still trying

Does the motor have an expansion chamber creating a power band, (This is not desirable in trials, go with a long parallel pipe, and not too large, slightly smaller than enduro spec. I will increase the back pressure slightly and that will help the motor build torque). The big thing is smooth power and torque growth as revs climb, and as much low down torque as you can get and still have reasonable acceleration. So, no expansion chamber, heavier flywheel maybe, (try the std one first for a while). I had good results with a smaller diameter and longer exhaust pipe and lighter flywheel. Motor was a KT250 so already a trials unit. when riding you will (98% of the time), be trying to get or keep tires gripping the ground, so sudden uncontrolled bursts of acceleration from the rear wheel is not helpful. Typically you will need short bursts of acceleration to get over "stuff". at these times you will be "pushing down" with your weight through your legs to increase grip to handle the power increase. The timing of these two actions is half the battle, balance being the other. Oh and then there's stopping, reading the section, mental self control,.............But I'm sure you've got all this already, Good luck with the build, bet your learning heaps, I did with mine.

What was the repair?, and how much of the motor did you pull apart. Also how was the damage done, (it may have resulted in other issues). If the motor was fully dismantled then there could be something binding and stopping the selector drum moving. Really need to see the motor selector assembly with cover and clutch removed to make a decent guess.

For learning on, go modern. All brands are good, just give each a try and find one that feels right, If the bikes is in good condition , even as old as 2010, will get you a modern bike that has good handling, suspension, breaks, clutch etc. The modern controls are much easier to operate. The breaks are way better and consistant. the power and clutch way better. Maintenance wise, there's less to do. And yes 20kg lighter is a big deal. The two strokes definitely do not need frequent rebuilds, even if you thrash them. Mine has done expert grade for three years, left in the shed for 17, dragged out, given new air cleaner, changed the fluids and away I went, so far for the last 7 years, (its a 1995 Gas Gas JT35 (327cc) ). More modern bikes are far better than mine that's for real. And its easier to ride than my KT250.

If the rubber shows no signs of degradation powdering etc, and holds air, then they would be worth using.

Does look like a Honda XR200a tank, Nice build by the look of it. Good luck with yours Ftwelder, also looks cool. Awsome to see creative bikes, especially when the finish and fitting is good.

I've run E10 petrol in my KT250 for years no problem. But I also rebuilt the motor (using std hydraulic industrial rotary shaft seals) back in 2013, and have no problems. fuel line that i use is polyeurethane airline tube from SMC, and was expecting to be frequently replacing it, but am still on the first tube. Its colour has faded a bit, but no more than when used as airline. I guess what I'm saying is try to use compatible materials where possible and plan "end of life servicing" as standard maintenance, and you will have no problems when out riding.

you could try acetone. I have used it on carburetors that have been sitting with dried two stroke petrol for 40 odd years, and it worked. Not quite black sap level of crud. If you do try acetone, I would think the same procedure as you did with petrol would be the go. I have recently restored a '70s Honda TL250, (ali tank) and its tank looked like it had a coating of some sort in it, (Black/ dark brown in colour ), I thought it may have been a sealant or protective coating (it was all over the inner surface to some degree) so washed it out with petrol as you did and left it. So far no problems.

For me; I'd go for a Fantic 200 or 240, nice and light with good handling. The ones I owned "back in the day" were as reliable as the Yamahas' and Hondas'.. Once you get used to it the kick starter it is much easier to use than the conventional ones. I have no idea about parts in the US, but getting bits from around the world these days is pretty good. Honda TLR250 would be best, Yam TY175, nice and light, and can be setup really well, with some careful research. SWM twin shocks were also really good in their time, along with Montessas', and Bultacos'. Without knowing you fitness, off road experience, etc, I would suggest go for; light, nimble, with predictable power, and good breaks. Most of the bikes are pretty reliable as long as they were/are serviced properly. Good luck with your search

Here's a thought, Which lasts longer, Spending the day enjoying riding a trial, or finding out you've won. I find that if I've won it feels good for a few moments, but if I've had a good ride it lasts days and makes me want to ride some more. As old bikes are few and it would be good to have the sport/class survive, accurate replicas should be allowed. They Must use the same technology as the genuine bikes.

here's a thought; Is winning that important. Or is enjoying riding your machine the point.

