dan williams

Hi Tony, Here's a google maps link that will show you exactly the field the event is at. http://maps.google.com/maps?q=http:%2F%2Fb...p;hl=en&z=7 The venue is Highgate VT

Hi Tony, Sorry I can't help you as I'm going up both days to work but I can post a link to this thread on the NETA web site and see if anyone's available. Dan

Hi Kip, Posted your message on the NETA site. http://www.newenglandtrials.org Hope to see you up in Vt Dan

OK two different systems here. The two tubes that come out the side of the carb are atmospheric vents. They are never meant to see fuel, only to keep the air pressure above the fuel in the float bowl at ambient. In some cases fuel will get splashed up into these vents and because the tubes attached to them are too long and end below the float bowl they act as siphons and will drain the tank if left unchecked. There are a few solutions to this. Raise the end of the tubes so they are higher then the float bowl or drill a couple of extra vent holes into the bowl or cut a hole in the vent tubes above the float bowl. The single brass tube that comes out of the bottom of the float bowl is the overflow. If the fuel level in the float bowl gets too high this is where the excess leaks out. This indicates either a damaged float (sinks to bottom of bowl so never shuts off fuel supply), a damaged float valve (check valve and seat, both can be replaced on Mikuni), the float level is set too high or a float is binding on something usually the float bowl gasket. Since you say it's coming out the overflow on the bottom of the float bowl I'd pull the carb and check the valve seat for dirt and make sure the seat is clean and smooth and the rubber tip of the valve isn't damaged. Next check to see if there is any fuel that has leaked into the floats. There should be nothing in the floats but air and no damage should be visible on the floats. Re-assemble the floats and move them through their travel and look to see if they could be binding on anything. If they are do what you must to get them moving freely with out interference. It's possible that they may not show a problem with the float bowl off so look to see any potential rubbing spots and take an X-acto to them if its the gasket or file a little bit if aluminum. A quick check (though it spills fuel) is to reconnect the fuel line with the float assembly together and turn on the tap while holding the floats closed. if no fuel leaks out the valve is working.

Clutch plate wear usually just shows as slipping. Wear of the hydraulics usually shows up as inconsistancy of the actuation. Trials clutches do tend to actuate fairly far out since they try to make the pull lighter by having a longer lever throw then an enduro bike.

No you're not confused. I'm an idiot. Got it backwards and as punishment I'll leave it there for all to enjoy. Only excuse it was past my bedtime.

It's not really the oil that provides the seal. It helps certainly but mainly it's the pressure above the ring that does the magic. The high pressure above and behind the ring force it into the cylinder wall and seat of the ring groove. When you're spinning the engine by hand there's a lot less pressure so the seal isn't as good plus there's a lot less time for air to leak at running speed.

The throw on a trials clutch is very short which means the range for adjustment is very small and any minor issue with the system can really mess up the works. Forgive me if this seems too simple. I'm not trying to insult. One thing I learned as a tech writer is start at the very basics as more advanced readers can skip over but novices need to be given enough info to get started. OK to make sure we're on the same page here. Is the clutch slipping when it is fully disengaged? Is the clutch dragging when it is fully pulled in? All I can understand from your post is that the engagement point is too far out. Fair enough. There are two adjustments on the lever. The first is the stud type screw that is in-line with the master cylinder piston. This screw adjusts the engagement point of the clutch. Screw it in towards the master cylinder and the clutch engagement point moves closer to the grip. Once that's adjusted to taste the lever stop screw that determines where the lever sits at rest must be adjusted out far enough to let the master cylinder piston come all the way out. That's pretty much it for adjustment. There is one other adjustment that is often forgotten and that is the position of the lever perch on the handlebar. Most trials guys run this fairly far from the grip to get more leverage. There have been reported instances of things like water being absorbed by hydraulic fluid and improperly drilled master cylinders but that sort of thing is extremely rare. Aside from assembly issues like leaving the ball bearing out that acts as a bearing for the push rod there's not that much to it. It helps to have the documentation, motor http://www.betamotor.com/system/attachment...t_04_motore.pdf chassis http://www.betamotor.com/system/attachment...0cc_veicolo.pdf On my last two Betas I've done a modification to the clutch fiber plates where I take them out and clean off the excess glue between the fiber blocks and smooth and polish the sides of the tabs. This makes a world of difference in the behavior of the Beta clutch. Details here. http://www.trialscentral.com/forums/index....15689&st=0# That's all I can think of at the moment.

Unless you've ridden the thing almost every day it would be unusual to wear a clutch so far it needs a full replacement after only four years. Can you tell us what the symptoms are? As pointed out, if the clutch is slipping or dragging it's possible you have the lever adjuster in too far so the reservior port isn't being uncovered at the end of the lever stroke. This causes the hydraulic system to be a "closed" system where either not enough fluid is in the system to completely disengage the clutch or the fluid heats up, expands and causes the clutch to never fully engage. Look at the master cylinder with the lever not pulled in. If the piston has not come back all the way to the snap ring you either have to back the screw out that pushes against the piston or you have to back out the screw that acts as a lever stop to allow the piston to come all the way back in the cylinder. It is also possible to have a weakened spring in the master cylinder due to a crash that smashes the lever in too far. The comment about clutch pack height and fingers and such is true for a "new style" Gas Gas clutch but not the Beta.

The reed are held closed by the back pressure from the downstroke. It's not that significant if there is a little space at the tip at rest. If you put light pressure on it and it sits flat against the seat it should be fine. Also the air leaking past the rings, if you are turning it by hand is normal. If you pull the cylinder and see significant blowby on the piston then it's time for set of rings.

