feetupfun

I have a lovely 1968 M49 so am always interested in other peoples M49s. I was pretty shocked and speechless initially with you making a tailpipe using plumbing parts, but accept that everyone has their reasons for why they do things. You did ask for feedback though so here is my 5c worth: The main section of the exhaust is probably not made of copper. Maybe it has been repaired using bronze welding which made it look like copper. Those mufflers are usually made of pressed steel. I can even see the weld along the seam on yours so it's probably just a normal Bultaco item made of steel. By using such a long tailpipe of such small internal diameter, combined with the 45 degree elbow and the steps in internal diameter that accompany the use of BSP plumbing fittings, you have probably created a design with more resistance to flow than the original triangle muffler. The piece of 1/2 steel pipe and the gal elbow with the super trapp on the end will put a lot of load on the end of the Bultaco muffler when you ride the bike on rough ground so probably need to be supported from the frame somehow. That is a pretty cool idea to use that super trapp muffler and I'm wondering what it came off. I haven't seen one with a 1/2 BSP thread on it before and was thinking maybe it came off a Briggs and Stratton stationary engine because they have a threaded exhaust port. One thing about the Super Trapp is that because the gas comes out all the way around it is hard to avoid the exhaust gas overheating things in line with the louvres. I managed to melt the edges of a few rear plastic guards when I had a super trapp on my 4 stroke enduro bike in the 1980s. I figure that might have been why you relocated it from where the previous owner had it mounted. Another way around the heat problem is to fit a heat shield part way around the outlet of the louvres. That did work for the heat problem, but after the super trapp fell apart for the fifth time despite reinforcing all the bits that failed previously, I put a normal muffler on. A super trapp on a M49 will have a much easier life than on a 400cc hotrodded 4 stroke enduro bike so it probably won't self-destruct for years. An alternative way to fit a low resistance tailpipe and muffler is to use smooth bore steel tubing of approx 22mm ID leading to an absorption muffler supported from the rear frame loop. If you need it to also be a spark arrestor, then something like a TY175 or TY250 muffler would do the trick. That size tubing should fit inside the shockie, and additional clearance for the tyre if necessary could be gained by making the tubing flat-sided where required. Regards David

Where I live most motorbike shops have that needle and seat set on the shelf

el cheapo chinese 240V approx 15 litres tank

You take the bits off that stop you seeing the frame and wheels, like the tank, seat, exhaust, mudguards, airbox and leave the wheels in place, then sight from the front and rear from all heights. Common frame bends with Sherpa ts are: Front end of frame pushed to one side or twisted at an angle to vertical or both Swingarm twisted (one side higher than the other) Swingarm arms pushed to one side (symptom will be rear wheel not in middle of bike) Front and/or top frame tubes curved (from frontal impact) Tubes under motor curved from banging on things

I'll bet the builder assembled the case halves with the crank seal retainers in place

Michelin rears $180-$200 IRC rears $150-$180 depending on Tube or Tubeless type

Can get IRC front and rear pretty easy up here in Gladstone through any of the three motorbike shops and sometimes they even keep them in stock. Can get Michelin too but Michelin sometimes takes months to arrive. No idea where to go in Brisbane for trials tyres. Sometimes at big trials in SE Qld, trials bike dealers set up shop and have tyres for sale. I use Michelin fronts and IRC rears Regards David

there are probably lots of free how-to videos on youtube, and there are also training DVDs available for sale. I bought a DVD to learn how to bend and do welded joints in metal tubing (on motorbike frames) and it was quite good

Depends on which type of tubed rim. Some are ok some not. I may be wrong, but from what I've heard, standard TY250R rim is OK with X11 Michelin. Do you know different to this? By the way bird, which Michelin is on the rear now?

