I bought the piston for my TR34 from Wössner in Germany, I gave them the used one so they could fabricate a custom replica. Wössner did then also the coating of the cylinder all in all it was then very priceworthey. The piston came with upper piston pin, roller bearing, piston pin clips and piston rings.
Wössner does cylinder coating only if they can reproduce the piston too!
To me it sounds that some of the incast electronic items are beginning to failing, that is something that happens especially to electronic ignitions when they get older. I had this issue with SEM and with Motoplat ignitions which could be solved by replacing the electronic parts. Or you buy a brand new one, powerdynamo have one when I remember right.
I would enhance diameter of the tube to around 25 - 30mm, then a holetube connection between them, then I would fill up with void with insulation for two stroke exhaust.
Close the box again but as such that it is easy to take apart for cleaning and replace the insulation.
Then you should have a bit better performance without more noise, much more effect would have a bigger exhaust volume in general..
On Bultaco ignitions, the spark should be a super bright flash!
Try to locate the timing with a multimeter with inbuild "beep" for connection and disconnection of wires, then use a mm gauge for finding OT and measuring distance of spark before OT.
That is IMHO the easiest way to check the right triming.
You want to check too the distance of the points which should be precisely 0,4mm, more then 0,1mm off and the ignition can fail to deliver spark.
Bultacos are a way more reliable then Montesas, Montesas have issues here and there.
Ossa's do well if once rebuild properly, but to get the parts is a problem, while Bultaco parts are easy to get, second best is Montesa.
Try to get a runner wich is in very orignial state, These are best, even if a bit more expensive you pay around 4 times as much for a replacement spare part then to a part bolted to or on a bike!
And no the answewr to the silde repair,
I would suggest to try out to use metal kned which has the properties of Aluminium.
ToDo:
1. clean the slide,
2. the Surface where you want to apply have to be rough, (Dremel)
3. clean the surfaces again from any oil,
4. kned the two component of the metacl kned,
5. allpy where in need,
6. mill and grind away excessive material, (the properties are like aluminium).
Parts for bing carbs have got very difficult to get that is true!
And I know your dilemma, have gone through that by myself, what I did was get i functional Bing and a second replacemnet with better habits (Dell'Orto PHBH) for riding, now I can go back to the route of the original path in need.
If you are interested I can give you (via PM) a ressource for Bing carbs which can sell you a new slide or even a brand new Bing carb either from German production (expensive) or made under licence in Spain with 28mm, albeit the last ones have the fuel supply on the "wrong" side other than that 100% original.
There are guys in Germany that make slide out of brass to the Bing carbs of their twinshock Enduros and MX bikes here with enhanced design for better air flow and too to have more weight as more weight the slide have as less flutter will happen.I can proviode you with their adresses too, but that production will take time ...
Last not Least the mentioned 28 or 26mm Dell'Orto even wih Malossi transparent plastic bowl is time correct, with 26mm the bike rides very good, with 28mm more agressive.
Announcement of te Malosse plastic bowl in 1981 (mounted on a Dell'Orto PHBH):
Be careful with the long front bolt, if its rubbing / tight to mount, it will wear the tank causing leaking.
Yes very important, thus there are special rubbers for the bolt with angeled surfaces to follow the tank distributed from Bultaco, you should get them through InMotion or other Bultaco spare parts distributer.
The hard chromed stanchions with a slight grind have the best properties depending sticktion, smoothness, beeing gas and oil tight, durability and lubricating the seals.
The same system is used to ecxcavators and their hydraulics.
The slightly grinded surface of a fresh cromed stanchion offers an oil film which gives the mentioned advantages.
With the time the stanchions get "polished" and will loose the oil film thus have more sticktion, will wear the seals faster and is not as tight.
Thus I personal recommend steel stanchions with hardchrome and a slightly grinded surface over aluminium ones with fancy coating and chemical etching.
- after the engines smells burned are may be the crank seals not proper sitting thus gear oil get burned.
- ignition is set correctly,
- less oil 1:50 is very good and sufficient, then oil with low burning point, also best fuel you can get with as little as possible ethanol.
