pschrauber

There is a Motobecane trials club in Belgique, they have lots of pic's and videos with there Montebecane trials bikes: Montebecane Trials Club Tobec's is a French a nickname for "Moped" I believe. Small bikes with 50cc and pedals from Montebecane and Motocomfort as they produces thousends of these small 50cc bikes for getting around. You find them googling Pic's search using "Tobec AV 42" / "Tobec AV 44" / "Tobec AV 46". I have still a likewise build "Tunturi mopo" from 1964 with Puch fan cooled engine very nice bikes for getting around, (sadly no pic's on hand to show ).

If your gear puller is fitted with an additional joint it is nearly impossible, If you have a puller with straight arms mounted to a rectangle arm where they can be fixed in a adjustable position it should work as it stucks normally not very much? May just a little bit of heat or better warming up to get the rubber soft and then turning with a good plier on the edge not the surface for the oil seal? To the part itself, may be Bultaco UK have them, if not Orlando Calonder should have them, or just refabrication, not a so difficult part to reproduce as it is round and you "only" need a lathe.

The bobbin (Kurbelwellenbüchse) should been removed to replace the the inner O-Ring as you said. May be you need a gear puller to pull it out. After intsalling the crank seal it is first possible to mount the bobbin as the outer surface of the bobbin is the running surface of the outer crank seal. How did come the oil seal of the crank seal off if you did not detach the bobbin? As the seal has to slip over the edge of the bobbin it must have been not so easy? May be it's just some corrosion use some penetrating oil and wait, while attaching a puller small strokes with a small hammer might also help, (no force!). I personal would not try to heat up the shaft of the crank, might change the hardness of the crankshaft.

As you have already opend the mid section. The old mesh is the riminding part of the old insulation which kept your former rockwool insulation material which sat between the mesh and the holetube protecting it from beeing blown away. A new wrap with silencer insulation pads and then with silencer steel wool will reduce noise and might too improve performance. If the holes of the holetube look clogged clean them so the holes have the full diameter, this will increase noise reduction, easiest way to clean the holetube is blasting.

It depends to the point of view: A: If the discoloring, ... is real nice patina it might look good too, it's may be better to preserve it as it is. B: If there are discoloring and scratches from former abuse by a pre owner in combination with erratic painted logos you might not have any consederations about the texture because the erratic logos and scratches are so ugly that you have to get rid of them. C: Mounting a brand new gas tank, (you get the gas tank as a replica as already mentioned here before), on a bike with has some patina might disturb the complete look IMHO too? So as a gas tank has something of the "face" of the bike this question is not so easy to answer. Show some pic's so any comments get a basis.

Brakepads: As you already have steel lining, NewFren still produces grooved brake pads for Bultaco, they are an improvement, btw. as newer the pads as softer and better they grip, (the age of your pads can be your problem, aslo do the have full contact with the linings in the hub? Newfren: NewFren Italy I believe Bultaco UK has them too. Exhaust: No experience with other exhaust as the original one, (beside a second custom modded Bultaco exhaust, end and mid section), will get the engine more lively without gaining noise, (not more noise is very important IMHO). Clutch: Never have tried a hydraulic rebuild of the clutch, is this contemporary? Hans-Jörg Pfahler in Germany still offers a complete clutch rebuild where he will modify the actuator and the clutchbasket, ... with different plates, ... at the end you get a one finger clutch ... Pfahler Bultaco (no hydraulic components used) Or ask Wayne Weedon from billetparts, he can also enhance the clutch actuator: billetparts, This is alraedy a big improve over the standard set up, in my experience. To rework the complete clutch, add hydraulic actuating,... (belongs to the owner so it's up to you). I have a second sidecase with the modificated clutch actuator, so if I want too, I can always switch back to the original set-up, (therefore had no need for the Pfahler modification, (my personal view)).

I the gum isn't too old, (some kind of slimy), a carb cleaner will do the job, even normal gas and diesel oil. When it got gelantinous a carb cleaner may get it dissolved may be not. Then you can give the carb to your next shop where they have a ultra soni cleaner. If the gum got "crusty", (couple of years and some other weirdo debris show up too then this can bee a real issue), looking like this: As "our" new gas don't have a long storage time, I drain the carb, (and gas tank), for longer storage period then two weeks.

