solex starting problems

I have a solex 660.This model is 1956.I change the spark and i make a service to the magnator but the motor dosen`t start.Could anyone help me?maybe someone knows about a user manual for this model

Re: solex starting problems

The manual for the 660 is hard to find. The 3800 manual user's guide sold at www.velocruz.com has a lot of information in it that will help you. I recommend buying it.

Was the bike running and stopped running? Or are you trying to start it for the first time?

The first thing you need to do is to check for spark at the spark plug. Detach the spark plug wire from the spark plug, remove the spark plug, reattach the wire. Hold the threaded portion of the plug against the cylinder head and spin the flywheel clockwise. Check for a spark at the spark plug electrodes when you do so. The spark should be blueish in color and you should actually hear the spark. Let me know if you have a spark.

I will e-mail you some literature to help you. Let me know if you receive it.

Solexly,BrianSolex/Rickbrendan

Re: solex starting problems

I am trying to start for first time.I check the spark plug and it`s ok.I think that the problem is to the carb.The piston works good and has good compession but the motor doesn`t start.I don`t know where is the gas and the choke button.

Re: solex starting problems

Did you receive the literature that I sent to you?

The gas and the decompressor is a thumb-lever on the right side of the handlebars. The choke lever is on the carburetor. Put the choke lever to the left to start. Push in the decompressor/gas lever and start to pedal. When you are moving, release the decompressor/gas lever to start the motor. After you drive a little bit, move the choke lever to the right.

You can remove the brass fuel jet from the rear of the carburetor and blow air through the jet to clean it.

Re: solex starting problems

thanks for the literature you sent i receive it.when i start petal the motor sounds like start but don`t start.it start immediately or must petal for a long distance?

Re: solex starting problems

It should start in a few meters. Have you adjusted the breaker points as it says in the literature? Did you move the choke lever to the left before trying to start?

Re: solex starting problems

yes i move the choke to the left.the choke lever says depart.i try to start and i beleive to start

Re: solex starting problems

First you must check if you are getting a spark at the spark plug like it says in the literature.

Next you must check for fuel at the carburetor like it says in the literature.

If you have spark and fuel, then the problem maybe is the compression. Maybe the piston rings are too old.

Sometimes carbon is blocking the exhaust port of the cylinder. Sometimes the exhaust pipe is restricted.

Re: solex starting problems

I'm having starting problems as well.

I just picked up a 3800 after going about 20 years since first riding a Solex (when I was 14).

Hey Brian, any chance you could forward that literature to me?

I'm finally getting a spark, however I think the wrong plug is in it. Also, one of the fuel lines was clogged. That's been corrected but I think it's running rich and have no idea how to adjust the carb.

I can't even hear the piston firing, but believe it is because I see a little smoke coming out of the intake. Might that mean that the plug is too cold?

Any help is much appreciated.

Re: solex starting problems

Hi John,

Which plug are you using? The correct plug is NGK B5HS. Some equivalents are:

Champion L86

Autolite AE 32

Bosch W 175 T1 (aka W8AC)

AC 44L

Denso W16FS or W16FS-U

Gap the plug at 0.018-0.020" which is 0.5 mm.

There is no adjustment on the carburetor. The bronze screw on the back is the fuel jet. You can remove it and blow through it with air. You should be able to blow through the threaded end and air should come out of the two holes on the side. DON'T use a piece of metal/wire to clean it as it is soft metal and easily scraped which will change the dimensions of the jet.

Disconnect the tube that goes from the carb to the tank at the tank. Spin the flywheel and fuel should come out of the tube. This means fuel is getting to the carb and the pump is functioning. If your jet is clean, the fuel should be getting to the motor. With the air cleaner off, you can lower the motor and push the Solex. You should be able to look down the throat of the carb and see fuel spraying into the throat from the side each revolution of the flywheel.

