dan williams

That's the zap. Heffergm is quite correct that hitting the front wheel compresses and stores energy in the suspension. The other critical part is getting off the gas to let the suspension release that energy. Most people fail to zap properly because they stay on the gas too long, the suspension never decompresses and the rear wheel never leaves the ground. When done properly the rear wheel hits the obstacle close to the impact point of the front wheel. It's a violent maneuver and the first few times you do it you'll scare yourself as everything happens so fast you are on top of the obstacle before you know it. It's also unnerving to purposely ram your front wheel into an obstacle but that's how it's done. Approach at slow speed. Weight slightly back Blip the throttle to lift the front wheel to an impact point on the face of the obstacle. On impact with the front wheel blip the throttle again and jump forward and up snapping the throttle off. Bend your knees to let the bike come up while pushing forward on the bars. If done properly the bars will whack you in the chest. Don't aim for too high a spot to hit the front wheel on the face of the obstacle. Optimum seems to be with the frame at about a 45 degree angle to the ground.

I just meant in general the projected tip shouldn't be a problem. You never really know why some things get incrementally changed Maybe Beta got a deal on a big box of one type of plug or the other.

As Billy observed you can't go wrong with the stock plug. The resistor plugs actually came about to suppress radio noise in autos. By reducing the edge rate of the spark the resistor plugs reduced the radio waves generated by the ignition firing. They also slightly increase the duration of the spark while dissipating a small part of the available energy. Performance wise there is virtually no difference. Cleaning your air filter will make a much larger difference. Can you blow up your CDI with a non-resistor plug? Very unlikely. Consider how the CDI works. A coil charges a capacitor up to around 300V. The charge in this capacitor is dumped through the primary of the ignition coil by triggering an SCR. The SCR is similar to a transistor that acts like a switch. A pulse of current from the trigger coil (yeah the bit that usually fails on a Beta stator) shorts the SCR. I admit that's a bit simplistic as the modern CDI has a microcontroller in it that senses the trigger pulse and adds a delay to the trigger based on engine speed (which is how you can have programmable ignition curves). So this large current of respectable voltage gets dumped into the ignition coil which is actually two coils with a common core A.K.A. a transformer. The primary winding which is thicker wire with less turns to build up a nice strong magnetic field, and a secondary winding with lots of turns of smaller wire to build up a nice high voltage in the tens of thousands of volts at a still respectable knock you on your ass current. The spark plug gap in the cylinder is what's called a negative resistance device like a flash bulb or a lightning bolt. With no voltage across it presents a resistance of many giga Ohms. As the current in the ignition coil secondary builds up it has nowhere to go causing a voltage to build across the plug gap. It's worth noting at this point that the 10kOhm resistance of the plug cap and/or resistor plug in series with the giga Ohm resistance of the gap is insignificant. As the voltage builds up the air fuel mixture in the plug gap starts to ionize. Electrons are stripped away from the atoms in the gap and a path of ionized gas is created between the electrodes. Once this happens the resistance of the plug gap effectively goes to zero. When this happens the energy stored in the magnetic field of the coil is dumped across the gap. Since the resistance of the gap is now nominally zero the voltage out of the coil drops as the current is dumped across the gap creating the hot part of the spark. Now the plug/cap resistance come into play limiting the peak current the secondary winding can dump across the gap and extending the duration of the spark. Current will continue to flow until the voltage of the secondary drops to the point where the mixture in the gap is no longer able to maintain an ionization path. The only possible mechanisms I can see for a non-resistor plug to damage a CDI is if a larger inductive kickback to the primary coil occurs. I think that's pretty unlikely though as the impedance looking back into the SCR is fairly low The projected tip plug is a similar story. In the early days the wide temperature swings of air cooled bikes running 32:1 mixtures had better plug longevity with projected tips because they are better at cleaning residue off the insulator. Modern water-cooled, electro-fusion cylinder bikes running at 80:1 - 100:1 oil ratios with higher compression ratios don't have the fouling problems so a projected tip plug isn't necessary. Will it hurt the engine? Not unless there is an interference with the piston.

Main jet tower is in the center of the float bowl to make it relatively insensitive to acceleration/deceleration. The float center of buoyancy is also centered along the side axis of the carb for the same reason. This helps with the angle of the carb as well but it's not the main reason as most designs are really throw backs to street bike design. I've often thought it would be fun to design an actual "trials" carb. Something that was completely insensitive to angle. It looks to me that these mods actually are intended to help with issues caused by fuel aeration.

I guess we know what Beta did with the leftover stock of kill switches.