Just stumbeld here, as I had this question to myself just a couple of month ago too here my 0.02

To get the engine deassembled with the headstady mounted doesn't work. To get the engine out underneath is not so easy, because you have to turn the complete engine in its axis across the driving direction. There is only very little space to do so in my personal experience and as you have already figured out, (otherwise you would not ask here) you will need to demount the haedstady too to get at least some space for doing so. It would theoretical work when you bend the steady down to get the engine free, but then the plate of the headystady is cold-formed and will when rebended again and assembled the stady will - when the bike engine is operating again - crack later, so this is a NO GO! If you want to get rid of this problem depending the headstady in the future, build your own headstady whith looks like this posted in topic "headstady" here: Headstady, (By the way the thread was intoduced by yourself.) This construction might not be original to your bike, (199a), but an improvment for sure.

The sentense in complete translation: Beim Drehen im Uhrzeigersinn wir der Z

Befor , this leave some ??? to me, as I did the adjustment only a cuple of month ago, have I recalled wrong, so for record I looked the workshop manual up again: Im - Uhrzeigersinn = clockwise => spät = late Gegen - Uhrzeigersinn = anticlockwise => früh = early Anyway you will find out by using the TDC Gauge:

Rotation of the stator plate: - setting the iginition early you turn anti clockwise, - setting the ignition late you turn clockwise, The stator plate can only be adjusted when the rotor is off. Just turn the stator plate a little bit, then remount the rotor and check the position of the rotor plate and the distance of the points. For setting the points / contacts the rotor has to mounted. This has to be done several times until you will get the right distance between the points and the right amount of mm befor TDC. I start with the points as they are mounted to the stator plate, then check the timiming of the ignition, demount the rotor, then adjust the stator plate, remount the rotor and check again, (normally I have to these adjustments two times, (sometimes three ), until I'am pleased). As already stated by the other members here in another thread you should disconnect the green cable from the loom. The lamp or buzzer has to be conected to black, (the cable that goes to the ignition coil) and earth. Here: Ignition - Timing - Bultaco

I does not only sound weird it runs poor also. Remembering when I was a teen we tried to get the Bul running backwards on purpose, because we thaught it was "so cool". In fact it was difficult to do so, rolling back- wards from a hill for get it started had sometimes success. (After we discoverd that it not only sounded weird, ran very bad and steering + balacing was quite difficult our curiousness was pleased.)

My 0,02 penny worth opinion: The magneto/rotor case side includes the secundary front sprocket and clutch engagement. For cleaning after som muddy session you might clean up the engine components mentioned above there too, it is IMHO easier to use a thicker self made gasket that you can use serveral times as "playing" around with sticky sealing compount stuff. (Gasket sheets are not expensive) I use the gasket several times and had no issue so long, if you need a template for a print out for a recut, (pdf) -> PM

This is a very interesting information to me as it worked without disconnecting the coil wire? Today working a little bit around in the garage for the bul I tried again and it worked. This made me curios why as the explanation sounds very convincingly. looked to my two electrical devices that I use for adjusting the ignition: An electronical multimeter with an automatic range selection and my contemporary Motoplat "Aparato puesta punto sonoro" which I bought in 1981 for adjust the ignition. I found out that there are some electronical devices inside, the unit making the buzzing sound is in the right, then thee are some resistance units a adjusting device and a condenser. in the middle is a logical unit made by TI (Texas Instruments) too. The backside is by the way the operation manual, stating on Spanish just to place the clamps on mass and where the point/ignition are connected. only thing that has to be done extra is to disconnect any battery devices. Then I took a look in the manual of the multitester: The manual reports that this device detects measuring values of approx. < 10Ω for the troughput and permanent signal sound. No I understand! A normal bulb or buzzer and batterie electric circuit connected to the ignition will not work proper because of the remaining coil as this coil consumes too much electricity. When the coil is disconnected this consumer of electricity is off and you can detect the closing or opening of the points as there are enough electricity avalable to light the bulb or operating the buzzer. While the other devices mentioned are measuring the resistance and any difference detected will affect the operation of their buzzers. Anyway thanks for the information, good to know if you are on a journey and don't have them with you.

You might check all the small ducts, and brass tubes. They have to be free and not clogged by gas gum or any other debris, also jets can be covered by gas gum too. A very good carb cleaner, a ultra sonic cleaning can be very helpful Carb with around 15 year old gas gum and residues.

