dan williams

The vent tubes are THE reason for the leaking fuel. There is one overflow tube. That's the little brass tube that sticks out the bottom of the carb. I've only seen one carb with the problem of leaking out there and that was because the floats were rubbing on the bowl gasket. Easily fixed. Take the carb off again and get some cutting pliers and nipper a hole in the tube about halfway up the carb body. That will stop the leaking. What happens is as the carb is bouncing around the fuel sloshes up into the vent tubes. Since the vent tubes end below the float bowl they turn into siphons and will drain the whole tank in short order. If you nipper a hole in the tubes above the float level a little fuel will come out the tubes but stop as soon as the bike is upright as the gas would rather go back into the floatbowl. Basically reversing the siphon. As for getting the carb in and out I wrote a procedure here on that subject. Search my old posts and you should find it. A big help is lubing the rear airboot with WD40 or something similar. The other thing is to have a rounded tool to chase the airboot onto the carb bell. I use a pair of curved hemostats so I can chase the boot on and then grab the flange to pull it the rest of the way on. It seems like a real nightmare to get the Mikuni on and off but after the first few times it takes about 1 minute to get it off and 2-3 minutes to get it back on.

Ah I've had about four weeks now to ride and tweak the new bike and it's really getting me jonesin to ride. I'm never quite sure what the reception will be when I post about problems and fixes with my bikes so here's my impressions so far. Fixin's, Got an Akropovic pipe Got Vforce reeds Removed the excess glue from between the pads and leveled and smoothed the tabs on the fiber clutch plates and removed two springs Reset float level and re-jetted the Keihin with a 50 pilot and moved the needle clip up to the second notch Removed the lighting harness and re-grounded the kill switch to the coil ground Dropped the fork tubes in the triple clamps to the top notch Added several turns of preload to the front and rear springs Added a few turns to the damping of the front and rear suspension to control the additional preload Backed off the rear brake As far as I'm concerned this is just normal setup for a bike and the difference is amazing. The clutch is one finger and progressive with no stick. The new bike is very neutral handling. The wider and lower footpegs compared to the '05 make the bike extremely stable. Last weekend I aimed it at everything I dared go up or down and the bike never gave the slightest twitch. This is definitely the most stable Beta I've ever ridden on dropoffs. On climbs the front comes up easier then the '05 making the transition seem less jarring. I don't know how else to put it. The new bike does want to hold the front wheel in the air longer then the old bike after the initial hit which is probably a combination of less flywheel and rearward pegs. It's a little disturbing until you get used to it. The benefit is the backend sticks to the top of steps with a vengeance and any wheel trap that follows a step is easier to hit on top. It's almost scary the way this thing leaps up steps. The '05 required some clutch technique to build revs and slingshot an abrupt climb. The '08 will do the same with just a snap of the throttle. Still trying to get used to that. The engine is a cross between my friends 250 '05 (fast revving no flywheel) and my 270 '05 (lotsa grunt, extra flywheel). Now that the jetting is closer to perfect it's easier to ride. I think I screwed up the float adjustment first time round as the bike was stalling on downhills. That and the rear brake was set to maximum touchyness. The behavior went away with the proper float level and I went all day without a stall. I went one size larger on the pilot jet because I noticed a slight knock coming off high revs on the loop trail when chopping the throttle. The flat spot on the bottom has been replaced with a smooth grunt that transitions to an arm pulling top end in a nice progressive curve. Last week I was showing a friend a practice technique to get him comfortable with getting his weight over the rear of his Sherco to feel for traction on a climb and I told him you could practice this technique in any of the first four gears. To show him I rolled up a 45 degree slope just above idle in fourth and the Beta just chugged away. I knew I could do that on the old bike but I hadn't tried it on the '08. I love that VForce reed. Knowing that torque is there lets me correct when I screw up on a climb. Just roll off the throttle to get re-centered and roll it back on. No problem. I wasn't sure I was going to like the new motor with less flywheel but I'm lovin' it. Anybody who's afraid of a 270 hasn't ridden a properly set up bike. Tomorrow is the first event with the properly set up bike. Should be fun. Next week my buddy and I go to pick up his '08. Game on!

