BGF Hongdu/Solex

[mopedjay]

you have to replace the stupid throttle you can tell its a French design right away cause its at full throttle until you squeeze the lever the French seem to do everything backwards

my solex 4600 used to aggravate me all the time cause of that so i changed it to a twist throttle

if you never seen a solex carb just wait till you see it it is the weirdest carb you ever seen theres no float bowl no diaphram no adjustments at all 2 jets but doesnt really seem to do anything well both solex bikes i had ran better with out the air jet it has a main fuel line and a return fuel line that "puts unused fuel back into the tank" wtf

also they have a vacuum diaphram fuel pump thats kind of a pain at least with the old ones you have to clean them out a lot

solex are really weird engines but they are very reliable and when running well they are supposed to get almost 250 mpg

your prolly right about the Black n Roll i forgot thats not really a real velosolex those were actually sold by another company

you prolly wont ever seen one anyway cause who really wants to spend $1600 on a 19mph motorized bicycle for that much one could buy a nice tomos sprint that goes 35 and have $600 left over

 

[cannonball2]

Yeah, you are right about the carb being strange. But is is very simple, I guess you would call it a recirculating carb. I have a clear return tube and you can watch the fuel flow. The WOT design might make sense as thats about where it stays all the time. Might be easier in the long run to just pull it back to idle when you need to and leave it wide open the rest, for sure if on a longer trip. I imagine the French lever has a different pull ratio as the universal handle supplied only has a 1/2, maybe 3/4"" travel over the whole range. Not a big deal just different. I have adjusted the idle to where the clutch disengages. I lost the ability to slow down to a crawl, which was cool because I could ride around stuff in my shop to get to where the thing stays. Might change it back. Could see it as a real advantage in traffic though. Flipping the spring to the top of the throttle lever did not affect the clutch operation, thats an idle issue. As I posted earlier I have an original Velo carb and it designed in idle is much higher than the Hongdu carb. I imagine it is just about perfect to disengane the clutch.

 

[mopedjay]

if anything the levers that come with the china kit are better than the original solex levers

what a pain it is to change the cables on a solex with the old style levers the cable goes through the handlebar and the lever mounts into the bar end and pulls backwards so the lever points toward the engine instead of outward like on a normal bike

 

[Colony Five]

i have just taken delivery of mine, now i'm trying to figure it all out. i think anyone that has never been around a solex motor before is going to find it confusing. when it comes to small engines i've got experience with weedeaters and mowers, moped engines and the ubiquitous GY6 scooter engine, but this is like nothing i've ever seen. no kidding about that carb...i wouldn't have even known that's what it was if i hadn't been expecting it to be so odd from reading this thread. i'm sure it's all very simple, i just need to figure out what's what on it. i'm just glad it arrived undamaged. now i am off to study the breakdown diagram on the previously posted link. i think the hardest part will be connecting and routing all the linkages and cables properly. what a mess!

 

[cannonball2]

Its not that bad! Look at all the parts. The piece with the big hole and four small ones is a mystery to me, I believe the part with the slot and a bolt on the end may be an exhaust stay. I didnt use these parts. The hook we know about now. That leaves the mounting clamps, the bars that mount to the engine and to the clamps, and the hardware. The Handles and cables are a non issue. Look at the thick flat bars and you will see 2 bolt holes line up with the engines plates, bolt em on there on the outside of the engine plates. The clamps bolt to 2 of the 3 holes on the other side of the same bar, your choice which ones to use that best fit the bikes fork. At this point mount it to the bike. You dont have to pull the handlebar grips to mount the handles, remove the screw, they will pop over the bar. There are 2 throttle stop screws, you only need one for the compression release, the hook up to that is pretty obivous. If you are going to leave the carb spring as it is route the cable through the cable slot on the bottom, around the pulley on the carb lever and under the cable lock screw. Thats bascially it. I did shorten the cables so they would look better but they will work as is. Once you begin work this will make sense to you. Glad to answer questions.

 

[cannonball2]

Forgot the exhaust, real easy. Slip the muffler assb. onto the head pipe, you will notice the bracket on the pipe lines up with a bolt hole in the engine plate. Bolt it on with a large washer on the pipe bracket. If you are not going to use a stay or mount it to the fender brace(I highly recommend to do so) then thats it. The rest of the job is just tweaking.

 

[fall_down_stand_up]

This were I found the latest BGF e-bay site....
motorized bicycle kit gas engine front friction 49cc FF - eBay (item 150552350727 end time Mar-22-11 15:25:48 PDT)
John

 

[Colony Five]

thanks, cannonball2...that is far more helpful than that diagram...it's so blurry it's practically worthless. that long bar with the slot and bolt really had me scratching my head! and then i was wondering if there was supposed to be 2 of them. the clamps that came with it are really too small for my thick suspension fork. they might work, but i haven't gotten to that point yet. there is a good deal on a bike on my local craigslist that has a standard fork, so i may pick it up to skip all the nuances of my telescopic one. i also have no fender to secure the exhaust on, so i will have to rig something up (or get a fender.)

