pschrauber

Mmmh 1:30 that is really quite rich, even with 1:50 the engine is spitting left over aka unburned oil out from the exhaust. Back in the day's I used the Bultavo oil, (at least produced for them). This was the only oil which was recommend by Bultaco for use with 1:100 as a mix ratio. Now I use 1:75 as premix no problems so far ... And you really use SAE 30 as premix, here I am very curious... Isn't the Sherpa spitting oil like hell or might I have misunderstood something ?

A fresh repacked exhaust will improve the flush of a two stroke engine. The SWM doesn't have a diffusor like. My 2-stroke KTM from 1989 run much better which a repacked mid and end section. The effect might not be very much but its quite remarkable. A sticky piston ring that have come loose might also have been the case, I have heard about but never heard from anybody that have found them beside in old barn finds, but why not, sounds like a good exploration. It could as a guess also have been a tiny piece or fibers of a cleaning rag which stuck somewhere in the carburetor and is now flushed away. when something suddenly runs better then before there was mostly a fail that got fixed by itself ...

As the Bul has an seperated containment for the gearbox I use SAE 90 (EPX) with API GL5 specification, which is also been used for differential gearboxes. advantage: can manage real high pressure loading downside: works really smooth first when warmed up by the engine in winter, not for use with clutch! ATF for primary is perfect

Yes I had the tab washer mounted , this prevented the nut from getting really loose, it was the old one, very dented and rough cut on the edges. I took the old one because the other one I got (NOS new old stock!), was bigger in diameter then the 11 teeth sprocket and the chain sat on it. Now I will take the new one but will have to reduce the diameter first to get this plate proper mounted. Some sort of weird that there is no tab washer that fits right on for the 11 teeth sprocket, this is the standard sprocket for the 199b ??? And probably I was to fearful when I read that the nut has to be tightened with 100Nm! in my repair manual (from Switzerland) and 90 pound-feet is even more around 122 Nm. I will also take 50 pound-feet like Scot Taco did which is around 65 Nm and will bend the tab washer on two sides. This will hopefully help in future. Maybe off topic but Bultaco related, another problem I had - also some kind of weird-. I mounted X-Lite tires and also a new chain to the bike and when mounting the chain I counted the roller of the old one to cut the new one in the right length, I counted 97 roller (with the mandatory half link), mounted the chain (with the half link) and discovered that the tire rubs a lot to the swing arm. (I now think that the X-Lite which is an 120/100R-18TT/TL is bigger than the old competition or the Pirelli which had 4.00R-18 TL) I had to replaced the half link (three rollers) against a standard link (4 rollers) no everything is OK again, (total length 98 rollers) ... and thought may be the chain will lengthen a bit. So far the chain did not lengthen a mm, at least for the Bul I can recommend DID 520 ERV3 very much, as light as the standard ones and very durable so far. To the name: Patrik or Paul not a problem as both names starts with P

Are there any recommendations for the torque of the front sprocket nut? Its a M24 but only 6.5mm thick. Mine was a little bit loose a bit but the security plate hold it in place. Now I would like to here some practical recommendations. Spec's in Nm if possible. Thank's in advance. Patrik

engine size: bore x stroke: 46,5mm x 44mm capacity: 74,7 ccm compression: 12,5 : 1 primary gear: 14/63 plug: Champion N 84 G

I would suggest to look up Italian craiglist for parts there are most used and new parts available. The engine is bone stock minarelli and actually a Minarelli engine where parts should not be a big problem. The 100 shares a lot with 50cc bike, even the engine. Gearboxwise is for example just the primary drive and 6. gear different. There some 80cc bikes with Minarelli engines in Germany around as there was a special bike class for the youth installed back then and the T100 fitted very well in this class with 74,7 ccm. Many other bike brands in this class shared this displacement. Anyway I wish good luck finding the parts you need.

Cool and there is a mud flap too, well I couldn't see the flap on the other pictures which is now visible. Depending where you ride the flap will be OK, where I live with much mud and sand I would have very fast a pile of debris between the wheel and the engine.

Looks very sanitary. I like the modified tank and side panel design. As Chris mentioned where is the airbox? have you mounted a K&N filter? I would place some kind of a shield or rear fender extension between the rear whell and the engine as the Bultaco likes to Transport a lot of ground debris there. Another thing I personal would change is the throttle at the handlebar, cabels going rectangular from the throttle can get you in weird situations as the cable likes to fasten in brushes and other jungle plants. I would Mount a throttle where the cables goes parallel with the bar. With best regards Patrik

I too believe that as long as you take commen colors or colors that are period you will not loose any money as long as the quality of the paint job and the overall design (stickers ...) will match. It would be probably difficult to sell a violet Italjet ...