Yes the Mikunis all leak because the air vent tubes are too long and end below the float bowl. Billy Traynor did an excellent piece about setting the floats and nippering a small hole in the vent tubes near the top of the tube. It cures all for no money. See here http://www.r2wtrials.co.uk/html_files/betacarbsetup.html

Ah a GasGas 300 is going to require a somewhat more aggressive style then the Beta just to keep up with it. I find that because of the lightness of the rear end on GasGas Pros I have a hard time finding traction when I take a putt on my friend's bikes. They seem to get along just fine though so it may be just a style thing as you get used to the new bike. I think you're going to need to get used to riding the rear wheel a lot more. It may sound trite but it may be worth watching how the local experts ride their GasGas'. Really observe how they attack obstacles as far as body position and listen to their engines. It may show you places where you have to adjust your technique for the new bike. Also have a look at their setups as far as bar placement and how their suspension is setup. Even though it's a new bike doesn't mean its proper right out of the crate. I've spent the last four weeks tinkering with the setup of my '08 Rev3 and it's now at the point where I'm willing to say it's close to perfect for me. I probably could have done it in a week if I had a riding area nearby but such is life. Don't be afraid to make suspension/jetting/setup changes. Just do it with a little thought behind it and you'll be OK. It always good to have experienced help though, preferably a knowledgeable dealer who is also a rider. The payoff for knowing your bike inside and out is a big boost in your confidence level and if you tuned it yourself you will be much more attuned to the machine's needs.

A couple of things related to bike setup. The usual mistake newbies make of having to much air pressure. Get a good gauge and try to get a feel for optimum tire pressure. 3-5 PSI in the rear seems to be about the norm. More then that and you're just wasting that fine 2 ply radial. Suspension setup is another area that has a huge effect on grip. The suspension on a trials bike has a somewhat different job then the suspension on any other type of bike. Usually a suspension does two things. It makes for a more comfortable ride by absorbing quick shocks from the terrain by acting as a low frequency filter, transferring energy to the frame/rider over a longer period of time. The other job of the suspension is to keep the wheels in contact with the ground. The place where a trials bike is different is there are times we want the suspension to unleash its stored energy quickly for wheel hops and zaps. So tuning the suspension is a compromise no matter how you do it. The first thing I try to do with any suspension work is get the front and rear working together. I'm amazed how many times I get on a bike and the front or rear will sink down almost to the end of its travel and the other suspension will barely move. A bike moving through a rock field with a mismatched suspension will go through rapid geometry changes that make it difficult to stay on the bike let alone hold a line. A mismatched suspension will also cause the wheels to be suddenly loaded and unloaded making traction very unpredictable. If you find that you're tooling along just fine and suddenly a wheel slips it's not always a matter of technique or terrain. Usually I'll back off the damping and set the preload of the front and rear springs so pressure on the pegs moves the front and rear suspensions equally. This provides a starting point and rider preference for how stiff or soft the suspension can be set from there. I then adjust the damping based on riding style. Less damping for a more active trick rider and more damping for us sedate old guys who get one hop in the parking lot and think we're Jordi Tarres. Another critical setup issue for traction is jetting the bike. Aside from causing the rear wheel to break traction just from too much power an uneven response from the engine loads and unloads the suspension in an unpredictable way. I learned this when I had a '95 Beta with the Del'Orto carb. At the time it was a new carb and getting jets for it was impossible so I had to run the factory jetting. Unfortunately the carb came with a pilot jet that was far too rich. To compensate for the pilot jet the needle was set all the way lean. The result was a bike that seemed to run OK and made lots of power but the delivery was all wrong. It would bog at low throttle then all of a sudden at a little over 1/4 throttle the bike would suddenly get real interested in the proceedings and take off like a scalded cat. I had an awful time finding traction on any slippery, bumpy terrain especially up hill. Steps were real problems too as it was impossible to time hits and I

I think what you're asking for requires one of us with a perfectly running bike to pull off our flywheel to take a picture for you. You might be waiting a while. Maybe Lampkins or one of the other importers can pull a part out of the bin to shoot a picture but you're not likely to get any volunteers among the proletariat.

Thanks Jon, Not really necessary with the Keihin though. Once the boot is slid back towards the air box the intake bell clears the boot by about 1/4" and it looks like the air box part is just a straight tube. It's actually easier then the Mikuni now that I've figured out the sequence. Now if I can figure how to do it without taking the fender off...

Fine tuning my Keihin now so I'm getting good at taking the carb off. It's not necessary to take off anything more then the rear fender and not even that if you can find a way to position the air box boot clamps so you can undo them from the side (I haven't). Here's the procedure. Wash the bike. Doing carb work on a dirty bike is asking for trouble. Remove rear fender. Yeah it's a pain but the only way to get at air box hose clamp. Loosen both air box boot clamps. Slide air box rubber boot as far back as it will go. This will expose the leading edge of the carb intake bell. Loosen engine intake manifold hose clamp. Open twist grip cable cover on throttle and disconnect throttle cable (gives you a little more slack to work with). Twist carb intake bell away from rear boot and out of front boot. This take a little work to get past rear brake line but it's not a big deal. Lift carb body slightly and pull bottom of body out towards you and the carb is now free. Reverse to install. It may be easier with a squirt of WD40 or a little lithium grease on on the rear boot so it will slide on the air box easier. I also had the floats adjusted wrong this week and had the problem with the bike stalling downhill. Readjusted them to lower the fuel level in the float bowl and it is now fine.

