dan williams

Whacking the throttle open quickly tends to cause the bike to run lean because it drops the air speed through the carb. This is the reason for accelerator pumps. Any engine will do it under load if the throttle is opened fast enough but your bike may be jetted a bit lean so the situation is a bit worse. One factor to consider is temperature. If the air temperature is cold and your bike is jetted for summer then it helps to go up one size on the pilot and main jets. Just for starters you can try raising the needle one notch to see if that helps. Another thing that might cause this is a broken reed valve petal. At low throttle settings the carb is closed down so air velocity through the carb is fairly high and constant. An engine designed for a reed valve has aggressive intake timing. When a reed is broken mixture can blow back through the carb loading up the engine as it gets multiple passes through the carb until the engine can get up enough RPMs to keep the column of air in the intake moving forward even when the intake manifold is open on the piston down stroke. Reading the plug isn't going to tell you much for this since it is a transient condition and really doesn't affect plug temperature much. It's highly unlikely this has anything to do with ignition.

Careful Neil, Not only does Martin have ways to track you down but he's a big guy who could rip your arms off and beat you with them. Heh heh just kidding. (or am I?) Hi Martin!

I have one in the truck right now as I picked up the 08 today and had an Akropovic and VForce reed installed. Unfortunately we also had a pretty good snow storm yesterday so it will be a while before I can try it out. Pity, the ground was completely clear before.

Damn that thing sounds like a purring tiger. (the four legged kind, not the triumph) I want one.

Before you get into the whole carb drilling bit try just nippering a small hole near the top of the vent tubes. The reason the Betas pee fuel is the vent tubes are so long they end below the fuel level in the float bowl. The usual bouncing around on a trials bike occasionally causes fuel to get up into the vent tubes causing them to act as siphons. With a hole in the tube near the top the fuel just retreats back down into the float bowl. I've done it on at least four Rev3s and they have all stopped leaking fuel and show no ill effect. The Mikuni is a good carb but like most dirt bike carbs it was originally designed for the street where it wouldn't get bounced around so much or placed at such odd angles.

OK so I'm a bit touchy. Since I figured out this clutch improvement method my main concern was that people would take shortcuts and not only not see the benefits but make their clutches worse. Blame it on the engineer's paranoia that the exhilaration of the "Ah HA!" moment gets ruined by poor execution. It happens often. Dilbert cartoons are too real for many of us. If it makes you feel any better I get to do it again myself. I'm picking up my '08 Saturday. I'm psyched! Can't wait for that new bike smell. Oh yeah one other thing to note is that the pull is just the pull. In a static environment (engine off) the effect of the unfinished clutch plates is going to be extremely small. I'm actually surprised you measured any difference in clutch pull from dressing the plates. The question that is raised by the smoothing of the plates is how much force is required to move a fiber plate under side torque as is the case when the engine is running and the clutch is partially engaged. For that you would need to know the rotational torque pushing the fiber plates into the basket. Remember the heavier springs don't do their mojo until the clutch is starting to engage and the plates are wedged into the side of the basket. If they are jamming against the side of the basket and the springs are not heavy enough to overcome the drag then the plates will never sit flat to make full contact so all the friction material comes into play. On the flip side when the clutch is disengaged the plates are still jammed into the clutch basket sides and can't release until the side torque is reduced to less then required to slide the plates apart. That leads to another question. If the plates are not making even contact around the basket are they disengaging cocked in the basket grooves. This would cause the plates to skew in the stack and possibly warp. This may not be a bad thing though as the main mechanism for the plates disengaging may require this to some extent. Basket wear is definitely a consideration. One of the reasons I'll be fixing the clutch on the '08 before I even ride it so any unpolished edges on the plates don't wear themselves a groove. All this is academic though and the simple truth for me is I've never had a better clutch on a Beta then the one in the '05 with two springs out and the plates polished. The pull doesn't fatigue my clutch hand anymore, which used to be a major problem, and aside from the initial stickyness of the clutch from a cold start the clutch doesn't drag or stick all day and hasn't shown any signs of slipping. Even with my fat A** on the bike.

