mcman56

I have used KBS with good result on an aluminium and a steel tank. https://www.kbs-coatings.com/cycle-tank-sealer-kit.html

2016 Beta 125 also has sealed main bearings.

I did notice that quite a few 15 mm spacers are sold for car wheels. Could any of them be small enough to modify? You could probably use something much less robust than what I did. IIRC the TL250 sprocket mounting studs are 10 mm. Modern trials bikes use 6 mm.

The drawing is not to GD&T standards but implies a circular hole pattern with a 1.771" radius and holes every 90 degrees to match the stud locations....if that makes sense. You could probably make a simpler spacer but I tend to over design. The sprocket got thin at the groove area and I wanted to support it well. If the groove was faced away from the hub, a simple flat spacer would work but you would need washers or something similar in that groove. I'm really curious what the groove is for on the 125. Could Honda sell some kind of lock washer part that fits in there? I got the chain and sprocket kit from TY Trials. Pricing was quite good but for some reason was shipped 2 day to the US which almost doubled the price. TR216 60 428 was the rear. TG314 12T (428) was the front. From what I can tell the front was a special order because that P/N is normally a 520 chain. They show a spacer as unavailable on their web site. Speed and Sport in the US also showed a spacer listed as unavailable. If I were to do it again, I would consider a 520 chain. I saw at least one sprocket company on line that still sells 12T sprockets for the 1976 XL250. They could probably supply a rear sprocket with the correct number of teeth that would be flat so the groove would not have to be considered. I'm guessing they do spacers also. sprocket with groove https://www.tytrials.com/trailandtrialsuk/prod_49834-Rear-Sprocket-TL125-60t.html

I made one out of aluminium. The sprocket was a Talon supposedly for a TL125. It was not totally flat so had sort of a groove on one side. I'm really curious what that groove is for on the 125. A drawing is attached. I did add a 45 degree chamfer on the hub side. A custom sprocket company may also be able to help. https://sprocketspecialists.com/product/rear-sprocket/ sprocket spacer.pdf

I have found that Forma is taller.

I used something similar on a DT175 with 12 volts. It came without any kind of regulator and would blow up bulbs. This basic type regulator cured that issue. We had some kind of variable AC voltage generator at work so I hooked it up to see how it worked. It did nothing until about 13.5 volts and then interacted to hold the voltage down. I guess the diode "opened" at 13.5 volts and sent excess power to the resistor that dissipated it as heat.

If I am following this correctly, the diode plus resistor you mention make what is a basic voltage regulator as used on various small motorcycles. Its purpose is to limit voltage to the lights so they do not fail. Something like this: https://www.rexs-speedshop.com/product/universal-6-volt-ac-regulator/

I already had some PB blaster on the threads overnight. With some heat form a MAP torch, they came out OK without a lot of fuss. I was surprised.

I bought a new chain and sprocket kit for for my TL250 but no spacer was available for the rear sprocket. I can make one but am seeing only two ways, neither of which is highly desirable. See picture 1. -If I mount spacer to hub and then sprocket to spacer, I will have to open up holes in the freshly anodized sprocket for nut clearance for the spacer to hub attachment. -IF I could find longer studs, I could use them and basically sandwich a spacer between sprocket and hub. However, I suspect that studs that have been in place for 1/2 century will not come out easily. What have others done? Pictures? The sprocket is supposed to be a TL125 sprocket but has an undercut on the back side. Does anyone know what that is for? Sprocket at required spacing https://ibb.co/tXpwXfJ Back side of sprocket https://ibb.co/FgMt0nQ

I don't remember the Techno but there was a CDI/ coil combo replacement for the 2008 Rev3. I bought one as a spare and still have it but have no idea if it would work on a techno. The 2008 Beta came with separate CDI and coil. https://www.hpi.be/item.php?item=CD13201

I'm not sure if this helps but I had a Techno and it was likely a 1997. I once put a timing light on it and got 6 degrees at idle, 20 at mid range and 25 to 30 at full scream. If the CDI advance stuck at full advance it may kick back. In contrast a 2008 Rev3 200 had 15 degrees BTDC at idle and revved up got 20 degrees I'm not an EE but from my understanding, an ignition with no designed in advance will give you about 5 degrees due to higher generated voltages at higher RPMs making things happen a little quicker.