If you definitely have spark and your fuel system checks out like I've explained, then check the compression. Lower the motor and lightly push the Solex without decompressing. The bike should buck and you should fell stiff resistance. Anything less is not good. You'll have to check things like the piston rings, cylinder/crankcase gaskets, decompression valve, cylinder/piston condition, crankcase bearing shield, tightness of nuts and bolts, etc.

A flooded motor and a restricted exhaust are two common problems also.

I will send you some service sheets. Let me know if you get them. Don't hesitate to contact me through the site or directly with any questions or info requests.

Solexly, Brian

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Re: solex starting problems

Hey Brian.

Thanks a lot for the info. I'm proud to say I got it running this afternoon. However, not as well as I would like.

I (probably prematurely) put in a NGK BPR4HS that was recommended by Weronika's Velosolex site. Not sure if this is why there's such a lack of power, but it could probably be a few things.

It seems to be running rich and wants to stall unless the throttle is wide open. I think my next step will be to replace the fuel pump membrane and all fuel filters. The bike does 'buck' pretty decent, so I don't think there's a compression problem.

Anyway, thanks again and let me know if the thought of these symptoms brings anything to mind.

Re: solex starting problems

John,

That plug is fine. Just make sure it's gapped to 0.5 mm which is 0.018 ".

Definitely change those two fuel filters and the pump _diaphragm_. While you have the pump and diaphragm off, check to make sure the concave side of the plastic seat is facing forward (towards the pump) and that the seat is attached to the crankcase spout. When installing a new seat, it should be tapped onto the spout. If not it will lose its concavity and not function properly. Also clean out the 2 fuel pipes. I use a can of carb cleaner with the red tube attached to the nozzle and spray through the pipes. The fuel jet should be taken out and cleaned with carb cleaner or compressed air. Don't use a piece of wire or metal to clean the jet as it's soft metal and easily scratched. Check the air filter.

A bad or loose spark plug lead will cause stalling.

What is your procedure concerning the start/choke lever? It should be at the left to start the motor cold, then moved to the right as the motor warms up. In what position are you putting the lever?

I've seen restricted mufflers cause a lot of problems. They are difficult to test and they are not easily/efficiently cleaned. When diagnosing engine problems, I like to install a new muffler to eliminate the possibility of a restricted muffler right of the bat. Some mufflers seem OK, but are not, or they are fine cold, but when the crap inside heats up, it restricts it.

A blown bearing shield on the crankcase bearing can cause some problems as the shield provides the seal for the crankcase. It's difficult to tell the condition of the shield unless the motor is taken apart. Single shielded bearings are used originally. I use double-shielded bearings.

Carbon buildup in the exhaust pipe, manifold, and combustion chamber causes problems. See the attachment on this post and the one on the first e-mail I sent today.

If the motor is stalling when you come to a stop, it is sometimes possible to adjust the cable on the carb pulley so that the throttle barrel doesn't close so much.

Hope this helps. Keep me updated. Solexly, Brian

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Re: solex starting problems

Hi Brian,

Sounds like you are the go to guy for starting problems. Could you forward the liteature to me as well.

I'm new to the solex thing, just bought my first one. It wasstored for quite a while. It had a gas line blocked so I cleaned it out. But, it still does not appear to be getting gas to the carb. Any suggestions.

Thanks, Dan

Re: solex starting problems

Hi Dan,

Yes, I'll send you some literature, no problem.

First thing you can do is: at the carburetor, disconnect the tube that connects the carburetor to the tank. Put a little cup or rag under the spout on the carb from which you just disconnected the tube. Now blow into the tube. Air pressure will fill the tank and should push fuel out of the tank, through the tank filter, through the intake pipe, through the pump, through the supply pipe, up to the carb, through the carb filter and out of the spout into your cup or rag. If it doesn't, you have a blockage somewhere. Work backwards disconnecting one item at a time and blowing through the tube until you have fuel flowing out of whatever's left connected.

