Quicker åttiotals Velo Solex

Two more questions.

How far shall I put the level arm for lowering the engin while driving. I can put it all the way down to th etank, but in this postion th eengine goes heaveY Soo I use to ride whith th elevelarm at lets say 11 o'clock locking from th eright. Correct?

Exhasust pipe is connected to the outlet manifold, Shal ther be any kind of sealing there? I recognized exhaust gasses coming out there at idle which should influence low rpm torque. I hav attached a spring that pulls the parts together to minimize this leak but it feels like there should be a sealing which I don't have. shall it?

mhowing skrev:

Idle issue: Compression is 115psi, should be ok then. I can turn the flywheel when holding the roller with my fingers. A bit Heavy to hold it though...
So the cluth is not locked ( I have i fact two clutches and I got the same result with both). Is there a way to tune the cluth, by adjust the springs for example.

I got a new tuning cylinder from germany with the post today, so I will change cylinder tonight...

I don't know of any way to tune the clutch. I am interested only in stock engines, and so I have never had the need or desire to modify or tune the clutch.
The most important thing is that the crosses (X) on the arms must face out towards you.

115 is enough compression, and the clutch does not seem to be the problem. So you I would guess that you have a fuel problem or ignition problem, or a crankcase compression problem.
spark plug - NGK B6HS or equivalent...it must be gapped at 0.5 mm.
spark plug wire - I recommend replacing the original with a copper core wire. Make sure there is a clean connection between the end of the wire and the tab on the back of the ignition coil.
condenser - the condenser often causes problems. You can somewhat test the condenser with a meter..see "How do I test the condenser" on this page:
http://briansolex.free.fr/faqs.html
Solex recommends testing the condenser by replacing it with a new one.
ignition coil - it is difficult to test the coil. You can test it with a meter, but even if you get the correct readings, the coil can still be defective. Solex recommends testing the coil by replacing it with a new one.

In my experience, something involving the fuel system is often the cause of stalling.
Fuel - must be perfectly clean. Use high quality two-stroke oil. Semi-synthetic is best for a Solex. Mix at 40:1.
filters - one in tank, one in carburetor...must be clean of course
pipes - must be clean
fuel pump - glass check balls (two) must be present and not gummed. Interior of pump must be clean, with no corrosion. Front cap must be sealed (glue/epoxy). M6 copper washer must be present bewteen top stud and pump body. Holding your thumb over the hole in the back, you should be able to blow into the bottom port and have air come out of the top port...blowing into top port, air must not come out of bottom port. Screws must be tightened in a criss-cross pattern, to 16 inch pounds (in lb)
plastic seating piece -  must be firmly attached to the nub on the front of the crankcase (see my video on Youtube - BrianSolex). Concave side must face membrane and pump...flat side must face crankcase. If you cannot easily determine which side is flat and which is concave, you must replace the seating piece.
membrane (diaphragm) -  must be not stiff, with no holes or slits
carburetor - often the cause....dirty or damaged fuel jet, worn or corroded carburetor body, dirty or corroded passageways, worn throttle and/or air choke barrels, etc....

With a clear tube installed between the carburetor spout and the fuel tank, you should see no air bubbles in the fuel flow.

Crankcase compression - the crankcase is sealed by:
- the side cover gasket on the fuel tank side...the gasket must be present and in good condition, and the 8 bolts must be tightened in the proper sequence and to the correct torque.
- the cylinder base gasket...the gasket must be present and in good condition, and the four cylinder base nuts must be tightened in the proper sequence and to the correct torque. The machined face of the side cover must be level with the machined face of the crankcase.
- the crankcase bearing...the rubber shield of the bearing is part of the sealing of the crankcase. The shield is often deteriorated or damaged. The bearing was not designed to be replaced..it is captured in the crankcase. Solex rcommends that the complete crankcase, crankshaft, bearing shim and seal be replaced if any problem arrises with any of these parts.
- the crankshaft seal - often worn or deteriorated, allowing air and dirt to be drawn into the bearing area

mhowing skrev:Two more questions.

How far shall I put the level arm for lowering the engin while driving. I can put it all the way down to th etank, but in this postion th eengine goes heaveY Soo I use to ride whith th elevelarm at lets say 11 o'clock locking from th eright. Correct?

Exhasust pipe is connected to the outlet manifold, Shal ther be any kind of sealing there? I recognized exhaust gasses coming out there at idle which should influence low rpm torque. I hav attached a spring that pulls the parts together to minimize this leak but it feels like there should be a sealing which I don't have. shall it?

The arm should be moved all the way until it rests on the fuel tank.