Dunlop bead wont stay on the rim below 10psi if you have standard rear rim Pirelli rear has very stiff carcass, stiff compound and smaller gaps between the knobs IRC tube or tubeless is fine Michelin tubeless is fine

there is a Scorpa forum on here - there is more probably chance of getting your answer if you post there

That SWM looks quite non-standard to me. The tank, seat, sidecovers and forks all look odd and at first viewing I thought he was on a mid-1980s Montesa. Is that what the last of the SWMs really looked like? Gilles does still ride very well

good video Zippy and it's good to know that Biff's footwear has a sensible name there - they are "Thongs" here in OZ and I think in New Zealand they are "Jandals" Kinda like how sticky tape here is called Durex and the most popular beer in my state is called XXXX

The rate of mechanical failures does seem to be high in Spies' bike compared with Lorenzos' bike, but those failures have also affected Yamaha's points in the manufacturer's championship as well as Spies' rider championship points, so it is unlikely that the failures are anything deilberate on the part of Yamaha, if that is what you are suspicious of. My guess is that there is something different happening within the group of people who work on Spies' bike that is resulting in the work standard being lower than it needs to be.

the photos are "SSDT photos courtesy of Peter Paice (Mick Andrews' Aussie riding companion in the 1975 SSDT)" ie they were taken by one of the riders (Peter Paice) and have not been published in a magazine or a book

Yes it will weaken the clutch springs. If you roughen the surfaces of the steel plates it will stop it sticking

That bike has similarities to the bike ridden by Mick Andrews' Japanese (Yamaha employee) riding companion in the 1975 SSDT (kickstart shape, tank graphics and top shock mount location) There are also differences - the bike in the SSDT photos has strange extended fork tops and a standard TY250 exhaust heat shield SSDT photos courtesy of Peter Paice (Mick Andrews' Aussie riding companion in the 1975 SSDT)

Guy from memory the modern off-the-shelf VM26 is a physically bigger carby than the standard carby so it may not fit in the space available

did the abrasive blasting remove the chrome plating or just make it rough enough for the powder coating to stick?

I also wanted to be able to buy bars like 1970s Renthals and recently had some sets of new bars custom made. They cost $120 per set. The red bars are 1970s Magura trials bars.

Maybe someone has fitted an extra base gasket?

The red plastic tanked 242 is just the last model 242 and was not limited to Spain. Sorry I don't recognise the tank on that bitzer Montesa in the photo. The fuel spout on it makes me think it might have been made for fitting inside a fibreglass cover. Here is an Aussie 242 photo to show what the red plastic tank looks like

Thats great Guy. To see both bikes arranged like that makes it easy to see the differences. Well done mate. David

what is the address of the delay website?

There are a few different clutches fitted to 5 speed Bultaco motors. Yours may not be the original clutch, and Bultaco are known for changing the design of things like clutches during a production run. Not a real issue though because while the clutch baskets and hubs may be of different types, the type of clutch plates you have described are common to all 5 speed motors from about 1969 onwards. The important thing is that you fit as many plates as you can, to minimise the pressure plate loading needed to prevent slip (more plates = more torque for the same clamping pressure) Limits to how many plates will fit are the length of the basket fingers, the length of the hub splines, and how far the spring retaining nuts stick out after you have adjusted the springs correctly. If they stick out too far they will rub on the clutch cover. If you have retaining pins on your clutch hub rather than studs and nuts, they are not adjustable so won't be a problem as far as sticking out goes. . By the sound of it, the Hugh's Bultaco manual may be referring to either the aftermarket type (Barnett) tabbed plates that have friction material on them (and so are thicker), or Hugh may be referring to the early 5 speed clutches (1965 to 1969) that also had friction material on the tabbed plates. By the time your Alpina was made, the standard plates should have been all steel with no friction material and should have "T" shaped holes in them. If you think about how the clutch works you should be able to work out which plate goes in first, but if you have problems with that, if you post up a clear photo of your clutch basket with no plates in it, there are many people on this forum who are very familiar with Bultaco 5-speed clutches who should be able to help further.