See if you can download a manual from t'internet.Don't know if its the same as a Beta but if it is,drain,refill from top with required amount,compress and replace top-I think if my memory is reliable-remove wheel and its up to ypu if you remove the whole fork or not-i do as it just seems easier.Best to have a look at the manual really.Fairly useful items!
Try cleaning out between the seal and the stanchion-a bit of camera film if you have any or some such similar stuff.There often gets trapped here some grit/crud that causes oil to weep through and appear like a seal has blown.I have had seals'blow' four or five times since replacing them and each time have done the above with the film and the result has always been a good seal that has lasted until the next time,generally months.Of course if its worn or pitted,sort that first.
Beta engines do develop a characteristic whine some more than others it would seem.If its not too excessive and youv'e got oil in there it's probably just that.Change of oil could have contributed.Maybe.
What sort of condition are your brake shoes.?You might find new shoes will take up all that slack in the cable.Suprising how much slack worn shoes give to the cable.I had a similar problem with a front drum brake.Thought the shoes were ok and the cable was wrong but it turned out to be the other way round and problem solved.
If you are handy with a welder,the best way may be to cut it open at its wider section and clean it from within.and weld it up againIf not,caustic soda is an option.Burning all the oily gunge out can help too.
Jitsie do an easily adjustable tick over screw that you can change(adjust) as you ride.I didn't think I had any reason to have one but bought one anyway because it was bling but have since found that I actually use it quite alot over the course of a day.
I dont think sealing the ignition cover completely helps.I know there are some folk who even seal the top of the wires at the headstock to stop water running down like through a drain into the ignition.Water WILL get in.It only takes a second to take off the cover and let it dry out after cleaning it or riding.Hey Eddie L-those 13 Betas you had;how long you keep each one?
On the pedal there is a sleeve.The bolt is hexagonal at the top(ie it just looks like a normal 17mm bolt) then its just a short rod wide enough to fit the sleeve flush-no bush etc-the bolt here is smooth.The bolt then slims down with a thread on it and this is what bolts to the frame-thats it.Excuse the lack of technical language!
There isn't an 'indoor' trial mudguard.Some are more flexy than others.I've had mine bend over on itself and then come back again but eventually it snapped.My solution is to buy a nice new shiny one and put it away in a cupboard.Then I fix the broken one with cable ties,put it back on the bike and carry on fixing it with cable ties.Like that they last quite a long time but do look a bit like a porcupine.
Someone has and he's called Lee and he'll probably turn up sooner or later,if not try Bill Pye.Or make your own out of aluminium sheet.Very easy and look loads better in my opinion.