carl ekblom

It´s quite a bit slower with 10/48 then 11/46. You can roughly estimate 1 teeth smaller on front sprocket equals 4 teeth larger at rear sprocket. Try and see if you like it. Use 2nd gear if you need speed. Will also be slower on 2nd gear and all other gears. Perhaps 2nd gear will be more usable

Gearbox oil should have no contact with engine. Thick gearbox oil may possibly affect gearchange and clutch action (if the same oil). Unless oil leak would not have anything to do with engine.

Yes, gearbox oil in engine smoke and smell. Best you can do, is as soon as possible, completely drain the tank and replace with fresh petrol and correct two stroke oil. However, it may need a period or a few tanks to get rid of all gearbox oil. Also check spark plug for carbon build up. If done promptly and properly, I don´t think your engine has taken any damage. When I was young, I ran hours with gearbox oil in petrol without noticing any permanent damage.

35x47x6-10mm seals are standard and can be found in many options. If they are thinner, don´t worry. It is easy to put a 35x47x7 seal in a space for 35x47x10. If you like, you can machine a spacer, but in many cases this is unnecessary. Be carefull not to scratch or damage the seals when assembling the forks. Grease/oil and some tape might be your best friend. Use a scraper ring above the seal.

I would say ordinary NBR seals are fully adequate. Use original seals and bearings. Take seal out then heat the halves with hot air gun or similar (gasol?). Check temperature with an IR thermometer. I guess 100C is good. Later when putting the crankshaft back you may heat the bearing(s) to max 150C (no more). Check with IR termometer(IR thermometer is important). IR thermometers are not expensive nowadays.

I don´t clearly see, but is it a modifed Norton Roadholder?

You may try without one shaft each time, to find out where problem is located.

I guess your gearbox is OK. I think it´s the selector mechanism. To examine it, as far as I can remember, you´ll have to remove the clutch basket.

It looks the Finnish flag blue is Pantone 294C which seems to be little more blue then RAL 5015 so correct shade of blue looks to be 294C for 199B and RAL 5015 for 199A

Had a discussion with a number of Bultaco experts some time ago about possible shades of Bultaco blue. It ended "there is only one known Bultaco blue from factory". Different shades of blue seen on old colour photos is possibly due to agening photos. This is good for me unless someone has different and more correct information. My remark is RAL5015 suits well (or perfect) and it´s easy to find https://www.ctborracha.com/wp-content/uploads/2019/02/3-RAL-to-Pantone-Conversion.pdf

Agree👍 They are surprisingly durable. A replacement is not the first thing I would look for. Go for the Domino and as said previously, do not overtighten the bolts.

https://s3parts.com/en/footrest-and-parts/173-trial-footrests-s3-hard-rock-steel-8435645010398

https://www.splatshop.co.uk/s3-hardrock-steel-footrests.html You may find similar from Jitsie

Think you need weld on brackets for the footpegs in mention. Most people feel comfortable if they move the footpegs slightly rearwards and slightly downwards. Slightly is up to a couple of cm. I like the S3 steel ones. S3 steel footpegs are reasonable light and are long lasting

https://en.wikipedia.org/wiki/High-density_polyethylene "HDPE is resistant to many different solvents, so it cannot be glued. Pipe joints must be made by welding"

199A head steady is not a good design. Mine has been broken for at least one year now. Seems to work well nevertheless. Best is of course to loosen all necessary bolts and retighten to avoid extra strain after assembly. For my 199B I have made a new and better design but not tested yet.

As far as I know, usually no major problem with PWK. Splatshop are good at carbs and have spares,,jets etc https://www.splatshop.co.uk/performance-parts/keihin-pwk-spares.html

Also check you don´t have an air leak.

It might be residues from air filter spray that follows the airstream into idle system and get stuck. It is not dissolved in clean petrol. Some people use Carb-Cleaner to dissolve. Have no experience of that liquid. When blowing, should use well filtrated HP-air. The passages are very small in the idling system so it can be difficult to clean. It happens it is a nightmare. Perhaps you should concentrate on cleaning the carb body and buy a new jet. As jets can be dirty from factory it is best to have it ultrasonic cleaned before assembly. For safety´s sake, HP-blow the jet after the Ultrasonic cleaning. Is it a Dellorto VHST or Kehin PWK? My last carb-cleaning-nightmare was approx 8-10 years ago with a Mikuni (original) on a Beta evo 4t. Eventually a man (not me) fixed it.

To me it sounds like you have a problem with dirt in idling system. Not easy to clean. Must take everything out from carb and carefully blow and clean. Remember to blow and clean all drillings and passages in carb body. After only use a good, clean and oiled airfilter and change often. As I see it, dirt in idling system is one of the most common problem in a dirt bike. If problem is only at certain throttle openings I would say it isn´t the ignition. Ignition problems is most often at all throttle settings.

Accordingly to this list https://cemoto.tripod.com/list.html 199B started in May 1981 and ended ? Numbers should be 12876-14653. It is unclear when production ceased. Some sourses say in 1983. Rumours say the workforce assembled the last bikes from remaining parts https://cemoto.tripod.com/photos/blue.jpg

Also check the chrome inside the brake hubs are intact. Some brake cables are very tight and does not slide as they should, but RH brakes are poor. Engine and frame numbers can be found here https://cemoto.tripod.com/list.html

The sealing is often (always?) made of radial type seals . This is possible because differential pressure is low and speed is moderate Pic 1 is the scraper side. Facing upwards. You also have a separate dust scraper above this. The spring is there only to make scraper effect better. Totally there will be one dust scraper and one oil seal. Your oil seal has one scraper side and one oil pressure side Pic 2 is pressure seal side. Facing downwards. Oil pressure pushes the lip harder against the stanchion. The spring gives an initial sealing pressure Some radial seals doesn´t have a scraper lip. Take the dust scraper away every month or so, and clean under (above the fork seal). This may prolong oil seal life Put some grease (or similar) on the retaining ring to prevent rust The retaining ring is above the the oil seal and hold it in place

The pressure in in the lower leg on a normal fork so the seal should seal downwards. Looks to be OK in the first photo. I recommend SKF (original at newer evo) fork seals. To protect the seal from damage (easy to do) cover the all sharp edges with some electrical tape and grease or oil the stanchion and tape before assembly. The guy in the movie clip seems to do it correctly

I agree with turboforall but would add: You must test different bikes and find out which one you like best A good dealer and spare parts supply is also important. Then find the best deal for a bike in good condition. No barn find