dan williams

Tim Thorp on that downhill to section Novice 3. He was minding for Robbie. How he didn't crash I'll never know. I asked if he was alright since he was stopped on the side and he rotated his bars on the remaining bolt to show me where it had sheared off. Scary as ****.

Saw a rider at our last event with a sheared off handlebar mount bolt. He managed to wrestle it to a stop (on a nasty downhill) without crashing. I’m not saying it’s a fault and not a freak occurrence but just putting it out for information as the consequences can be serious. So one more thing to check from time to time.

Yeah the 4t’s also use all six of the 3mm thick plates so they are different than the old thin plates. The newer bikes are also a lot better as far as the glue application. As Beta gets better with the quality of the plates the fix becomes less relevant. Of course the first thing I’ll do when the 2018 comes in is open the clutch and have a look.

Lineaway is (as usual) correct. Since it’s typically only one finger operation for trials controls you can run the lever perch closer to the bend in the bars. This also adds a bit of leverage. You can also leave the perch loose enough to rotate in a crash or put PTFE tape around the bar. Also note you have a fairly short activation throw with trials controls so there’s no need to have the out travel of the lever hanging too far out. Not really related but sorta... I highly recommend bar ends. They save grips but also protect the throttle assembly and I do think they preserve levers a little bit.

Welcome to the sport. I recommend chewing through the Beta forum here. Tons of information there. Trials is in general harder than it looks but you’ll get better faster than you think and it’s a lifetime of fun.

Cold without starting the engine there’s not really enough vibration and shearing force to separate the plates, especially with thick oil. You’ve still got two large surfaces trying to pass by each other. Wait until you get it all back together and can ride it before determining success.

Welcome to the sport. Warning though it’s highly addictive.

In general the bigger engines are more fatiguing to ride. They can be smoothed out a great deal and there is no substitute for that generous low end torque provided by a big motor. As others have said, if it's in good shape and it floats your boat jump on it. I have a 300 Beta with carbon reeds, a low compression head and went down one tooth on the countershaft and it is very controllable but still jumps like a scalded cat when needed. You may not think it but that power that seems hard to control now will be something you rely on once you get the feel of it.

59 and land with a thud. No bounce but innards protected by fat layers.

As said above. It's all about the careful setup and few "trick" parts. 4-5 hours making sure your jetting is spot on is much more profitable than $1000 worth of titanium. Of course the problem with new riders is they don't know what is a good setup so they will crank their spring preload way up and run their tires too hard and crank their levers in too far and rotate their bars back... There is a wealth of knowledge on here about setup and it's well worth digging through old posts to find the tidbits of info. Just remember the setup of your bike has to fit you and has to work in the sections you'll be riding. A bike set up for trick riding and huge splatters is going to make life miserable for a novice doing slow turns over round rocks.

I’m all for fine tuning but at some point you just have to ride the damn thing. You should be pretty close at this point. You have all the baseline stuff. Any fine tuning from here on is ride, tweak, ride, tweak.... only you can say the bike is tuned properly for you. On my ‘13 I spent many hours fettling with the carb and eventually went back to stock on the pilot and one size down on the main. On the older bikes 27.5 pilot always worked and the main depended on the nature of the bike as Beta tuning is variable year to year. Go out and play for a bit.

What oil/gas ratio are you running?

Old bikes came jetted rich for break-in and new bikes come jetted so lean for emissions they barely run. 27.5 pilot makes a big difference in how the bike pulls off bottom. You’ll be pleased.

I’ve noticed Beta schematics are often a year late. I guess they are tweaking the wiring right up to production but the manuals are printed ahead of time.

Looking at the 2014 schematic there's one that goes on the line from the regulator to the horn. Black wire on one side and what I think is blue and black to the other.

A 15 year old that works on his own bike. That's excellent. Even if you don't get an easy answer rest assured that all the cranky know-it-all's on here (yeah me too) started the same way and there's lots of times we put something together only to have to take it apart again and fix it proper. It's how we learned. It's how you'll learn. Welcome to the brotherhood (and sisterhood) of "I can fix that!" You are now one of us.

Lineaway is correct. Also what oil/fuel mixture are you using? If you are like most new trials guys you are throwing far too much oil in. Modern water-cooled, plated-cylinder bikes are quite happy at 80:1 and a lot of real plonkers (riders who don’t race between sections) are fine at 100:1. I think the injected bikes run even higher ratios. It’s been many years since I’ve seen an oil related failure in a trials engine. Carb is VM26-208 to be specific but that’s an OEM number so the generic VM26 will get you to the right place. There is a Mikuni thread pinned to the Beta forum chock full of good info. Despite what some say it is a good card that provided years of good performance on my many Betas.

