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What model Sherpa is it you are rebuilding? In Motion are a mine of information and it always pays to ask if you don’t see what you need on their website. Its worth a look at the available parts and there are others that have parts but In Motion is also Bultaco UK. Enjoy the bike the Bultaco is not a difficult engine to work on but the gearbox has caught a few out with selectors that can fit the wrong way. Just be careful and all should be well.

Prepare for cuts and scrapes to the head. Like your engine stand, like your storage solution. Do you have head room to clear the parts facing down.

Forks, wheels, seat and fuel tank and you are away??

RTL’s can be very expensive, there are some that are worth the high cost but you must be very careful as some bikes are not genuine RTL’s. Parts and their associated costs can be prohibitive. Right at this very moment what with the virus and ‘lockdowns’ perhaps it would pay to do the research and build a rapport with a few sellers and chase down the best and original RTL that you can comfortably afford. The market place has apparently quite a few to choose from, but as an investment it might be prudent to hold off any purchase until the world can get back to normal. You could end up with maximum investment and no increase in potential future value. I personally would love to have a genuine RTL in my possession, not for any investment purpose but just because of the history. ?

Sounds like you have a reasonably sound plan with a good idea for either bolting or welding. However have you considered Sif-Bronze welding, properly done its very strong, allows you to use the 4/5 mm plate ....mild steel. Stainless will not be suitable to weld to to the Miller frame, under the chrome plating you will probably find Reynolds or just plain mild steel tubing(difficult to tell) about 3mm wall thickness. With the Sif-Bronze welding (looks like brazing but isnt) lots of frame makers used/use Sif-Bronze, you can heat up the weld and take it off to go back to standard or modify more.?‍? Take on board b40rt and his suggestions before finalising positioning.

Have you measured the cylinder bore and checked its condition?

Pneumatic or good electric nut runner usually works. This puts less load on the shaft. Use it to undo only, tighten with torque wrench.

I did say at the end of my post ‘bending a normal feeler gauge is the easy way to go’. ?

If you have one and can mount it in the right way you can use a DTI dial or depth test indicator. With the dti resting on the rocker..engine on compression you can rock the rocker and get a reading. Space is minimal and it is fiddly. The most important thing is to re check the clearance after tightening the locking nut. Bending a normal feeler gauge is the easy way to go.

Condenser, are the contact (points) faces blue colour....indicates condenser faulty. Check that contacts open and close freely.....the pivot bush can dry and grip the pivot post causing opening and slow to no closure.

Toilet roll....food way to visibly mark out the sections. Come in handy for those ‘touching clothe’ moments?

Does it have a spark at the ht lead ? Kill switch functioning correctly? Re cleanorbust carb float valve not sticking?

Yamaha tried a version on there enduro or m/x can’t remember exactly when but is was hydraulic drive much like the SWM device.

Can’t see if you are using a chain tensioner. The bike looks really good but the chain coming off the sprocket could be an alignment issue, allow by the standard presented in the photo you have probably covered that. Do you have sufficient clearance between the rear tyre and drive chain, its possible with tyre flex for the tyre to force the chain out of line and jump the sprocket. Your final drive ratio of 4.57:1 seems a bit low.....high engine revs not much speed. Running a smaller gearbox output sprocket may create chain inertia problems. I’d see if there is any data on a genuine BSA C15’T’ available. Here are some C15 specs. C15 road first 16.27 second 10.74 third 7.80 fourth (top) 5.98 gearbox sprocket 17 rear wheel 52 C15T trials first 28.53 second 22.05 third 14.67 fourth (top) 9.00 Quite a difference a difference with top producing an estimated 40-50 mph. Bear in mind the C15T had a larger inlet valve and different camshaft, there was an optional higher compression piston available giving a 10:1 ration. The BSA B40 WD spec bike had similar low gearing i.e. first and second virtually useless for road work but good for slow progress with a Squadie aboard furiously footing away through mud and crap. But third and fourth producing useful forward progress. I cannot claim the specifications as from my knowedge, rather 5 minutes on Google and all was revealed?Certainly using the ratios you have indicated will lower the internal gear ratio considerably, which will need you to decrease the rear wheel sprocket size and also the gearbox sprocket. Good luck?

