Basket Cases

[David Lahey]

These old shagged KONI shocks were on the silver frame bike. I've not seen that type of spring retainer or preload adjuster on Special D KONIs before. The half-circle spring retainers are made of zinc and the preload adjusters are made of steel, so I'm guessing they were not trying to make them particularly lightweight. Does anyone know what era or application those KONIS are? They are 320mm long

[Greg Harding]

Hi Everyone,

The front downtube has a curve near the bottom. Trouble is that on some other model Bultaco Sherpa T frames there is a deliberate curve higher up in the front downtube, and there are also plenty of Sherpa Ts that have crashed head-on into solid objects, causing curves where there were none previously.
At first I tried to imagine how a bend like this could be caused in a crash, because if I could work that out, I would know where else to look for other damage bends, and would also know how to get the frame back to original shape. I couldn't imagine how any crash could do what I was seeing, then remembered that I had just bought another M80, and did a comparison.
I'm now pretty sure it is meant to have that curve in the bottom end of the front tube, but would be happy to hear comments from people who can contradict or support this. The top frame tube is straight and the rest of the front downtube is straight. The front gusset is completely flat

David, I think the solution to your question is parked in your bike shed ! A lot can be learnt be looking at the evolution of anything and yes things can be similar in appearance because they have been copied. Alternately if a design works, let's try and refine it or adapt that idea for our purposes. How much does the M80 frame weigh?
Now back to the solution, my M49 series 3 frame (pretty much same as M80) has the same curve at the bottom of the down tube. Check your earlier M49, from memory the down tube continues under the motor with a big radius Bend? Is it possible that BULTACO continued using pre made downtubes in their jig and cut the bottom off for the newer style frame Bottom?
Twisted fronts of frames seems to turn up on all makes of bikes, here is another example:

1440320983935.jpg (125.14 KiB) Viewed 3527 times

Anyone recognize It?

[David Lahey]

The compliance plate tells me it is 1976 or later, and the frame piece that joins the sides of the rear subframe also looks like post-1975. The seat hinges make me think japanese trail bike. That weld up the centre of the headstock is very distinctive but I can't remember where I have seen it before. Front engine mounts and single front downtube look like Suzuki. I'm going to make a wild arsed guess and say Suzuki TS250X

[David Lahey]

David, I think the solution to your question is parked in your bike shed ! A lot can be learnt be looking at the evolution of anything and yes things can be similar in appearance because they have been copied. Alternately if a design works, let's try and refine it or adapt that idea for our purposes. How much does the M80 frame weigh?
Now back to the solution, my M49 series 3 frame (pretty much same as M80) has the same curve at the bottom of the down tube. Check your earlier M49, from memory the down tube continues under the motor with a big radius Bend? Is it possible that BULTACO continued using pre made downtubes in their jig and cut the bottom off for the newer style frame Bottom?

I thought of that, and compared the series 1 M49 frame. The series 1 M49 front tube is dead straight until below the front engine mount. They really went to town when they made the later series M49 frame, getting it tucked in beautifully close to the engine casings

[David Lahey]

Looking at that photo of my M49 just now, I'm now wondering if the M49 motor will fit into the M80 frame with that old style magneto cover on it. I think the clutch cable mount might interfere with the frame tube

[David Lahey]

Every now and then, while no-one is looking, I get to escape to my workshop and have a great time. This afternoon's fun involved flames, lots of clamping-down and big levers, and I ended up with a straight Bultaco M80 frame and a fair bit of burned-off paint and gunge

[David Lahey]

Here are two photos taken by brownie of his beautiful series 3 Bultaco M49, illustrating that the later M49 frames have the same curved front down tube as the M80 frames

[JC1]

These old shagged KONI shocks were on the silver frame bike. I've not seen that type of spring retainer or preload adjuster on Special D KONIs before. The half-circle spring retainers are made of zinc and the preload adjusters are made of steel, so I'm guessing they were not trying to make them particularly lightweight. Does anyone know what era or application those KONIS are? They are 320mm long

Dave that style Konis were common in the early 70s, same ones used for dirtbikes as for streetbikes, up to mid 70's. I think the ones with the lighter adjusters came out about '75/76 if I recall correctly.

Also I checked a couple of Bul frames I have & the M49 (series 3) & M80 have that bend at the bottom of the downtube, but the M91 & 116/138 Alpina frames don't

[David Lahey]

These old shagged KONI shocks were on the silver frame bike. I've not seen that type of spring retainer or preload adjuster on Special D KONIs before. The half-circle spring retainers are made of zinc and the preload adjusters are made of steel, so I'm guessing they were not trying to make them particularly lightweight. Does anyone know what era or application those KONIS are? They are 320mm long

Dave that style Konis were common in the early 70s, same ones used for dirtbikes as for streetbikes, up to mid 70's. I think the ones with the lighter adjusters came out about '75/76 if I recall correctly.

Also I checked a couple of Bul frames I have & the M49 (series 3) & M80 have that bend at the bottom of the downtube, but the M91 & 116/138 Alpina frames don't

Thanks for that KONI info John. It aligns with the KONIs I bought from Mayfairs in 1976 having the lighter components. I think the tool engagement holes in the seal holders are different too on those old KONIs.
About the frame designs, I was amazed the other day when comparing frames that M116/117 and M137/138 Alpina frames have so many differences to the Sherpa Ts of the same era (M91/92 and M124/125).
I'm interested in knowing if the M85 and M99 Alpina frames are more closely aligned with the Sherpa Ts of their era than the mid 1970s models. I had an M99 as a kid but was not into comparing frame designs at the time, more like "how can I get this thing to keep running?"
I am also interested in how similar the M198 Sherpa T and M212 Alpina frames are and will get them side-by-side eventually

[Greg Harding]

Hi Everyone,

What a FANtasTIC Trial

Congratulations Chippy for getting a KT 250 on the Podium!

My plan was fairly simple, snap photos of all the old bikes that were competing while they were in Parc Ferme. However there wasn't one, so here are photos of some old bikes that were on display:

1441102502638.jpg (107.39 KiB) Viewed 3986 times

1441102544099.jpg (181.15 KiB) Viewed 3986 times

1441102229917.jpg (170.28 KiB) Viewed 3986 times

1441102591799.jpg (169.71 KiB) Viewed 3986 times

1441102654609.jpg (191.76 KiB) Viewed 3986 times

1441102709372.jpg (155.57 KiB) Viewed 3986 times

1441102821994.jpg (214.66 KiB) Viewed 3986 times

Please help us out here with photos of the bikes that we're competing, preferably in Action?
Thanks in advance