When you are sure you have no blockage and you can blow fuel out of the carb spout, reconnect the tube. (This tube should be clear, by the way, so that fuel flow going through it can be checked.) Remove the air filter assembly by removing the bolt that is in the center of it and lifting the whole assembly, hood and base plate, off. Lower the motor and push your Solex while looking down the throat of the carb. You should see fuel squirting into the carb throat with each turn of the flywheel. If you don't, or the spray is weak, the fuel jet could be clogged or restricted. It can removed from the rear of the carburetor and cleaned with carburetor spray or compressed air. Don't use a piece of wire or metal as you will scrape the insides and change the dimensions. Blow through the threaded end of the jet...air should exit the two holes on the sides.

If you have no blockages and the fuel jet is clear, and you still don't get fuel to the carb throat, chances are it's a problem with the pump. There are two check balls inside that can get gummed up. Also, if you had the top cap/stud off of the pump, one of the check balls may have come out. You can carefully remove the top stud/cap and look down inside of the pump. You should see a little 2.5 mm glass ball in there. With the pump off the motor, you can basically test it. Put your finger over the hole on the back and blow into the inlet (lower) port. Air should exit the outlet (upper) port. Now keep your finger over the hole in the back and blow into the outlet (upper) port. No air should come out of the inlet (lower) port. If this checks out, check the diaphragm for holes or slits, etc. The plastic pump seat must have the concave side facing forward (towards the pump), and it must be tapped onto the crankcase spout so that it is secure to the crankcase.

Check that stuff and let me know how it goes. I've attached a small service sheet to this post and I'll send you more by e-mail. Please don't hesitate to ask any questions.

Solexly, Brian

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Re: solex starting problems

Brian, Thank you so much for the advice. I got it running today. It seems to run pretty good, but it doesn't seem to have the power and speed it should. The compression seems to be real good so I'm not sure what else to check. I think I'll change out the plug and see if that helps.

Thanks again,

Dan

Re: solex starting problems

Congratulations Dan,

Do you have a speedometer? Or perhaps you have one of those automatic radar signs near you that tell you your speed as you drive by? Or some other way to tell just how fast you're going? 20 mph on a flat is normal. You have to pedal assist going up a steep hill. 16-18 mph on a regular incline is average.

-The first thing I would do is install a new muffler. It is impossible to check or efficiently clean an old one and a restricted muffler will drive you crazy when trying to diagnose a performance problem. Some old ones seem fine when they are not. Put your old one on the side and and install a new one to totally eliminate the possibility of a restricted muffler.

-If you have not totally decarbonized the cylinder exhaust port, piston top and cylinder-head, do so next.

-Install a new NGK B5HS spark plug gapped at 0.5 mm and double check the points adjustment so that they just open when the rupture marks on the flywheel and motor line up. Check the literature that I sent you for a couple methods of doing this.

-I wish I had a dollar for every time somebody said they had good compression when they didn't, not that this is the case here. Just a little loss of compression on a Solex will make a big difference. An incorrectly adjusted decompression valve, one deep scrape in the cylinder wall, an old leaking cylinder gasket, loose nuts or bolts on the cylinder, slight wear in the rings or piston...all of these and more will cause a slight loss of compression. I have come across many motors that have a blown out seal on the crankcase bearing which affects crankcase pressure. How are you checking compression?

-Lift the motor off the tire, then lift the front of the bike off the ground. Spin the front wheel. It should continue spinning for some time. Any drag at all will slow you down. Check the rear wheel the same way. Make sure the tires are filled to 30 psi.

-Always use new gaskets when working on the motor and never use any gasket sealant.

-Make sure the throttle cable is adjusted properly so that the carburetor throttle barrel is opening completely when it's supposed to.

-Occasionally a slipping clutch will cause power problems.

-Restricted exhaust port/muffler and compression loss are the two biggies for lack of power on a Solex.

-Keep me updated and let me know how it goes.

(Solex newsletter attached containing an article and a translation that I did.)

BrianSolex

Re: solex starting problems

Brian, Thanks again, your advice is very helpful. I removed the bottom piece of the muffler and tried it like that. It did seem to help the performance a bit, so I'll order a new muffler. I also noticed what appears to be a small leak I think from the bottom of the cylinder head so I suppose it may have a bad gasket. I am also running it right now without the flywheel cover, and engine cover as they were missing when I purchased it. Could this be why it seems to chatter quite loudly as it runs?

