Quicker åttiotals Velo Solex

I'll check this tomorrow! BR/MAts

Hi, I took a rest on my tryes to make my solex work.
Now I am back but with poor results, I am afraid. I bought a new ignition coil, capacitor and also a "new" cylinder head (it was restored), and a new (used) clutch bawl). The cylinder head was a piece of shit, not plane, the valve does not seal, compression below 2:1. I use the old one. There is a difference between the two coils (old and new) when I measure the primary side of the winding. 1.8 ohm on the old one, 4 ohms on the new one. I disassembeld the complete Engine, transmission etc and reasembled very carefully. checked for leaks and other faults.


Still the Solex don't run at idle! There is no torque to run the clutch. and now the top speed is even lower.
This is what I have done soo far:

New fuel filters
New fuel pump, membrane etc (checked several times)
new airfilter,
new cylinder with new piston and rings
new plugs (several)
new ignition wire
new ignition coil
New crankcase bearing
new fuel jet (using a varaible home made), tryed different sizes.
Tested different air jets.
The airflter cap has drilled holes 8 mm
carburateur cleaned, I also have a new one => no difference.
Compression 7:1
The only "part" that is not yet changed is the mechanic and driver. Maybe there is time to admit the lack of skill for 2 stroke's...
At least I don't see any more options for trouble finding. I don't understand it.
If someone feels for it: Give me a bid on the machine! Maybe I should sell to someone that are better skilled.

Have you tried running it without the air filter assembly installed?

And without the exhaust installed?

Yes I have, no difference.
I also fixed the leakage between exhauste manifold an dexhasut pipe/silencer. The silencer is new.
/Mats

Are you using a Tuning Cylinder and Piston?

Yes. Righy now I do. Earlier I used the original chylinder 80A with new origional piston.

I wish that you were nearer. Can you make a video of the Solex running, riding and then stalling? Perhaps I can see or hear something unusual.

Are there any forum members that are close to you that might be able to help you?

Otherwise, I must guess that you have some unusual crankcase leak.

Hi,

I'll see if I can film while riding....
I have also been thinking a lo about a posible crankcase leak, but I cannotfind any. Any tip whould be helpful. What should I look for. There are no oil lekage etc that I have been able to see?
The bearing is a tught bearing with steel seals. Should work to my opinion. I can' see any oil leakage through it anyway...
For me this is mysterious!

Sealed bearings are not 100% sealed. Bearings with steel shields are less sealed than bearings with rubber shields. I always use high qulaity (SKF or KOYO) 6203 2RS bearings.

My first guess would be the bearing area. It is not good if you did not save the material around the bearing to fold back over the outer lip of the bearing:
http://www.rezoweb.com/forum/moto/solex4600/391.shtml

Replacing this bearing on the Cyclomoteur 3800 engine can be tricky. It was not meant to be replaced. In the old days, if there was any problem with the crankcase, bearing, shim, crankshaft or seal...the complete assembly would be changed.
Did you change the crankshaft seal when you changed the bearing?

Sometimes air gets sucked in, but no fuel mixture gets pushed out...so there is not always a sign of a compression / vacuum leak.

I have seen crankcases with hairline cracks, and with pin-holes from casting defects...very rare, but I have seen it.

Another area that often is a problem is the area where the crankcase, crankcase side cover, and cylinder meet. All of the nuts and screws must be tightened in a certain pattern, and the gaskets must be perfect. The top of the side cover gasket must be trimmed perfectly even with the top of the side cover and crankcase.
First, you must tighten the two inboard cylinder base nuts. (the nuts on the studs in the crankcase). This levels the cylinder to the crankcase. Next, you tighten the two outboard cylinder base nuts (the nuts on the studs in the side cover) to make the side cover level with the cylinder and crankcase...then you loosen these two nuts 1/6 turn. Next, you tighten the side cover bolts to 65 in lb, starting at the bottom and working your way to the top. Lastly, you fully tighten the two outboard cylinder base nuts.

Brian,

The crankcase is leaking through the bearing. When I got this Solex the original bearing was weared out and needed to be replaced. It was a open bearing with no sealings.
The holder for the crankshaft sealing was damaged during this operation or earlieer. So I tryed with a sealed bearing. First with a bearing with rubber sealings. I expected it to be enought tigt and it worked except for the sealings that lasted for a week only.Ttherefore I changed the bearing to a sealing bearing with steel seals. I talked to a SKF expert to help me to pic a good bearing for this job. Still asssuming that this bearing will be tight enough.But it isn't I have realised today by using my compressed air. It leaks. The bearing needs some play to work in this Environment and this doesn't help the sealing attribute eather. Soo, I need to find a way to attach a good crankshaft seal again. Or else a need a complete new assembly. I'll figure it out.

/Mats

Yes, I have seen crankcases damaged like this. It is usually done by installing a new bearing without supporting the crankcase. (I did it myself like this when I replaced a bearing for the first time..many years ago.) Or by using an improper technique to remove the bearing.
Can you post a photo of the damaged area?

