dan williams

One electrical engineer to another.? There is the clutch fix thread pinned to the top of this forum that helps smooth the clutch and stop the cold clutch launch. Long thread with much learndings as Ralph Wiggum would say. I didn’t expect it to become a magnum opus but it kinda grew wings and took off. Most people seem to like the fix. Some think it’s a load of dingo’s kidneys.

Michelins are the gold standard but the 803 Dunlops are very good and cheaper. I find about 1 pound less air in the Dunlop gets traction similar to the Michelin. I tend to like to crawl over stuff and it's usually muddy or deep leaves/pine needles here so I'm typically at ~3PSI in the rear and 6 in the front. The pushing the front end is normal for a new rider especially with a Beta. Don't think about weight front or back. Think about centering and using pressure into the pegs to let the bike turn. A twitchy clutch makes it really difficult to turn as the abrupt grab/release loads and unloads the front making it skid. You can help this by feathering the rear brake against the clutch but the real key is to bend your legs and steer with peg pressure while keeping your torso straight. You may have noticed most of your dabs are on the inside of a corner. That's because you keep your legs straight leaning your body with the bike which is fine on a street bike or an enduro bike but doesn't work on a trials bike. When you lean the bike and keep your knees straight you compensate for this by twisting your torso and sticking your ass to the outside of the corner. This does a couple of things; first it keeps your core muscles in torsion so it's fatiguing and second you have no flexibility to deal with any situation that knocks the bike off line. To get an idea what I'm saying try this. Find a hill side and stand perpendicular to the fall line of the hill so one foot is higher than the other. Your weight is centered between your feet because this is the natural stance. This is how a turn should feel. You lean the bike and the outside leg bends more and the inside leg straightens a bit but your center hasn't moved from a line between the contact patches of the tires. Still on the hill try straightening the uphill leg. You will twist your body and stick your rear out to counter balance. This is an extremely weak position. Have a buddy poke you in the shoulder in both positions and you can see how little effort it takes to move you when you're twisted. Centering is the key. Unless you're doing a dynamic move you always want to be centered. This holds true for up and down too as you let the bike come up to you or let it drop away. You'll hear a lot of silliness about weight the inside peg or the outside peg but it's pointless since any imbalance in peg pressure has to be countered with bar pressure and you're right back in that core torsion situation. So let's assume you're centered and want to initiate a turn. Think pressure not weight. Apply a little more pressure to the inside peg to make the bike lean keeping your torso straight and your shoulders level. Once the bike is at the desired lean angle back to center and the bike will turn. Once the turn is done apply pressure to the outside peg to straighten the bike and back to center. Once you get the hang of it full lock figure eights are good practice and you can impress your friends by tuning around in a tight trail while they're bulldogging their non-trials bikes around. Thinking pressure can help on a steep uphill too. New riders will typically throw their weight forward thinking they need to hold the front end down. That unweights the rear wheel and they get wheel spin while the experienced guys just crawl up the hill. Watch videos of the top riders and you'll see on steep hills they squat low over the back wheel for traction. It takes practice to get used to this idea of weighting the rear wheel on an uphill but it works. The secret is getting low over the bike. When you stand up tall and accelerate you are a big long lever that wants to turn that acceleration into rotational force and going uphill that means a loop out but if you are right down on the "seat" of the bike the moment of inertia is greatly reduced and so is the tendency to loop out. A good way to practice is going slowly up a slippery hill and when you feel you're losing traction pull on the bars. Once you get good at it you'll find you can walk up slippery stuff at a crawl and since your knees are bent you can turn and go over things while still centered. OK it's late so I'll leave it at that for now.

Much of this is fine tuning for personal preference anyway. It might be better to have the option for us old guys for a slave cylinder with a slightly smaller diameter and longer throw since we’re reducing the clutch pull with lesser spring preload. The other thing I wonder is are we losing some throw with lever adjustment. Not something I’d typically think about since my main worry adjusting the clutch is the engagement point. Almost seems like some kind of rising rate system would work. Hmmm more ideas to chew through.