There is no seal between the manifold and exhaust pipe. The male and female knuckles wear. It must be a very tight fit between the manifold and pipe. When removing the exhaust, you must need to wiggle it back and forth and pull to release it from the manifold...if not, it is not tight enough.

Great information,

When I move the arm towards the tank the engine works heavier and the solex slows down... Something must be wrong! Need to check.

I have a new exhaust pipe/silencer, it is not that tight that you describe. The old one was not that tight either. I have sealed it with a glassfibre sealing, same as used for stoves/fireplaces.
Can this leakage cause the weak torque at low rpm's? To my opinion i could....


Sparkplug is right now BR5HS but i used B6HS Before, gap 0.5mm
All sealings are new, crank case, cylinder bottom and top, exhaust manifold,
All filter are brand new, Air and fuel
Fuelpump is brand new
Crank case bearing is new. The old one was worn out. I changed it but when I did this I broke the sealing behind. As you mentioned, it is not ment to be changed. I have put in a new Bearing (consulted SKF sweden about bearing choice). The bearing has metal Shields that should do the sealing job. It is also glued in.
Ignition wire is new (original type)
I haven't mesured the coil. Ohm meter? Value?
The capacitor is mesured to about 200nF.
The spark is blue and clear.
Rupture plate, not new but looks fresh

I mounted a new cylinder today. A German manufactored tuning cylinder 50cc. The port are bit different timed... With this cylinder the top speed should increase but....
The engine work more or less exactly the same as Before. Compreesion a bit lower 95 psi, need to give it some time maybe...
Top speed 30km/h and still stalls at idle....
I'am using a home made adjustablel fuel jet. (No difference regarding problems if I switch to th eordinary ones)

So I guess I ´can exclude cylinder an dpiston issues..

Soo, something is still wrong:

-Crankcsase leakage should give thes problems but i don realize where this leakage could be. Can the compression be measured somehow?
-Ignition...? don't feels like it. Your opinion?
-Exhaust pipe leakage?
-Friction somewhere? crank shaft)

My wife is now a bit tired with me, so a solution would be nice to find......

https://2img.net/h/oi58.tinypic.com/2mpg3ex.jpg

The picture of my brake experiment....

Its time for bed!

When the arm is moved all the way to the fuel tank, the crank should release from the engine bar, and only the two suspension springs should be pulling the drive-roller down on the tire. If the crank is continuing to be engaged in the bar and pushing the engine down, there is some problem.

Very few new parts are of good quality and fit, including the exhaust mufflers. I find that the Impex style mufflers have the tightest fit. These are made on the original Solex machinery, which is in Hungary.
Yes, I suppose that the exhaust leak could affect the engine performance. The heat escaping from the joint can definitely affect the carburetor, the fuel supply pipe, and the fuel itself.

BR5HS is not the correct plug. It has a resistor in it and is better suited to an electronic ignition. B5HS is OK, and, for a Cyclomoteur 3800 engine, a BP5HS can be used...but avoid the BR5HS.  

It was not good that you broke the lip around the crankcase bearing. It is best that you heat the bearing and use a puller ...next time. On the Cyclomoteur 3800 engine, it is extremely important that the bearing is solidly captured in the crankcase. The glue will not last. Also, a 6203 2RS (rubber shields) would have been the best choice, not the 6203 ZZ. Neither is 100% sealed, but the RS is more sealed than the ZZ. Also, in the case of a bearing failure, those metal shields will destroy your engine.
Here is a thread detailing my method of replacing the bearing and seal:
http://www.rezoweb.com/forum/moto/solex4600/380.shtml

To check the values of the coil...I'm sorry if I don't describe this clearly...I'm not so good with electrical terminology and such:
With the meter on the 200K scale, between the coil body and the tab on the rear, you should have about 2.7 - 2.8.
With the meter on the 200 scale, between the coil body and the wire terminal, you should have about 0.8 -1.5.
The first reading is more important.
Remember...even with the correct readings, the coil could still be defective.

I don't know the correct meter reading for the condenser...I use the method on the Brian's Velosolex site.

To what measurement did you set the piston ring gaps?

I don't know any method of testing the compression of the crankcase.
You can thoroughly clean the crankcase and look for visual clues of leaks after running the engine.
You can remove the top end and fill the bottom end with fuel...then look for leaks...especially underneath the engine near where the drive-roller meets the crankcase.

A stalling problem is especially difficult to diagnose from afar, but, in my experience, it is usually related somehow to the carburetor / fuel jet, or the crankcase compression...and sometimes related to the fuel pump...and occasionally related to the condenser and/or ignition points......but so many different things, and combinations of things...can cause a stalling problem.

