BGF Hongdu/Solex

[Mike B]

I will after the new fuel pump comes in.

I'm not touching it until then. Allready took it off once and cleaned it, not messing with the tiny little check valves, just going to replace the pump.

 

[Mike B]

New pump in, looks like they changed the design somewhat. The old one had a steel ball under a hex bolt and the new one is sealed off and has a plastic flapper in the diaphram port.

Weekend project -

 

[Mike B]

It's been a good day -

First I finished the electric, then I put the new fuel pump in the Solex and guess what, yup rolled down the driveway let out the compression release and putt-putted right down the road like it used to.

Which is a good thing 'cause it's 94 out here and pedalling might have killed me.

Good to have old faithful back. It was bad when the easiest starting gas bike I had refused to start.

 

[Greybeard]

Last weekend I decided to get the HD Solex going. It took a while as things were missing, and the decompression lever broke on first application. The gas tank was free of rust and scale.
I mounted it on a Schwinn Hollywood womens bike that's 50 years old. In fact, the tires are the originals. I had to build the mounts as the Schwinn had the thin forged steel forks.
It started in 5 feet and I rode it around for about 30 minutes. It ran pretty good right off the bat, and then acted like it was leaning out from running out of fuel. When I gave it about 1/4 choke it came back and ran as before so I suppose I've got a fuel delivery problem.
It was fun running it around the neighborhood. Prolly ran 12-15mph even after the 1/4 choke.
The CC worked first stop I made.

After I get it running well and get a few hours on it, I plan on pulling it back off and doing some mods, and paint it. I have a Solex carb NIB, and I bought a OEM gasket set.

Stoked!!!

 

[wayne z]

That's great GB, I have 2 of them and I love the way they run. They don't realy have a choke, the lever just enrichens the mixture some, so when the lever is moved, it doesn't restrict the air flow at all.
A good tip is to use clear fuel line on the return fuel line. That way as long as you see fuel dribbling thru it, you know the fuel is getting pumped.
I had trouble with the fuel pump working intermittently on one of mine. Turned out to be a small piece of trash caught in the output check valve. I could see it when I looked in the output fuel hole, and I used a small probe to depress the ball, and low pressure air air blown thru the pump to blow it out,.
I heard that if you dis-assemble the check valves they are hard to get back together.

I like to use the cpmpression release like a jake brake to slow down or on downhills to not go too fast. Love the funky sound LOL

 

[Greybeard]

Wayne
Thanks for the heads up on the fuel line. Makes good sense for trouble shooting. I didn't know that about the "choke". I took my real Solex carb out of it's box and looked at it closely and it looks like it only controls an airjet. Gives a guy another way of knowing which way to go on jetting. Is that the one everyone is filling and drilling?
I'm at sea-level to 200ft where I ride. The air is moist for the most part, and cool on average, so I will probably end up needing to be richer than most.
It is a pleasant little thing to ride, and after I get it sorted I hope to get my girlfriend to ride it. She won't ride my Tanaka/Staton fd cause the bike it's on is too tall for her to be comfy on. I need to get her 4stroke Panther done, and as soon as this is sorted out it'll be the next project. Then my Felt, and back to the '37 Chev.

 

[Greybeard]

Put about an hour on it, it didn't seem to use much gas as I only put maybe a pint in it and it's still slopping around. Runs a little better and smoother each time I get on. Fantastic starter. I push it out of the garage with the compression release. Get on and just push forward as I release it and it goes. Not very powerful, but it's growing on me. Can't believe I've been running around the neighborhood on a 50 year old bike with original tires and tubes. I want to go see my Mom and show her that her bike is still on the road and not in the dump, but I am going to put new rubber on it first before I attempt the 20 mile round trip.

 

[wayne z]

Wayne
Thanks for the heads up on the fuel line. Makes good sense for trouble shooting. I didn't know that about the "choke". I took my real Solex carb out of it's box and looked at it closely and it looks like it only controls an airjet. Gives a guy another way of knowing which way to go on jetting. Is that the one everyone is filling and drilling?
I'm at sea-level to 200ft where I ride. The air is moist for the most part, and cool on average, so I will probably end up needing to be richer than most.
It is a pleasant little thing to ride, and after I get it sorted I hope to get my girlfriend to ride it. She won't ride my Tanaka/Staton fd cause the bike it's on is too tall for her to be comfy on. I need to get her 4stroke Panther done, and as soon as this is sorted out it'll be the next project. Then my Felt, and back to the '37 Chev.