You guys aren't paying attention. Smoothing the rough edges of the fiber plate tabs, matching them to the clutch basket slots and then polishing the tabs MUST be done before reduction of the clutch spring pressure. The reason for the heavy clutch springs is the rough edges from the forging process on the tabs dig into the sides of the clutch basket slots causing the plates to not engage or disengage properly under load. Just removing the springs will make for a slippimg clutch but not due to insufficient spring pressure to hold the plates together but insufficient pressure to slide the plates together completely before they bind on the side of the clutch basket slots. Take a look at any of the really good accessory clutches and you'll see they use steel inserts in the clutch basket slots and polished ends on the fiber plates for just this reason. Either do it right or don't do it.

The absolute size doesn't matter. One size up from what you have in the carb already should fix it. An engine that surges is typically running a bit lean. Fairly common on a properly jetted bike once the weather gets colder. I try to carry +/- two sizes of main and pilot jets in my tool box. Just ordered a set for the new Beta since I have Mikuni jets in the toolbox but none for the Keihin. A good $12 investment.

Yeah move your bars so they are more forward. Somewhere between in-line with the fork to just forward of vertical. It will make the steering very twitchy at first but you will get used to it. Then you will depend on it. It will also help on downhills. It's counter intuitive but if your bars are too far back then your center of gravity will be too far forward. That's because you will compensate for the bars by standing taller and moving your hips forward. Yes your back will hurt. All our backs hurt at the start of the season. The biggest thing to learn though is how to turn. Right now you're tooling around on flat ground at a good speed. Trials is rarely on flat ground at speed so you need to learn how to turn in balance at a crawl. The best advice I can give is to get off the bike. Now go find an incline and stand on it facing perpendicular to the fall line of the hill. i.e. one foot higher then the other. Stand there a minute and relax and bend your knees a little. Now look down at your knees. Notice one of them is bent more then the other. This is the proper position on the motorcycle for a turn. Center of gravity between your feet and no twist to the hips. If a friend comes over to push you up or down the hill you are able to fight the pressure and stay upright. 90% of the dabs in trials are dropped during a turn to the inside. The reason for this is new riders (and old riders when they forget and get back into bad habits) keep their legs straight. When you turn a motorcycle at speed you get used to leaning your body into the turn. This is OK on an enduro, MX or street bike where momentum can be used for correction. On the trials bike, riders will keep their legs too straight, lean into the corner and will be forced to dab when the slightest obstacle steals the meager reserve of momentum. This is the initial stage of a trials rider's technique. The second stage is the correction by trying to counter weight to the outside with your butt. To get a feel for this stand on the same hillside and try straightening your legs. Not very stable is it. You will naturally try to compensate by sticking you butt out and twisting your body. Not very comfortable and if your friend comes over and gives you a little push you're going over. When the butt correction is done on a trials bike you may well be balanced but your ability to correct a wheel slip or loss of momentum is seriously limited. It's best not to get into this bad habit in the first place. When you watch a good rider they will stay centered compensating for the rise and fall of the footpegs and bars by bending their elbows and knees. That is how they can stay balanced as they lean the bike one way then the other. It is also why they can attack an obstacle from a very short distance. They don't need the momentum to feel comfortable because they are already in a state of balance. Practice using your knees to turn and staying centered and you will improve dramatically. The Bernie Schreiber/Len Weed book on trials is still one of the best for novices as what worked on a '79 Bultaco is true today on an '08 Beta. Schreiber said that the most important skills he needed to win a world championship could be learned in a driveway and this is one of the biggest. Try doing figure eights at slow speed and getting used to hitting small obstacles while doing it. By small I mean starting with something 1-2 inches high. When you're doing it right you'll be able to stop at any point in the figure eight and balance. When you get really good you can go from steering lock to steering lock and feel completely in control. Once you can do that take it out to your practice sections and try to keep that same centered feeling as you ride. Most importantly have fun. You're not going to make a living at this but it will make you feel like a 10 year old again and how cool is that?