Thanks again!

i will switch th eplug to the NKG B6HS then.
Regarding the bearing. h eglue is a special metal glue that i've got from our labs at Volvo Cars... It's tough soo I think it will last.
I will however disassemble the engine and check again,.Maybe there is a way to manufacture a new sealing holder and add a new sealing.

For me it is clear that soemthing is or several thing are wrong and I need to find it. I will start all over again and disassemble the engine and take it from the beginning.

But to start with, strategy is:
1) change plug
2) try another fuelpump, I have a different sourced new one, so why not test.
3) disassemble and focus on crank case leakages.
4) New ignition coil and capacitor needs to be ordered

I don't understand your question:

"To what measurement did you set the piston ring gaps?"

If you mean the position for the gaps i set them in different positions away from inlet/outlet ports.

With the new cylinder/psion there was "locks" for the pistin rings gaps.

BR /Mats

question: Can a defect ignition coil create a spark? Have you seen that? The sparks I have look very good...

Yes, a defective coil can produce a spark. I have seen it many times.

It is easy for the coil to produce a spark when the spark plug is removed from the cylinder head and tested by resting it on the crankcase. But, when you install the spark plug in the cylinder head, it requires more effort by the coil to produce the spark past the compression and fuel.

mhowing skrev:Thanks again!


I don't understand your question:

"To what measurement did you set the piston ring gaps?"

If you mean the position for the gaps i set them in different positions away from inlet/outlet ports.

With the new cylinder/psion there was "locks" for the pistin rings gaps.

BR  /Mats

The space between the two ends of the piston rings must be set to a certain gap...for the Solex, the gap should be a minimum of 0.15 mm and a maximum of 0.3 mm. 0.2 is the pefect gap for new rings. The gap is checked by pushing the ring down into the cylinder...then use the piston to level the ring in the cylinder...then the gap is checked with a feeler gauge. If the gap is too small, one end of the ring is filed to produce the correct gap. If the gap is too big, valuable compression will be lost.

Dear friend Brian,

Interesting knowledge about piston rings. Had no idea about that.
However I have good news today. I have done some progress. I have changed the sparkplug, I looked for crankcase leakage without finding any, adjusted the ignition timing 4 mm ahead the marking.
I sealed the exhaustpipe (there is a 0.1 mm play!) with aluminum tape, but that tape left after a few minutes.... I need to fix this, but how...?
But the importat finding was the fuelpump. I mounted the pump 2-3 weeks ago. Today the membrane had changed shape a lot. Also the plastic support was very deformated by the petrol. https://2img.net/h/oi57.tinypic.com/34tbar8.jpg I changed pump to another brand new. Then I went for a test ride:
Now the topspeed has ingreas with almost 5km/h. (New tuned alu cylinder still) The hill climbing perfomance is much better. I still have to pedal but now with a much easier and with a higher speed, lets say 20km/h instead of 12 Before. So far I am very pleased! (even if a fell twice... slippery autum leaves...)
But!!! It still doesn't run at idle! It stalls! even if it seems to be closer to run. I do not recognize that the cluth is slipping at decreased rpm either. I don't know how that should work, maybe you can explain how that is noticed. i thingk I should notice a slip at let's say 1800 to 2000. Right now I am supspiciois about the clutch.. Is it maybe to stiff? But should I then loosen or tighten the springs?? Maybe a lubrication (careful!) should do the work. Any idea?
If I fix this last issue my Solex will be a Dream to run!
Br
/Mats

Forgot to tell.... The level arm dit not release from the bar. t e arm/crank is adjusted and now the solex runs just fine with the arm Close to the tank! Thanks!

At 1500 RPM, the clutch will slip.

I have never heard of anybody needing to adjust the springs. I have never had to do so. I don't know what the procedure would be. I don't think oiling the clutch is the best solution.

You can watch videos on my BrianSolex Youtube channel...perhaps you can see or hear some difference between how my engines are running and how yours is running. At the end of many of the videos, I stop and show the engine idling.
https://www.youtube.com/user/Rickbrendan

Are you sure that you have the clutch installed correctly...with the crosses facing out?

What type/grade/octane of fuel are you using? Regular, Extra, Super?