Hey GB, the little brass nut facing rearward on the carb is the main jet, the one we solder and drill. I had to close mine a little to get it to stop 4 stroking so much. I think I finished it at .024" for both my engines.
They don't run real good until they are thoroughly warmed up.

Be sure and remove the outside nut and tin plate on the flywheel and tighten the main flywheel nut. I and several others here had the cast-in flywheel key shear from loose flywheel.
I also put an axle mounted kickstand on the front wheel to use along with the main kickstand.

 

[Greybeard]

I can't get mine to 4stroke unless I have the enrichment lever past 1/2 to the left, so I'll assume I may have to open my jet. I have no plans on playing with it until I put a couple tanks of fuel through it, since I can control it with the enrichment lever. I'll prolly try the Solex made carb before I start filling and drilling, or in this case maybe just drilling.

 

[wayne z]

That's a good thing, if it is reluctant to 4 stroke before it's broken in, you prolly already have good jetting. Tighten that flywheel.

 

[Greybeard]

Thanks, I will

 

[Greybeard]

Checked the flywheel today and it took another 1/8 turn. Thanks for the heads up Wayne. Bought some clear fuel line and will install it in the morn. Sure is a simple little sucker.

 

[Mike B]

Disaster Averted

Took the Solex out for a spin today, started up great as usual. Noticed a "tinking" noise and took a look under the flywheel cover. The nut holding the cover plate was loose (not even finger tight) and I found the same thing on the flywheel. Flywheel was still stuck good on the shaft, I pulled on it and it didn't move at all.

Tightened both and all is well. Nice and quiet as before.

Thanks for the heads up Wayne -

 

[gotrootdude]

My kit was missing the air filter, air filter collar, an o-ring and a fuel filter. Overall though it was in great shape with no rust. The motor had to be ran recently because there was oily residue all over. I tested the motor with a little fuel on an old bike just to make sure it was in running condition and it fired right up.
I ordered the missing parts from Velocruz (was about $10 cheaper than Steve's for the parts I required).
I picked up a Adventurer Single-Speed Folding Bike w/20" tires from Camping World (On sale for $134) and used a $20 off $100+ coupon to bring the cost down to $125 shipped which already has a rear rack and an axle mounted kick stand.
My plan is to replace all the bolts with stainless steel, then use off the shelf steel flat stock mounted to the forks and then mount the motor to the flat stock using stainless steel bolts with wing nuts. I'll also run a piece of flat stock from the original motor mounts to support the muffler.
I've got some alloy motorcycle mirrors and universal mounts for the handlebars, a strap on mp3/torch headlight, a bullet rear brake light and bullet turn signals that I've accumulated over the years to go on it.

This should be a pretty damn cool bike for traveling.

 

[Greybeard]

I took my fuel pump off, couldn't see anything in the inlet, almost lost the check ball out of the pressure side. Set it on the table and blew into both ends a few times. Put back together and reinstalled. took a look at the filter in the carb and there was nothing there. Installed a clear plastic return line so I could watch fuel flow. It flows at low speed and then just stops until it's down to walking speeds and then starts flowing, I road it about a mile and it just keeps cycling.

Fuel pump is all I can figure.

 

[wayne z]

Sounds like the gas cap might not be venting. Have you tried loosening the cap when it acts up?

 

[Mike B]

I think the tank is vented really good via the return.

 

[wayne z]

Have you checked the tank filter, or the flow from tank to pump?

 

[Greybeard]

No sir. I was not aware that there was a filter in the tank. Do I remove the tank, then line, or?

 

[Greybeard]

I checked the line from the tank to the pump, and it's clear. It is rpm related. It pumps just fine when I push it with the compression release on. It.ll start. when it get up above about 5mph, fuel stops flowing, at least enough to be coming back the return. I can nurse it along and get back here by closing the throttle.