Hi, I'm afraid I can't. I made a new crankshaft sealing support and soldered it in. I had a sealing from an evinrude 4hp outboard Engine, 40x17mm with a case that i rebuild in my lathe. It's in Place, but In thingk it builds to much though. I Think I will try to find a new crankcase.

Picture:

I removed the sealing holder. It added 7mm which is to much, I realised.
/Mats

Be sure that you purchase the correct crankcase. There are at least 3 different Cyclomoteur 3800 crankcases. You need the one made after 1969...which has the support platforms for the spring and engine lift bar.

Thanks! Most valuable information!

what happened to the Picture? That was not the one I uploaded...

I've seen two different photos there. First, was a photo of three people at a party. Next was half a photo of a Solex crankcase.

My photo was the crank case!

The photo of the crankcase is too large for the post. Only half of it can be seen. I think 500 is as large as you can make it to fit in the post.

Brian!
Finally!
I've got my Solex to roll as it should! It rolls fine during idling (topspeed (about 30km/h) maybe decreased but I Think it's related to ignition and carburettur adjustments).
I was out driving for one hour tonight just enjoying it! Uphill is much easier now, of cource I need to padle but I don't need to crank the enghine anylonger, it's runs by itself and contributes with power.

I repared the crankcase I have. I manufactored a new holder for a smaller bearing and a new sealing for the crankshaft. The bearing dimensions are 35x17x8.
I made a holder with the same dimensions as the original bearing diameters. But 15mm wide, to create plase for a new sealing.





The "holder" is glued with the special metal glue that I used Before (it's not just any glue, I needed to heat the crankcase to get the old bearing out. tricky..)
I also punched the lip around the holder.

Hej,
Efter att ha fixat läckaget i vevhuset så har jag borrat upp förgasaren till 7.5mm samt svarvat ner toppen 1 mm, dvs sänkt toppen motsvarande för att få lite mer kompression. Resultatet är en Solex med bättre moment i lågvarvsområdet. Den klättrar bättre i backarna och accelererar bättre från stopp. Toppfarten ligger på knappt 30km/h.
Den är en fröjd att åka på nu!
/Mats

Lät ganska trevligt med bättre backtagningsförmåga. Absolut något man behöver som boende på HägerstensÅSEN !

Hej, Nu har jag experimenterat med en reed ventil på motorns insug. Jag använde en reed-ventil från en Evinrude 4hk utombordare och tillverkade ett hus i aluminium som monterades på solex motorns insug.
Jag har provkört och resultatet var en liten besvikelse. tanken var ju att få upp vevhus kompressionen och på så sätt få upp effekten på motorn. Resultatet är en motor som har ett klart "tuffare "ljud som resultat av den högre ko,pressionen. Vridmomentet på låga varv blev bättre och take-off prestanda något bättre. Toppfartern blev inte bättre och "hill climping" inget vidare bättre heller. Min teori är att reedventilekl iofs fungerar men den påverkar luftflödet på höga varv negativt, den är för trång. Man skulle kunna laborera med en mjukare fjäder i reed ventilen möjligen, men jag har nu hittat en bättre väg till bättre prestanda så reed ventiil projekten är lagt på is t.v.
Den bättre vägen är ett mer öppet insug. Jag har sedan tidigare monterat en tuning cylinder som inte gav någon nämnvärd förbättring. Köpt på ebay. men nu har jag tillverkat ett nytt grenrör, tillverkat av kopparrörs detaljer för vanligt VVS, siolverlött.. Jag har på så vis ökat arean på insuget med ca 60% och på utblåset ca 35%. Nu J-r går moppen som en riktig moppe! Toppfart ca 33 km/h och den går uppför! inte i de värsta backarn akanske men i de mer "normal" iaf. Jag bor i en ort, Flosda som är väldigt backig t och tidigare har Solexen knappt varit användbar. Nu går den betydligt bättre... Att behöva sakta ner innan en kurva har inte varit aktuellt förrut, det är det nu.
Ikväll har jag borrat upp en förgasare till 8mm som skall provas imorgon. Motorn är provkörd med denna justering och den går iaf, varvar upp till 6000 rpm. Så vi får se i morgon hur det blir med effekten över varvtalsregistret.

Intressant. Kan du ge bilder eller video?
Var försiktig. Över 4000 varv/min, motorns svänghjul eller drive-rullen kan explodera ... mycket farligt.

Hi, Upploading a Picture of the exhaust/inlet pipe that I made with cupper pipe parts. Soldered with silver.
I need to take a few Pictures of the reed valve later. I'm aware of the risk of to high rpm. The 6000 is met without load. At driving the rpm is limited. Topspeed stel quite limited to Abou 33kph but torque increase at the bottom is significatnt! When the machine is standing idling on the sand on asphalt ( Which is used in sweden wintertime on the roads) the frontwheel is spinning very easily.
will try the new modifed carburator later today. A film may be seen on my youetube channel "mhowing" Its a downhill ride from last weekend shown thee (alos take a look att my hot bulb Engine excercises, its fun. That Engine is made 1933).