dan williams

A low compression head goes a long way to taming a bigger motor. Kicks easier. Runs better on low octane fuel. Still maintains that lovely low end torque.

I’ll bet clear mudguards would look quite stunning.

I think the hex ones are all the same. Just make sure it fits VM series carb.

To be honest I don’t see much difference between my ‘13 Evo and my ‘18 Evo other than better shifting. After I got my ‘13 I noticed just how much better it handled and tracked than my beloved ‘08. The difference was astounding. You know you want a newer bike. You’ve been cleared by the boss. What the hell are you waiting for? Seriously any Evo with the hydroformed frame is a quantum leap from your 2001.

ok here’s the condensed version; The Mikuni VM26-208 fitted to the Beta isn’t a bad carb. The fuel valve needle and seat are easy to replace and redily available. There are three hoses that come out of the carb. One is attached to the bottom of the float bowl. This goes to a brass tube inside the float bowl and is the overflow for the float bowl. If gas is coming from this hose you may have a valve or float problem. The most common fuel piddling problem with Betas equipped with Mikunis comes from the other two plastic hoses which come from the sides of the carb body. These are atmospheric vents for the float bowl. They are never intended to see fuel however the bouncing and tipping that a trials bike is subjected too can splash fuel up into these plastic tubes. Because these tubes are long and end below the float bowl they can act siphons if the level of fuel is high in the float bowl and the bike bike is tipped enough for fuel to cover a vent hole in the top of the fuel chamber. Typically you see this when the bike is leaning on a side stand. The cure per Billy T’s instruction is to nip a small hole in both vent tubes at a point above the float bowl about halfway up the vent tubes. This prevents the siphon effect. The other piece is the properly set float level where the valve shuts off and float travel to limit the effect of the bike bouncing around on the fuel level. There are notes on how to do this on here but I’m on my phone so a bit limited in my ability to link to them. Do a search for Beta setting Mikuni should turn up either Billy’s excellent explaination or something similar from one of the SSDT prep documents. There are other documents that talk about fitting brass tubes and other vent trickery. Overkill I think. Just nip the tube, set the floats and be done. If you do decide you need a new valve needle and seat it’s worth the money to make sure they are genuine Mikuni from a reputable source.

Read the Mikuni thread pinned at the top of this forum.

All joking aside the 300 vs 200 argument is most valid for beginners who ride street bikes and have no dirt muscles. With your experiance and size a 300 shouldn’t be a problem. A 300 can also be detuned to make it less alarming on the top without losing the low end torque that makes it easier in some trickier terrain. There are videos of Toni Bou going over advanced obstacles with his engine off so it is obviously not all about the motor. One aspect of a larger engine is it can fatigue you faster if you are not subtle with your control. If you haven’t ridden a trials bike you won’t be used to the immediate reaction trials bikes have to input. This is what surprises newbys the most but once you get used to it you depend on it though it’ll still surprise you now and then and that surprise is just a bit bigger with a larger engine. As stated condition of the bike is probably a bigger buying consideration. I suspect you will be like most riders in that if you try a bunch of bikes one will just speak to you. The best place to look is a local trials event if you can find one. If you’re in the market there will be bikes to try and you get to talk to the owners and it’s easier to negotiate price if you got a wad of cash in hand. Especially this time of year when new bikes come out and riders are looking to sell their old bikes to get the latest “Bold New Graphics” machine.

Awesome. I bungled putting the Jitsie kit on mine so I need a new o-ring. Some days it just doesn’t go together like it should. On a side note leaving for work the other day my Subaru made a noise like a yard full of barking dogs. Weirdest machine noise I’ve ever heard. It stopped after a minute and remains a mystery.

Did you fix the squeeeeel?

Yup you might need to go up a couple clicks on the rebound damping but you will have more control on the bouncy chewy stuff. I’ve done the heavier springs with less preload on my Betas for years and it really does help.

You will maintain traction better with the correct springs. With “normal” preload your suspension will be too soft so your geometry will be much more variable over bumpy terrain complicating control. If you crank up the preload the suspension will require your weight on it at all times to work as the springs will not compress until you have enough weight to overcome the preload. Up to that point it’s like a hard tail. A heavier set of springs will allow less preload making the suspension work better on smaller surface irregularities while still absorbing bigger hits without hard frame breaking bottoming out. And as Lineaway points out front and rear need to work together.

Sheared off woodruff key on the ignition flywheel. Fairly common occurrence. If the woodruff key didn't shear you run the risk of twisting the crank so it's actually a protection mechanism for the engine.