Depending how you ride you might go to a hotter plug as the engine might not produce as much heat you neet to start the self cleaning process, thus I would recommend to try a hotter plug (carefully), I have had great experiences with hotter plugs (going down from NGK BP 5 ES to NGK BP 4 ES to my Sherpa and my SWM TL.NW) which now work proper for years while the colder plugs had to replace frequently, the named NGK is too without internal resistor which helps too.
I can state my empiric observation that there is no rule, sometimes the wheel bearing last "for ever" and sometimes the got bad after a couple of rides.
I have used OEM, Aftermarket, NoName and first class industry standard, all the same.
Original handlebars where made out of steel with an extra bar in the middle.
That was the standard set up for mostly all bikes back then and guess what these handlebars where not heavier the the aluminium bars of today I still have some steel ones from Bultaco, Italjet, Montesa and SWM (which was for the export bike model TL.NW yellow at the MK II from 1980).
The simple PRO Version with one air cartridge in one side and a couple of springs in the the other fork leg is good but two cartridges is much better, believe me, I had ordered the PRO version with one cartridge and wasn't pleased in comparison with the two cartridges version for both fork legs one, which works so much better. (I have now three HFS Systems mounted all of the are double cartridges systems now).
Standard chains are good, if you have to use half links ISIS or Regina should be considered as these have half links.
The ISIS half links due fit in my experience also to DID 520 ERT2 chains which I chooses mostly due to their very good performance in tensile strenght (and so little wear) but still are OK in weight, (under 6 pounds). There is just one chain better in tensile strength which then again is 7 pounds or 15% heavier. For a Chart of tensile strength see here: http://www.didchain.com/chainSpecs.html
I would NOT use any kond of O or X ring for dirt bikes if you are using them also in weat, muddy and clayish enviroment, the fine sand will eat up the rubber rings in only some hours.
* half links:
Very important if you have even numbers of sprockets front an rear, especially front!
Points and the point gap is a common issue depending Sherpas.
- The point gap should be 0,4mm exactly not more not less,
- The points should be in very good condition too.
The new points made today are not as good anymore as the old ones, try to get NOS. Here especially the material of the small metal bit's pushing against each other seems to be much softer nowadays then before in my experience.
Trial hiking I do a lot especially in the Alpes, the Italian calls it Motoalpinismo, sadly the possibilities are getting limited, but it makes a lot of fun also with old machines.
I had good experience with Woessner, who made the piston, rings, piston pin and also did the cylindercoating to my TR34, all in all verý convinient and cheaper as if it would have been done separatly.
I now can get through my engine workshop spare rings just by sending them the batch number, (I refer to German Woessner here…)
Yep they have an effect to the bike makes it a bit snappier, most effect you will get by using carbon fiber ones, be aware of replicas sold one E-bay for cheap not made by Boysen of bad qzulaity (I suggest not to use them). THe backdraw is price and they do wear not fast but after 500km on the speedometer mine had a bit fuzzy ends when looked ap through mangnifying glases.
What is also a good idea to improve performance and so have more effect then the Boyesen:
- using the cage and reeds of the TY250, (a bit of miiing is needed)
I think that was a rare incident where someone was rushed into high bidding during an auction.
Anyway a very complete bike and in very well technical status with bike registering and history will get good prices.
And when you look a bit closer now bikes in original status even with patina are going straight up because restaurations are easy made but original paint and plastic can't be restored just right preserved and that the complete bike live time thus here the highest prices will be archived.
Yep would get a antifreeze tester and test to how low temp. the coolant can go. The other method would be to get the bike from one warm place to the other to put some movingblankets around it, as a two hours route will not cool it down too much in a closed trailer. When it is an open trailer I would definetly mix the coolant to be valid for these low temperatures.
BETA TR34 PISTONS
in Beta
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I bought the piston for my TR34 from Wössner in Germany, I gave them the used one so they could fabricate a custom replica. Wössner did then also the coating of the cylinder all in all it was then very priceworthey. The piston came with upper piston pin, roller bearing, piston pin clips and piston rings.
Wössner does cylinder coating only if they can reproduce the piston too!