Bulb type horns ok up to about (manufactured)1976. After that it is a continuously sounding electric single tone horn. Two tone horns a debatable point...my partners Nissan Juke has some lovely loudish two tone horns these were factory fitted. A single horn able to produce a two tone note is akin to a police siren. Where as two separate horns sounded at once will produce a better sound warning. The regulations are not clear so a torch battery type powered horn could be classed as legitimately an electric horn. What ever you say about said MOT tester, they are probably worried about their job.

Spoilt for choice, but I’d be going for the 19 .....its so easy spending someone else's money.??

Well you can use an ohmmeter, so you should be able to check the wiring for the headlight and other components for short circuiting. disconnect the light and see if you can still hear clicking. Make sure there is no live loose connector(s) touching an earth point. Sort the throttle and hope that the cylinder is not badly scored. ?

Hi Dillypoop. When you say ‘a new’ Sherco are you meaning brand new or new to you...recent used bike not new. I would be going for the youngest bike that I could afford. The manufacturers tend to iron out the issues year on year...so a $1500 difference could soon be eaten up in spare parts, loss of use due to down time and a significant reduction in resale value if you went for an older bike. By my maths that 17 bike is quite a bit older than the 19....obvious really. Try to negotiate a few $00 extra discount to sweeten the deal if you can, or extras thrown into the deal. ?

First off, plug the exhaust and block off the air box entry. Rather than a pressure washer, a garden hose on domestic water pressure will get most of the large crud off....if you do not let it dry out i.e. harden. Thats what happens when you throw the bike in the garage/shed and bugger off down the pub??! Back to cleaning, after you have hosed as much crap off as is reasonably possible, make up a mix of wash and wax 50/50 in a sprayer and liberally spray everywhere....thats on the bike! Leave for 3/4 minutes and then with a softish brush clean the wheel rims and hubs. Take care near any oil seals on any area of the bike as you can force dirt into the seals.....not good. Sponge to clean the plastics with lots of water and wash and wax (from a bucket) wash the bars snd controls. Tyres may need a scrub with a stiff brush, use a separate stiff brush for the chain. Don’t forget to clean under the mudguards....! Now hose off the whole bike and with a critical eye check for stowaways....lumps of crap still clinging on?....Happy....now if you have a compressor do not go mad and blast the water off, this will just drive moisture into all of the places you don't want it, use compressed air from a distance to the bike so it acts more like a drying draft like the wind. Use an absorbent cloth such as a soft bath towel....use the other half's if you have no old towels....micro fibre cloths are excellent for mopping up water and polishing....WD40 is an excellent product but it is also quite good at softening sticker adhesive, I prefer to use Silicon as a dressing for most parts of the bike. Obviously not any where on the brake surfaces. Now check you have not forced any water into the air box or exhaust, remove blocking plugs etc and air box drain caps to ensure no water is lurking about in the bottom of the air box. Gently operate the kick start to ease the piston over TDC. Make sure you have not dislodged the plug cap and try to start the engine. If it wont start as is usual for your bike, stop kicking and check fuel amount, kill switch in operate position, spare plug put into HT plug cap and swift kick to establish good spark or not, WD40 sprayed onto spark plug ( the one in the engine) and inside cap and refit.....try engine again...you may well need choke, don't forget the engine will have been chilled right down with all the cold water. If it still will not start, its something you have done will cleaning or introduced by way of water deluge. If it starts, shut the engine down, any residual heat will only cause condensation in the cylinder and exhaust. Don’t wash your bike, car, van etc with warm or hot water, this reactivates any salts or chemicals and the hot water carries the residue into all of the crevices and ledges ...not good. Use wash and wax as this helps hold back corrosion and gives a shine to smooth surfaces. There you go all done, nice and clean ready to go into sleep mode until the next time. With the exhaust cold a spray of WD40 ( other products are available) onto the front pipe and silencer system will help prevent rusting/staining. Silicon spray on the rims, hubs, bars and plastics will help stop the next lot of mud etc from getting a hold when you next ride. Some old stagers wipe the frame and rims over with a rag lightly soaked in engine oil, gives a nice shine and leaves scratches to frames as scratches not rust areas. Happy cleaning.......I ‘ll be waiting for the “ah but.....” comments??

