/4" orange silicone firesleeve tubing, from Aircraft Spruce Supply co. and 2 small width worm clamps.

It has fiberglass liner on the inside that has to be trimmed some to use. I have about 200 miles on one engine, still looks great.

Check RC racecar suppliers. They sell a high temp silicone tubing to use on their exhaust systems.

WZ

 

[cannonball2]

Second that, I used silicone tubing from the tuned pipe from one of my R/C engines after the heater hose finally gave up. Simply pushed down snug and secured it with stainless saftey wire. Sounds like maybe you are running a very rich oil mix. They dont run well on the recommended mix. After the first tank I went to 50:1.

 

[MB Dave]

Thanks for the tip on silicon hose. Will try that.
Just an update for people in Australia, another Solex copy is on Ebay from the same seller I bought mine from item no. 250828108574

 

[MB Dave]

Oil mix is 16/1 with Castor based oil 30 weight. It says on the packaging "For Racing Use Only" hehehehe
It's still in the run in period. Although having said that, it is currently off the bike and I'm looking for a suitable bike to put it on. It was just on the "twin engine Indian" because I'm an impatient bastard and wanted to see how it goes.

 

[cannonball2]

Wow, castor, messy stuff. I quit running that in my R/C stuff and switched to synthetic, because the castor was so hard to clean! I have a bunch of miles on my#1 engine on 50:1. I pulled it down to install the original Solex parts and the Chinese parts looked fine wear wise. For sure go for the extended spark plug.

 

[MB Dave]

Yeah, might switch to a semi synthetic after run in period.
Although I do like the aroma of castor based oil.

 

[MB Dave]

Thanks again fellas.
Got me some Fire Sleeve from a place that sells hydraulic hose.
Size is 3/4" (20mm) Inside Diameter.
Not cheap at $50 a meter, lucky for me they cut to size, so ordered 20cm.
That's enough to do 3 or 4 exhausts. Never mind, have enough for spares.
Here's some pics. Engine is not on bike, but you get the idea.

 

[MB Dave]

Got me a suitable bicycle to mount the Solex engine on.
Just need to strip it, paint it Gloss Black and re-pack the bearings.