section swept

Sam you already have the ‘large’ air box fitted, just rework the poor waterproofing as mentioned already. The later model Sherpas had the smaller side panels that looked sleeker. Your set up correctly fitted will allow the engine to breathe more easily from the larger air volume.??

Aaron you could try InMotion which is also known as Bultaco uk. Google will supply contact details. They are very good and supply parts etc for all the Spanish makes plus. Others on this forum will recommend different suppliers and contacts.

The main thing is to check the bid end and connecting rod little end for wear, play and visible signs of other damage. Welding up the crankshaft should not pose too many problems provided that there are no inclusions and you allow air cooling naturally. If you are going with the stick method then select rod material type with care flash grinding will indicate type of similar metal by spark colour. You have little choice with mig. Penetration could be a strength problem. Maybe you could find a good condition crank half on eBay etc. Not sure from pic but if it’s the drive side you are repairing there will be a fair amount of torque loading on the shaft. If it’s the generator side then there will be a lot of inertia going through that side of the shaft. Add up the cost of new big end bearing and conrod kit and you maybe better getting another engine and using both to make one good engine with your original cases. Hope there’s some useful info for you.?

That rear hoop deletion was a works mod. From the picture it looks to have been carried out well. There could be more history to this particular bike and may well be worth checking further?? Also check the top tube for straightness they tended to bend especially if the bike was jumped like a m/x er. Looks fine but a good check is needed. I’m just over the ridge if you need help, tools, etc.

My frame tubes were like yours ‘well dented’. I cut them out and made replacement tubes and welded them in place. Previous owner had deleted the useless bash plate and fitted an alloy version, didn’t save the frame from his rock bashing riding techniques though? when you fit the engine back into the frame install some thick rubber mat to absorb impacts and note onto engine cases. Mat should not be over frame tubes.

Yep the air box is correct, it’s one many riders used to replace later model air box with as they were smaller. Your frame could be a Miller Hi-Boy but looking at the original frame which has the rear loop deleted I’d be using that one. Chrome plating frames can make them more brittle and as they get older; even more so. If you are selling the original Bultaco blue frame I would be interested as I’m in Nottinghamshire. I’m currently rebuilding/remaking/restoring a M80 Sherpa 250 this to came with a chrome frame and was supposed to be a Miller Hi-Boy but it turns out to be a Bultaco Frame chromed. There were some other small manufacturers that dabbled in frames for the Bultaco and others. Contacting Sammy Miller may be helpful but I doubt he has any records of frames produced, nor do I suspect you’ll get much info from the previous and new owners of Miller Products. The more I look at your bike the more I’d be inclined to go with the Bultaco frame as it’s going to be easier to prove ‘provenance’. Hope you find my input helpful? NB the waterproofing on the air box is not good, you will need to look into making this area better than Bultaco did.

They may just think (doh!) wow spares????

Beautiful and so full of character. Time now to fit a heel and toe gearlevergear-lever makes for much better selection, especially with those really set back footrests. Envious?

Greeves still advertise in Old Bike Mart. They offer a spares service and new build versions of the Anglian. Recently moved to new location tel no. 01263 734688 Marsham, Norwich, Norfolk.??

You haven’t flooded the air filter element with fuel or engine oil from the breather, this will certainly cause the issues you have. Sediment may also have blocked the carb idle jet. Next time, unless you’re doing a Dougie Lampkin and wheeling round the Isle of Man park your bike on the side stand etc?

Well first off you will lose the engine/frame number pairing. If you ask Bultaco UK / InMotion the question they ought to be able to offer knowledgeable advice and parts if needed as they did have recently a new stock of gearbox internals.

Really nice looking pair of Sherpas. As for twins no, the frame tubes are different, rear dampers different, front guard stays different, kickstart angles different, tank decals missing on M49 plus extra sticker on top of tank unit. Other than that ‘twins’. I just hope my M80 when completed comes somewhere near to your standards of preparation?? What state were the bottom frame tubes (beneath engine) I had to make up new tubes and weld in as originals were crushed and dented way beyond resurrection????

Ah but you see you are older ?and wiser ?and not so easily scarred ?by impossible sections ?and obtuse angle rocks ?waiting to jump out at you! No batter, not even salt and vinegar.

Get someone who knows what they are doing to actually show you! There’s no better way to learn than to actually do the job with guidance. Everyone has told you good information, but you sound like your practical skill levels; indicated by not knowing about the security bolts, should be improved especially for wheel removal and more importantly refitting and working safely. Hope you take the comment as well meaning and in no way critical of your abilities. There are good videos ....and bad on the subject of tyre changing but doing it is best?