All looks very highly polished. You have deleted the speedo drive then? I’m going to recheck my front wheel spindle spacer set up. The lipped spacer is fitted on the speedo drive side, plain spacer on the opposite ( brake ) side. Wheel centralisation i.e. rim to fork leg was off the first time of installation, took it all apart refitted and rim was then central. The spindle and fork mount are susceptible to tiny burrs from indiscriminate force when entering the spindle into the fork.

You could use a quality duct tape or Gorilla tape which seems to be quite robust and stays in place. Use in place of a rim tape then you can run your tubeless set up as normal.

Leaving the brake lever/pedal under pressure overnight can produce a more solid feel when operated as the overnight under pressure will cause any microscopic air bubbles to find their way to the fluid reservoir, thus producing a more positive feel!

Is this bike registered for road use? Have you given the area around the frame no/VIN a really good clean....is the fourth character a definite T? If all is not explained then maybe a photo and an e-mail to the Gas Gas Importer or a reliable dealer may shed some light on what you have. Did you purchase this bike from a private individual or a dealer? I know how disconcerting these little things can be, but at the end of the day if its not a stolen reappropriated machine and you like it then all is not lost. It could be that your bike had a factory hiccup where the person punching the VIN needed glasses or was suffering from too much wine? It could be that VTRTG was a small production run with some mods or additions to clear out a model ending run.

TLM 50 front fork oil.....use this data at your own discretion. With the forks completely drained use 130 -140 cc of fork oil ( the higher the grade the more resistance offered so take care...possibly a 10 grade to start with but it also depends upon your weight) thats 4.4 - 4.7 fl.oz. If you have too much oil in the fork leg it will force its way out passed the oil seal and make a real mess, too little and rapid wear may take place. Some people prefer to measure the oil level as the internal components are not always identical and differences can be quite a bit with just quantity added. Blatshop show how this is done provided you have the tech info, i.e. the measurement. Your TLM is a proper trials bike and many have taken the bore out to 60 + cc even using other parts to bring it up to 100 cc with carb mods to suit. The original exhaust was very special in that at low revs it gave the little engine extra grunt for section work. Look after it and keep it standard, you are the custodian of a fairly rare bike the likes of which got many a top trials rider started on the wobbly sport.?

Whats been going on with that flywheel locating nut, looks to have been punched with few blows to possibly make it a tighter fit (staked) with regards to coming undone. The waterproofing where the loom passes through the case looks as though its been compromised and certainly moisture will cause running issues. The rust will eventually have an effect on efficiency, although in your case it doesn’t look too bad....certainly clean it up and the face of each coil but be careful to not break any insulation sort the waterproofing as well. These ignition systems do suffer from coil break down so as everything warms up then a minor break in a coil winding opens up to interrupt the circuit....hence your 10 mins of running and then dead. There is a thread on GasGas trials central about this issue, you may be lucky and it might only be the ignition coil (ht) or it could be the pick up unit which is not so good. Some basic resistance testing may give an indication to the fault but have a look at the thread I mentioned. Some one else might pinpoint the fault straight away for you. Good luck.....whatever cleaning the carb is always a good thing, check the fuel flow from the tank as these can be affected by the dreaded ethanol and/or ant lining that may have been added.