[Kurt-Patrik Beckmann]

The Aprilia trials bikes are very nice and reliable, the quality manufactured is in an outstanding high standard.
As is the Rotax engine too, but parts are difficult to get, to which model year do you need parts and also to the engine?

I have the TXR 280, the last 276cc air cooled model of the trials model, I like it very much for Motoalpinismo as it has
such a good suspension, the engine is very powerfull but still smooth and you can still still sit on the bike too.

Sadly as it is so good made the bikes are on the heavier side. A restauration or repair manual do not existst.
I have a manual for use and parts books and lists.

What do you need? You might send your e-mail address via PM to me and then we look further.

My TXR:
https://lh3.googleusercontent.com/_5B-FnlazFNXTBii49-Ax2anIc3qwwr0hGMbxJl7V3Nb8VkBvM1gHiEw8CPDsYlCdcOTTFxXvJbd_fi31yBt_xAeD5xnDQRyOrr6yPVjcYWupOQ8DqlfjBZ689Ag5LnMNxodYxMwoNqKAVaQkCTpcL1XN-YsTNrbKnaD36hzub8UatXttUZ9uX-NtUfe6XxX2kdHRbvx9CU0zb2dyDV1mQ-IgB7nvizs5EqJu3xhlbcKiS5prJ5W4YmTrQHTuot9apGlbNLHEYBG3cbZUjbCJ5ZWNZd6jpHJVCBxUQ91keAGTmSbajJyUdfmLwmyB_LN9eyCHeTRcrpq0XabaoNaeNQJ8BNx3WTWbHqgk0ie06b132AbK0sE_xGsNbR2q-rfvb39M2YbR-VTABZxeexcjjU2ayCLQYU3Uw4rG1CrpuTjXkm6lnBWnvasxKAYpZjDY1YLcd8SVcHbz8RQBom1yGWxX5FtKqt0CldxVJcanwlMnrZ-OW1Al14diAznGxQ6Z5ZU2l_cwkKPJ1PHfoJvJqIDPUuX88YUq0LPaYcJ1zyNINVViWsxF4L2XmG86tP2sjHTUZgvio-aGfDOsN0Z2meC93IJ5DOdyb6pj4ciY1BGz63d8Ssni95WxghY7fqx3Ot1Bv3YnVA557K92AR5dKSeqzHONLS9cjDID7qoBDd5anM44EfzHBUyp2EnA-xNuv-Ioq3HXil4eC635qOot7W2=w743-h418-no

[Kurt-Patrik Beckmann]

Cierto, gracias por la rectificación. La Jumbo ya llevaba motor de láminas, no de válvula rotativa.

Los modelos de SWM fueron
– TL 1977 (blanca/roja con chasis rojo)
– TL NW Guanaco 1980 (amarilla con chasis negro)
– TL NW 1982 (amarilla con chasis azul)
– Jumbo 1983 (amarilla con chasis azul, modelo nuevo más grande) aquí unas fotos:
…

The first yellow model made in the late 1980 is named SWM TL.NW Guanaco, (I have one with registration papers!).

Otherwise very correct, the SWM Jumbo is a Jumbo too much power,
it is considered to be the twinshock trials bike with most power build.

The Jumbo trials bike got few because the engine is so powerful the trials bikes where
canibalized so the engine could used in the Enduro models by many Enduro riders.

[Kurt-Patrik Beckmann]

Puede ser reconocido por los documentos de registro / importación y el número de serie.

Todo hasta octubre / noviembre de 1981 es todavía de la producción original, a partir de 1982 vinieron de los pasillos de Derbi.

[Kurt-Patrik Beckmann]

The Plumbing unit:

The redone Airfilter:

My TXR:

Attachments:

• WP_20160102_16_51_12_Rich__highres2.jpg
• WP_20160423_17_14_35_Pro1.jpg
• WP_20171030_14_58_40_Raw1.jpg

[Kurt-Patrik Beckmann]

Hi that looks not good.