Yup you are correct. The ignition coil is basically an autotransformer that steps that 200-300V up to tens of thousands of volts. The old point systems had primary voltages that were somewhat lower. Basically running a current through the primary side of the ignition coil and setting up a magnetic field that would collapse when the points open. The collapse would develop the secondary voltage for the spark. Instead of running a constant current through the ignition coil CDI systems store the charge on a capacitor. On the Beta CDI I disassembled it was a 400V polystyrene cap. When the timing pulse is given the energy in the cap is dumped into the coil through an SCR or Triac which is a high current latching electric switch. So through the rotation of the cycle the capacitor gets charged, the trigger pulse fires the SCR which dumps current into the ignition coil building a magnetic field and generating the high voltage for the spark. The advantage over points is you can control the ignition curve very precisely and since you are able to generate a spark on the rising edge of the building magnetic field you can sustain spark on the falling edge giving a longer duration spark.

Wow. That’s somethng new.

Did they lengthen the kick starter or did somebody just not put it on right at the factory. Doesn't seem to fit in the notch in the pipe as it used to.

New boots are pretty cheap and just screw into the wire. Just cut the wire ~5mm and screw the new boot on. The older ignition systems have three types of coils. 4-6 big coils with heavy wire to power the lights/fan ~16-20 volts ac A coil that provides the power to the CDI. These have smaller wire with more turns to generate ~100-300 volts ac. This charges the capacitor in the CDI (capacitor discharge ignition) and powers the electronics in the CDI. Most modern ones contain a uController. Basically a one chip microprocessor. The last coil is the trigger coil. This coil is a small coil whose sole job is to send a pulse to the CDI at a certain point in the engine rotation to tell the CDI to dump the charge stored in the capacitor through the ignition coil to make a spark. Some systems used two trigger coils to tell the uController how much advance was needed based on engine speed. if you look at your flywheel you will see one or two odd magnets that look split. These are the trigger magnets. The trigger coils are oriented in such a way that they don't generate a signal from the magnetic field of the other magnets in the flywheel. Typically it's the trigger coils that go bad so the CDI charges up but never fires. On the newer bikes the trigger coils/magnets have been replaced with Hall effect sensors. These live outside the flywheel in that little pod where the cable exits the case. There is a notch in the flywheel that trips the Hall effect sensor to generate the timing pulse. This is the same system used in cars. OK that's my major geek out for the day.

It sounds like something pushed the pistons back into the caliper. A bent rotor will do that as will badly worn wheel bearings or even picking up a small rock or piece of wood that gets jammed into the brake pads. to make sure there are no leaks while parked grab a handfull of front brake and hold it to see if it goes soft after a bit. If it does then you have a leak somewhere in the system. Could be a seal in the caliper or master cylinder. If the lever stays firm I'd check the front rotor for true and check for play in the wheel bearings. Also pull the caliper off the rotor and look for anything on the pads that doesn't belong there. Obviously check your fluid level and make sure caliper bolts are tight and the lever has enough free play to open the reservoir port in the master cylinder.

Going back to this as a friend had a GasGas with a PWK28 that did the same thing. Bounce the front end and the bike would die. Nose down and the bike would sputter and die. Fixed by replacing the carb. I had hoped to do a postmortem on the carb but the dealer who replaced it already disassembled it for parts. Very curious.

Yeah much of what's in this thread is completely wrong. The double blip is simply a technique where the first blip of the throttle lifts the front wheel to the top of an obstacle. The second blip drives the rear wheel into the base of the obstacle. This is effective for small obstacles up to about 1/2 the wheelbase of the bike. The Jap Zap (yes it was first deveoped by a Japanese rider) is intended to get up higher obstacles by intentionally running the front wheel into the face of the obstacle at a height that will store maximum energy in the springs and using the rebound of both suspensions to lift the entire motorcycle. Essentially when it is done correctly the front wheel is vectored straight up followed by the rear wheel which impacts the obstacle near the same point as the front wheel. This allows the rider to climb obstacles greater than the wheelbase of the bike. The technique where the rear wheel contacts first is called a splatter and it involves violent compression of the rear suspension and sometimes a "kicker" to get more lift. Splatters require dumping the clutch at high revs to get the bike to rotate after lift-off to contact the obstacle rear wheel first at some altitude above the base of the obstacle. The size of obstacle you can get up with a splatter is solely limited by how high you can jump, hence the kicker, and the size of your, er... cajones

That's great. One thing I noticed on my bike after I did the bleeding is the braking was weak until I had some time on the bike. I attributed this to the mechanics of the caliper. Basically the pistons are self calibrating. They can move a small distance but are pulled back from engagement by the O-rings. Exceed the elastic limit and they slide in the O-ring which is the self adjusting bit. Until they have moved in the O-ring far enough it's possible to have them contact the rotor but pull back too far to be in the proper working range. The clearances are so small that it's amazing it works as well as it does. This could explain why the weight trick helps the feel as constant pressure forces the piston/O-ring position closer to the rotor and gives more time for the O-ring to move on the piston. I could see this causing a bit of drag too if the piston slides a bit past the optimum position. Ain't mechanical engineering fun!