Move your bars forward. Perpendicular to the ground or even slightly forward. Yeah it’ll make you wobbly at first, especially on loop trail, but you get used to it. You also want your levers much closer to level with the ground. If they point down you can’t control the bike as well on drop offs and steep downhills. You also run the risk of rolling your wrists on downs and that’s bad. Really it’s bad.

As I think of things on your Techno I’ll try to add to this. The stock pilot jet for this bike was a 30 but most people ran a 27.5 as it made response off idle a little crisper. If your bike is running fine you probably already have one though. Your bike looks to be in excellent condition with no apparent wear on the titanium nitride fork coatings. You might want to find some fork guards. They’re cheap insurance to prevent a nicked fork stanchion. For basic techniques there are other threads but stay centered. Steer with your feet. Keep your weight low and over the rear wheel when climbing... Have fun. It’s a silly sport but you can have stupid fun fur hours on a small pile of rocks. Welcome to trials. You’re now one of us.?

Hi Eric ? that looks like the Beta “Factory” clutch. The thing that bugs me about the factory clutch basket is it is directly coupled to the primary gear without the cush drive rubber thingys. I’ve seen lots of these shatter the teeth off the primary gear.

Right on the money!

Awesome! That’s a lot of success for one round of tweaks. I can’t claim the fuel piddle fix. That was the genius of one of my gurus Billy T.

To be more precise I prefer to SPEND hours HELPING PEOPLE ENJOY THEIR BIKES MORE. ?

Well the clutch fix is to deal with one set of issues the spacer deals with a different issue. Both clean up production tolerances or wear issues.

I put that together out of the parts bin but it's easy to make one. The normal bleeder is a vee bottomed screw that sits in an angled seat in the banjo bolt. Since it was threaded at the top of the bolt I figured I could just use a screw of the proper size with a copper sealing washer to seal on top of the bleeder and it should work. Yeah it spills brake fluid when you bleed it but I think that is going to happen no matter what. Plus it's titanium! Bling! A regular steel bleeder bolt won't have the higher part on top so it would probably fit better. It'll take some fettling to make it work but it's not difficult. Pretty sure it's effective since I almost went over the bars hitting the back brake over a log Tuesday. ? Of course you can just burp the bolt that's in it if already. Works just as well and is cheaper.

The ‘92 with the gold frame was hideous. Especially after the black and green beauty that was the ‘91.? The ‘96 was a lovely smooth bike. One of the reasons the Mikuni piddles fuel is the vent lines for the float bowl are so long they act like siphons once fuel get up in them. If you nip a small hole in the vent lines above the level of the float bowl they usually stop piddling.

Ask ten Beta owners what the worst maintenance task on a Beta is and eight of ten will say bleeding the rear brake. The other two don’t work on their own bikes. OK maybe that’s an exaggeration but it really is evil. My rear brake has been squeeky and weird since a get off last year that bent the disk. Replacing the disk helped but still not right so I went to replace the pads and the hex head on the pad retaining bolt stripped out. Ugh! Screw it. Replace the caliper though I know it meant the dreaded bleed. Hook up the lines, fill the reservoir and pump, pump, pump.... Too much air to make it work. Syringe back bleed to the master alternating push/pull monitoring level in the reservoir got rid of most of the air. Some resistance to the pedal and some pump- hold-bleed-close cycles got it closer. Now the party trick. Pump-hold-bleed-close cycles with the bleeder on top of the banjo on the master cylinder. Took about ten cycles to chase out the remaining air. Still not quite the pedal of doom so I eyeballed down at the disk while the pads engaged and the disk was moving. Disk brake systems are designed to be self aligning and they are on a car where the disk is strong enough to force the pistons into equalizing but the disk on a trials bike is so thin it will flex and then flex back once the brake is disengaged. This little bit of flex acts like a bent rotor only pushing one piston back and the caliper never sets up properly. The fix was to feel the direction of disk flex when applying the brake and apply gentle pressure to the opposite side of the disk to force the weak side piston to adjust out to where applying the brake doesn’t flex the rotor because it is centered between the pads. Much better. This is my custom bleeder setup. Yes it’s easier to just take the airbox out.

