dan williams

He's got a point. I've never seen anything on the Beta forums about dodgy clutches, flakey Keihins, dribbling Mikunis, cracking EVO frames, frying stators, crap kill switches, weak main bearings, clunky head bearings, corroded water pumps or strange grounding schemes. I guess we Beta riders just don't talk to each other much. They all have their foibles. The one thing I can't stand is when there is an issue and the deniers come out of the woodwork. I'd much rather a manufacturer just say, "Yup, we screwed up. Where do we send the new frame."

Possible suspects, Ignition, Shorting kill switch, plug fouled, ignition coil, CDI, Stator, intermittent connector Carburation, Bad gas, contamination in tank, blocked jet, air leak, blocked gas cap vent Mechanical, Broken reed, torn air boot Identify symptom Does engine run well at lower RPMs? Does engine run well at higher throttle settings when throttle is rolled on slowly? Does engine recover if allowed to cool off? Does engine recover if allowed t run at lower RPM for a while? Obviously you want to go for the cheaper solutions first. A good disassemble and clean of the carb and fresh gas is a good start. While the carb is out inspect the air boots and reeds to make sure all is well. All Beta stock kill switches are crap. Replace it. Make sure you can blow air through the gas cap vent. Throw a new plug in and ride again. If the problem isn't fixed it's probably about to get expensive. Try a new plug cap on the HT lead of the coil. If that doesn't fix it you may be looking at the dreaded stator failure. Diagnoses of ignition component failure is a swap and check deal. I'd love to tell you there was an easy way to test for failed components but there isn't. Metering the stator even with an LCR bridge is iffy at best. Good luck.

Billy's comments on viscous coupling are very good. I remember being told years ago not to fill the Beta gearbox all the way as it caused the clutch to drag and that the factory guys ran less than the spec oil level. I can also confirm on the new EVO I still have some low speed drag as well as very quick clutch engagement. Certainly quicker than I am used to compared to the '08 which has a clutch "like buttah". Gonna have to get me some of Billy's magic oil. He hasn't steered me wrong yet.

If the resistance of the kill switch is high or one of the contacts is through the head bearings as with the classic single wire kill switch a high revving engine can still generate enough voltage to trigger the CDI. Another scenario is the engine is running so fast it is acting like a diesel and just firing the mixture from the free radicals not scavenged by the previous combustion cycle. You could also have a drastically over heated plug or contaminant in the combustion chamber that is just lighting mixture on its own. The Zip-meister brings up a great point about revving I hadn't thought of. Heh heh the spell checker suggested "moister"

Did you polish the tabs on the friction plates?

I see the 2014 has a pinch bolt now.

Hmmmm, I sold my '05 with a fresh rebuild of the bottom end for $2500. $1800 for a 22 year old trials bike is rather optimistic. Look at prices around the web for used bikes to get a better idea of what the market is. One bit of advice is to go to local events. There's always a few bikes for sale that you can try out and you get to meet the people you'll be riding with and see what the sections look like.

Exeter has held several world rounds and many US national rounds. Great terrain and good spectating.

Hmmm I realize the ignition epiphany thread points to a dead link. Let's see if this upload stuff works. Beta_wiring.pdf

I run BelRay H1R at 100:1. If you tend to ride hard 80:1 is fine.

I don't have the factory 300 just the regular. I did the clutch tab polish as they were still pretty rough but I skipped the glue removal since they were loads better than what they used to be on the older bikes. The washers on my bike were stepped so there is about a 2mm difference in spring preload depending on the way they are installed. It probably didn't make much difference but it was free and I had the thing apart anyway so... If you're getting pins and needles in your hands you are putting too much pressure on your hands. You need to fix that before you damage the nerves in your wrists. Check your bar position and make sure you have gloves with proper padding. Bars too far back will make you lean forward to compensate especially when you get tired. I think the EVO position is slightly different from the Rev3 and when I'm tied I start to feel like I'm falling forward. The riding gets really sloppy when that starts to happen. I think the stock grips aren't as good as Renthals but I haven't changed mine yet. Too lazy and/or cheap.

Ah back from visiting the in-laws. Glad to be back at work where I can relax, sort of. You have no option but to jet to the available fuel. You can jet rich to eliminate a pre-ignition mostly because the extra evaporating fuel cools the combustion chamber but it isn't optimum. Another gasket under the cylinder to slightly reduce the compression is also an option. This reduces the pressure in the cylinder to something a bit more in line with the lower octane rated fuel.

Lesson noted.

Betas ping without race gas. Carb will stop peeing fuel if you nip a hole in the float bowl vent tubes about halfway up the carb body.

You are missing a ground connection. There is a big black wire that connects to the top triple clamp behind the headlight. Reroute it down by the ignition coil and hard ground it to the frame. See if you can find my post on the same thing on my 08. Ignition epiphany or something like that. I'll post more when I can because I'm away from home at the moment.

That's an '02 and yes the fix is intended for just that problem. At least the deglue part. The tab polishing makes the clutch more linear.

Hey Scotty, on the 300 you can flip the washers around to lighten up the pull. If they're the same as on my bike. I haven't taken any springs out of the 300 though I did do the clutch tabs. The '08 is slipping a bit now 5 years after the clutch mod on four springs so I guess it's time to put the other two back in. Might as well I don't ride it anymore.

