pschrauber

Yoj might search up o-rings made out of Viton (trade mark). These are heat resistant. You get them in every dimension.

There are one or two that keeps the gears between the gear shafts "aligned" the "spacer" has an edge too, the on my Bultaco was warn out and I had to refabricate the part as it wasn't available anymore. I have pic's of it but I'am not at home yet, first on Friday ... . Anyway if the gear shafts aren't very well alinged shifting can be difficult and setted gears can " hop" out.

I use it too, I started using it first for the brush cutter and then for the chain saws, then too for the lawn mover and now also for the bikes. It's very good as it doesn't get old, it can be stored in years even with big temperatur differences. - 30 deg. or + 30 deg. Over years doesn't change the "petrol" even premix will be as good when mixed a couple of years ago. My problem is the price standard Aspen isn't cheap and only has 91 ROZ, for the bikes I need at least 95 ROZ and for my KTM I need at least 98 ROZ. Aspen+ has 95 ROZ but you have to rejet the carb because the engine will run to lean when before being used with standard petrol. There ia Aspen Racing available which has 100 ROZ, this works very fine with any bike engine so far as I van tell, the price ... well ... is around three times as much as standard gasoline,and it's not so easy to get it. Known issues so far, none, no problem with plastic tanks, aluminium and aluminium magnesium or steel. I once had an issue with a rubber tube which was dissolved by the gasoline I think, the rubber got extremly soft like chewing gum. After replacing the gas rubber tune no problems so far. I have a replica glasfiber gas tank here I also had no issues.

Yes the ignition setup looks very contemporary. Next time you get in the situation for taking off the rotor you can look up if there are some holes (Sacklochbohrungen) just on one side, may in different diameter and only a couple of mm in depth. If so the rotor is fine balanced. I have not seen any marks of fine balancing on the rotor of my bike so the rotor was not fine balanced at least for my bike. If you want to get the rotor fine balanced let it be done if you not have the machinery to do so. I personal would wait until the next crank rebuild. Then the complete unit crank, rotor and flywheel can be balanced in one step. This would not increase the cost of the labor only a tiny little bit and the engine will run smoother too.

One moment please. There where both models/brands installed Femsa and Motoplat and to add a little confusion too, both where different in weight. I think it depended to which country the bike was delivered. Just now on vacancy and with limited access I have photos of both rotor brands even for both models, (250 and 350cc). The Motoplat ignition are some 100 gramm heavier. when I remember right.

Mmmh, I personal like the 11 / 39 gearing best, might be not very slow but the pic-up = acceleration is "OK" as the engine doesn't pick up revs very fast in need. And of course you won't hit any stone as easy with a smaller sprocket at the rear. Certainly in thight sections you might be in the situation to pull the clutch ... Anyway the Sherpa likes some speed then the bike rides easier in my obeservation likewise the frame setup isn't build for these very thight section when it goes straight ahead over rocks, stones, trees and steps the bike performes quite well, also in soft and slippery conditions. But it's your riding style and your bike so you have to figure out by yourself what is more important.

Try Sigma, they sells also in the US and have bicycle speedometers that are also illuminated and work very good, you can buy them with wire or without, (wireless is a benefit in my opinion). I have Sigma bicycle speedometer as road legal equipment for my KTM and use Sigma speedos too for my bicycles, they are waterproof, very reliable, easy to install and much more accurate then the standard cable driven speedos. Road registration for a 500cc KTM 2-stroke (former ISDT bike) with Sigma speedometer: The Sigma BC 1609 is with backlight but wire version, The Sigma BC 1609 STS is also with backlight and wireless.

Indeed very well ridden The Video is taken in France by P. Frei in Switzerland, he has a lot of nice ride reports with pictures and videos on his website.

Fur the clutch and primary drive: There can be used SAE 10 - 5 (older recommandations) from the mid seventies or SAE 30 (newer recommandations) from the beginning 80's, in pesonal experience ATF works too very good. (As thinner the oil as easier the clutch will slip). For the gear box where the transmission is situated SAE 75 - 95 works fine, Castrol EPX does the Job really well you can use either SAE 80 - 90 or even SAE 85 - 140

Just forgot the frame of the 125 cc and the 175 cc model are pretty much the same.