Welcome to the sport. Once you get used to the weirder parts of riding a trials bike it will start to feel quite natural and other bikes will start to feel weird.

Condolences on your loss John but thank you for sharing your dad’s piece of trials history. I’m sure there were many amazing stories that came with those photos.

There are beginners of all different types. Much depends on riding experiance and physicality. A 250lb athletic enduro rider might handle more power than a 100lb teenage girl but the basic techniques are the same regardless of engine size which is why you will get your ass handed to you at events by teenage girls and old men. Bigger motors have more grunt and can be more tiring to ride but are also able to deal with fast loop trails and there is no substitute for pulling you out of a low speed greasy up hill that you got into too slow. A bigger engine can be detuned but a smaller engine is, well smaller. The other thing to be aware of is sometimes the smaller engines are tuned a bit peakier as some were intended to be quickr revving than the bigger bikes. Beta in particular have oscillated back and forth over the years on the tuning of top models. For example the ‘94 Techno was a high revving abrupt bike that experts loved while everyone else crashed their asses off. The ‘95 was a much easier to ride bike and the big ‘96 was considered by many to be too soft but the 250 was peaky and popular with experts. You really have to try a bike to see if it fits what you need but you will in any case adjust somewhat to fit the bike you’re on because no matter what you choose the bike is never the limiting factor. As pointed out a well maintained bike is the first thing to consider. For that an older rider’s bike is probably best as they don’t beat up their bikes and have the money to replace what they break.

Betas in general don’t seem to have the best method of routing. Tighten the adjuster for immediate response and it will runup the engine in a turn. Make sure the end of the cable is properly seated in the carb top. Add a little slack to the adjuster and get used to that extra 5 degrees of rotation off idle. For a real thrill catch the cable on a tree branch mid loop. Very exciting.

Cable routing? Betas are a bit touchy if your body position is far forward. I know if I lean too far and press on the cable it’ll rev. A ripped or cracked carb boot will also cause what you describe so will a carb that isn’t mounted properly. Another thing that can hang the throttle is the closed end of the grip catching on the end of the bar. Usually happens after a fall or leaning the bar against a tree. Main advantage of running bar ends.

It’s aluminum threaded into aluminum so it can’t really swell. As pointed out though it’s real easy to overtighten and gall the threads especially when new. Tiny dab of antiseize or just wait until it wears in. Duh just looked at my ‘18 and it’s plastic so what I said above is obviously the ravings of a madman. My apologies.

Ah I like this guy! Buys all the spare parts before even cracking it open.

Hmmm if you suspect the water pump pull the screws and have a look. Those plastic impellers are known to disembowel themseles occasionally. Best to look and be sure. I usually put one of the Jitsie high volume pumps with the metal impeller on a new bike. Mostly because of all the reports of damaged plastic impellers and a little extra pump capacity couldn’t hurt right? Oil bathed bearings usually don’t squeal. They knock or get crunchy like a rock crusher. Squeals are usually something rubbing. Does the squeal change with crank speed or wheel speed? Does it change under load? Does it occur in neutral? Is it just something like airbox noise? I know my new 2018 has a surprising amount of airbox squeek compared to my older bikes. Sounds like a fun diagnosis.

You suspension fluid will also be thicker so a couple clicks off the dampers may help. Cold dense air will also affect how the engine runs and will usually result in more power. Depending on your jetting this can also result in a change to the power delivery. As above you will probably want to keep more over the back wheel. This is actually very good practice as it’s pointing out weakness in your technique. When you can turn on the really slippery stuff you are properly centered. All the little tricks that allow you to get away with bad tecnique when there’s traction won’t work on ice so view this as an opportunity to fine tune your skills. Don’t move your bars once you have a natural comfortable position. It’ll just screw up your muscle memory.

As long as you got it to the correct torque it’s all good. I was thinking about it and I would imagine you want it to move and shear the key under unusual loads rather than twist the crank.

Sorry late to the party on this but here is the flywheel holder I cobbled together for use on Betas. Actually I've made a few since they keep getting borrowed then disappear. Works like a charm. Piece of bar stock. One cut, three holes. Can even make a handle on the far end. Vitally important to not screw in the bolts on the flywheel deeper than the flywheel or you destroy the stator. Short bolts or washers/nuts as shims is a good idea.

I’d be happy to have it weight the same as my Beta with a larger battery too. I just had a thought. Would be interesting if someone like Honda bought Jordi out and started cranking these out. They are surprisingly quiet on the electric bike front. I guess there’s that e-assist thing. Ewwww. The Beta decides where I’m going on its own enough already.

I suspect they will not be able to keep up with demand once the bike is finalized.