feetupfun

Rims or rim? Modern fronts are tubed

All the bikes shown in this topic so far have their standard upper shock mounting (ie they are not modified). Yes it seems that there will be too much bending moment in those frame tubes, but it seems to work out just fine in real life

bestrcpilot, I'm interested in building a replica OW10. Are you willing/able to share the blueprints you generated?

There are different rules for twinshock trials bike eligibility in different parts of the world. TLS brakes lie in a grey area in our part of the world for trials, because the only common dirt bikes that had them back in 1982, were MX and enduro bikes that also had monoshock rear suspension, and some people consider that any parts from a bike that was originally a monoshock, should not be allowed in Twinshock Trials. Luckily we are a laid-back lot and don't really care much what forks or brakes are on a Twinshock trials bike, and the rules are suitably vague, so there has not been a protest that I know of. Nice looking bike by the way, especially the graphics and finish on the fuel tank. Also thanks for showing the brake pedal. My Whitlock TY175 frame came without a brake pedal and I am planning to make one that looks correct. What is that kickstart lever off? I'm guessing Yamaha WR200?

you can't get more original than this

Have a look in the topic about Mini Majesty seat/tank Units after your question there. I posted a photo of a full-size Majesty 175 for you

The question is about an odd-looking item on the parts diagram that appears to fit into the cap of the chain oiler

for Scorpa250 - full size Majesty 175 - not red though

Weird hey? Maybe it's a magnet? That cap on my TY250A fell off years ago so I can't check what it does

Here are photos of a friend's bike with a Sammy Miller TY175 seat/tank unit on his TY175 Mini Majesty

I haven't ridden a 4RT since 2005, but would get the Repsol if I was getting a new 4RT. What's strange about that? Where I live the new year models of most brands only come in one or two shipments and most bikes are pre-sold anyway. The only time I have ever had a chance to have a go on a demo bike of a new model was the 4RT when it came out, and the Rev4 250 when it came out. If you wait to ride a mate's new bike of the type you are interested in, there are none left in stock, so you have to wait till the next year's model, and then it will be different anyway. One of my riding friends wanted a Rev4 300 last year and it took about 6 months for him to get it. Is that enough reason to buy a bike without test riding?

Ok just pulled a seal out and measured. The distance from the seal seat to the circlip groove is 12.5mm and the seal is 10.5mm thick

Something sounds fishy with the 15mm dimension in your forks. I would have thought that standard was about 12mm. I will measure some TY250 forks in the morning. Be aware that the circlip is not really essential unless you are going to run with air as the spring. Plenty of times when I've gone to remove the circlip there has still been clearance to the washer that was there when I fitted them - ie the seals have not moved away from their seats in use, and I use anti-sieze on seals so they are easier to get out when I change them. I also run sealed fork caps in my Bultacos that do not have seal retainers and have never had one of them have the seals move either.

It's not unusual to need a few basket cases to make one complete bike. I have a TY250B that is made up from three bikes that were all worse than what you have there in their own way. You can always sell off the excess bits when you have a complete bike, to recover some costs I like that saying Guy

I thought it was common to have a steel backing in TY250 fork seals

your photo shows what looks like the steel innards of a seal with a piece cut out. You say you have tried all methods but did not mention which methods. To loosen the steel "flange", gentle heating of the aluminium slider around the "flange" would be a good idea. After that, a slide hammer with a 90 degree hook on the end of the shaft should get it out without damaging the aluminium. If there was a seal under the "flange" then what you have there is not a standard arrangement. I'm thinking maybe someone replacing the seals previously could only get seals that are thinner than standard, and used the steel part of the old seal as a spacer to make up the difference.

there is a chamber inside where that hole is, and that chamber is connected to the gearbox by a small passage. The passage between the chamber and the gearbox is located in a way that avoids oil going from the gearbox to the chamber If you don't like that design, you can always block that hole and install a vent in the filler cap. The Montesa design actually works pretty well (on my bike anyway)and I've not heard of anyone complaining about it.

That hole is the breather hole for the gearbox

have you checked the timing with a timing strobe light? Kicking back when you try and kick start usually means the spark is happening too far before TDC. Just because it is a CDI does not mean that the spark timing will be correct - may have happened when the camchain was off to replace the rings

I've never seen official instructions for this, but have had success with: Fix a piece of thin card or similar spacing shim to the outside surface of the laminations, set the stator coil towards the outward limit of its travel, set the screws with just the right tension so the coil can move if pushed, then fit and remove the flywheel carefully with no points (to make fitting the flywheel as easy as possible) but with the key in place, then tighten the stator coil screws

would help to know what bike

Lobito can be made into a reasonable twinshock trials bike with many modifications, but if it is still standard, the footpegs are way too far forwards, and the steering geometry is wrong. I think to ride an old bike you have to actually like riding old bikes. My wife started riding trials on an OSSA MAR in the early 2000s and thought that was OK until she rode a 2003 Beta, then wouldn't touch an old bike. Like twinnshock's local rider, I also started riding trials on an early model Alpina back in 1975, and thought it was OK until I rode a proper trials bike for the first time, and a Lobito is worse to ride in trials than an Alpina

thanks Bondy I was wondering what they look like on a bike. Is the fuel tap well located (with reasonable clearance between the hose and head)?

if it's only on overrun when the throttle is fully closed, and continues for as long as the overrun is happening, then changing the jetting will not make any difference. If it is a transitional effect as the throttle is being closed, then a jetting change (pilot jet size usually) will help The bong, bong, bong on continuous overrun that some 2 stroke bikes do is usually due to the fuel/air mixture going too weak to burn during overrun. Air ingress will usually be worse on overrun because the crankcase vacuum is higher when the motor is being driven by the rear wheel. It can be a bit distracting. Four stroke motors are susceptible to exhaust bang if they have air ingress into the exhaust system near the head end of the pipe. On a TY, the bong, bong is caused by air ingress which causes the air/fuel mixture to go too lean to burn for a number of strokes of the motor, until enough petrol accumulates to get the mixture up the point where it can burn in a single violent stroke (the bong stroke)

The only difference I have seen is in the branding on the lanyard part that goes around your wrist. All the magnetic ones I have seen are made by Leonelli (and are the same device).