feetupfun

Scorpa was bought out by Sherco and since then Scorpas don't have Yamaha motors any more The current Scorpas are quite different to the Scorpas that had the Yamaha motors

You can expect more things will come loose and fall off if you don't inspect and maintain the bike.

Bullylover, I could only find 2008 and 2010 photos of your Bultaco. Both taken at Conondale. I'm currently trying to get the photos to show up in this posting I have given up trying to embed the photos for now. Here are links to them http://img220.imageshack.us/img220/6226/pa310053.jpg http://imageshack.us/photo/my-images/689/pb090010.jpg/

I just found a photo of you and the bike at the queue for machinery at the Twinshock Masters in late 2010 and will post it up this weekend

Hi bullylover and welcome. It's easy to know who you are after that description of your ride bike. I might have a photo from when it still had the disc brakes. I'll have a look. Regards David

No not OK to use a rattle gun. Tighten it by hand. It is way too easy to overtighten things using a rattle gun. If you need a new nut and want to use lockwire, buy the nut and drill a hole in it. Maybe you are asking about using a single hex (six flats) socket vs a double hex (standard) socket because the nut hex is damaged???? I would use a single hex socket and tighten by hand using a socket bar. If in doubt about the torque, use a torque wrench instead of a socket bar. If you are having problems stopping the crank turning, wait till you have the motor in the bike and with the drive chain in place, shift it to 5th gear and hold the rear brake on while you tighten the nut. If you want to tighten the nut up with the motor out of the bike, there is a tool available from Bultaco UK to hold the clutch basket still.

The cover has a vent for a reason too. If you seal the space completely the pressure goes very low when the gas inside the cover goes from hot to cold suddenly. With a fully sealed space, I would be worried about sucking oil out of the crankcase or popping out the crank seal in those circumstances.

I use 3mm hole in the bottom and choose a place away from where mud might cover the outside of the hole

My memory of running lights on my Bultaco in the mid 1970s is that the 6V headlight bulb glowed dull red at idle, bright red at mid RPM and pale yellow at maximum RPM. If you brought the brake light on, the headlight went much dimmer. I'm sure that you can get your lights to work very well with modern technology. There is a place in South Australia that specialises in setting up all sorts of dirt bikes for racing right through the night and they have been doing it since I was a kid in the 1970s. I would not expect that the standard lighting on your Bultaco will work much better than what you have found already.

The cylindrical silencer on TY175 models B and C is the same as on TY250ABCD but the inlet pipes are different lengths and shapes (the TY175 pipe is longer). I don't know what a Ty175D silencer looks like but if it is the cylindrical type it will probably be the same. The bulbous TY175 muffler as fitted to the TY175 JC and JE will also work well on the TY250A but again the inlet pipe will need to be shortened.

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