Thanks,

Dan

Re: solex starting problems

Hi Dan,

Glad to hear you're getting a new muffler. Best thing you could do and most people are stubborn to do it.

Don't run the motor too long without the muffler as you may melt your fuel tank. Also don't run the motor without the flywheel hood and motor hood as they make up the cooling system. Vents in the flywheel hood allow cool air to be sucked in by the fins on the flywheel. The air is then directed through a duct in the flywheel hood, over the motor hood, towards the cylinder to cool it off. If you need help getting the parts, just let me know.

Not having the hoods in place will not cause any chatter that I know of, though. Is it chattering when you're at a stop? Or when you're riding along on a flat? Is it a consistent chatter or does it change with motor speed? Do you have any more clues for me?

The chatter may be the motor four-stroking. Where do you keep the start/choke lever? What is your procedure concerning the start/choke lever? If the motor is warm and you have the lever to the left too much, the mixture will be rich and the motor will four-stroke which is a chattering noise. Also, on some motors, you can't move the lever all the way to the right when it is warmed up, (for one reason or another) or else the motor will not run smoothly or at all. For example, if the air and fuel jets are not matched with each other or your climate, it may be necessary to keep the start/choke lever somewhere in the 10:00 to 2:00 position. Or if air is leaking into the inlet pipe.

Chatter can be caused by loose bolts and nuts which are a common problem on a Solex and is the reason why ALL nuts and bolts on the bike and motor MUST be checked regularly, so check EVERY nut and bolt on your Solex. Slightly loose cylinder-head bolts will cause a chatter. Some chatter is normal as it's a centrifugal clutch which is always rubbing. Wear in the cylinder, piston, rings, bearings or bushings will cause a chatter. Things like the decompressor lever on the cylinder-head tend to rattle. A stator bolt or a coil screw which has worked loose will rattle or chatter inside the flywheel.

If the piston, cylinder-head and exhaust are carboned up, which is normal, that will cause some chatter. Have you decarbonized these parts?

Solexly, Brian

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Re: solex starting problems

Hey Brian,

The chatter seems to be coming from the flywheel area. It is constant and doesnt seem to change from idol to full speed. I wanted to check in the flywheel but it appears that a special puller is needed.

When I start the engine I put the start lever all the way to the left. After the engine starts I move it to the right, but when it is moved all the way over the engine doesnt run right so it's moved until it is about at 12:00. Sometimes as I'm riding I have to adjust it a little as I go to maintain power.

You mentioned you know where i could find the flywheel cover and engine cover. I believe my solex is a '75 3800 and the headlight is on the handlebars not on the engine cover. It you know where I could find the parts I need please let me know. Used parts are fine with me if they function properly and are in decent shape.

Thanks,

Dan

Re: solex starting problems

Hi Brian,

Your advice was indeed very helpful. Thank you! My Solex is running very nicely now. However, I'm in the same shape as Dan, I need a few parts. I'm missing an air cleaner, flywheel cover, engine cover & headlight. I looked on www.solexusa.com but they want more for those parts than I paid for the bike!

Please let me know if you have a source for these parts used.

Thanks again for all your help.

John

Re: solex starting problems

Hi John,

Glad to hear your Solex is running nicely. Unfortunately, there is no source for used Solex parts in the US. You may get lucky on ebay, but I doubt it as many people are in the same boat with you and Dan and Bill and...

I don't recommend running a Solex without the air cleaner, flywheel hood, motor hood or headlight.

If you have any questions, please don't hesitate to ask.

Solexly, Brian

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Re: solex starting problems

Hi Dan,

Yes, a special puller is needed to remove the Solex flywheel. DON'T try to remove it any other way like with a regular three-jaw puller or by prying or hitting it off...you'll ruin it very easily. The puller and other special tools are available at http://www.velocruz.com

Non-normal chatter in that area could be something like the flywheel or crankshaft being slightly bent which I see happen all the time. Could be loose stator plate screws or loose coil screws. Could be a stator bearing or clutch problem.

