Depends to the "size" and the type of the rim, back in the early to mid 80's there where most trials bike fitted
with rims from Acront and of these where of type TR.
This type was the lightest rims available for the trials tire and legal for use in traffic,
back then labeled with a red sticker by Acront.
TR model rims are not manufactured anymore, instead TXR and TC type,
(back the labeled with a yellow sticker by Acront).
The measurement are made inside the rim the outside might differ and is not regulated.
Here a comparison from LoLo in Austria about the TC (WM) type rims with each cut and where to measure them.
Between the 1.85 and the 2.15 is a difference of 15%, what this difference does is that the broader gap result in
steeper tire walls and thus gives a better bigger and better foot print.
The original Acront rims with red label are super light.
The original rear rim is a bit narrow, (1.85) it would be of much more useful traction effect to use a slightly broader rim (2.15) from Acront which is now named Morad.
You can mount tubless IRC or tube type IRC on classic trials rims, these will stay on the bed and are as good as Michelin.
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Edited by pschrauber spelling issues as usual ...
There is no big differences in production manners at Bultaco for the last model.
The engine hasn't been changed between the 198a and 198b, it is the chassis that is different between the a and b model and identical between the 198b and 199b and here the same mods where done to the 270 250cc models during the production run from the early b's to the later ones as I know and have followed.
Yes a very good structured write up and apply able to all kind of carbs to which you get different jets, needles, needle nozzles and slides and so on.
The only thing's left out is determining choke, the gas valve and the float weight.
I personal had no big joy in adjusting the VM at my TY it is very costly to obtain spare parts besides standard main jets for VM carbs in Germany,
Dell'Orto is so much easier to get and much less costly (beside the slides), thus I went that route.
It is nearly impossible to get a clue what was mounted to 199b models after Bultaco went in bankrupty. From there on the bikes were build as a social program for the reminding workers of Bultaco that did not found a job after the factory had closed it doors. Instead they workes got a corner at the Derbi factory nearbywith a pile of parts to put together what was left.
I know that might sound harsh but that is how it went.
Better 199b model bikes with a good and more consistent quality were those build in the beginning of 1981 until October of 1981 as they all really wanted that the Bultaco factory would stay alive.
Parts are getting more and more difficult to get, the TXR is a bit different to the forerunner TX and too to the following Climber model, that makes it a bit hard to find parts.
I know a resource for part- catalogues and engine- catalogues to that model with explodes views and so on, pm if interested.
To the air fillter as b40rt stated build your own. I know a guy in the US who can make all kind of rubber parts, but due to the shipping costs nowadays I don't think that this a priceworthy solution but I can provide his address to you too.
(I have already thought to make a small production run too but the costs are high, as I hve to make a rubber mold too which will cost again ... If there would be at least 5 people buying each 2 then I would start ...)
The thump throttel indeed solves the problem of grip to the handlebar while riding in addition to the position of the throttle tube.
I can remind myself beeing in several incidents where a bad position of my hand while giving throttle did not support my riding and vica verce.
Here the thump throttle has an advantage. The disadvantage is in my view the adjustability and stability here I still think the standard gas throttle has an advantage as far as I have used agricultural and forestry machines with a thump throttle.
And as both exists and we formerly had thumo throttle on bikes of the ore war era and this ergonomics has vanished the question is why and why shozld it for motorcyckes be reinvented?
I personal don't like the thump throttle it is my view nit so stable, I like the throttle grip, zoo the throttle lever like a break lever or as on motorsaws the push button.
Depends what I wear, during a competition I only take with me the car keys and leave all other stuff inside the car.
The key comes into the pants pockets if I wear normal pants.
When I wear the elastic pants the key comes inside the jacket pockets.
When it is very hot I put the key inside the piggy pack.
When doing training at my training ground I don't lock anything when I ride at our trials competitions in my region I leave the key at the car or the trailer unvisible to a view.
But it doesn't prove anything. With a modern PC and software I can create an invoice for anything you want with a pretend company in seconds. What is needed is a proper registration scheme and most governments run one for road machines. Even then a lot of vehicles are stolen and sold on with false documents.
Of course a normal bill is a proof nowadays, because of the tax you and the dealer has to pay, look at the bill it's nowadays all written up and for high price items you still get _ because of the warranty - a stamp and a signature.
A stamp an an underwriting is very difficult to create by Photoshop and then you still have to put in your address as a seller too to the contract, would you buy from someone that will not share with you his identity?
This is thread/Theme not about espionage it's just about secure deal.