I'm a little confused as to why the question. Going cheap on such a critical component is usually a waste of money. I'm not trying to be a jerk. Believe me I have bought plenty of stuff that was a little cheaper and almost invariably I find I have to get the real item shortly thereafter and ended up saving nothing and actually paying a lot more then if I had just bought the genuine article in the first place. ...like this continuous printer inking system that was supposed to save me money and has only managed to spill ink all over the inside of my printer and make my fingers look like a Jackson Pollock painting.

If you have the stock kill switch on your bike it can do this. I've seen it happen on several Betas. Ditch it and get a Yamaha kill switch.

First nephew I taught to ride had a similar experience. Then I learned to put a piece of fuel line on top of slide to limit power. As they get better you can remove more line to open it up. Other critical skill is to teach them it's OK to bail. They don't know that and will stay with a losing cause until it's too late. I had nephew #2 and niece roll down a hill with the motor off and push off the rear. It teaches them how to get off by throwing the bike as well showing you won't be upset with them dropping the bike. Bike parts are cheaper and easier to obtain then body parts.

I had one odd thing happen with my '05. I was getting a slight clunk out of the front end and did the usual snugging of the triple clamp but the clunk kept coming back. What I found was the top triple clamp and the pivot that it rides on were not as snug of an interference fit as usual. I wound one layer of teflon tape around the pivot and that cured the clunk. A little unusual but worth noting.

I have only worked on 250-270s but I think this is still accurate. Sorry if this seems too simple. I find it easier to be basic in my description. Disconnect throttle cable from twist grip to give yourself a little more cable play. Undo the clamps and take them off the bike. They're easy to get back on. Pull the back side of the carb out from the airbox boot by rotating the carb out from the intake manifold. Grab the fuel hose clamp with a pair of needle nose pliers and slide it up the hose and remove the hose from carb. Unscrew top plate from carb letting the elbow on the top of the carb unscrew (it won't come out all the way before the carb top comes off) and slide the throttle slide out. Wrap slide in a paper towel so it doesn't get scratched and gently lay on cylinder. Stuff a clean paper towel in intake manifold to keep nasties out of it. Now you can take the slide/needle assembly off the cable. The hard part is getting the beastie back in. A big part of the process is to not be shy. Until you get the method down you're not going to be a finesse player. One tip that is a huge help is a spray of something like WD-40 on the airbox boot. The other thing that I find is a help is to use a curved pair of hemostats or similar rounded curved tool. This lets you get in around the backside of the intake bell to slip the airbox boot back on the intake bell. This is the hardest part of the process but after you've done it a few times it gets easier. Don't over tighten the hose clamps as they strip out fairly easily and you can chase the boots off the carb if the clamps aren't straight. That reminds me. Be careful to make sure the front clamp is straight relative to the carb not the intake manifold. Relax. It's a pain for everybody and requires patience.

That's the spirit! How did any of us learn how to work on bikes but to dive in until we were in up to our ears. The "let a pro do it" attitude is why you can't walk into a bike shop to buy a spark plug without them asking what brand and model you have and saying they can't sell it by plug number. Few people jet carbs or split cases on their own anymore and it's really not that difficult if done carefully. Besides all newly spoked wheels have a tendency to settle in after a few rides and should be tuned again. Look for articles on the web about spoking and truing bicycle wheels as the basic rules apply and bicycle wheels are considerably more finicky. A truing stand helps but truing it on the forks will work too. You can rubberband on some dowels as position indicators for truing. When truing remember it's not all about tightening to pull the rim in the direction you want it to go. You have to loosen the opposite side as well. As long as you don't dramatically torque the rim you can adjust the truing till you're happy with it. Let us know how it comes out.

If it's a Rev3 with inverted forks it's a 2000.

Yeah filing the tabs was me. It worked like a charm. It's the first thing I'll check when the '08 comes in. The idea is to make the edges of the tabs even and smooth. Remember they are bearing surfaces that have to slide while under side loads. A rough edge makes it difficult for the clutch to engage and disengage. You may also want to have a good look at your oil. I use Specto Golden Gear but have used Mobil1 motor oil with good results. I tried the ATF fluid before but it made the clutch way too grabby like an on/off switch. And it took several oil changes to get the ATF completely out of the gearbox.