That works too?. If your working in your garage it is easier to just take it all apart and once you’ve done it you realize it actually pretty easy to pull the whole bike apart. But for parking lot, mid-event fixes like a blocked jet it really is pretty easy to pull the carb out one you figure out how. For me the big ah-ha moment was sliding the rear air boot back.

Worth pointing out two tools that are extremely useful and hardly thought of. Hemostats are those locking tweezer thingys that are used in surgery. I use them (depending on size) for holding components for soldering to chasing rubber boots onto carbs to retrieving small parts from inaccessible places. You don’t need them often but once you do you’ll be glad you have them. Places like Amazon or Harbor Freight sell cheap sets. Other surgical tools are also handy like small angled scissors. The other weird tools that have proven really useful are dental picks. Stainless steel picks bent at various angles with sharp points. I used one yesterday to clear dirt from around an air screw on a carb. Also useful for picking o-rings out of recessed grooves or cleaning silt out of calipers during rebuild.

Squirt some WD40 or similar lube on the inside of the rubber manifolds. The best way to get the carb off is to remove all the clamps and slide the rear air boot all the way back until it bottoms on the air box. It’s easy to pivot the carb out. It takes some force but not so much you’ll be worried. Same to reinstall. Twist carb into engine side manifold first and rotate into position. This will collapse the rear boot. Use a thin tool (I use my comically long curved hemostat but a screwdriver works in a pinch as long as you’re careful not to puncture the air boot or shave metal off the carb) to chase it around the intake bell and once it’s on slide the boot onto the carb until it seats. Reinstall the clamps. Lubing the rubber makes a huge difference just like changing a tire.

It’s a fairly simple idea. There is only a small amount of throw in the clutch mechanism and tolerances and wear can cause freeplay before engagement which just wastes some of that travel. Hydraulic clutch actuators should compensate to some degree but they seem to not quite get it done. Bultacos used to have a screw to adjust the position of the throwout bearing to compensate for this. Maybe time to see if it’s possible to implement on the EVO. I feel another custom part coming on!

The world guys used to stuff steel wool into the silencer for sound test. The Betas are a fairly high compression engine which is why the need for high octane fuel. Also why you get that pop when the exhaust port opens. Restricting flow in the exhaust will slow down the top end of the engine as well as make it quieter. You could try blocking some of the holes in the silencer core to achieve this. A piece of thin sheet metal should suffice. Alternately you could buy a low compression head to reduce the pop and the need for race gas. One thing to keep in mind though is despite how loud it seems standing behind the bike the sound of trials bikes doesn’t seem to carry. Honestly. Losing track of your friends in the woods is a common problem as if you can’t see them you usually can’t hear them. Only know where they are when they yell.

Anything really different with the 2020? Aside from the bold new graphics that is.?

Snug em. The springs will keep them from backing out.

Yes it comes up from the underside of the card throat oriented opposite the picture.

4T has all six of the 3mm thick plates. I haven’t got one to play with so I’ve got no idea how to smooth out the engagement. Swapping plates might work either with some of the thinner plates or the kevlar plates from Barnett but it’s pure speculation.

Yeah the more screwy the behavior usually the simpler the fix. Your intuition was correct all along.

Be careful with air pressure on the Keihin as there’s a gasket at the base of the float tower that is impossible to find a replacement for. One other thing that can happen is putting the needle jet in upside down. Sounds ridiculous but I’ve done it.? The tapered hole goes up.

Keihins are prone to needing an occasional cleaning. The exit hole for the pilot circuit is tiny as in microscopic. Yes it looks bigger if you eyeball it (the little hole in the bottom of the carb bore behind the slide) but it necks down significantly. Even a tiny bubble of water in that hole will make it bog coming off idle. Best to pull it apart and run some carb spray through the holes. Usually clears it up.