feetupfun

If you are going to pull it apart, if you can get the cylinder off without separating the head from the cylinder, you will save the substantial cost of a new head gasket.

Ok what do you mean by "allso the thiner off the to goses on the bottom is this right"

Different pistons have different design rings. It's very hard to tell what you have there from your description but maybe one ring is shaped like an "L" in cross section? and the other is not? If the rings are different then the grooves in the piston should be different too - more info needed here

Buckles can usually be cured when respoking but it is pretty hard to say for sure without seeing the buckle you are talking about No need to reline the brake drum if the chrome is good. If you learn how to assemble a wheel and use anti-sieze on the spoke threads you can pull it apart and reassemble it yourself to get the drum relined if you ever need to. I don't understand the question about the compatibility of stainless steel spokes and a new rim. There is no problem with material compatibility/dissimilar metal corrosion. The rim holes would need to be the right diameter, the right number of them, and the holes aligned correctly for the Bultaco hub. A standard pre-drilled off-the shelf rim may have the wrong hole angles for your wheel. Wheel builders can drill a rim to suit your wheel.

The voltage on a basic system like that will depend on the RPM of the motor. What RPM are you measuring the voltage at?

Lengthening the wheelbase and steepening the steering head angle are the two biggies for the TY175. I modified a TY175 to match the wheelbase and steering head angle of my Godden Majesty and fitted TY250 forks. It is a dream to ride now.

Do you really mean a well-sorted TY175 or do you mean a well-modified and well sorted TY175? With suitable mods to the frame and swingarm, a TY175 can be made to handle and steer very well and quite similarly to a Godden Majesty 175 but a standard frame TY175 is not in the same ballpark. Don't know about Whitehawk having never ridden one. Mini Majesty 175 is very good to ride, also much better than a TY175, but too small for larger riders.

Yamaha TY175 TY250 twinshock (easy to get and good value) front wheel spokes fit standard front wheel of Cota 348

Tony I have gone through the process of lightening the flywheel on a couple of my TY250 motors. I did it in stages removing a bit at a time and trying all different types of riding to see what suited me. It took ages bgefore I was totally happy and I enjoyed the process. Flywheel effect is such a personal thing there really is no way that someone else can say what will be ideal for you. The two Cota 247s I have ridden had standard flywheels and while the 247 motor is slower at pickup than a modern bike, in my opinion the 247 motor performance is quite well suited to the handling and overall behaviour of the bike. Sure a lighter flywheel would be better for obstacles requiring double blip, but will be inferior in many other situations.

Sounds like a leak from the coolant system from a location above the level of the water ie at the highest point - maybe the cap seal leaking steam or maybe the pressure relief device in the cap is leaking a bit of steam. Try also loosening the fuel tank cap while the noise is happening to test if the noise is from there or not.

sorry this might be a bit obvious but have you tried adjusting the idle speed yet? There should be a thumbscrew on the side of the body that adjusts the height of the throttle slide to adjust the idle speed with

If you have Alpina triple clamps from an Alpina model that has taper seat fork tubes, they are the triple clamps from one of the very early Alpinas, which shared geometry with the late 1960s and early 1970s Sherpa Ts. So if you also have leading axle sliders, I suspect that you already have the best arrangement available using standard Bultaco parts. Further improvement may be possible by making the sreering head angle steeper, but beware that on some Bultacos, the front tyre OD/mudguard is already very close to the exhaust header and front downtube when the forks are compressed, so a head angle change may not be that simple.

Hi Dave If your Matador front end looks like the Mk2 in the brochure photos, you will make the steering worse if you fit forks with an in-line axle. To make it steer better for trials you should be trying to reduce the trail dimension which requires moving the axle forwards relative to the line of the steering axis. If you want to get rid of the handlebars that clamp to the forks as well as improve the steering, an easy way is to use a set of triple clamps from a trials Bultaco and if you get the right ones you can still use your Matador forks. First off, can you confirm that your fork tubes have a taper at the top end where they fit into the top triple clamp? David

If the noise changes when you pull on the clutch lever it could be the bearing that the basket runs on, or a gearbox bearing, or the thrust bearing for the pressure plate. If pulling the clutch lever makes no difference to the noise then it could be the chain tensioner tapping the case.

if riding without using the clutch, work the motor against the rear brake and practice doing very tight turns until you get it all working automatically if riding with clutch, same as above but also control the amount of clutch slip at the same time

If the clutch nut was loose it will be making weird noises all the time and the clutch release probably would have gone way out of adjustment If its only happening in second gear it sounds like it is not fully in gear and the clunk is when it jumps out and back in again. I would check the action of the indexing device that holds the shift drum in position for each gear to see if it is moving freely or maybe has a spring that has lost some of its tension. I don't know where the indexing device is on a Rotax motor but most bikes of that era have a plunger that can be removed from the outside and looks like an extra gearbox drain or fill plug. Worst case is that the second gear dogs have lost their edge, which would be an exceptionally rare thing to happen on a trials bike. A left field suggestion is to check the rear sprocket bolts for tightness.

Is it a 4 speed or 5 speed Matador? Softer springs front and rear Sherpa T triple clamps from M10, M27, M49 or M80 Move footpegs rearwards by about 150mm Bigger rear sprocket Flywheel on primary drive side from Alpina or Sherpa T motor. Sorry don't know if 5 speed motor drive side flywheels fit 4 speed motors. Bring wheelbase down to 52.5 inches using shorter swingarm Regards David

Getting rid of the stiffer fork springs will help the steering as will getting the motor, rear brake and clutch working perfectly and fitting a new tyre. There is nothing wrong with the geometry or weight distribution on a Cota 242 if it is set up right. Just because your mates 348 feels better, it doesn't mean there is anything basically wrong with the design of the 242. I have standard 348 that I have spent years getting set up nicely, and recently rode a well set up 242 and I found the 242 felt quite a bit lighter to ride than my 348 but not as powerful. To me the steering on both felt quite similar.

A thread tap with grease on it will clean out the media without damaging the thread form

The idea of having an advance curve is so that the timing is ideal for different RPM. When the motor is turning at the slow end of the scale, it is better if the spark happens just before top dead centre and when the RPM is at the top end, it is better to have the spark happening earlier (more advanced) so that when the big push is happening the piston is starting to go down. Ignitions that do not have an advance curve suffer from being a bit too advanced at low RPM and a bit too retarded at high RPM. People set fixed ignition to what they consider is ideal for how they ride. There is no perfect setting for everyone but the manufacturers suggestion is usually close to what most people like. For your new ignition with its built in advance curve, you should set it to what works best for you, on your bike, not necessarily what other people have done. I would like to help more but need more info about the behaviour of the motor. Communication by typing is very difficult for things like this and I'm having dificulty with what you are meaning to say.

BMW = Bavarian Money Waster BMW = Bob Marley and the Wailers

Looks to me like even with the fork tubes slid down and long shockies it has very modest ground clearance under the motor

Woody those badges are not all made by the same place. With some I have bought the contact adhesive on them has been useless. Others have been fine.

I thought that was what Andy had said but in less words?

Alan both seals can be changed without splitting the cases. RH seal requires removing the gear on the end of the crankshaft and LH seal requires removing the flywheel and ignition stator plate. I use a self tapper screwed into the LH seal to pull it out. The RH seal runs on a spacer so it is even easier to get out once you slide the spacer out. I fit mine with a little oil on the OD so they slide in smoothly.