I respond in English, I can not speak or write Spanish, I do understand some … but writing …

Anyway the ignition is NOT original to an air cooled TXR it is something different it seems to me you have an ignition module of the Climber.

Check out the timing, it should be after the maintaince book fpor the 277cc model 2,5mm before TDC, (so really early)!
(If it is the 240cc model just 2,4mm)

The other problems of the engine,

1st (Disc): If you have problems with the disc you can hear that then the disk is sliding against the case making bad noise.

2nd (Weird Plumbing): Only the TXR has a plumbing (tubes) attached to the crank case underneath the engine and then through a bottle connected to the carb and the air filter. This item drains the crank case from gasoline as the older engine has no drain screw attached as the earlier models.

If the tubes are damaged you simply have a hole in the crank case and a bad running engine,
If the «plumbing» has been taken away the reminding hole or tube might not be sealed.
I still have that unit and replaced the tubes it now works great in my experience

3rd (Air filter and hose to carburator) The airfilter might be clogged also the hose to the carburator damaged, it is very importand to have an filterfoam that is very light oiled and a filterfoam is in very good state allowing much air to go through.
You might replace the foam, a bit tricky but very important. Also any cracks in the hose should be sealed.

4th (Rubber boot to engine), that rubber can have deeper cracks which can too lead to additional air or extra gear oil thus should be replaced if old.

5th Old style plugs without unbuild resistor are also important, the engines run better with them.

All in All a great bike, when it runs one of the most underrated air cooled monos, I don’t know nay bike air cooled mono bike with better suspension an smoother but still super torquey and powerfull engine, surplus the engine is too super quit, actually the quitest trials bike I have.

[Kurt-Patrik Beckmann]

Here a photo of a CZ ridden at the Scottish Six Days in 1962 I think:

Here a bad copy of an advertising to Jawa bikes of the 1955 Scottish Sixdays with the female rider:

I think the Czech as the East German two stroke was so good because they still did big research to get better engine design, thus they where so good engine wise. The chassis had some backdraws but the engines very good indeed.

Attachments:

• IMGSchottischeSechstagefahrt_Seite_06.jpg
• IMGSchottischeSechstagefahrt_Seite_25.jpg

[Kurt-Patrik Beckmann]

One of these CZ’s they run really very good, (from 1963 a 250cc) at the Hanse Classics in Lüneburg:

The other an Indian used as a trials bike, very heavy but rides nice, here at the Fourstroke Trials in Brockhöfe:

I tested one, a 200cc from 1963, part one:

Part two:

Kickstarter is super cool or «Total Irre»

I have seen Volker with his Indian last time in Hergenroth July this year, since then not but he is very often at the Hanse with his Indian most challenging thingy is the hand shifter, brakes are there but not really in need. I haven’t ridden since then and right now too much office and preparation stuff… no riding :(

Attachments:

• Indian02.jpg
• Indian01.jpg
• CZ250.jpg

[Kurt-Patrik Beckmann]

Uuh I was completely wrong, excuse me.

But to the light there is contemporary fix, you can look a the Italian Proma fanalino trial.
This rear light was made in the from the beginning to the end of the eighties and is unbreakable.
Thus has been used by many riders an all twinshocks and air cooled Monos of that era fitted with lights.

The unit is made out of rubber and has two lights, one for the rear light and the second for the brake light.

I have them fitted to most of my bikes, they show up sometimes here and there, see in the attachments.

Attachments:

• PromaMontesa.jpg
• PromaBeta.jpg
• PromaSWM.jpg

[Kurt-Patrik Beckmann]

The rectangle model is better then the tobacco purse also better then the banana shaped muffler that came in between.

The bigger model offers more voids and is more effective to reduce noise also it doesn’t restrict the fumes so much getting out.
If you look at the diameter of the tubes that transport the fumes to the outside you see the difference.

The more inner space and too the more chambers allows a less restrictive airflow of the exhaust fumes inside the rectangle model then with the other models.

In case of design the later model is so distinctive to the Bultaco Sherpa I wouldn’t change the outer form.