Hi, The clutch is installed with the crosses facing out.
But It come to my mind today that the drive roller may be damaged. You see, when I bought my Solex there was a lot of faults. Among these the clutch was stuck. The reason for this was that one of the two pads had left its positon in the seating and was stuck between the housing wall and the clutch mechanism. That s the rason why i bought a new clutch (I have however repaired the old one as well. The engine stalls with both).
Tonight I disassembled the roller housing and put it up in the lathe, and guess what.. It is not round. It is wobbling about 2 mm. I Think I found the reason for my stalling issue! I guess you agree.
I'll see tomorrw if I can fix it, otherwice I need a new one.
I have a question regarding the 37 mm nut that holds the housing to the roller. I don't have the tool for that size soo I havent tryed to loose it yet, I have just used a plier and felt that it is quite stuck.. . Is there something I need to know to loose this nut? threads right? left? How to hold the toller without damaging it?
I will by a tool tomorrow.

The fuel i use right now is 95 Octane with 2.5 % 2 stroke oil for mopeds.

In this thread, you can see how I hold the drive-roller with plastic blocks:

http://www.velosolexclubuk.com/apps/forums/topics/show/8776419-cyclomoteur-3800-drive-roller-assembly

The thread is standard, right-hand thread.

You can drill a small dimple in the nut and use a punch and hammer to loosen the nut.

Please post a photo of your worn drive-roller.

Do not use very high octane fuel...use the lowest available...your system of octane rating is different than ours, so I do not know the number....for us it is 87 octane. We call it Regular.

I'll try to post a Picture of the roller here. It is worn a bit but I don't know if I need to replace it... You can tell I guess!
I don't understand the process to upoad pics, th eend up at some other website..... I paste the link here.. Does it work?

https://2img.net/h/oi58.tinypic.com/2roqerb.jpg

95 octane is the lowest I can by in Sweden today. 98 is also available.

Yes, I can see your photo by clicking the link.
I don't think this wear is the cause of your stalling problem.

Misunderstanding!
It is not the roller that is the problem! It is the housing that is holding the clutch! The part the you disassemble on you photos when loosing the nut.
That housing is not round, its oval du to the earlier clutch issue that I described before....

The housing is not a tight fit on the drive-roller. Only the rubber seal that is inside the housing touches the bronze drive-roller bushing. The housing does not support the drive-roller in any way.

Still a misunderstanding.. caused by my limited engllish skills.
What is the name of the "tin can alike" metall thing that the clutch is installed in? Its, bolted with th e37mm nut to the roller axis and seen on you Pictures:

http://www.velosolexclubuk.com/apps/forums/topics/show/8776419-cyclomoteur-3800-drive-roller-assembly

This part, whatever the name is, is not round!

Your English is better than 95% of the people that I encounter every day.

That part is usually called the "clutch bell" or "clutch bowl".

Thanks Brian! Mopeds and Velosolex is a new experience for me so there is a lot to learn, even names on parts in both Swedish and English. I am much better on automotive parts as a Volvo Cars engineer.
However, the clutch bell is straighten up and you know what, the Engine didn't stall at idle! But tell me the luck that lasts.... the solex got weaker and weaker and weaker... top speed Went down from 30 to 20 after 10 minutes... I returned home to find out that I had a flat rear tire... Probably this is the reason for this "behaviour". I checked both ignition and fuelpump an dthey seems to be Ok.. but th egut feelinh says that thers is something else,... We'll see tomorow night how it works..
A question. I am using a adjustabel fuel jet that i have manufactored myself in my lathe. Maybe I should by a "real" one. Do you know where i can find such? I haven't seen them on ebay.

Is it a variable fuel jet for which you are looking?:

http://www.ebay.fr/itm/GICLEUR-REGLABLE-FIXE-SOLEX-VELO-SOLEX-HOMOLOGUE-COMPETITION-/390964395029?pt=FR_JG_Moto_Pi%C3%A8ces&hash=item5b074b3c15

http://www.ebay.fr/itm/SPECIAL-COMPETITION-GICLEUR-VARIABLE-SOLEX-DU-330-AU-5000-SUPER-QUALITE-/390966172190?pt=FR_JG_Moto_Pi%C3%A8ces&hash=item5b07665a1e

My solex i stil stalling at idle. It was a happines tha lasted for a few minutes earlier this week. The torque seems however to be Ok. Uphill it goes quite well. Right now I don't know what to do.. Maybe it ithe clutch bell still.... I was out riding tonight, fo ran hour. It is quite fun and the solex works fine until i stop and it stalls.

I don't think the clutch bell problem will cause the stalling problem.

Check for possible leaks at the decompression valve...perhaps grind the seat with valve grinding compound and install a new valve. Adjust the bronze nut by screwing it all the way down until it bottoms, then back off one and a half turns.

Remove the air filter assembly and ride the bike...see if it stalls without the air cleaner assembly installed.

Do the same with the exhaust muffler/silencer.