Yeah what he said. Be careful when you pull the pressure plate off not to drop the thrust bearing that'll be stuck to it. It helps as you disassemble to have a nice clean spot to put the parts like a table with paper towels on it. They are greasy parts after all. You can get the clutch pack out by hand but it's a pain. I used to use a small screwdriver with a bent end until I realized the toolbox held some of the bent dentist picks. Those stainless picks are one of those tools you pick up on a whim and just keep finding uses for. I'll just take two and stick them under the clutch pack and it comes right out. Don't worry too much it really is pretty simple. Oh yeah one other thing to be careful of is the o-ring under the cover can be a pain to get situated back in the groove. Be patient and if it remains intractable a few dabs of lithium grease will keep it in place. I also just lay the bike over. Also wash the bike first. No point in getting the innards dirty. ...and one more thing, don't over tighten the bolts that hold the springs. they are held in place as much by the spring pressure as bolt torque. If worried put a dab of Loctite on. Too much torque can snap off the studs from the basket. Been there, done that.

I'm afraid the best course of action is the usual, take it apart and do the fixes/adjustments/cleaning and then put it back together and see how it runs knowing at least the carb is sorted. All else is speculation. Idle changing from lean angle is a little weird but I'd suspect float level. The water bubble in the exit hole of the pilot circuit is not really variable. When it happens the bike runs awful in the lower throttle range all the time until it's cleared.

What was funny is I was dreading the shock spring change. I pulled the back wheel and airbox off and crawled under the bike on a stand to get at the bottom shock bolt but it really was pretty easy. The forks that I thought would take me 5 mins took a lot longer as the adjuster was solid in the fork cap. Even with a big wrench and breaker bar on the allen bolt it wouldn't free up. I had to lay into it with a big propane torch which carbonized the small o-ring in the cap. Only when it was really hot could I move it at all. When I finally got it all the way out it wasn't the threads of the adjuster that were jammed. (surprise) It was where the adjuster shaft with the allen socket goes through the cap that was so tight. Dremel tool with a grinder bit and a new o-ring sorted it out but man was that a bear to get apart. I've only ridden the new springs once but it was immediately apparent it was a good choice. The bike has lost none of it's stability but seems to be easier to time over obstacles. It's a little more enthusiastic about rotating the front end up when I hit somthing with the front end.

Tear in inlet boot between carb and cylinder? Sticking throttle cable? Rev3s use a rather short sleeved cable. Contaminant in the throttle bore? A disassemble and inspect is the only way to go.

I just dropped the stiffer fork and shock springs from Steve Saunders into my 2013. Very happy with the feel of the bike now.

Yeah water in the oil. Source can be water ingress from the water pump seal as mentioned or from riding through water and it getting in through the transmission vent or just from condensation. When oil is churned up it creates an emulsion which is why it turns white as the water is suspended in the oil. Eventually the water settles out into the bottom of the gearbox where it gets churned up into the oil again. You have to change the oil several times to get the water out and you can never get all of it as it settles into the nooks of the transmission. Best thing to do is get the oil all churned up before you change it. That way more of the water will be removed as part of the emulsion. With a couple of oil changes you can get most of the oil out but it takes a few.

Basics first, how does it run when it's running? If it runs properly you can ignore the next batch of questions. Are you using it as a trials bike or playing enduro racer? Is the choke properly off. I've seen bent choke rods holding the choke open a bit. Is the ignition timing set properly. OK the laundry list; Wrong plug heat range. A lot of people think the plug heat range affects engine temperature. They're wrong. Plug heat range is to make sure the plug tip stays hot enough to burn off contaminants while staying cool enough to not cause spontaneous combustion. Common. Plug fouls, bike stops, runs fine with new plug. Wrong fuel/oil mixture. People new to trials bikes often mix extremely rich mixtures for a trials bike that merely clog up the works. Typical mixtures in a modern water-cooled "electrofusion" bore engine run 70-1 to 100-1. Very common. Exhaust will be smoky. Again plug fouls, bike stops, runs fine with new plug Incorrect jetting. Standard Mikuni on that bike is probably a 30 Pilot 145 Main. Needle in the middle groove. Possible someone richened it up to play motocrosser or to try and compensate for bad gas. Wear of the needle and seat are also possible as well as damaged jets if someone ran a wire through them to clean them. Float level can also be way off due to bad adjustment or a damaged float filling with fuel and sinking. Somewhat common Plugged exhaust. If the mid muffler and/or final silencer are full of goo it affects the engines ability to breath. Weak running and fouled plugs can result. Somewhat common. Often will have a very smoky exhaust after a prolonged high speed run. Can ignite fire in exhaust system that will burn after bike is off. Ignition timing off. Either set incorrectly or due to a sheared flywheel key. Uncommon but can happen. Engine will run soft off the bottom. Oil leak. If transmission oil is finding a way into the area of the crankshaft through a case defect, bad primary side seal or leaking center gasket it can foul the plug. Uncommon but possible. More likely with an older engine. Usually smoky exhaust Choke stuck on. I once saw a bike that had the bent choke rod holding the valve just slightly open. Bike was hard starting and ran rich off the bottom. How the rider bent it I don't know. Weirdest thing I've seen. Very rare. These are the first places to hunt.

The '08 uses the Keihin carb and it is finicky around water. If you've got any water in the fuel or you've been out in wet conditions it is possible to get a water bubble in the pilot circuit that will sit in the air passage that comes out just behind the throttle slide on the bottom side of the carb body. This water bubble won't evaporate as the passage is small and surface tension holds the bubble together. I chased one of these for quite some time before I figured it out. The best thing to do is pull the carb out, start by sliding the back air boot as far as possible back onto the airbox, and disassemble and clean all the carb circuits. The main jet tower requires a security torx bit. (star bit with a hole drilled into the center) if you really want to take it all apart. Important to blow out all the air passages with compressed air.