This is for TY 250 and Majesty 250/350. Plug gap is 30-40mm on contact breakers and 70-75mm electronic ignition. There that was easy? B7-ES plug

Stay with the Mikuni but first return it to the original specification/settings. You don’t mention float height and as this is important because it is easy to bend without realising it must be checked accurately. The ignition timing needs to be accurately set to Yamaha’s specs. The spark plug also needs to be as standard but an iridium to the same spec is ok. Ensure all breather/vent pipes are correctly routed, not kinked or blocked including the carb fittings. With a Wes exhaust you would possibly need to go up a couple of sizes on the main jet and try the engine performance; plug chop is a good way to establish main jet and needle type. But as I say start from standard settings first to establish a base line, note every adjustment and make small adjustments. Check the main bearing crankcase seals as you could be drawing air from unwanted places. For the engine to be running hot at low throttle openings are you allowing for the lower air flow around the engine? What method are you using to measure engine temp. A richer mixture may help with cooler running at slow speeds but may also cause 4 stroking and bogging down/stalling issues. Have included a picture of my E model this has standard jetting but synthetic reed valve and modified stop plates, also standard exhaust as Yamaha knows best.??The idle mixture screw has two settings, one for work and one for off-road that’s why you can see the original nylon cap in place. This cap gives approx. quarter turn in or out but the cap must be removed to perform the initial set-up. I’ve not ignored you’re stated 0.020 thou lifted exhaust port but I doubt that will have had much if any effect to the engine performance temperature wise. Not advertising but I found Yam Bits to be very helpful with parts and I dare say a certain Mr. A might offer some useful advice??

Well my Sherpa came with a banana ( not battered or bruised) but I suspect that the club foot is better performance wise as Bultaco progressed to that style. The system with the largest volume is usually better.

How about trying to use the later double spring retainer as on the later Sherpas and MX models. Heat shrink around the exhaust port on an aluminuim barrel could be problematical with loosening etc. I’m sure that there are really large Helcoils available and there are also solid thread inserts on the market. Alternatively you could open out the exhaust entry ( damaged thread area) to accept a new short pipe threaded to match with an internal diameter as the original screw in front pipe sleeve. I wanted to say plumbers thread tools if you follow my drift.???I hope there’s some useful ideas here to sort your problem. Good old Google should have some answers too!

Setting the gap on an Iridium plug is no more difficult than a standard plug, just be careful. Top tip...if the gap has altered with normal running and no outside interference then the plug should really be replaced as it’s worn out. Top tip no 2 iridium plugs should last for 60+000 miles in a car engine so expect at least a lifetime (40+000 miles) in a Trials bike engine. For my sins I used to be a NGK Wholesaler.??

Doubt that you’ll like taper top yoke as you will also need tapered fork tubes. Early Bultaco Sherpas had taper top assembly i. e. M80 and M49 but then some of the M80’s had the deeper bottom yoke whilst others had a straight yoke. Chase T Y might have some special triple clamps but not tapered and not cheap either.

Yambits are excellent.

Depends where the previous owner fitted the condenser, it could be next coil or still in original position behind flywheel/mag. Check carb breather pipes not kinked, crushed or blocked. Fuel tank cap breather is this clear as guy53 suggested. Full ignition check, contact face condition (dark royal blue colour on contact faces indicates condenser ? Air filter is this clean and unrestricted/ bunged up with crap etc. Is exhaust relatively clear and not carbon loaded or oiled up. Piston is compression good and not too noisy piston slap wise, rings could be gummed up and causing running issues. At the end of the day diagnosing running faults etc is very difficult at a distance but hopefully you have enough to go at. Let us know if you sort the problem??

The clutch on a TY 175 should be nice and light with a smooth take up. Too thick an oil will cause more issues, follow Carl Eckbloms suggestion for oil grade. A good look at all the parts of the clutch including checks for buckling etc and careful assembly following a manual should produce a more effective operating clutch for you. Clutchless gear changes should be ok on the TY if you are sensible about it. TY guy has the right method, clutch is for emergency only in section, assuming you are in the right gear!

Agreed?? the head steady is an awful? piece of engineering. Do you mean the head steady set off the Pursang moto x? A proper bit of kit that. On my bike the one in the pic the head steady has been boxed to make it a bit stronger.

Blindly what type of parachute do you carry? You are clear for landing, use runway Echo 5 winds North Easterly watch out for powered hang glider club members using grass area.