To other classic bikes that have no record, then set up a contract and combine the contract with the copy of the ID or if the seller will not do that (Actually he don't have too) but he has to show up a legal ID which is a ID-card or a passport and you can then check the ID/Passport and write up the number in the contract by yourself. That is proof enough.
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Edited by pschrauber misspelling if words
4 hours ago, ChrisCH said:
I fear then that very very few bikes would ever change hands. I doubt I can find the receipt for my bike and the missus' was without any paperwork off eBay. I would now be unable to sell them.
What is so difficult to save one sheet of paper? Many people have so many so in detail going advices how to handle this and that to their bikes that is near an ideology. But can't save one sheet of paper that is something I can not undestand.
And by the way especially you have very in depth going comments and demands depending bikes.
As mentioned everyone can run his household in their own way but too have to deal with the outcome of their actions or failed actions and not to blame other or the "circumstances".
Never buy bikes without any documentation or "papers" like bill of sale, even a not road registered bike had once a bill of sale with a serial number, period.
At least the diameter of the tube should not get decrease instead increase then the holetube at the beginning is not cleaned up, the self made hole tube has too little holes and will due to the curves even more limiting the fumes to get out out.
At the rear exhaust you want to get rid of thefumes as quickas possible but too get rid of the noise, you can use a hile tube and insulation as an absorber to let thefumes out while absorbing the noise here it will not happen so well because the flow for the fumes is not provided.
That new holetube is providing less area for the exhaust fumes to get out of the muffler then before and the hole tube isn't a real one either, thus I have some personal concerns.
The rear exhaust is based partly to the Helmholtz priniples with it's inner tubes and chambers these work great but are limiting the flow, they put an air cushion to the rear, thus btw. the lack of the typical two stoce sound.
To replace the old dampning wool is a good idea, a much bigger effect is provided by cleaning the holetube inside or replace it by a more modern style that is to cone shaped which will help to dampen different noise levels but can too help the engine to perform better.
There is not only a holetupe in the midle section but too in the rear section at the flat beginning up to the point where the rear silencer gets bulky, then you can too "play" with the length of the exhaust maifold wich changes behavior too very much, but you have to know what you do and the secrets are inside and hided, thus my tip is to do the math and calculations upon your needs, and too you have to try out, why I took apart the mid section from the manifold. The exhaust of my Sherpa is modified so I could keep the stamps and markings for our TÜV.
The transformed rear section:
The transformed midsection:
The transformed rear secton mounted, the mid section here original
You might ask them as I have followed news threads from KTMTalk they do custom sprockets up to 124 teeth and you can get all kind of colors holes also to different chain sizes and so on.
The "Problem is the fixing between the gas tank and the metal mount. The gas Tank is made out of PE or PP so glue does not work properly,
The only way are mechanicly by screws where there is material / wall thickness of the gas tank available or to glue the metal piece together by heat and
then melt plastic rivits upon as fasteners.
Why don't you fabricate an attachment / mount that will have the fasteners at the same position as the old ones, That is what I would try?
I have two air cooled monos and I do like them these have been and are still captable of doing advanced trials riding.
In terms of modern artistic riding they are acceptable if you are very good, but when it comes to trials riding without stopping they are easier to use then twinshock bikes and as mentioned you can use them for trials hiking very well too.
Then they look quite nice too.
Biggest problem are spare parts especially to Italian (except Fantic) and Spanish bikes.
Fantic 200 is the best option for a beginner in classic riding.
A TY mono was and is the best clubman trials bike if you like air cooled monshocks.
It is simply up to you what to choose and Yes! the TY twonshock or a SWM are nice to have too, but a bit heavier.
In modern trials riding the electric bikes are in a clubman level also not only nice to ride but too nice to have, so little maintaince and the power output is great then again so different... it will spoil any gasoline driven bike, any!
Actually, thinking about it I have some Stihl premix kicking around, and that doesn't go off. It's 50:1 mix, maybe I could try that in the old bikes when they're going to be laid up for the winter (and if they don't like it much I can drain it and use it in the chainsaw, lol)
I have some containers of Aspen premix fuel for forest machinery and too some canisters of Aspen Race fuel with 100 octane.
I have stored this fuel types several years even a decade and that storage is not harming the fuel when stored tight and in darkness.
I use Aspen with my brush cutter if you cutting brush and high grass for hours like I do in the summer then you want an healthy environment around you.
The Aspen race mix I bought for my MX 500 as that bike likes to mess around a lot with gas and oil, with Aspen no mess, no smoke and no deposit!
Rim choice
in Classic Trials
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