feetupfun

Hi Wes. We are the same age and I still ride competition trials. Make sure the bars and pegs layout allow you to ride with comfort standing up. A lot of old trials bikes have relatively high pegs and when they were new, they also had high bars. Modern bars are not as high as the old bars. I find when practicing that I ride for 5 to 10 minutes on trials stuff, then stop riding and sit on the seat to recover. Riding competition can be easier on your body than practicing because you usually have to wait to ride each section, and also on a twinshock you can usually ride between sections sitting down.

There is no reason to assume that the big end pin will be OK to reuse after a motor suffers a failed big end bearing. When the crankshaft has been pushed apart, the pin can be inspected for damage.

If someone posts something new, it is visible to everyone who looks at the Trials Central forums, whether the topic started recently or many years ago.

I enlarged the steering stem hole in a spare top triple clamp and made an eccentric to fit in the hole to move the top triple clamp forwards slightly. I did not aim for parallel. I can't remember the concentric dimension for the eccentric piece offhand but there is still some angular offset. From memory, the goal was to move the front wheel axle rearwards by 5mm. To get the fork tube holes to line up again, I twisted the bottom triple clamp then twisted the upper triple clamp. What I wanted was for my KT250 to steer like a TY250 and it now does exactly that.

Ah OK. I guess it's a bit different here where there are lots of derelict TY250s lying around. Plenty of TY250 parts in the US as well.

I'm glad you mentioned using the KT triple clamps as well as the forks. Did you realise that KT triple clamps are a lot further apart than TY triple clamps, so there will probably be some work involved with fitting the KT triple clamps into a TY frame. I haven't tried this to know what's required but at least the angular offsets of the KT fork tube holes will be incorrect if the KT triple clamps are moved closer together. The other stumbling block there is that the TY steering stem may not fit the stem holes in the KT triple clamps. As for attaching the TY brake link, it would be pretty easy to make a clamp that fits around the left side KT fork bottom for the TY brake link to attach to. No idea what spacers might be needed for TY wheel in KT forks with KT triple clamps. If you have a TY wheel or TY forks in their triple clamps and some KT forks in their triple clamps, you can measure them up and compare. Also have a think about where the KT fork tubes will end up at full lock relative to the TY fuel tank. Unless you limit the steering angle, I suspect they might hit the TY tank. This is because the KT triple clamps are designed for leading axle forks which usually positions the fork tubes more rearwards when straight ahead and closer to the midline of the bike at full lock, compared with (in-line axle forks) TY triple clamps. For what it's worth, the standard angular offset for both sets of triple clamps is the same (1.5 degrees). I modified my KT triple clamps to reduce the angular offset to achieve the same trail dimension as a TY (to make my KT steer better). You could do something similar to a set of TY triple clamps to achieve the same trail as a KT250 with a lot less trouble than doing a front end swap. However, I'm only guessing that this is what you are trying to achieve. What are you trying to achieve?

Yes 4 pot front brakes were a huge advance in brake control compared to 2 pot. The EVO also feels substantially lighter to ride than the Techno. I remember riding my first Rev 3 in about 2001 and being amazed at how light it felt to ride compared with a Techno.

I've done it the other way around, fitting TY250 forks to a KT (wanting to increase the trail). I used a TY wheel. An axle spacer was needed for this. It was just an experiment and I went back to using KT forks on my KT. There were two problems with the TY forks on the KT. The amount of trail was too much which upset the steering and the front mudguard hit the exhaust header on full compression of the forks. I then modified some KT triple clamps to provide only about 5mm extra trail over standard and was very happy with the result. If you fit KT forks to a TY250, the KT wheel assembly will be a bit too wide because with KT triple clamps, the fork tubes are slightly (2-3mm) further apart than with TY250 triple clamps. I've not tried to fit a TY wheel to KT forks. KT forks are longer overall and have more travel than TY250 forks and would reduce the trail by about 20-25 mm due to the leading axle design. They are functionally very similar inside with the main difference being that the KT forks do not have anti-topping springs. They are so similar inside that you can use TY internals in KT fork tubes and vice versa. It sounds like a fun, interesting project.

A standard 250 1997 Techno has a lovely soft motor. Technos came out in 1994 and were highly responsive - probably too responsive for the average rider. The 1996 model was made much easier to ride for the average rider and it stayed like this for the rest of the years of the Techno (96, 97, 98, 99). By the way, is your Techno a 250 or a 270?

One way to judge piston ring seal without pulling much apart is to inspect the cylinder wall via the exhaust port or the plug hole, looking for dark areas (carbon). Carbon on the walls indicates piston ring blowby. Be aware that trials two strokes nowadays commonly suffer from having the rings stuck in their grooves by gum and carbon. This can happen quite quickly depending on how the bike is ridden, the type of premix oil and how well the bike is jetted.

TRS sells electric start 250 and 300 two strokes and they are very popular.

The ball and spring can be installed or removed with the engine assembled

You can use the TY175 head or the DT175 head. If you use a DT175 head, the compression ratio will be higher but you may need to trim the head fins for exhaust pipe clearance. You can mount a clutch cable holder on the engine casing or on the bottom cylinder fin. The DT175 cylinder fins will not interfere with anything physically. Trim them if retaining the original TY appearance is important to you.

DT175 1974,75,76,77 (DT175 ABCD models) cylinder will fit and function well but has different finning outline to TY175. I have not tried or measured up a CT1,2,3 cylinder.

Which brake plate is standard/correct depends on which hub is on your model 92. Also, they might both function OK. Can you do photos of the hub showing the brake drum and an external view showing the finning and both spoke flanges?