I'm not saying you've done this Hugh but if you're three keys in then... It's been said before and I'll say it again, it's virtually impossible to hold the flywheel tight enough to put the flywheel nut on by any method that includes holding the back wheel. Not to mention that it puts tremendous twisting torque on the crank. A proper flywheel tool is the best and safest bet. A lot of guys in the know use air drivers which I suppose do the job but I'd be more comfortable with a holding tool and a torque wrench. This comes down to do it right or do it over. A sheared key could throw your timing off enough to scorch the valves. Hmmm.

When I was a poor teenager I'd bead blast them at the machine shop I worked at. Seriously though given the cost of everything else on a trials bike the plugs are the cheapest thing on the bike. Easiest to just buy new.

Yup, running backwards is an indication of the timing being way off. Check it with a timing light first. Takes a little jury rigging connecting to a car battery but it can be done. Make sure the timing is advancing with increase in RPM and that it is in the correct place. Make sure ground connections and all are good. Make sure all connections are the right way round. I had an Armstrong that ran backwards, over heated and generally ran bad. Turned out the trigger and charge wire from the stator was reversed so it was retarding the ignition when it should have been advancing. Took two years to find that one. Be a shame to spend

70:1 - 100:1 with a full synthetic is typical on a trials engine. Anything more and you'll be replacing muffler packing every few months and having to rev the motor before each climb to clean the goo out. Maybe 50:1 if you plan on running an enduro flat out on the thing. After 20 years of running at between 80:1-100:1 I've never had an engine failure. After about three years I'll change rings but that's pretty much it. Every time I've opened a trials engine I'm amazed at how little wear there is on the top end. I also notice, even when run at 100:1, there's always residual oil on the bottom of the crank. I've run Spectro, Mobil 2T, Belray MC1, Melray HR1, IPONE. So far the bikes just don't really care as long as the jetting is correct. I think compared to a road race engine there's a lot of time for the oil to stick to the parts so the mixture can be a lot less saturated. At 35:1 you'll be the guy with the smokey bad running bike. People will think you've blown a seal.

Check out the ratings on a site called dpreview. They really do test the cameras pretty throughly. The Panasonic Lumix are highly rated as are the Canon G series. A lot depends on how much you want to spend and how proficient your dad is. Some great shots can be taken with very inexpensive cameras but it's easier to really push it with a more advanced camera that lets you manually set F-stop, shutter and exposure.

Membership? Site supporter? I've seen this mentioned several times and noticed it on some people's sig but nobody ever says how to do it and how much. It's a classic case of assuming the other guy knows what you know. If you make people dig for information they won't. Andy?

No big secret. I own the website for newenglandtrials.org so I have my own server space. Once Stu EMAIL'd the pics to me I FTP'd them to my server and put a pointer here to the pics. The pointer is basically a set of HTML tags that say "<img> picture address here </img>". The tags tell your browser that the address points to a graphic so treat it as such and the picture address is the file location on the web accessable server. Essentially the pictures have to be on a computer somewhere the internet can access them. A "server". When you put them up on flicker or some other picture server you're throwing them up on a server that is open to the internet. I don't know if Andy has any setup for uploading to his servers. It's a real pain to maintain if it is and I can understand limiting the access. Disk space can be eaten up fast by photos and there are serious consequences if a server you're responsible for gets loaded with, er... shall we say questionable material. Best to just rely on the photo sharing sites to hold content as they are equipped to handle such issues.

They have a web site but I can't remember where I saw it. Took some digging and it really said nothing. I think they don't do the trials helmets anymore. Pity as I really liked mine.

I don't know 10-15lbs. Hurt a lot. That's odd clutch behavior. Requiring more pressure to statically hold in is just wrong. Once it

Beta's like high grade fuel but if it runs good down low and sputters on top the it's probably time to pull the carb for a good cleaning. Complete disassemble and blow out with compressed air. Also might be time to repack the silencer.

Point taken. Just as a side note it takes about 6 amps to start the fan motor so if you try to spin it up it takes a beefy supply.

Helping out Stu with posting pictures. a bit odd for sure. What kind of oil is used in the bike at what ratio? Did it sit unused for a long time? The reeds on one side definately look more abused then the other. What does the inside of the cage look look like? It almost looks like one side isn't opening so it isn't getting cooled by the incoming mixture.

With engine running, short the thermostat switch. Fan should come on. If not a new fan is probably in order. 70:1 - 100:1 common oil ratio with good synthetic. Racing fuel is best because the bike won't tolerate marginal pump fuel at all well. ATF in a Beta tranny makes the clutch very abrupt. I prefer any of the good synthetic gear oils like Spectro Golden Gear or Honda HP.

I run Delco #4 platinum plug in my '05 but you have to change the plug cap as the tip isn't threaded. The resistor is there to limit the rise time of the spark for radio interference. There is usually a 5kOhm resistor in the plug cap as well. 100:1 BelRay MC1, VP C-12 fuel. Spectro Golden Gear in the tranny. ATF makes the clutch grabby.

I put carbon fiber reeds in my bikes now so I have a set of the stock reeds and cage rattling around in my truck somewhere. I'll try to find them and have a look but I seem to remember in the back of my little mind that there was what looked like overspray of black paint on mine to some extent. On the old piston port MX bikes and certainly highly tuned road race bikes a back fire through the carb was possible but the port timing on a trials bike is so conservative that I'm not sure it's even possible and if the timing was off that much it's a pretty safe bet the thing wouldn't run at all. I've seen a lot of things but I can't think of anything that would cause the reeds to be scorched in a trials engine. Then again I'm always learning new things. Maybe if the engine was getting super hot because it was lean from a blocked jet or something but it would have to be spinning over very fast with a light load to sustain combustion. Odds are it would seize very quickly. I keep running it over in my head but I'm drawing a blank. Wish I had your reeds here to throw under a microscope. Did you buy the bike new or second hand?