Sorted with new carb. Waiting to get the old carb from dealer so I can dissect it and find out why.

I did the rebuild on my '13 with an AJP kit though I believe it is a Grimeca caliper. From what I've read they are made by the same people. Anyway the pistons in the rebuild kit measured out to .003" smaller than what was in there. I split and cleaned out the caliper. Put a little fluid on the replacement seals and slid in the replacement pistons, poured fluid into the brake line hole, reattached the hose that I had ty-wrapped to the handlebar to keep from draining. Remounted the caliper and did the lever pump bleed until there were no bubbles and my front brake is back to excellent. Practical upshot is, don't be afraid of the "AJP" rebuild kit. Works fine.

Good bike but the previous owner was obviously a hack. I feel for ya.

Problems with the IRC and Dunlops on Betas as well. Michelins for me too.

Also make sure the spark is in the right place. Not uncommon to see a sheared woodruff key when the flywheel isn't torqued properly.

I put an S3 low compression head on my 300 and it made the kicking easier. If you're down in Meriden Sunday come give it a try.

The new bikes have a stem pinch bolt on the top triple clamp.

Betas tend to be more front heavy than other bikes. They are good machines but so are the other brands. They all have their peccadillos. With Betas its the trigger coil on stators on bikes before they went to Hall effect sensors, corroding water pump housings, cracked frames on the '09 EVOs, piddly carbs on bikes with Mikunis, Sticky clutches and most recently leaky rear rims when fitted with IRC or Dunlop tires. One thing I like about Beta owners is that when something is screwy they nod their heads and say, Yup, we've seen it. Here's how you fix it." I've noticed a tendency with owners of some other brands to have a bit more of a fanboy attitude and deny there's a problem or blame the owner for using the "wrong technique" and causing breakage. As for looks, I've owned a lot of Betas but I still think the Shercos are amazing looking bikes.

Hmmm I just bought sheets of PTFE to use as optical diffusers for work. Maybe I should try to see if I can make a shim out of the .005 sheet.

Replace with titanium

Love my Betas. Though the TRS looks mighty tasty.

I've never been able to start a GasGas and it always felt to me like there just wasn't enough energy stored from the kick to get it fired easily. Very interesting that a flywheel weight makes that much difference. As for 74, I regularly get my ass handed to me at events by guys in their 60s and 70s. I keep telling them I want to ride like them when I grow up. They just laugh. As they have for the 30 years I've been riding with them.

Depends on economy of scale vs market share gain due to multiple brands. If Sherco selling GasGas bikes steals sufficient market share from other companies it makes good sense. If Sherco selling GasGas bikes steals a large share of market from Sherco probably not. There is a business model that has become fairly common in saturated markets. When the possibility for "organic" growth has stopped due to stagnation of market size growth comes through absorbing your smaller competitors. It's rampant in the semiconductor industry these days.

That Mikuni is a workhorse. If set up per Billy T's instructions it works perfectly and doesn't leak. The only carb I ever swapped out on a trials bike was from the stock Dell'Orto to a Mikuni on my '95 Techno. Since it is a 15 year old bike I'd check the slide, needle and needle jet for wear. Possibly replace the float valve but usually not necessary. Check the floats for wear marks and make sure they aren't rubbing the float bowl gasket. Trim the gasket with an x-a to if necessary. Around here the pilot jets are usually switched to a 27.5. Then go ride. Welcome to the sport.

Heh heh I had to look up "seeger ring". I put the impeller kit in my '13 without any problem. I wonder if Beta thickened up the castings in the newer bikes.

What exactly are they bidding on though? The name? The facilities? The patents? For Sherco I can see it as an expansion of manufacturing capacity. A bicycle manufacturer that makes kids electrics is very interesting. No telling what their plans are. I agree an investment fund is likely to polish it and divest as soon as possible (profitable). Perhaps the bicycle manufacturer is looking to expand into adult electrics. That would be very cool. Just have to wait and see I guess.

The return of the Alpina'ish type of motorcycle. It's been a long time coming. Trail bikes for people that want something they can actually touch their feet on the ground yet with decent performance.

Just curious WTC what mods you have made.

I agree with flat steels. Patterning them just reduces surface area but several people have had luck cutting holes or oil channels to allow oil to escape faster from under the friction pads. Perhaps there is a need for a design that has a quicker engagement just for pros? Maybe something like a continous pad ring and patterned steels like disk rotors to clear oil. It would be interesting to see what difference having engine driven steels and transmission fibers would make too.

A ride on one might just push me over the decision threshold too. We need Ryan to come up to Mass to sell us on it.