dan williams

Well in all fairness the idea of soliciting opinion on a public forum is to see if an event is more than an outlier. If it happens to one, a few or many. Since we are rarely a statistically significant group locally it’s nice to be able to ask the rest of the world.

What fuel are you running? With a high compression ratio octane rating is critical. You can jet richer to reduce preignition but then you are throwing away power. This can be especially bad if the ignition advance is aggressive. Beta's were notorious for this.

One of those things a lot of people do but not on a conscious level.

I know that drill. My wife has to color coordinate her grips. Not even gonna mention the riding outfit. ?

If you mean a lot of work for no benefit I agree. But like buying her titanium screws and other goodies I figure she's good to me so I should spoil her. ? She's put up with the indignity of repeated teardowns just to figure out how she works and still runs like new. Good bike.

Yeah that's "normal". Beta replaced the two outer plates with slightly thicker plates so you will have four 2.7mm thick frictions and two 3.0mm thick frictions. Not sure of the logic behind this. I usually replace the 3.0mm thick plates with a couple of the 2.7s and dress them all to the Clutch Fix document. Or you could just dress the 3.0mm plates like the others and put it back together. The newer plates are a lot less gluey so the removal of the glue between the pads is optional. The older plates were a mess.

Neutral is always difficult because the neutral notch on the cam is smaller and in between two larger notches. As pointed out clutch drag doesn’t help either. I find getting neutral from first almost impossible. From second just a light tap on the lever usually gets it but it’s not a sure thing.

I had custom indexers made to improve the shifting on my 300 and they look the same on the diagram. Can you get a pic of the shifter mechanism on your sons bike. Also what year is it so I can see if they take the same part numbers.

Would probably look better without the fork guards but forks are expensive.

Covid boredom project. White plastic. Bold No Graphics.

Now there’s a question you don’t wan’t to ask.?

As do we all. I had the kick stand on my current ‘18 on the longest of any bike for years but took it off end of last year when it got wobbly and I got tired of re-tightening only to have it get loose again a few hours later. Fortunately here in New England there’s a tree every two feet so it’s usually no big deal.

Yeah they never quite get back to the original shape plus they turn into butter once bent.

With every part intended to be as light weight as possible the sidestand is only meant to hold up the bike. I took a friend with a Harley out to ride trials bikes and the first thing he did was sit on the bike on its stand. Instant bent stand.

First time I’ve done it but I have been on Betas since ‘89. Really wasn’t necessary but I didn’t like the damage I’d done to the back of the assembly so I figured I’d just get it done. The clutch has actually been really good.

In the process of experimenting with the shifter I messed up by not properly loctite-ing the cam screw which backed out and scratched up the back of the basket. Still worked fine but looked hack. Since the basket is getting grooved it’s time to atone for the sin of not using loctite and replace the basket hardware. I’ve also noticed significant wear on the throwout bearing. And something else which is a bit weird. The throwout bearing has become magnetic and is picking swarf out of the tranny oil. Maybe that’s why the bearing is a bit rough? Much smoother after a flush.?

You’re a better man than I. I tried to drop the fork on my 2018 to look at the internals and ran into the same issue. Screw loose but not releasing. Couldn’t get it to tighten either. Much bodging of tools and many bad words later got it back in and haven’t touched it since. I’ve been into a lot of Paiolis but these Sachs forks are a different animal despite looking the same.

Sounds like you’ve picked yourself quite a project. Good luck and let us know your progress.

It works ok but it did before. I’m just weirded out by the basket moving. That could only happen with play in the transmission input shaft. I’m still trying to sort out how the logic of this shakes out. The Japanese video shows no movement of the basket and some dead travel before the throwout mechanism engages the pressure plate. I’ll pull the whole thing next week probably but I want to ride tomorrow so it’s fine for now. Not trying to fix a problem. Just trying to understand.?