Having to keep the start lever at 12:00 is an indication that you either have a jet mis-match (fuel jet too small or air jet too big) or there is an air leak into the fuel intake system/inlet pipe/crankcase, or there is a restriction in the fuel supply.

Your Solex is most likely not a 3800 if the headlight is on the handlebars. The motor may say 3800, but that is the motor type, not the model number. The cyclomoteur 3800 was used on the 3800, 4600, 5000 and Micron. If you let me know the seven digit serial number _stamped_ into the top rear of the motor and the seven digit serial number stamped into the right side of the frame downtube near the neck weld I can tell you exactly what you have so we can get the proper parts.

You most likely won't find used parts. I can find just about any part you would need for a Solex, but it will not be inexpensive.

Please don't hesitate to ask any questions.

Solexly, Brian

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Re: solex starting problems

Hey Brian,

The number on the motor is #7220820, and the # on the frame is 8089955. I checked with velocruz about the flywheel cover and the engine cover. They said they had the parts I need. The price for the engine cover is $29.95, and the flywheel cover is $18.97. Are the prices fair?

Thanks, Dan

Re: solex starting problems

Oh, that's one of desoto53's Solexes...orange..right? From Kalamazoo, MI?

It is a 1975 model 4600 V2 made at the SINFAC factory in either 4/75 or 6/75....6/75 I think. The 3800 on the motor is the motor type, and this 3800 type motor was used on the 3800, 4600, 5000 and Micron.

You can read an article I wrote entitled "The 4600 aka the Horse" about the model 4600s at:

http://cyclo60.myouebe.net/4600/4600en.asp or in the attachment

Yes, I think those prices are fair.

Originally on your Solex, the motor hood was orange and the flywheel hood and fuel tank were white. You can use Krylon Fusion paint to paint the plastic pieces the correct colors if you want it to look original. (The flyheel hood and motor hood that Jeff will send will probably be black.)

Re: solex starting problems

Hi Dan,

The price for the engine cover is different than advertised. Is he giving you a 'deal' or something? The engine cover shows a list price of $49.32.

Re: solex starting problems

Hi Brian,

Yep that's the one. I bought it from desoto in K-Zoo. You have me wondering how you knew that. Thanks alot for the info in the attachment. Another question though, (what a surprise huh?) It says to use 4% mix with 20/30 SAE motor. I have been using regular 2 cycle oil, is that OK.

Thanks again,

Dan

Re: solex starting problems

Hi John,

Idont know if he is giving me a deal. I think the cover I need is a different stye than the one shown.

Re: solex starting problems

Hi Brian,

Thanks again for all your help. Could you tell me what I have here with my Solex?

Stamped engine number is #5293711

...and stamped into frame is #8026708

Re: solex starting problems

Yes, the cover you are getting, Dan, is a different hood than the one in their online catalog. The one you are getting is for a 4600/5000/Trotilex and doesn't have any provision for a headlight, because those bikes have them mounted on the handlebars. The one in the catalog for 40 something dollars is the 3800 style which has a provision for a rectangular headlight and it also has the switch and wiring strip.

Re: solex starting problems

Dan, No big mystery with how I know. I usually write to the sellers and ask for the serial numbers to a) correct them about any mistakes in their ad, like the date of manufacture b) save for my research and to help make dating charts which didn't exist for the US and Canadian bikes, and to write articles. The French have very little info on the bikes exported to over here. The 4600s were not available in France and most people there know very little about them, only what I've posted on that one site, Solex-Millenium. They also have very little info on the 3800s sent over here. So I have made charts for them, too.

The usual fuel mix is as follows: "Mix four ounces of a high quality two-stroke oil with one gallon of unleaded gasoline."

Always mix the fuel in a separate clean container. Never add oil directly to the tank.

In what manual did you see 20/30 SAEmotor oil?

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