Bultaco Sherpa 175 Salvage by Rob Sloggett

Posted on November 30, 2017 at 9:00 PM

Take a brother, a phone call and £425 and what do you get? A box of bits and a resprayed frame!

My introduction to trials in the 80's as a schoolboy provided me with quite a list of bikes. Infact it went TY80, Italjet 50, Montesa 123, Whitehawk 200. After that I had the chance to do the odd event on my brothers Fantic 240 and Beamish 325. He did have one of the last Bultacos but I can't remember riding that in a full competition (althought I think I did ride it at an arena trial once).

So where is this going? Well getting back onto twinshock with Aqueduct I have tried a few bikes. Started with a Montesa 348 but it spent more time not running that running and the spares were getting hard to track down. Then a Beamish 325 came up and I quite enjoyed that but it was a bit heavy and to powerful for my short, slender frame... Ideally I would have loved another Whitehawk 200, by far the best bike I ever owned but they are quite rare now so a phone call from my brother one evening peaked my interest. He had bought a Bultaco Sherpa 175 from a guy at Bath MCC and had started to restore it. The frame was painted with primer and then a white top coat (not original colours for that bike but he was trying to match it back to his last Bultaco). He did not have the space or time to finish it so wondered if I wanted it. He had paid £425 with it in bits and just wanted his money back. It sounded an interesting opportunity and a smaller 175 put me back in the Whitehawk / Montesa 123 range which were my favourites. The clubman and inter routes at Aqueduct do not need large capacity machines so I went for it.

To be honest, it did not need much. Yes it looks like a shed in that it still has the original paint on the tank and fork legs so it looks "aged"  but everything was there. So what was the rebuild process?

Well the starting point was an electronic ignition. I am not a fan of points and condensors (the Montesa taught me that) and if a modern electronic ignition exists I see that as a good way to eliminating DNF's. Luckily both InMotion and Electrex could supply one for the 175 so that was quickly purchased. The second item was a new carburettor. I had used a Mikuni VM26 on the Montesa to good effect and was able to get a starting jet configuration so whilst maybe a bit large for a 175 it gave me a starting point and if I chose to take the bike up to a 250 (as the 175 is just a sleeved down 250) the larger size may be useful. I also asked a club member who ran his own engineering business just to give the top end a health check. A new set of rings were advised but that was all.

Bolt on a pair of Rockshocks, a new set of bars, cables and tyres and then hope she fires up.

The bike has been incredible. I love it in both the size and power delivery and certainly suits the streams that Aqueduct offers in a lot of the events.

So what has happened since the re-assemble?

Well the Foel in 2016 was a bit of a turning point. Within the first 2 sections the engine note was not the same. One of those "should I carry on or stop" moments. I carried on and the bike was fine until the run into loop 3. I have never experienced a full engine seize before but luckily I was able to detect the engine note change before it locked up. Within 5 seconds the kickstart was seized indicating something serious had gone wrong. Taking the engine apart exposed the issue, one of the main bearings had come apart, seizing it on the crank. Not good and time for a full rebuild. Having spend months on the Montesa previously with the engine and working away, I decided to "outsource" the rebuild. I stripped everything down and then over to Jim to do his magic. Jim and Paul have been excellent in rebuilding the engines for me and we are lucky to have great mechanics and engineers in our club who are happy to assist for sensible acknowledgment of their time and skills.

The engine came back with every bearing and seal replaced plus the cases stripped back and polished (thanks again Jim) and a few holes drilled in the the head and barrel fins to reduce some weight. Since then I have also had Paul offer to cut open the exhaust and clean and repack it. The bike is great, I still love it and has allowed me to progress up into the Intermediate class in the last year. The challenge of the new sections has highlighted one small flaw with the bike which I did not feel whilst riding clubman and that is the finest of flat spots when running low/slow tickover elements and transitioning quickly to a climb where the throttle needs to be opened quickly from idle. The flat spot is small but noticable to the extend where sometimes you need ot feather the clutch to get it in range. This has allowed me to continue to learn carb theory and whilst the VM26 may be a bit big I am playing around with pilot jets, air screw setting and slide cutaways and slowly tuning the flatspot out. I have put the jetting below for anyone who is interested.

So whats next? Well a few thing in mind once the carburation is fixed. Bearing in mind I dont tend to ride the Kia rounds and this bike is a keeper, I am toying with the following:

1) Allow swing arm modified from a Gas Gas

2) Lightened exhaust system. I have seen two different replacements both using a Sherco front pipe. The first is a "Vesty" style where the triange where the airbox sits is fabricated into a single back box with two small exit pipes by the peg and the second using a Sammy Miller TY type mid box and rear box

Once that is all done the final colour scheme can be picked (I have seen a lovely chrome and white/red combination) and then the final bits such as new footrest, wheel rebuilts etc can be considered.

I am reliably told that their were only 400 175 Sherpas made and as a general rule they are not seen as competetive (comments such as "made for the Spanish tourist market" have regularly been read) but to be honest I don't care. I love it. When it is running right and my brain is in gear I think we make the perfect combination. Not quite up there with the Whitehawk 200 but that is never going to happen again and I am sure if I got the chance to ride one it will not be as I remember so me and the Sherpa are sticking together and lets see where we end up.

Carb Configuration:

Mikuni VM26: Air = 0.5, Pilot = 37.5, Main = 130, Needle = 5DP3 (middle), Needles Jet = 182 O-8, Slide = 2,

A permanent work in progress!

I know she looks tired and one day I will get around to giving her a full restore but at the moment the focus is keeping her in a condition where I can ride her regularly.