The learning continues... so with Ward’s success with the spacer washers I decided to throw some in my bike out of pure curiosity. My clutch wasn’t having a drag problem except a bit while cold but it can’t hurt to give it a try. I’ve always thought this shouldn’t work since the actuator mechanism should be self adjusting to take up play in the mechanicals caused by wear. So before pulling the pack with the clutch access cover off I pulled the lever to see if there was any dead zone in the actuation. The pressure plate moved immediately, as it should, but then I noticed something else. The basket also moved about 0.5 mm. Huh? Pulled the pack and checked the hub nut. Tight and locked in place. Tried manually pulling on the basket. Tiny almost undetectable movement. Actuate the clutch without the pack, no effect on basket. Re-assemble pack with two 0.25 washers and actuate lever. Pressure plate moves immediately and basket has no movement. Put cover back on for test ride and clutch feels slightly different. So here’s what I think is going on. Without the shims the entire clutch pack including the basket is able to move as a unit determined by the play in the basket. This pushes the clutch slave piston rest position back from the optimum position adding slack in the clutch actuation that cuts into the full throw of the actuator. I have to sit down and figure out exactly how the mechanicals interact. If anybody wants to give me a sanity check on this I’d appreciate it. Pull off the clutch cover, actuate the lever and feel the basket to see if it’s moving with the pressure plate.

Try dressing the steels with fine emery cloth. 2.7mm is nominal thickness. At least that is what I’ve always measured.

Ah good info. Idle speed wandering is often a symptom of running lean. Have a fire extinguisher handy just to be on the safe side. Try spraying starter fluid around the intake boot to make sure you don’t have an air leak. WD40 used to work as it had propane (can’t write that without hearing Hank Hill in my head?) for a propellant but I’m not sure if it still does. Short bursts while the bike is running. If the idle changes then you have an air leak. Gotta be fixed before any jetting will make sense. As for the knocking, Betas are famous for needing high octane. The come down knock is very common, especially that era bike. You may get rid of the knock by jetting it rich but the power gets all lazy. If you have access to race fuel or 100LL avgas give it a try. Even premium pump fuel is a crap shoot and I won’t use it after some painful get offs from a crappy running engine. I’ve run VP C-12 for years. It has the advantage of consistency. Day after day the engine behaves the same. Something that just doesn’t happen with pump gas. Another thing to consider is a set of rings. Pistons and bores on trials bikes last a long time but a set of rings will give you back engine snap you didn’t know you were missing. Another thing new trials bike owners often do is mix the oil/fuel like a motocross bike. Most trials bikes are happy at 80:1 and some will mix at 100:1 if they’re real plonkers. The Vertigos are running 200:1 but I think 80:1 is the sweet spot.

I’m just learning with the rest of you guys.? Everybody whose added to this thread has provided insight and now we know the Barnett plates will work on the 4t. Thanks to Ward for being the guinea pig.?

Ok Billy the holes to lighten the floats made me laugh. Basssound OK, I just had to make sure. Betas turn the tightest of any bike and reward good technique but will punish bad technique and pushing the front end is a common complaint. The first thing must new riders will assign blame to is the engine/clutch. They can be a contributing factor. Especially the clutch (see clutch thread pinned to top of forum) but the usual issue is just lack of control working engine vs clutch vs rear brake. Add to that most new riders will try to steer with upper body and weight distribution and though you may cobble together a working riding style the fundamentals are wrong and will limit progress to a certain point. Watch videos of good riders and note how they keep their torsos forward and steer by bending the inside leg and arm while straightening the outside leg and arm. Even the top guys will only de-center to start a dynamic move and get their body re-centered as quickly as possible. You’ll hear a lot of BS about weight the inside peg or the outside peg in various terrain. Ignore it. If you weight one peg without the intent of changing the attitude of the bike you will have to counterweight the opposite bar to keep the bike from flopping over. You’ve now induced torsion in your body that limits your ability to respond. Rule one: Stay centered. Rule two: Steer with your feet. Rule three: Think pressure not weight. Rule four: See rule one. If you can find a copy of the Bernie Schriber/Len Weed book Observed Trials buy it and give it a thorough read. It may be old but the basic instruction in it is as true today as it was when it was written. You’ve just started and have much to learn. I’ve been riding trials bikes for >35 years. I also have much to learn?. But damn it’s been and continues to be a fun journey.

Wait a minute. Did you mean the travel adjust tang was pointing to the bottom of the carb? That is where it’s supposed to go as it limits the float travel while the carb is bouncing around. If that’s the case your float arm is now in upside down. We need pictures?