I use Swedish Aspen R (racing) as fuel for the bikes, its a fuel that was invented for forestry machinery like brush cutters and chainsaws. This alkyd based gasoline don't have any ethanol admixtures. I use this gasoline already for many many years for the chainsaw and brush cutter, expecially because you can store it for years. They have already a couple of years ago, - don't remember how long, at least five to six years -, developed alkyd gasoline with a higher octane rate. Aspen+ with 95 octane and AspenR (racing) with 102 octane. The racing gas is a very good or even better equivalent to any high octane pump gas you get at the gas stations. You normally don't even have to rejet the carburator, (which you have to to when using Aspen+ f. e., (normal Aspen has "nly 91 Octan which is OK for a chain saw, ..). This gasoline is also approved for beeing used in indoor events by the FIM. Benefits: - can be stored in years, - don't harm plastic, - is not a poisen as gas, just unhealthy - no smoke, very little residues, no soot deposit, Information about AspenR: Aspen R (racing) To Premix: 1:40 is very rich, even my KTM MX bike uses only 1:50, the trials get around 1:70,(IPONE or Motorex synthetic). (Back in the 80's I used Bultaco oil (made by Optimol) in a 1:100 ratio!, sadly this oil is not destributed anymore).

Disconnection of cables to the pionts, never done, seen or heard? The places where you tried to connect the lamp are OK, like the workshop manual if this might please you. BTW: Before adjusting the timing, be sure that you have the right distance between the points, should be 0,4mm exactly. The points should be fresh, not worn, no residue between them, if you have any doubts use a points file*: *not sure about the right expression in English The Lamp should burn as long as the contacts are closed. Much easier are beeper in use, as you can better focus your eyes to the scale for measuring the TDC. Many multimeter have this feature, (mostly not known).

Don't think so? 1 white, 2 kill button, 3 red from stator, 4 coil ground,earth 5 plug 6 coil 7 green from stator 8 black from stator 9 yellow 10 stator You might check your electrical cables and devices.

I did not know that Kreem is available in the UK? Anyway, if you will still use Kreem there are different products (types) for a gas tank sealant available, also three different products for the preparation, like cleaning, ... I would ALWAYS call or e-mail the manufactor of the sealant which type of product for preparation and painting you need. in your individual case. Number for a call: +49 9721 41455, (they speak english). E-Mail: herbert.ammon@ammon-technik.de

Gummed gas is a task to clean, as it is still liquid you can try carb- or enginecleaner, like Sea Foam in the US and UK? or Fertan F1 (sold in D), follow the technical description. If it got really dry (not sticky when touching), even this may not work anymore. Then the only method that works is to remove it mechanically using a tumbler and some stones for tumbling. How to: - close the petcock opening very well, - fill in the stones inside the tank until the stones reaches the level where the gum ends, - fill with carb cleaner too, - close gas tap very, - mount the complete gastank on the tumbler, very importend in the center of the weight! - best way to attach is using a lot of massive duct tape - turn on the tumbler, it depends on the thickness of the gummed layer and the sort of stones you took how long it will take, you can always control the process by lookig through the gas tap, (tumbler should be off then). (I would guess it will take around 3 hours up to a half day.) You can also use a concrete mixer, (completly cladded inside with foam material, the gastank wrapped with in foam sheets and then tied to the shovels of the concrete mixer, any cavities also filled with foam Material). Bad thing with the concrete mixer is that you can't control the process and every surface of the inner gas tank wil be treatend. Through the abrasive process you have to paint the gas tank inside, using Kreem (in D) or whatever is recommended and able to deliver in the UK. The standard glasfiber works, normally no problem with gas, diesel, ... even alcohol. It depends how the joints are closed when building the cave for the gas, thats one of the problem zones mostly. Also bad repaired places where the epoxy is cracked and the fiber is visible from the inside can be get you in trouble.

A iittle bit of grease is probably OK? In my personal experience the best way I get them mounted is just cleanig the noth where the oil seal has to go in. Some WD40 applied with a rag is all I use. Then I push them in. I use the chamfered steel ring that is inside the old oil seal as an guidance, (I feddeled away the rubber so it's just a mm or so narrower in diameter), and a socket that suits. I believe that to much grase might get the assembly slippery and the chance that you accidently jam the the new oil seal will increase.

Not so good, boiling water will soften the coating of the paint.

To replace the oil seals of the crank is a lot of work: left side: - take of rear brake lever, (might be in the way), - take off rotor and clutch arm cover, - not really necessary but in case you wont get too dirty, take off chain - take off rotor, - take off ignition plate, (mark position befor you do so). - there you are. right side: - drain clutch oil, - take off gear lever, - take of clutch cover, - deassemble clutch, - for better clearance, the internal gear lever to the jack, (I have no experience to the M80 engine) - demount primary chain tensioner, - take off clutch and flywheel and primary chain, - there you are. It's good to have an engine manual for all the spec's and special tools, (clutch springs, gear puller and clutch holder) you need. A lot of work, so I would first look through all the other possibilities befor I personal would start replacing the here. Another place to look at, - even if you have a good spark -, the points and the condensator just in case.