BGF Hongdu/Solex

[mopedjay]

yeah rays went around 15 on the first run

mine should be here friday and im gonna take it all apart to paint some parts and check everything out and prolly locktite everything and stuff

 

[cannonball2]

Have you had a chance to tear it down a bit to see whats up? My second engine had the base gasket on the head and the head gasket on the base. Not saying thats your problem , just the kind of crazy stuff to look for.

 

[wayne z]

Haven't torn it down yet. How are the head and base gaskets different, I can see a small bit of copper gasket showing at the base gasket area.

My bike has 1 1/8 dia forktubes. I re-shaped my clamps by hammerimg them against an old fork and used longer bolts(rag joint bolts)

I have no fender, so I drilled a hole in the slotted strap at the end with the welded bolt and put it on the nearest clamp bolt. Then I bent the muffler bracket some and bolted it to the slotted end of the strap

 

[cannonball2]

Well I maybe wrong but seems that the copper gasket should be at the head and the paper one at the base. Also I had two papers on the head, got to lower compression. Glag you were able to use the slotted hanger. I never could figure how it was supposed to mount. I also hammered my clamps to a larger size, used some longer bolts I had " in stock" and added some spacers so when the clamps were tightened they pulled down on the spacers just after clamping the tubes. Was anticipating a lot of vibes like a China girl, so didnt want to stress the clamps unduly. Turns out vibes are a non issue.

 

[mopedjay]

the stock solex head gasket is paper just to let ya know

 

[wayne z]

the stock solex head gasket is paper just to let ya know

Thanks, What is the stock Solex base gasket made from?

are there any other Hongdu owners out there that can tell us what their gaskets are at the base and head? Just tryin to figure what's the right placement. I too, would think copper would be for the head.

 

[cannonball2]

Strangely, my runner has paper on both the top and bottom, but only one each. When I pulled it down when I got it, I thought it strange to have a paper head gasket. It seems fine with it. I believe the compression ratio is only around 7:1 so it probably doesnt matter except for heat transfer, and 7:1 doesnt make a lot of heat anyway. The bad news is once the paper gaskets have been heated they pertty much self destruct on removal. They are not difficult to make from gasket material though.

 

[cannonball2]

Forgot to mention, maybe since its running, just leave it be until it breaks in. I am going to order new gaskets from Velo USA. Then we will for sure know which is which by part#

 

[wayne z]

Ok. I found no air filter in the cover. Did yours have any?

 

[cannonball2]

A piece if poor quality foam, no retainer. I used a section of Briggs prefilter and a cable tie to remedy the situation. Just got off the web looking at the gasket situation. The head gasket is #60437, base # 60016 both cost $4.74 ea. In the pic they look the same, not copper, but not the cheap blue original stuff on the engines, look like way better quality.

 

[Colony Five]

wayne, make sure you aren't putting too much pressure on the roller when you lower it onto the tire. if mine isn't just right, it performs poorly.

i never tore mine down, but with all the quirks you guys are finding maybe i should have.

i had to reshape my clamps and use longer bolts too. i don't have a fender and i ended up using the long slotted bracket as well. i didn't have to modify it to get it to fit, but i would have needed an even longer bolt for the clamp which i didn't have so i wired it to the clamp instead. it works good. that bracket is definitely an exhaust stay. that leaves just the one mystery item in the kit-the bracket with the 4 small holes and handlebar stem hole.

 

[cannonball2]

Looks Good! We may never know the purpose of the mystery part. I have looked at pics of these things on domestic Chinese bikes and could not see anything it was used for, so into the junk box for a future project. Hey if its running god dont worry about it. Being a wrench twister for years I just cant leave stuff alone. The tension on the tire does seem to affect it some. Since I am running balloon tires I had to remove one of the tension springs to clear the tire, and it still bites hard.

 

[Colony Five]

a couple other observations i've had...i was far too concerned about keeping my front brakes. although i did, they really are not necessary at all. besides the rears being enough, the engine compression also works as a brake on the front wheel if you kill the engine.

if you aren't worried about having a clutch, you really don't even need to connect the throttle lever and cable. i did but i never use it. i just run it at WOT all the time and stop it with the compression lever. but i'm also not driving in stop and go traffic.

one thing that i overlooked that cannonball2 had addressed was the need for some kind of seal where the exhaust meets the pipe. after riding i noticed i had oily residue all over my pants and the bike where it was coming out of that joint. and it doesn't help that i am breaking mine in on 20:1. i hoseclamped a cut section of innertube over that part. i haven't tried it yet but i hope it helps.

i know i am enjoying mine because i normally don't go for joyrides, i only go somewhere if i have a reason, but that hasn't been the case with this. i keep riding it just for fun.

 

[camlifter]

i'm almost done fixing up my 1943 western flyer, had to ditch the skip tooth system as the chain and rear hub were shot. hope to start mounting the engine this weekend. there are 2 wires hanging out near the head light, what are they for.

 

[Colony Five]

i'm almost done fixing up my 1943 western flyer, had to ditch the skip tooth system as the chain and rear hub were shot. hope to start mounting the engine this weekend. there are 2 wires hanging out near the head light, what are they for.

that's how mine arrived too. those are for the headlight. other than that you don't need to hook them up. i don't know how they go though because i haven't wired my light yet.

 

[wayne z]

ok, I pulled the manifold to look at the ports and had some interesting observations.

The ports and gasket aligned very good.

I was suprised to see 3 rings at the top of the piston. The top one was bright and the lower ones were dark.

When I ran the piston to TDC, what looks like another ring groove appeared at the bottom of the port,on the piston skirt.

I've seen motors that used a bottom ring like this. If this one is missing a required skirt ring, that would explain my extremely low performance, 10mph cruise and not enough power to take off at all without help. Cranckase pressure would be leaking into the exhaust port.

Hey Cannonball, did you pull your jug? If so, what did your piston look like?

 

[cannonball2]

5/8 heater hose works good, I just slipped it on and wired it with safety wire. Being an old airplane guy its got to have safety wire some where. The hose "cooks" for a while(stinks) but hangs in there. I ocassionally have to push it back down as it moves up over a period of time rasing and lowering the engine. I also feel when it is pressed comepletly down it runs better, probably my imagination. Your inner tube may be too light for the heat encountered, or may work just fine.

 

[cannonball2]

The pistons are no longer 4 ring from what I have seen, they were originally. I saw a pic of a current production piston and it had a half moon cut at the bottom of the skirt, this was a performance mod I believe incorporated in production. If thats the case and your piston was installed 180 out it might affect running. Dont panic yet, I will run over to my shop and look at old #2 which has the jug off and see if this is fact.

 

[cannonball2]

Dont worry its notched on both sides, rule that one out. Have you run something up the tiny exhaust outlet to see if its fully open? Its so small it could get easily clogged by trash in production. If you have good compression, its not restricted some where and the carb is working correctly, maybe its related to timing, there is no adjustment but maybe the keyway got missed on assembly, that cast in key is awful small, does the flywheel run farily true?

 

[wayne z]

OK, I found an exploded parts view on a Yahoo group's files.(solexownersofamerica) It shows a slight groove near the skirt, but no lower ring.

I think my light coil is missing. There's a round coil that is prolly ign module? And a rectangular coil mounted at abt 8:00 positon that's it.