Not necessary the dimension of the cylinder is normally easy to detect as the cubic cc is printed on the cylinder from the outer side! You find in near the intake on the left side (in driving direction), if it is a 125 cc model there should be printed 123 cc If it is a 175 cc model there should be printed 171 cc It is not possible to rebore the 123cc cylinder to a 171cc piston! See here:

600cc for the gearbox, 300cc for the clutch and between 150 to 180cc for each fork leg. To the quality: good gearbox oil SAE around 75 - 95 works fine, for the clutch SAE 30 or SAE 5 - 10, here ATF work's very good Elf HTX even better. Forks should be SAE 10, I personal use SAE 7,5 being a light rider.

Yep condensator might be the problem. To check the condensator turn the rotor until the points are open, then connect the condenser to a multi meter, adjust measuring resistance (20M Ohm), when the multi meter is connected the resistance should rise up. If the resistance goes down or a short circuit is shown the condensator is faulty / broken.

No disadvantage in my very personal opinion

Very sweet, I' am too in the process of electrical wiring, where are the switches? BTW.: In Germany you have to have silly flashes for road registering if the bike is younger then being build in 1962! I don't like flashes they are very weird on a trials bike. Using the Hercules K125 flashes that are mounted to the bar ends as these are made out of polished aluminium, at least contemporary and they are really solid and do work also as bar ends ... (will of course take them of once the bike is registered ...)

Yes the left foot brake assembly works much better as it doesn't have to deal with the cable bow and can be actuated with a steel rod. But you have to get used to the flipped operating elements. Here I have my (personal) problem I can't switch with ease as my other bikes have the brake paddle on the right side. Therefore I am still using the brake set up on the right side. To avoid as much flex as possible got these cables which are NOS / 100% clones and work very good, (the upper one with the brake light switch integrated works even better then the lower one where the brake light switch is detached). While rebuilding the bike I tried out different Bultaco levers for the foot brake, the black painted earlier ones are much fragiler as the later polished ones: But you need different spacers for the shaft to mount them proper. (Sorry for the bad capture). I manage to bent the black one with ease where the polished one is really solid and very resistant. To the foot pegs: I am still using the original foot peg position on my Bultaco and even on the SWM (The SWM also with the tiny original rests, I would otherwise have the problem of a not well placed front footbrake position on the SWM).

You can get these cables still on the continent, even with integrated brake light switch (or without). With the very strong inner cable around 2,5 - 3mm inner diameter, oiler and the solid bend where it is attached to the swing arm. Not too expensive: around 35 Euros when I remember right.

Somewhat exaggerated. The left foot brake is really better then the right one, but for the gear lever it's up what you are mostly used too.

<p><p>Femsa model 92.20-010 with 3,4 kg will fit definitely, this model is installed to my 199b from the factory, (my Bul was produced for the Italian market in August 1981).

The lighter flywheel sounds too, truly will eliminate the little break you have when picking up rev. but too will reduce the "rubber band" effect the engine have which I now after 1'5 years of riding with the bike like more and more. My be I'am getting old style ???

Yes very nice, there is one thing that does look somehow too modern in my personal view (or not matching too well). This are the rubber tune protectors for the stanchions. The standard dust covers look so much better ( in my personal view). Beside this very personal thing perfect, looking forward for an update !!!

Sort of cool to store the bike in the in the bedroom . my better half would chance my life dramatically (to the worse) ... if I would do or only attempt to do so.

The Femsa unit (rotor) is The lighter then the Motoplat unit. At least the models I know: Motoplat (210.20-001): 3,7 kg, Femss (92.20-010): 3,4 kg. As I have heard so gar from other riders there are no benefits from using the elevtronical system in comparison to the magneto system beside that the electronic system is maintaince free. If your original system is still working proper I would save the money for other useful stuff. To the Electrex ignition, here I have too heard about issues about their reliability, especial for older MX and Enduro bikes. Just my 0,02 € opinion.

May be a bit stretchy what about timing. The timing of the ignition could have been changed and was not perfect adjusted when you got the engine? With a bigger gap between the points due to wear you might now have the right timing? This would be an explanation for the better power delivery. BTW.: I have ridden once the 240cc bike and in this short experience with the ride I recognized that the 240cc engine is a little bit more lively then the 280 in low to mid revs, (it was a short ride).

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 ?