Velo Solex Times Two

[Weldangrind]

I can almost smell it from here. Lovely.

We need video!

[cheesy]

Will see what I can do this evening for a video.

[cheesy]

No soap on the video tonight. Last night I got fire by dumping some 2 stroke down the carb. Tonight, I tried to run fuel from the tank, through the fuel pump, to the carb. Even after replacing the fuel pump diaphragm.

So, I have a blockage somewhere after the fuel pump.

Try again on Friday.

[Weldangrind]

I'll wait here.

[cheesy]

Aw, crap. Looks like you are waiting a bit longer for a video. At least a week.

I got the fuel pump issue squared away, one of the check balls 'checked out' as it were and left the building. It just so happened that the fuel pump had been upgraded in the past with 1/8" steel balls instead of glass balls. I have about a zillion of those. So, replace the missing ball and reinstall the pump. Turn the flywheel over a couple times to prime the pump. Reattach the fuel line and flip the flywheel once. AAAAANNNDDD it starts and idles. And revs.

So, like an idiot, I decide to take it for a quick ride up and down the street. It runs great. For about two minutes. Starts to bog and backfire. Then quits. I wheel it into the garage and check to see what I did.

Spin the flywheel and no compression. Zip, nada, nothing. Crap. I did something bad. I stick the bore scope down the cylinder and see no hole in the top of the piston. Whew. So, I've either blown a head gasket or a shaft seal. Let's hope for a head gasket.

Pull the head and looky what I find.


Two, count 'em, two complete gasket sets are on their way here from San Fran. Along with a second air filter because it turns out neither bike had one.

So, next week some time for the video.

[Weldangrind]

Good news on the head gasket.

What is that interesting contraption in the left side of the pic? It's on casters, and it resembles a bike lift.

[cheesy]

Originally Posted by Weldangrind

Good news on the head gasket.

What is that interesting contraption in the left side of the pic? It's on casters, and it resembles a bike lift.

Ding ding ding ding. I expect the CX to be on it in a couple more weeks.

I promised a video, so here it is starring the yellow 4600.
https://www.flickr.com/photos/214992...posted-public/

Velosolex-wise, it was a good day. I got everything sorted on the 4600. All the lights now work and I swapped out the broken Aprilia kill switch with a Honda one. I also got the correct rotor cover, air cleaner, and fuel tank on each bike.


I was on a roll, so I made a head gasket for the 3800. A good look at the top of cylinder showed that the original gasket had been leaking for a while. You can see on the lower right where the gasket blew.


I rode the black one almost five miles after installing the head gasket, just to see what was what. Runs pretty good but doesn't seem to have the same amount of power as the yellow one. Then again, it hasn't been run for fifteen years. Also, my plastic welding job didn't hold on the the throttle tube. I remain undaunted, though, and will try another approach.

Now comes the onerous task of getting them titled and registered. That should be interesting.

[Weldangrind]

Thanks for the vid! Perhaps an LED 1157 is in order.

Your pic of the piston top reminded me to bring up a topic: what do you think about polishing the piston top? I would think that it would resist carbon build-up.

May we see the muffler?

[cheesy]

Never thought about polishing the piston top. Worth a try.

Mufflers. See the round black things next to the front wheels?

Them's mufflers. Believe or not but the exhaust pipe is 6mm. Header pipe is 13mm. My understanding is that the Hungarian Impex muffler is prized for it's 16mm header pipe and 8mm exhaust. All I know is that purchasing and importing an Impex would cost more than I spent on the bikes.

[cheesy]

Re:the led taillight. Plans were already afoot. I'll be snagging the 6v1157 from Super Bright LEDs for the 4600 and probably something else for the 3800. Only real issue after that is the install of a bridge rectifier somewhere in the lighting circuit to convert from AC to DC. Come to think of it, it may take three rectifiers for the 4600 because head, tail, and brake light are all on separate circuits. The 3800 don't care, it's got head and tail light on a single circuit. And no brake light.

[Weldangrind]

I'm wondering about a tiny expansion chamber that would increase power at WOT. It might be fun to play with one.

I kept an old electric pressure washer around, because I'd like to try hydroforming with it. That would be a quick way to create a chamber.

[cheesy]

Here's what Brian Solex has to say about expansion chambers on the solex engine. The last line is pretty good.
http://briansolex.free.fr/expansion.html
In fact, the whole subject of tuning the little mite is a good read. That said, watch this.

[cheesy]

Originally Posted by cheesy

Also, my plastic welding job didn't hold on the the throttle tube. I remain undaunted, though, and will try another approach.

Well, that other approach didn't work too well.

I bought the fancy HF plastic welder and succeeded in burning a hole through the throttle tube. Just like my first attempt at welding sheet metal in high school. Into the experience pile with it.

Oh, well. New throttle tube will be here before the weekend.

[Weldangrind]

Kaaden's comments are theoretical. Bah.

I'd still like to see the results with an expansion chamber. if you want to try one, I have one designed for a 50cc China dirt bike that you're welcome to. It closely resembles the chamber from a Yamaha PW80.

That race was awesome! Hang in the turns, keep the revs up and pedal on the hills! Love it.

Sorry to hear that plastic welding didn't work out for you. I haven't tried the fancy welder, only the cheap HF unit.

[cheesy]

Well, it was my first attempt with what is basically a high flow heat gun.

Thanks for the offer on the expansion chamber but I think I will these alone for now. That said, I bought a universal two stroke electronic ignition module for $12 just to see. Stay tuned.