feetupfun

Non-powerjet. If you want an OKO, the model is K-100 and people usually run a 26mm or 28mm

While it's probably OK to leave fuel in it, it would be kinder to the tank liner to store the tank dry over winter. Nowadays after a ride, I drain and dry out my lined fibreglass tanks if it will be more than a few weeks until the next ride. My oldest epoxy tank liner is about 20 years old now. For the first 15 years I left that one with fuel in between rides and it gradually changed from honey colour to dark brown over the 15 years. After I noticed this happening I started draining it between rides and now at 20 years it is still working fine. It may still have been OK if I had continued leaving fuel in it, but the colour change made me wonder if it was being gradually damaged structurally. For info, Caswell liner is epoxy resin

If you are using the Explorer exhaust system, there is no advantage in using anything bigger than the 27mm AMAL. The Pioneer uses a bigger carby because it sucks a lot of air when it is on the pipe. The Explorer exhaust will mean that the Pioneer motor will suck about the same amount of air as an Explorer motor at full power.

When you have finished riding, turn the tap off and run the fuel level down in the float bowl before you stop the motor. Otherwise the evaporating fuel can make the float needle sticky. You may even have a passing fuel tap which could exacerbate this effect by allowing lots of premix to evaporate between rides. As for the lanyard killswitch, it can be wired in parallel with the standard kill button/switch, so the standard kill button/switch can stay. Maybe post a photo showing the "actual" slide switch you are asking about

Mikuni or Keihin or OKO or Dell Orto are all a better option. Keihin most expensive. OKO least expensive.

If your rear drum is worn (bigger than standard), new shoes will not match the curvature of the drum, causing the friction material to have a reduced contact patch area. If you have your shoes relined and machined as Kurtas suggested, the friction material curvature can be matched to your drum curvature, giving full contact surface area. To determine if this is your problem, pull the rear wheel out and have a look at the friction material. It will be shiny where it is touching. The areas that are shiny are the only bits that are doing anything to slow your bike down. The other aspect of your brake performance is that the co-efficient of friction of your lining material may not be as high as what is available, so when the shoes get lined, choose a material that increases the co-efficient of friction.

Throttle pulley size is a personal preference thing, like bar position, lever position etc. I use the slow twistgrip on my 250 MAR and throttle control is exactly how I like it.

I saw some made from stainless steel last weekend. A friend had a few custom buckles for trials helmets made locally. While it sounds like a good idea, non-OEM helmet parts or modifications will render a helmet non-compliant in a legal sense.

I didn't see the post until tonight. You're probably right. I only ride IC trials bikes but the same applies about hearing the sounds of the motor being an important part of riding trials well. As far as electric trials bikes go, I have only ridden a clutchless EM and I could hear the groaning of the motor at low RPM quite well, but someone with poor hearing may have had difficulty. Do the modern EM bikes sound different to the original ones?

Good outcome. I suggest you re-torque the cylinder hold-down nuts after a couple of heat cycles. There's a good chance of generating another base gasket leak unless this is done.

Paint shops can usually match a colour by scanning what you are wanting to match

Maybe the cylinder studs or their aluminium nuts have stripped but that is unlikely. Maybe you have lost some of the cylinder base gasket. Maybe a leaking cylinder base gasket caused the initial runaway. Stripped head studs will not cause the barrel to move because the barrel is held in place by 4 (cylinder) studs at the bottom. I'm interested to hear what happened once you work it out.

Don't normally need hot air gun for Bultaco unless someone has used sealant on the centre gasket. gearbox output sprocket and seal spacer cylinder shift drum external mechanism shift drum indexing plunger all the nuts and screws - one screw is tricky to see

That means the frame is from a Bultaco model 199A. The 7895 in the number means that is the 7895th one made. The 199A is a Sherpa T 350 nominal capacity 326cc and made around 1979. Blue frame and blue plastics. The model before it is a 199. The model after it is a 199B.

There's a few possibilities here. Most likely is because you have wound in the idle speed screw, the slide might be too high for the start device to function. If it's a modern carb, the starting device is not a choke. Modern starting devices use the pressure difference across the slide to draw fuel through the cold start circuit and if the slide is too high, not enough pressure difference will be generated while kicking, to draw fuel through. If winding the idle speed screw back out again doesn't solve the problem, narrow the range of possibilities by putting a couple of drops of fuel into the cylinder via the plug hole, then see if it fires.