You say "I'm inclined not to think it's a 125 with a Sherpa engine".
Yes, you are quite correct. What I meant to say was you have a 125 Alpina with a 250 Alpina engine - apologies. In basic nitty-gritty essentials, that's a model 80 Sherpa.
I note your bike also has a later swinging arm with trailing tensioner - an improvement over the earlier type.
A long time ago (pre internet & access to online info.) I also bought a 250 Alpina, believing it to be a Sherpa..........
Your bike is an Alpina 125 with a Sherpa Alpina 250 engine. The tank/seat unit is Alpina. Sherpa tank/seat unit is very similar, but slimmer and with shorter seat.
Front mudguard bracket is a Sherpa item of approximately the same vintage.
Gearbox internal ratios would differ from those of Sherpa originally. Exhaust silencer originally would have been mounted lower inside frame tube (where it wouldn't burn your calf or set fire to your boot leg) on both Sherpa and Alpina.
Change the tank/seat and the gearset and virtually you have a model 80 Sherpa.
Why not clean the existing tap ? Beneath all that green-coloured rubbish in the slotted part of the tap (shown in the lower part of your pic.) you should find a fine mesh screen. Wash it out/ blow it out with an airline, if available. Try using a carb. cleaner aerosol, maybe.
If the leak persists, check that the gearbox breather is clear. It's a small hole high up on the left crankcase, just forward of the fixed end of the kickstart spring. If this hole is blocked, some have found that this can cause an oil leak from the gearbox or worsen an existing one, especially when the motor gets hot. (The air inside the gearbox will expand with heat, and it has to go somewhere, I suppose..........)
On this 199 engine I've pushed a piece of wire into the breather to make clear its position :-
You need to find a way of locking the engine/stopping it turning, Put it in 5th./top gear and apply the rear brake hard while attempting to loosen the locknut.
My parts does say my frame number (9077) uses the bushing.
The spacer in reality is narrower than it appears on the drawing. The frame bracket provides an ideal "chute" for the spacer to roll down and out (to get lost) when the bolt is withdrawn.......
Without the spacer, tightening the bolt will possibly deform the frame bracket and makes the bolt likely to come loose.
On 3/16/2022 at 7:32 AM, carl ekblom said:
199A head steady is not a good design.
.......and can give trouble even when all fixings are tight.
When you fit the head steady, make sure that the spacer #138.10 - 119 (no. 39 in the illustration) is in place on the frame fixing bolt , otherwise it will not tighten correctly. This spacer is easily lost.........
Holes in the pistons are one part of the booster ports, the other part being the slots in the cylinder liner. You need these if your engine is to perform as Bultaco intended. First o/size Mahle piston :-
The hat shaped sheet metal caps you refer to are oil baffles/deflectors (Bultaco called them "oil breakers") ; AIUI their purpose was to influence the amount of oil coming out the top of the damper tube. You appear to have non-standard dampers, and I can't see how the caps would fit, but who knows ?.
Based on my experience with these engines, your main area of concern is likely to be the crankshaft assembly and its bearings and seals, and piston and bore, rather than problems with the gearbox. These tend to be reasonably robust, although possible weaknesses are covered in feetupfun's post.
Did you use heat when dismantling ? Difficult to see, but from your tenth picture it looks like main bearings are possibly loose on shafts........
Are you in the UK ?
Don't worry about being quite young and lacking experience - we all were once !
After looking at the outer cases, they are pretty hammered,
Pics. ?
Unless they are damaged beyond saving, you may be best off cleaning up the originals. Cracks can be welded. The primary case is usually thick enough to get away with a fair amount of filing/grinding. Failing this, as Bloomfield states it is the same as fitted to various other models.
Not so the mag. cover, which is quite thin and fragile in comparison - and probably also the reason that it's in very short supply. (you may be very lucky to find one that's any better than the one you have). It was also used on a smaller range of models - (for Sherpa range, 198/199 A & Bmodels only)
This is a TRIALS bike, and most trials riders would expect well-tucked-away controls, to reduce the possibility of accidental operation or snagging on obstacles. The brake pedal you have appears to be a version of the standard l/h fitting ; the original version of r/h pedal offered by Bultaco was equally tucked away, but unfortunately also provided a less usable brake.(see responses above). For comparison :-
The Spanish pedals mentioned are very nice, but you may also want to consider something a bit less eye-watering, price-wise :-
It's your bike and you do what you like with it, but my personal feeling is that your views may change once you have ridden it a bit. Good luck with whatever you decide.
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Alpina with Sherpa parts?
in Bultaco
Posted · Edited by lorenzo
You say "I'm inclined not to think it's a 125 with a Sherpa engine".
Yes, you are quite correct. What I meant to say was you have a 125 Alpina with a 250 Alpina engine - apologies. In basic nitty-gritty essentials, that's a model 80 Sherpa.
I note your bike also has a later swinging arm with trailing tensioner - an improvement over the earlier type.
A long time ago (pre internet & access to online info.) I also bought a 250 Alpina, believing it to be a Sherpa..........