I have fitted Michelin X-Lite tires with inner tubes to my SWM which still has the Acront red label rims. The combination works quite well. The tires stay good on the rims, it had sometimes occurred that a partial section of the tube went off the tire bed, (around 10 - 15 cm). But only if you have very low air pressure. I did not recognized it at once first a week later. I pumped up the rear tire until the tire sat again right on the rim. I run around 0.4 bar in the rear tire works very good. The Michelin X-Lite's are one of the easiest way to save some weight (over a kg). I will probably mount them too to my TY together with a tubeliss inner tube ..

Oh This is a mixture of an early Gas-Gas bracket mount, (the golden one), and a fender mount made out of an aluminum plate. (the plate is available in Spain too, (Todo Trial classic have them)). For installing them you need to turn down the lower stanchions too, otherwise they won't fit. The front fender itself might be a shaved standard one or maybe one from a newer model. As there is no return for this modification you might too look out for a second fork. The modification will save some gramm but that's it, the fork seals are a good mod. as they will reduce stiction a loot, the rest is "just" nice looking. As the eyes rides with the bike too worth when You are interested in design too, if not there are probably other modifications that are too to consider.

I personal would leave the plug in the center and use the other hole which is a little bit off center for the decompressor. If you ask me why there is no real reason beside it's common to do so.

Yep, best way to do if the bike is fairly OK, while you keep it running you can easier detect issues and get spares in time before waiting a long with all parts spread in the garage because you have to search up something wicked. My Bultaco was stored untouched for over a decade in a garage when I found the bike, so there where issues with corrosion and to glue transformed gas ... I had no chance to get it running without stripping the bike completely. This picture I made when I got the engine sorted just to please me while fixing other parts of the suspension. Good luck for the assembling.

There is an oil seal it's behind the washer on your photo, (green plastic). For sealing the clutch push rod you need the felt seal, can be made by your self (that's how I do it) or bought by Inmotion for example. Here the oil seal: PS.: I believe you need a new front sprocket.

That's wear to the push rod done by the ball end due to too little slack of the clutch cable, or very much slipping the clutch while riding.

Mmmh looking at the piston the engine does run a little bit on the rich side. The dark brown spots a right but there are some black areas with carbon build up. Otherwise very sanitary, my compassion to the gear shaft ...

Very confusing that there were so "many" different sizes? But they (SWM) did change the swing arm and the rear shock in the development of the bike several time maybe therefore are so many different length in use.

Mmmh the standard Girlings which are mounted on my TL.NW Guanaco 320, (still working very well), are 360mm in length. I mounted Falcons now which are 372mm so even slightly longer. And I' am very pleased with the outcome. Mine is a 1980 yellow Italian model.

I' am not sure, but I think not the stop while still balancing on the foot pegs is the problem. It's in my opinion the hop around changing direction which is/was often the opposite of elegant. And of course the dab while the bike stand still which was counted with 1 point. The dab while standing is cured, which is an improvement. Still there is some "hop around" instead of forward there is the borderline in my 0,02 € opinion. They should allow the stop while standing on the pegs but not relocating while trying to get forward this is extremely difficult to observe and determine if someone is still in the move forward or only changing direction (turning) or rolling backward. I personal like really ridden sections instead of sack bouncing rides, a stop (a real stop!) in between is OK, but here I' am probably very lonely in my personal view.

There are indeed some very nice black Sherpas like this one which is stationed in the Netherlands around, but the colour arrangement has to fit to look nice, like here: But much effort and I would think very expensive too. The original red silver scheme with aluminium fenders, - posted already-, looks as good in my personal view, expecially when there is some patina shown. Like here, (the handle bar is nuts): http://classic-motorbikes.net/images/gallery/1975_bultaco_t350_159.jpg or here much better: http://bultacotrialclassic.superforum.fr/t148-elle-est-vendue-bultaco-159 * * French Bultaco Forum very nice topic's there ...

The rebuild looks very sanitary so far, as I could see you have done some welding to the foot rest area, so you changed the position ...? After welding the frame you will paint the frame, partial or complete and then in silver again which I personal like much more then the gray color that seems to be applied now. Looking forward to any progress in this rebuild.

Yep very true I mix it up very often as the Bosch and Beru plugs count up for hot and NGK down:

Looks like the either the mixture is still too fat or the plug could be a little bit colder. I had a similar look of the plug with a in my personal view very good adjustment of the carb, so I recently replaced my standard plug which is a NGK BP5ES to BP4ES and the plug looks much better now, hazel brown in the middle (electrode) and very dark brown on the outer ring. If you feel comfortable with the carb adjustment and you still have a too wet looking plug a switch to a colder plug might help.

If you have to spilt the motorcases, I would in your situation replace everything that is weard out, beside this every oil seal, as they get stiffed as older they are. Then I would take a look at the bearings if they still roll smooth, especially main bearings and lower con rod bearing, piston, cylinder and piston rings should be looked at. Often the mushroom like bearing for the clutch rod is behind wear, clutch plates?. I would also replace primary chain and chain tensioner. Some shims between the gears of the gearbox of my 199b where weard down too so I had to replace them too, (custom made). Points and capacitator come in my mind too. I don't know where you live so I can't give you a good hint for parts beside Bultaco UK.