I have MZ forks on my Tiger Cub. The size thing is a right pain! I currently have mine shimmed with bits of feeler gauge which is working ok.
As for the leaking, Mine were awful so I bought a pair of tubes and seals from somewhere in Germany, One of the MZ dealers) for about £100 delivered. Still no leaks.
The price will have gone up a bit since Brexit, Covid, the war, bird flu etc etc!
And Chernobyl, HongKong flu and Spanish Flu😷
I guess you have the MZ 250/125 TS forks. Any idea about Front Spindle diameter?
I have used 1,5% for decades and have tested 1%. No ill effects as far as I can see. Remember chain saws use 2% and they stay at high rpm for very long periods. Use good modern synth oil.
Make sure you have a problem with the 420 chain before even think about a 520 replacement. My experience tells me the 420 chain i excellent in low to medium powered trials bikes (as most classic bikes are). The 520 chain is for the higher powered ones. The 420 means less polygon effect. That´s good.
I have no help other then: The TLM is a two-stroke. Make sure your carb is meant for a two-stroke and jetted subsequently. Happens I see those carbs jetted for 4-stroke pit bikes. And make sure it completely closes the throttle valve and have no air leaks or something that can screw things up.
We are looking at the right side of carb so L(left hand) looks to be correct. No 3 throttle slide is quite normal. My guess it has worn out in the body and throttle slide as they often do. Buy parts or carb from a reputable Amal dealer as some seems to sell strange combinations of parts that may affect performance. During the years the carb went through a number of modifications and they may or may not work together and may affect performance. The 626 (26mm) has a smaller body then a 928 (28mm). Amal carbs are simple but the modifications and differences makes it to a whole science to get them correctly set up.
My opinion is when they are correct they work amazingly well
Do not pump the tickler. Press it down until you see petrol coming out. My guess is you can omit the choke slide and start he bike from cold, only using the tickler. Should be tested before first occasion.
Remember, 4-strokes often leaning out mixture somehow when opening the throttle. Thus the need for accelerator pumps or CV-carbs.
Inmotion have been working with Bultacos for several decades. They know what they are talking about. Have a look at their shocks. They are very Betor lookalike.
My guess is that Sherpa shocks can do equally well as Alpina shocks assuming they fit well and you have no intention doing motocross or extremely hard riding.
Mount the Betor with the cylinder facing upwards and the tighter wounds of spring also facing upwards in order to keep the unsprung weight low.
Vertigo should have hydraulic clutch. Stiffness is determined by the ratio of cylinders, friction and clutch spring hardness. Some thick oil inside lever (specially at the cup) may help little or cleaning if dirty. You also may look for a smaller diameter main cylinder or a larger diameter slave cylinder. This will cost you stroke. Softer clutch springs may cause clutch slip but will help clutch stiffness. First make sure everything is working properly as it was intended to do then decide what to do.
If it is a Crapioli it should have a rubber bump stop at the leg where the spring is. As I remember, it was a form of rubber ring. I don´t remember any rebound spring in Crapioli but normally they act as rebound stops and should not give any problem.
Note that Mk1 carbs spare part numbers often start 622/628 while Mk2 often start 2622/2928 and they are most often not interchangable. "Things to consider" is one important paragraph. Also note they changed the jet holder. Think it was around 1970 (from memory, not sure)
Betor often are around 24mm wide and have sort of rubber bush installed. I don´t know how to take it out undamaged. You may have to make your frame attachments wider to accept the shock. 24mm is quite normal.
If the shock has a bladder (or Internal floating piston) inside (think most of them have) best is to mount it with the cylinder facing upwards in order to keep the unsprung weight low
Looks to me as a Spanish Mk2. All Spanish Mk2´s I have seen are 2-stroke carbs. Body and throttle valve originally were made of zink so they will wear together and replacements might be needed. Think they do the valves in a a different material nowadays so it is worth considering.
Whatever you do make sure you have the correct parts for your carb. Lot of parts around that are lookalike but will deteriorate the performance.
If very expensive you may have to consider a replacement carb perhaps from a different brand.
Have a look at your clutch. Your clutch plates may not disengage as they should.
A common problem
Basket and hub must be free from notches. Plates flat and free from muck. Oil should be thin. I was using engine oil 0W-20 now HTX740(also for Bultaco Gearbox)
Mz Forks Not Quite 35Mm
in Pre-65 Bikes
Posted
And Chernobyl, HongKong flu and Spanish Flu😷
I guess you have the MZ 250/125 TS forks. Any idea about Front Spindle diameter?