here are the questions i have for now...there were a couple loose wires hanging out from under the plastic cover, so i took it off. this mostly looks like it is all related to the headlight operation. that's the headlight switch on the cover, right? with the cover off, there is a yellow wire grounded to what i believe is the fuel pump. that yellow wire isn't connected to anything...actually, all of the wires on mine aren't, but only the yellow one looks like it might be important, or is it part of the headlight circuit too?

i think i've got the compression release figured out. it doesn't move much though...about 1/8th of an inch. i might need to adjust it, but i'm not sure yet.

the throttle has me confused though. i understand the parts you are referring to, but what the heck is that double silver springed lever with the hole in the middle sticking up? is that some kind of choke or primer? it looks as if one lever would be enough but there are 2 doubled up.

also, is there anything on this i should loctite?

i had grandiose ideas of having this up and running by tomorrow, but i can see it's going to take me a LOT longer than that. i haven't even addressed the issue of my knobby front tire yet, which i know i will have to lose for the friction drive.

 

[cannonball2]

There is an output post(insulated pointed brass stud) for the light switch to contact when you move it to on. Mine never worked very well so I permanently attached one wire from the headlight to it and grounded the other. I grounded mine to the post screw that holds the headlight cover on. Leave enough slack in the wires to be able to connect/disconnect them while removing the cover. I had to unscrew the brass nut on the compression release a couple of turns. The valve itself has a slot to hold in the center of the nut for this purpose. The carb has a single sloted control lever that actuates the throttle barrel, has a single spring usually at the bottom. I think you must be talking about the choke lever, I sticks up above the black airfilter cover, does have a small hole. It moves left to start, slowly right as it warms up, usually 3-5min. Should have only one lever though. A single speed cruiser bike is ideal something like a Cranny. I had to resize and shape the clamps a little to fit the Macargi, which may be nec. on any of the newer bikes with the large tubular forks.

 

[cannonball2]

Loctite. Blue is probably a good idea, but I havent used any yet. Its a pretty smooth runner with low/no vibes. Use it if you want, sure wont hurt. Be careful tightening the cheap a$$ hardware! I am getting rid of it little by little.

 

[Colony Five]

yes, that was the part that confused me, the choke lever. they obviously put 2 of them on mine by mistake. so the choke is automatic as in it moves on its own?

i don't need the headlight because i never ride in the dark. are there any wires related to the ignition that are visible...i don't see any.

it looks like all the important bolts have lockwashers on them so loctite probably isn't vital.

i just noticed mine has no markings other than the S 4800 on the plastic cover and an 'HD' on the bottom of the cylinder. HongDU perhaps? i know it doesn't stand for Harley Davidson! but mine has no stickers, nothing about mix ratios.

 

[cannonball2]

No the choke is manual. Left to start right to run, but you move it in degrees as the engine warms up. No ignition wires are visible(except the plug wire of course). Might want to break it in on 32:1. I tried 16&20:1 and it hated that. I am now running 40:1, probably going to wind up at 50:1. Look everything over carefully.

 

[matthurd]

i want one for my sister, i honestly think shes to clumsy for the power a HT has and would be scared to let her do 30 mph on a bike of some sort, unfortunately i don't see any more of them on ebay

 

[camlifter]

i'm still looking for a bike to put mine on. have a mnt bike with shock forks but that may not work.

 

[cannonball2]

Unless you just want to get another bike(I always do!), why not just change out the fork? You can change it back at any time in the future. I saw several standard forks on ebay for $6.50 with no bids. Just a thought

 

[wayne z]

i want one for my sister, i honestly think shes to clumsy for the power a HT has and would be scared to let her do 30 mph on a bike of some sort, unfortunately i don't see any more of them on ebay

BGF still has 10 listed for sale on E-bay

 

[cannonball2]

Here are a few pics of the installation. Always easier to see what some one is talking about. I said in error about the throttle cable routing if using the WOT method set it up opposite the pic of the carb.

 

[Colony Five]

thanks for all the info cannonball2. i'm pretty sure i know enough about it now to get it together.

i don't want to put it on a single speed because i'm worried the solex could fail and leave me pedaling several miles with the extra weight of the motor and only one speed. on the long open desert roads i ride, the multi speeds are a must.

another problem i have where i live is the dreaded goathead thorns. they will cause flats on nearly every trip. i have used solid tires in the past to combat the situation and they did work, although they made the ride rougher, harder to pedal, and had a low profile that sometimes caused a pedal to hit the ground. they also totally wore out after about a year, but i think some of that was due to the desert sun as they became dry and cracked. still, i preferred them to getting flats all the time.

right now i have tube tires and i've been lucky so far, but at some point i intend to experiment with flat proof tires in conjunction with the solex. i think the solid tires would work with the friction roller, but i am sure they would cause a lot of vibration. i have a set of bell no-mor flats solid tube inserts i am waiting to try. i've never used them before so i can't comment on them, but i plan to try them soon so i will let everyone know if they work ok with the solex or not. from the info i have gathered so far, it could go either way.

 

[matthurd]

BGF still has 10 listed for sale on E-bay

got a link? i couldn't find em on their site.

edit never mind found it.

 

[cannonball2]

Enter this # into the ebay search --150552350727, will take you right to it.