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bmwblake 12-04-2011 10:57 AM

Reviving a Bultaco
i picked up a 1979 sherpa t 350 from a local rider and fellow adv guy. it had been sitting around his place and wasn't doing him any good, so i thought it would be a good candidate to distract me over the winter. i know nothing of trials bikes or bultacos so i'm sure this will be interesting.

here's an old pic from the PO:

and a pic as she sat last night:

i finally got the giant nut off that has to be removed before you can insert the flywheel puller. it was stuck in a grand way.

last night i was able to clean up the points and get a clean spark. now i need to tear into the mikuni and clean it up. i have good spark but a good round of kicking with the choke engaged leaves me with an overflowing carb and a dry sparkplug.

here's the goody shelf. the tank looks great except where the petcock mounts. i have some ideas for replacement tanks, but i may try and salvage this one first.

Brunow - 007 12-04-2011 12:13 PM

Neat little bike! :D

Cordless 12-04-2011 12:23 PM

On the tank you can sand it lightly and restore the color. Once it's smooth and regular, apply any fresh decals you can find. Then use a sealant to keep the color vibrant. If you don't have a sealant at hand, use Mop-N-Glo or some such floor product. Works fine and lasts longer than you might at first think.

PSchrauber 12-04-2011 01:14 PM

Very cool, at least .. first more modern Bultaco Sherpa (should be a 199 or a 199A) rebuild coming up ... very pleasant!

I'am also rebuilding a 199, (later B model).

To the gas tank, this item is made out of Polyethylene, (PE), any coating on this very flexible plastic is difficult,
but not impossible. As gas tanks from this model wasn't painted I personal would go for a very well clean up inside
and outside leaving it first as it is. Later one you can thing about what to to if you get the petcock problem solved first. (There are replikas available in PE and glassfibre.

(Normally new O-rings and a little bit bigger screws will do the job for getting the petcock thight again.)

Cleaning the carb is a good first go, as residues from gas gum f.e. can clogg the carb internal ducts and jets,
you might take a look inside the gas tank and the petcock too.

The mentioned Mikuni was not standard, they where fitted with a BING 84 type by-pass with 28mm.

Sherpas need a really good spark, good plug, good points and a perfect timing TDC.
gap point: 0,4mm
timing: is between 2,5 - 2,7mm before TDC,
plug: #bosch W145-T30 or Lodge CLNY or Champion UN-12y or N-12y.

Very important for a good start is a free and clean well oiled airbox/filter.

Something to check out, the clutch, (all steel plates!) and primary runs in own oil, really good synthetic ATF is recommended by practical experience, or for first check out: 300cc SAE 30, (clutch might feel slippery with SAE30).

The engine with its, huge rotor, extra flywheel and heavy crank is a real tractor, feels a little bit sleepy but with tons of torque just above idle, the engine does not like high rpm.

Gearbox has own heavy duty oil, 600cc SAE 140!

Looking forward to any progress!

bmwblake 12-04-2011 01:21 PM

thanks for the tips on the oil. i've already done new oil all around. it was low on the clutch when i got it home.

the issue on the tank is not one of cleaning up or sealing. the threaded insert stripped at some point. somewhere along the way a previous owner tried to fix things with JB weld and some countersunk nuts. i'll have to get some pics to explain it better. my thought was to get an aluminum brit tank of some sort and strap mount it to the frame.

the air filter is a uni and is clean and oiled. i knew the mikuni wasn't stock, that's why i wanted to mention it.

also, this isn't going to be a restoration. my goal is to get it running well without spending 4k on a 2k bike. :rofl

PSchrauber 12-04-2011 01:50 PM

Gas tank:
Countersunk nuts are a bad gas tank repair, the aluminium tanks are good but can get buckled easy.

If the brakes don't work very well, look inside if the chrome plating of the drums in the hub are still OK.
If not you need to mount steel inlays, (no easy job), maybe BultacoUK will swap the hubs, (they had this service).
The brake linings also might have got harder, fresh ones, (grooved!), will improve breaking a lot.

Yep, I would yours - if I would own it - get running very well and use it for twinshock trials, (pricing btw. depends on how complete they are, (bolts, nuts, washer, ... still original, bultaco made their own), all electrical stuff, attachments present, ... if they are also contemporary modded and last not least it depends too which model you have, a six speeder f.e. are rare and 175cc are very rare), this can in combination get the price up to 6,5 - 8,5K GBP.

