pschrauber

A new carb is a huge investment compared to the slide and some jets an needles. At least where I live as here you can get parts at a lot of places and you know the standard set up for the Bing too.

Yep gearbox parts are wicked to get had to replace some too. If you don't got parts from any of the mentioned ressources for your 199b and you can provide good photos from the parts which the main dimensions I might help out.

Piaoli's work great and as B40RT stated are legal, the 38mm would be unacceptable for our classic trials if grandfathering isn't involved.

Mmmh, there is now big advantage in fork action between the Marzocchie and the 35mm Betor. My bike had Marzocchis mounted and they worked pretty well, still felt a little bet more spongy and have more stiction then the Betors when they were sealed with one oil seal on each leg. The main advantage is that the Betors are shorter then the Marzocchies so this will let to a steeper steering angle and shorter overrun. The effect is better turning and less pushing out of the curve, ( if they are mounted to the Marzocchi yokes ). This will not happen if you mount the Betor yokes as I measured out there attachment points to the fork are lower thus compensating the less long Betor legs. Otherwise as Woody stated as long as the guiding bushes of the Marzocchie are not worn out not much difference, I personal believe the Marzocchies mounted to my TL.NW are a tiny little bit less good in damping (forks are rebuild and proper oil was used) then the Betors. I think if you use the yokes of the newer SWM with the 38mm fokes there will be not much change. You can check out the difference by lowering the clamps fastening of the Mazocchies around 20mm, if you then feel an advantage go for it if not you might let it as it is.

Would like to know something about the outcome aka performance and noise of the exhaust rebuild and modification in comparison, any news?

No idea, I have also a TL.NW from 1980 but no rubber at the front of the tank, just at the rear are two straps, but mine has a plastic tank ...

Completly OK, my 1980 SWM has the same "undercoat" and too there is no such blue base coat at the swing arm.

To the sprockets original the rear is using 38 and the front sprocket 13 teeth, still a "fast" gearing. I switched now to 38 rear and 12 front, wich works good, now I use second more and first only for thight curves. Transmission oil, I personal use Elf HTX 740 in all my bikes standard ATF works too, you need some amount around 1,2 Liter.

Looks cool, is the exhaust designed in this particular matter, did you use any calculations or the rules of thump from Simon?

That is a 1980 model SWM, the Marzocchi fork, the straight yokes, the steel rear swing arm and the rear frame loop. Mounted replica's on the bike: front and rear fenders, side panels, Not Original: Kicker, handlebar with levers and throttle, rear shocks, foot pegs and the foot peg mounts, rear chain cover and front rear plate holder (arm). Needs attention: lower attachment to the front brake cable hose, the mount is not the right one and looks bend and strange? Also the brake is already much engaged, probably worn out brake pads. But what to expect from a bike that will be next year 35 years old, looks tidy and well serviced on the photos, would give it at least a try out.

You need a very thick cable and a reinforced (and stiff) cable hose with a deflection tube were the hose is attached to the swingarm, most replica solution have far too little diameter for the cable and thus to the hose, when you then operate the foot brake much of your initiated force will be used to compress the hose instead to be used as breaking power.

The main issue to the Bultacos are the gap between airbox and swing axle, there a lot of mud will be piled up when riding under muddy circumstances and some of this debris will fqall over to the chain as there is a longer distance between swing axle and front gear. The mud there will be collected by the shaft of the kicker and stay there too. Easiest way to protect the chain and keep it cleaner is to mount an additional rubber flap at the lower end of the airbox that works as a mudguard / fender extension. Then there was an protection plate for the chain mounted in the gap betqween swing arm and front sprocket to the Sherpa which was needed for some countries to make the motorcycle road legal but difficult to find or you make your own. Additional you can use dry chain lube that isn't sticky this helps too a lot.

I had a nice effect while blasting with glas perls, done before engine rebuild:

The silencer was very advanced back in the days, the system is based on hollows in different volumes connected either through openings in different sizes or tubes in different length and diameter. They worked the Helmholtz-Resonator works as absorbers thus reducing the sound and gives a steady air resistance at the outtake of the middle section of the exhaust. These system was also used by brands like SWM, Fantic and Montesa, so it was very commen. The silencer has too a longer live time as he can't clogg so well, the system works also in rducing noise better then any silencer based one a holetube and insulation. The standard layout measurements their layout and "how-to" was dicussed in Trialsport issue 87, 107 and 128. I think it's not so easy to create something likewise for the Bultaco two stroke engine as the pipe section has barly any typical resonance function so the silencer must have it's part in it.

Oh a very nice 199b, very sorted and to the mounted gas tank, IMHO certainly OK. The tank seems to be from an earlier model as mentioned and if thight and with no bubbles I would leave it as it is. The original tanks get's bubbles in the paint and the replika gas tanks made out of glassfiber; some of them are tolerant against the "modern" gas some sadly not. To the brake gear set up that is not my fashion espacially as all other bikes have the footbrake and gear lever on the other side, but if it's OK to you ... I would look up if everything is technical OK, especially the swing arm axle and bushes well greased the ball bearings at the steering steam works well, (often weared out), the oil seals of the fork get weard out quick too (in my experience) and a look at the brakes should be done too as they are a weak point, cause of the chrome plating inside and the brake shoes are sometimes not aligned to the drum. These were the main to look at areas in my experience. Engine is mostly bullet proof and tolerant to wear, the ignition here I would check the points and the ignition timing.