Pushing a bike with the engine in gear and the plug out to purge a flooded cylinder is a recipe for disaster. That maneuver is the reason I always carry a BIG fire extinguisher in my truck. If my nephew didn't know where the fire extinguisher was I could have easily burned down my sister's house. There's no feeling quite like watching your bike lying on it's side burping fuel into a growing fire on a dirt driveway full of pine needles. BE VERY CAREFUL! Try a fresh plug. Sometimes a carbon foul or gas on the insulator will prevent a bike from starting..

Can't resist. Hub's been patching us up in New England for years. Thanks Hub.

Ah the Beta carb issues have been beat to death. Usually it isn't a sticky float. What usually happens is that because the carb gets bounced around and sits at a steep angle fuel gets up into the vent tubes. Since the tubes are long enough to go below the float bowl they act as siphons. There are a couple of different fixes. There is one that involves drilling out an alternate vent system. The other is just basic setup and takes about 15 minutes. What I've done to all my bikes is the 15 minute fix. I originally nipped a hole into the vent tubes near the top. Now I just cut them shorter. If you're not likely to submerge the bike they're kind of extraneous anyway. The other thing I did was adjust the floats so that with the float bowl off and the carb upside down the brass arms that the float pins contact should be level with the body adjusted with the tang between the pivot posts that closes the valve. The other adjustment limits the travel of the floats and can be adjusted with the little tang that sticks up next to one of the pivot posts. When the float valve is fully open the brass arms that the float pins contact should sit at ~45 degree angle. Basically pointing at the right angle corner formed by the pilot jet housing and the main jet housing. Be careful that the floats aren't rubbing on the float bowl gasket. I don't think I've ever replaced a Mikuni float bowl gasket. The full text of Billy Trainor's excellent suggestions which taught me is here http://www.trialscentral.com/forums/index.php?showtopic=310 Welcome to the sport. I hope you have as many fun years doing this as I have.

Do not tempt the gods!!!

My guess is that these "sandbaggers" are in the most popular and biggest classes. Yes? And by forcing them to move up you are hoping more people will get a chance to win trophys in the lower classes. Here's the conundrum. If they are the most popular classes why would you want to risk screwing them up? If most of the people in those classes don't have an issue then it's not an issue. There are two kinds of riders, those on the up side of their career and those who are out for fun and enjoyment. The rising stars are motivated to advance past the the duffers without the added incentive of the lower class trophy. The ones out for enjoyment however, "pay the freight". Mess with them by targeting them for promotion if they are doing good and you mess with the support base of the sport. Bad idea. If your so competitive you need a lower class trophy then learn how to beat them. If you can't then you will have a better perspective when they are gone and you are the one facing mandatory promotion. Relax and enjoy the ride. If you're not a rapidly rising youth and you're riding trials for any reason other then fun you're in the wrong sport.

You might have a contaminated disk which will make a pad swap at best a short term solution. You might want to swap pads at the same time you swap the rotor. One of the tricks I learned here from Ron Commo is to drag the front brake until it's hot and then pour water on it. I think this purges contaminates from the pad and rotor. Sometimes it works sometimes it doesn't. Remember GasGas and Beta are all using second source brake components and swapping brands for something like this may not do you much good. As for reliability they both have their peccadillos. Ride both to get a feel of engine characteristics and handling. Those as well as dealer support are reasons to choose a machine.

I've found after a number of years I've had to cut the opening on the end of the kickstart lever out a bit to get good dig on the splined shaft. Once I did that it stopped loosening up. A couple swipes with a hacksaw do the trick.

That shouldn't have damaged a solid state ignition but stranger things have happened. I agree though it's more likely connection related. One thing I've learned over the years is the more dramatic the failure mode the more obvious the problem. Make sure your kill switch is not messed up too. Be careful with sparks around gas. Trust me on this. Been there. Done that. Got the burned T-shirt.