Lighter pro clutch spring http://www.jackscycles.com/accesories.html

As much for others as yourself please put a proper kill switch on the thing once you get it fixed. It could save your friend's fingers as well as your engine.

Hi Billy, Nice to see you are still lookin' out for us. I've done the carb mods many times on many bikes with the expected great results. No drilling just the vent hose and tang thing. Many thanks for the enlightenment. It has made for many sweet running Beta's in this neck of the woods. Now if you can just come up with an easy way to get that &*%$*@& Keihin to go back in place I'd be forever grateful.

I don't want to give the wrong impression. Yes I steer people towards buying a Beta because of the good experience I've had with all of mine but there is a problem here and I'd rather do a service for my fellow riders (and in the long run a service for Beta) by admitting something is not quite right, finding a solution and presenting it. All bikes have weaknesses. The most recent I have experienced with other brands being the GasGas kickers and the Sherco shocks. GasGas USA went through considerable effort to fix my friend's Raga and finally get it sorted. I've got a lot of respect for that. As for the Sherco shocks I'd still like to see Sherco step up to the plate and at least offer a discount on a new shock or some formal acknowledgement of the issue. On the flip side of the coin we have to acknowledge that these are racing machines on the edge of technology with a very slim profit margin built by companies scratching just to survive. And we are a fickle bunch asking for super light weight then whining about reliability. I

The results of my investigation into the wiring fault on my bike. http://www.newenglandtrials.org/Beta_wiring.pdf

The results of my investigation. http://www.newenglandtrials.org/Beta_wiring.pdf

Wow, that's a pretty piece of work. You're hard core Jon.

Oh yeah, forgot the extra four petals in the VForce but the point remains that the lower petal mass is what has the most effect on low RPM power. Additional surface has two effects, making it easier to get high flow through the block and allowing smaller petals. The Beta doesn't have carbon fiber reeds stock. They paint them black but under a microscope it's pretty clear the fibers in the matrix are glass. In any case my original statement still stands that having the VForce gives a lot more grunt to the Beta. It almost feels like cheating.

The stock Beta reeds are four petals as well. The main point of the VForce or any carbon reed is the lower mass of the petal allows it to open and close with less pressure then the standard fiberglass reeds. This means the carbon reeds open faster to let in more mixture and close faster to hold more charge in the crankcase and let less blowback through the inlet tract at low RPM. At high RPM the reeds are always open so the design of the reed block comes into play but in most engines there is more then enough power at high RPM even given a less then optimal flow through the reed block.

Not Boysens but VForce3s, same as I have on my '05. They have the same effect on the '08. It'll pull a gear higher and lugs like a four stroke at low RPMs. I won't ride without them.

Bet you're glad you didn't get a piece of the action back in '99 when it was $135 a share.

It doesn't matter what the pursuit. At some point anything you do intensely for fun will burn you out from time to time. The pros do it for a living so they have to have a different attitude. Relax and take your time. Don

Nice to see the old dog's still got some bite.

Stamford is within 60 miles of Meriden Motorcycle Club as the crow flies. Slightly further as the horse flies. (sorry can't resist a Marx brothers reference). Meriden is one of the most active clubs in New England and has some great terrain. They will be holding the first event of the 2008 NETA season April 6th. This is the club that 10 time US champion Geoff Aaron came out of. The NETA page has a Google earth/Google maps link if you want a graphic of where the NETA events take place. http://www.newenglandtrials.org/

VM26-208, Beta has used that carb for many years. There are many posts here on the best way to set up this carb. Just search for Mikuni.

I assure you the response I get from the Beta faithful when I post is more along the lines of, "Oh crap, he's at it again." I'm not a fan of ignoring an issue. I'd rather figure it out so it can be fixed and move on. As for working for Beta no. I did PR work for the Fantic and Aprilia importers some years back if that's significant to you. Beta's people have treated me very well. Starting with not trying to squelch me when I think I've found something that can help other riders not only on Betas but other brands as well. I've got a lot of respect for that. The one thing that really grinds my gears is to see someone get on the boards with a problem only to be harassed into submission by the brand specific fanboys most of whom are dealers. Nothing turns me off from a brand faster then that. As for your friend with the bad experience I don't think it was a Beta specific problem he had. I think his dealer hooked his kill switch up wrong. It's the only explanation that makes sense. Maybe this thread will give someone the insight not to do that and save someone else from a similar experience. So Baldilocks are you a dealer?

OK I just looked at the schematic for the '06 and there is no diode in the kill switch circuit. That's good enough for me to say that's the fix Beta put in place on the newer bikes to prevent damage from the lighting circuit back feeding into the ignition if a ground goes intermittent. There's simply no other explanation for it being there. Should be easy to retrofit to an older bike if you're concerned. It still couldn't hurt to run a separate ground wire from the lights/horn to the "ground" mecca on the frame. See wasn't that relatively painless to figure out. Now there's no reason for anybody to blow out a single ignition let alone four.