That's good timing should be between 2.5 to 2.7mm BTDC. After the first running in procedure I would take out the bike and go for a longer ride on the street, starting carefully, going around 20km/h then advancing up to 50, going down again to 20km/h gearing up and down btw. and just drive in different rpm and under different loads just for let's say 15 Min so everything gets warmed up proper and any eccesive oil from mounting the new piston ... is really burned away. When you start the engine just outside the workshop/garge and let the motor idle there this might not handle all exessive oil the rebuild. If the bike is then still smoking a lot and you have changed the petrol then you might have an issue with the main seals at the crank again...

Nope far too young, and don't forget I'am blonde .

Interesting thread, my first trials competition must have been in 1982 I think, I was 16 years old and riding a 50cc Italjet. In fact I was already outclassed in my youth class as with 12 years you were allowed to ride 125cc and with 16 up to 175cc bikes back then, the other guys had Yamahas, Fantic's Montesas and SWM. Anyway it was kind of nice, I did not manage to clean one single section but when I remember right I mostly got through all of them there was one with bigger logs which I couldn't manage at all tried hard but failed every time. Anyway I was hooked even more as I was before, because all riding in diffrent terrain was thrilling too also to meet so much other people riding trials in my age. I only have one picture of me left from this special day the photo was taken by one of my parents when we started to the trials early in the morning here uploading the bikes to the trailer.

The bike is - in own experience - sadly quite loud, even with a NOS silencer which I have mounted know. The first TR34 from 1987 with the two rear silencer the middle section made out of steel and the rear made out of aluminum is even louder, I had the 1987 back then, now having a TR34 1988 Replica. You might look up the middle section of the '87 model and mount a much longer rear silencer from a bike that will fit, (no idea from which), still the high pinging noise from the pipe will be much note able. Anyway this bike model runs very nice and is astonishing powerful ...

Have you tried just heat reflector material or real heat protection foil that has a fiberglass inlay? I used a mat of this stuf to protect the plastic side covers of my KTM were the exhausrt goes very narrow with the side panel. It worked so far very good. The heat insulation nad reflecting mat is called zircotec ... ZircoFlex. http://www.zircotec.com/page/heatshield_products/97

Wow 15 ft/lb that is over 20Nm ? The bolts to the yokes are allen screws in M6 diameter with 1,0mm threads and with grade 8.8 the maximum torque (according DIN 912) is given 10,2 Nm = 7.5ft/lb. As they are bolted in aluminium I wouldn't use so much tension, the handbook of my KTM states 5 Nm for M6 bolts, were many screws are bolted i aluminium, which I think is OK if you realy need a number.

Having the same problems with insurances, this time even using different countries ... in own experience. A motorcycle or car is a mobile vehicle and can be used everywhere, and your insurance should therefore cover standard rood use of the bike. Then there are the contract terms of the insurances, which as I know are not very much different in Mainland Europe (sadly no knowledge abou the UK). A vehicle can be used at another place (town f.e.) for a shorter time period, (in Germany it is 3 months), then you have to get the registered at the different place (town ...). When done so you should too have the right to get the bike insured at a different place. What don't work is to have the bike registered at on place but using it in different places and insured at a different place, because the insurance rate might be different between the places. (The insurance f.e. is mostly much costlier in a big town then in a small village). The address for billing contact infos and so one can be different that is no problem, even for insurances in different countrys. I hope this helps.

A model 10! that's cool, looking forward to repair / rebuild of this very first model. As I have heard so far parts aren't as easy to get for this model as for most later models due to the lower production run, the age and fewer survivors. I would too ask Hugh Bultaco in the US because he was the Importer for Bultaco to the USA/America and Orlando Calonder in Switzerland, he was the main importer for Europe on the mainland. Both are still in business. As I know the importer for the Sherpa model 10 was back then the Rickmann's in the UK, might be a possible source for parts too.

There are bazillion possibilities to modify or pimp a Sherpa, before doing so we and especially you have to find out what you want.Get the bike, do the basics so it runs and then go riding. Everything else comes then, surplus you then know how much stiffer you want to have the front fork or how much more travel you need for the rear shocks ... ( for naming two examples, in my 0,02 cent opinion )

I had also some problems with adjusting the carb. My TR34 replica from 1988 had no bottom and the idle rpm changed from being to low or to high. An comparison with the original specs for needle and jets showed that there were a different needle and a different main jet used, additional the slide was worn and too the small gaskets for the air screw, at least the idle jet was too clogged. I replaced the jets, valve, needle, slide and air screw with gaskets and voilá all issues to the carb were gone. You never know what has happened to all these small parts during the last 20 years, in doubt as they are not expensive replace them. If the bike then run very well you have fixed the issue. If not take a look at the rubber manifold of the intake the rubber can have cracks ( mine had), it's also good to take a look at the reeds they too can be worn out.