Not really answering your question but I aren't all coils for CDIs similar? Could you use a pit bike coil? IIRC, there are inductive (battery powered) and capacitive discharge ignition coils and they have different resistance values. You could measure to compare. What brand is the stator?

Is there any kind of manual related to servicing the shock on a 2016 Evo 4t standard model? If not, are there any specifications for oil type, oil volume and gas pressure? I do see the remains of a sticker that probably said Sachs. I softened the fork valving and like the result so would like to soften the shock also.

Nice write up. Would this use the 60 volt DROK?

A friend has a 22 Epure and the battery status is stuck at 0%. The bike works and appears to charge OK. Is there a way to reset or calibrate? Does anyone know how this works? Is it a simple voltage measurement used to estimate % charge?

It turns out I was trying to push the rod out from the wrong location so it was not really stuck. I cleaned and polished the sliding parts. Steel plates were glass beaded and the friction plates replaced with Yamaha parts. Swapping spring locations while checking with an indicator got the plate to move out evenly within .05 mm. Clutch works great now. I suspect it was really the new friction plates that helped the most. I did polish the actuator but have never looked at another old one for comparison. I suspect that all 45 year old actuators look less than perfect.

My 2014 Factory model came with those. The parts list shows them in positions 2 & 4 of 6. There was something else different about the clutch too, maybe the hub. I could never figure out what the additional features were supposed to do. The clutch did not work any better or any worse than any other Beta clutch. plate https://trialworld.es/tienda-trial/en/clutch-trial/2668-beta-evo-factory-steel-clutch-disc.html

https://www.vmar.com/tripleclamp.html

I have had the bike for a couple of years but have no idea how old the friction plates are and am not sure what a "bad" friction plate looks like. What is the wrong oil? I have been using Dextron ATF but I think it is now called DEX/ MERC Clutch spring lengths are within 0.25 mm. I'll have to inspect plate movement when I get it back together. The basket has been filed but I'm planning to try cleaning up the fingers on a mill to ensure straightness. Friction Plate - https://ibb.co/fv3qJzk Hub - https://ibb.co/yhJrbdd

The sticking got so bad the bike would occasionally pull a wheelie when starting with clutch in.....even with a warm engine. I pulled it apart but nothing looks that bad. There is a little mark on the clutch actuator but I can barely feel it with a fingernail. I may be able to polish it out. Plates are not warped and specs in manual are met...if I can read the decimals in the manual copy properly. Steel plates had some minor corrosion in the past but had been sanded. Should that matter? The only odd thing was that I could not push the actuating rod out with a wire so resorted to 100 psi air. It looks a little dirty. Ball was in place. Pics Actuator https://ibb.co/60Q6Gs5 Hub https://ibb.co/74pXKdY Dimensions https://ibb.co/WtnFkN5 Plates & Rods https://ibb.co/pQTpTVd

I gave it away.

Are you talking about sticking when cold after the bike has sat for a while? That is common in many trials bikes. I have learned to live with it on some bikes. Start bike, pull in clutch and give bike a little roll forward while putting in gear. Ride bike forward with clutch in and blip throttle. It will break loose in 10 feet or so and not stick again until next cold start after sitting....if it is just a cold start issue.

Height is a problem. I'm 5'5" and the the top of the beta kicker is near hip height. It is difficult to get any weight above the kicker and I would assume really bad if you have a knee issue. I find Rev3 and Evo take about the same kick effort. The 4t kicks over very easily. At some point, I heard that Beta started putting a groove in the bore of the 300s to make them easier to kick. I did get a ride on a 300 super smooth and it was surprisingly easy to kick. I think it was a 2018...aluminium colored frame I think.

Beta's have a reputation as an easy starting bike. I have had 4. Have you cleaned the carb?