[Kurt-Patrik Beckmann]

No that is sadly not my bike, it is still in the hands of the son of Wolfgang Trummer,
the former rider of the bike in the eighties.

These where works bikes and never sold to public.

I think two one stayed in Austria and the other went to Spain as far as I know, Trummers bike has to
a fork without springs and some other features made by Trummer self.

[Kurt-Patrik Beckmann]

In my opinion much better this model tan the JUMBO SWM..

The Jumbo is a bike for heavy riders which have and need much power,
to me the engine of a Jumbo is still one of the most powerfull trials engines I ever ridden.

The Enduro guys take this engine and mount him to the Enduro models like the RS 440 GS and others,
unchanged!, that’s why so little of the Jumbos are left.

[Kurt-Patrik Beckmann]

Very nice bike I have one too, very original beside three things I changed so far:
– I replaced the original working Girling rear shocks, because they are not easy to repair in case of,
– I replaced the Marzocchi fork against a original SWM Betor fork as Burgat did,
– thus I had to replace the front mudguard and the mudgard holder with the brake plate holder, (all three NOS).
– the clutch has the internal 11mm ball fix from the Enduro modles which improves clutch,
beside this complete original and road registered, the engine is completly rebuild.

What is a bit different to all other trials bike I know of:
– the engine is very smooth and has very much torque in low revs,
thus engine is prune to stall, you can put in firstgear in when idleing and the bike moves forward ,
– the engine is therefor not very lively like a 199b but easier and also much more precise every mm of throttle change the motor rev.
– With the Betor fork and the MArzocchit triple clamps/yokes the steering is better and the tendency to push the front wheel is gone.
– the sond is great!

The bikes performs best when ridden old style.

Attachments:

• SWM-ToDoTrial01.jpg
• SWM-ToDoTrial02.jpg
• SWM-ToDoTrial03.jpg
• SWM-ToDoTrial04.jpg

[Kurt-Patrik Beckmann]

Nice bike but very rare.

Most of interest to me is the fact that the engine isn’t a rotary valve anymore and the fact that these bikes where build by Luft and Trummer thus being super light bikes.

Attachments:

• A926.jpg
• A927.jpg

[Kurt-Patrik Beckmann]

The riders back in the days made a lot of own research aa did the factorys. The suspension technologie wasn’t very well thought through. Bultaco had once rear shocks without springs mounted to the bikes of Vesterinen (he did not like them) and Martin Lampkin (he did not care so much). These shocks where proven not to be sufficient. Philippe Berlatier tried gas shocks again from Fournales which worked great but are very expensive and without the spring the inner tube can be damaged easely.

Anyway so many people had and often still have issues with the rear suspension and it mostly -even today- is a question of the right spring.

When you have sorted out the right spring everything else is easy, to try vica berge is a pain with no good result.

Thus to your classic bike asked if you can get the right spring to your shocks, if the dealer or manufacturer tell you he just have three or less of choice, then it’s not the best solution instead sufficient or average.

One of the reasons works riders tested Girling, WP, Öhlins, … Ack then and today are the big assortment of springs and dampers from these manufacturers, where you today can add some others too.

Btw. Puch had on their works trials bikes forks without springs which where reworked Betors just to add progression and save weight.

To figure out the right spring is just to record static and dynamic sag of the spring and compare them with spread sheets of proven and evaluated figures.

[Kurt-Patrik Beckmann]

Tires are important, also the rear monoshock damper, for me personally it’s the frame or chassis design that made much possible that wasn’t before, beginning with:

– steeper fork angle,
– more situated to the rear and lower mounted foot pegs,
(nearer to the gravity point of the bike)
– longer swing arm also with lower attachment to the swing axle,
too the swing axle was mounted nearer to the front sprocket,
to avoid momentum from chain to the suspension,
– compact and lower seat.

One of the bike that in my personal opinion showed all the new features in the design was the Beta TR34 with Tarres in 1987:

(The MK II from 1988)

Attachments:

• WP_20150914_0751.jpg

[Autor]

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