Beautiful build, Well done, now get it dirty.

Sorry about the delay Tony, yep its the same one. When I took a break from trials in '97, I knew if I sold it I probably wouldn't get back into trials. Might start looking for a more modern bike soon, but also keen to pick up a '70s TL250. I'm fixing one for a friend at the moment, what a cool beast for twin shock trials.

I ride a 1995 JT35 as my "modern" bike, and yes there's quite a difference to the modern stuff. Seems like about 2001 there was an upgrade (better brake, clutch feel and weight loss), , again around 2005-10, and the latest bikes with fuel injection and active electronic engine management are another step up.

If your looking for the flat type seal. I used one out of a plastic 20lt can cap, (look around the caps come in several sizes), and are generally chemical resistant. Note; anything that has rubber or silicon in its makeup description may swell when in contact with petrol.

Hi Sam, I've just followed my instructions and the web site has changed so they don't work. Try; Trials Australia, Forums, Twinshock (At the moment its on page 3) "Steer Clear, understanding steering" posted by Guy53, on sept 16 2016

Hi Sam, Have a read of the post in "Trials Australia", its all about bike geometry front and rear. Essentially it ends up as a series of compromises. But it helps you understand the trade offs, and how/what to alter for what effect. Really good for tuning things once riding as well. Anyway, go to; Trials Australia, then; Forums, then; Twinshock and Classic Trials, then; Steer Clear, Understanding steering Hope this helps. I had to read it a few times to get my head around it fully, but it was worth the effort.

Cool project, Love the coffin tank. You'll have a blast, good luck

Personally, I think the TY is a better pure trials machine (light and nimble), but a little under powered. If your just having a play and nothing too tight etc, I'd go for the RL It also does to a point depend on your physical size and weight etc. Back when I was riding a TY175 I was 69kg and would have struggled with the RL, now either would do me fine.. Both look like nice tidy machines, good luck and have fun .

Great time to learn to balance stationary. Once you can do this for say 30 sec, start on hopping the front. Back break on full, motor off, The motion is compress the forks, move body back and up using your legs (they should do most of the work). If you dab on the outside, you moved more that the bike, Dab inside, bike went too far. If you can do this, it is a brilliant fitness exercise.

If you want to read about bike geometry, steering head angles,swing arm angles, etc, go to, "Trials Australia", then; forums; next "Twinshock and classic trials", next, scroll down to, "Steer clear, understanding steering". Its really useful. Great looking project by the way, Good luck

I agree metisse, but then we're back to how many and what mods put you in the "special" class. Cut frames, steering head mods, laid over shocks, removed bottom cradle rails....I feel a headache coming on Initially perhaps set it up to get all those excluded bikes back out being seen and ridden Personally, I admire both, carefully restored/maintained originals, and the creativity of the specials. John, well done, your workmanship looks great, If we didn't know better it looks like a production bike with a different silencer.

Hi, the only thing I've done to my Carb is strip and clean, and make a new bowel gasket. My bike had been sitting outside before I got it in 1989, rode it a few times before storing it until 2014. Found some ali corrosion in the airways. bit of a mission to clear but got there. Since cleaning and putting motor in the new frame (see projects) its been faultless. Original bike was pretty rough

Oh be careful not to overdo it and have valve seats etc come out, Good luck

As above, heating the head is the way to go. From experience you'll be heading for around 400 C, At work I use the oxy acytlene torch for this, but at home I use an LPG burner, (its a little safer as far as melting the work goes). The thread in the head may get damaged as the studs come out, so I'd suggest helli-coiling or using thread inserts after extraction in the head. Then you can use, bolts, capscrews or studs, and they will be more serviceable.

I've got a KT 250 with original DID rims and the tubeless tire kept coming off, (front and rear). I used a sanding disc on an angle grinder and removed the tubeless sealing lip from the tire bead and no more problem. The bead land on the rims I have is small (narrow) and the seal lip sat on the radius to the spoke valley, so when the pressure was less than 30 psi it pulled the bead off the seat. My suggestion is to try unmodified first and go from there. As far as using a tube in a tubeless tire, No problem at all. The biggest difference I can find is that the tubeless tire has a lip on the inside edge of the bead to seal against the small ridge at the inside edge of the bead seat of a tubeless rim.