Anyway it's good to hear that another Sherpa is saved again.:clap

One Less Harley 12-04-2011 02:10 PM


PSchrauber 12-09-2011 11:25 AM

Bumped it up and is there any progress?

bmwblake 12-09-2011 05:17 PM

i rarely get any bike work done on weeknights. this weekend i plan to pull the carb and start cleaning.
thanks for the nudge.

bmwblake 12-17-2011 11:48 AM

last night was a big night. i spent a good bit of time cleaning all the jets and other grimey spot on on the carb. somewhere along the way i'd taken off the muffler to start cleaning it. i had little confidence that the bike was going to start so i didn't bother putting it back on before kicking. i engaged the choke, and then with a few good kicks and a small splash of starter fluid she fired right up and probably woke the entire neighborhood.

next step is to get some more ethanol free gas and mix up some more fuel. i also need to work out a fuel tank. i'm leaning toward finding a brit tank from a b50 or similar that i can use a post mount. anybody have one lying around? i could also stumble across a blue bultaco tank from 79 or 80 but i think the bike would look better with an alloy tank.

no pics from last night, sorry.

PSchrauber 12-17-2011 02:24 PM

The original one, in plastic as you have is still spot on and the very best for riding too.

Any other tank from a different brand/model will NOT fit together with the original seat and might disparage the waist of the bike which is one of the main characteristics of this bike.

The earlier alloy tank will probably fit but is not as cool and as useable as the plastic one shown on this model 199A:

A greater production run of replicas of the plastic tank has fortunatly been made, these are in the same good quality as the originals and you should get them also in the US, costs are not more then a really good piant job.

bmwblake 12-18-2011 08:59 AM

i talked to a local vintage trials dealer and he indicated that he'd seen a lot of fitment problems with the repro tanks. do you have experience to the contrary? i'd hate to spend 300 bucks on a tank that doesn't fit well.

i can probably get an alloy tank for half that, but my aim to eventually sell the bike so i don't want to bodge it together and it not look nice.

PSchrauber 12-18-2011 01:01 PM

I don't know from where the replacement gas tanks your dealer mentioned came from.

Mine fit very well, as it is a fiberglass unit the rubber spacers holding the rear side clearance of the tank has to be reduced some mm on each side and the in the rubber spacers holding the gas tank in the front, (where the bolt goes through), has to be broaden some mm on each side. there is no shortage to the full steering lock! So I assume the fiberglass tank to be exactly identical to the original, the walls of the tank might be a little bit thicker on the inner
side as original, but else fit extremly well. I can post some pictures if you want, (warning graphic content, I already said that I' am stuck to Bul's).

I've got the gas tank from Spain, another ressource as I know is UK, the plastic gas tanks, (probably the same manufactor), here in Europe as I have seen and heard normally fit spot on. The fiberglas unit has the advantage that you can paint him but the drawback to not be so resistant against scratches and more sensible to impacts.

Very important to use/get the tank with the right logos and emblems:

To the plastic tank the logos should be printed on, to painted gas tanks Bultaco used transfer pictures, (shown below),
not decals (shown above).

bmwblake 12-18-2011 01:58 PM

here's the tank that was mentioned.
my 79 has a plastic tank which to me is good. i wouldn't want to deal with a fiberglas tank due to all the ethanol in the fuel here now. i'd either have to be super selective on where it get gas (i usually am) or spend time lining a brand new tank.

PSchrauber 12-18-2011 02:52 PM


Originally Posted by bmwblake (Post 17542911)
here's the tank that was mentioned.
my 79 has a plastic tank which to me is good. i wouldn't want to deal with a fiberglas tank due to all the ethanol in the fuel here now. i'd either have to be super selective on where it get gas (i usually am) or spend time lining a brand new tank.

Look a little bit expensive to me?

Here the ressource from Europe:
(go to Bultaco new parts, then tanks & frame parts)

Next ressource from Europe:
(scroll down and go to: Depˇsitos trial plßstico y fibra)

There are some other ressources in Spain too but they don't talk English and will seldom reply
on foreign E-Mails, so I skip them here out.

By the way I don't use anly normal pump gas for my old bikes nowadays as it not only contains ethanol which we also have in Europe (up to 10% you don't get any pump gas with less them 5% now).

I use Swedish made Aspen gasoline which is based on alkylate, naphta and benzene, available up to 100 ROZ,
they made this stuf for two stroke forest engines like chain saws, due to their enviroment regulations.

This stuff is really etahnol free you can store it in years too, it burns nearly soot free and it is even not so harmful for the enviroment. The standard stuff does not work for competition motorcycles but they do have what they call Aspen R R= racing this workes very good, backdraw is the price which is twice as much as we pay here for pump gas.
But as you will never have issues with:
- gas gum,
- the storability,
- enthanoland
- any dissolve rubber, plastic ore fiberglass parts.

It's worth the money IMHO as I don't use the bikes so often and the consumption is very low for trials bikes too (compared to other twoństroke dirt bikes).

Forgot the ressource here:

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