dan williams

The Rev3 is a fairly high compression engine and really likes racing gas. The pinging is a sign of too low an octane. You may want to lower your compression with an extra cylinder base gasket if you can't get better fuel. I run VP C-12 at 108 octane in both my bikes one with Keihin and the other with a Mikuni and neither of them ping but they will ping if pushed using pump fuel, even with Sunoco 93. Well some batches anyway. I'm never sure of what comes out of the pump to be honest.

You don't say whether you have bumped up the idle which is a common way to deal with a misbehaving pilot circuit. This sort of bypasses the idle circuit, or maybe overrides it would be more accurate. One of the characteristics of the Keihin is the very small exit hole for the pilot circuit behind the slide. I have had the hole blocked by a bubble of water after riding in wet conditions and the only way to clear it was with a disassemble of the carb and a blast of compressed air. My suggestion would be to drop the carb and do a disassemble and clean. With compressed air and paying attention to blowing through the air passages in the carb body. I think that will fix your problem.

Only way to know is disassemble and have a look. You have to do it anyway.

Spot on, tire pressure is the most common newby mistake.

Hmmm I had a set go out on my '05. Paid a friend who's just become a dealer to fix them. Partly because I didn't have the space and partly because he needed the experiance. They didn't make any kind of swishy noise. They sounded like a rock crusher. Rather impressive actually. I'll have to keep an ear on my '08.

Sorry, didn't mean to be cryptic. Your carburator has several "circuits" for controlling mixture at different throttle settings and these all affect each other as they transition from one to the next. By circuit I mean a metered fuel oriface (jet) and various air passages in the carb body. From idle to 1/8th throttle the fuel air mixture is done by a combination of the idle air circuit and the "pilot" jet circuit. From 1/8th to 1/4th throttle mixture is controlled by a combination of the pilot circuit and the angle of the throttle slide cutaway. From 1/4th to 3/4th throttle the mixture is controlled by the "needle" and "needle jet" with influence from the slide at 1/4 and influence from the main jet at 3/4 throttle. From 3/4th throttle to full throttle mixture is controlled by the "main" jet. As you can see a fleck of dirt in one of these jets will affect performance in just one area of throttle. Cleaning with compressed air is really the best way to make sure the circuits are clear. One thing I have noticed about the Keihin is the size of the pilot circuit exit behind the throttle slide is extremely small. Much smaller that the old Mikuni and I have had instances where a bubble of water will sit in and block this exit hole bunging up the way the bike runs off idle. The hole is so small that the water won't evaporate because of its surface tension. It has to be blown out. I now carry a can of compressed air from a camera shop just in case I need to clear a jet in the pits at an event. Even though this is for a Mikuni it is still an excellent guide to carb operation http://www.mikuni.com/pdf/vmmanual.pdf As for the reeds they sit in that square block between the carb and the cylinder. You can take the four bolts off and the assembly comes right out. Just do a quick visual to make sure all the reed petals are in one piece and that there isn't any dirt or debris on the seats that would hold the petals open. Don't worry if they look like they are slightly open. Air pressure closes them so they don't need to lie completely flat to work. Make sure you get a good seal when you bolt it all back together as an air leak can mess with carburation. Cleanliness IS the rule of the day with these fiddly little bits. Happy hunting.

Yeah you probably should have. You can pay the same for stuff made in the millions by Feng Shui manufacturing if it has a fancy label on it. If these are made in the UK I have no problem paying that much. In fact now that I've poked around the website I think I'll see what they cost in the US.

I think it's a 10. It makes 2nd the default section gear and first for crawling. I find the stock gearing makes second a bit too lively and first still too pokey for most sections.

Usually the pilot jet circuit. Clean with compressed air. A damaged reed will also cause a flat spot off idle.

Well Billy, according to Jeremy Clarkson we're fatter in the US (he's right of course) so we probably need to run a bit richer. I'm assuming this is a 250/270? If so a 27.5 pilot runs cleaner on the bottom and gives a crisper transition to the midrange but will also accentuate any lean pinging you get from low octane fuel.

OK so I don't like ATF but some do. I think the better riders who like a faster clutch are more fans of ATF. Then again there are so many types of ATF that I should probably avoid blanket statements.

I find dropping a tooth on the countershaft sprocket makes the 270 much better behaved.

You have to remove the glue in my experiance as I believe it is what causes the sticky. The edges of the tabs should be slightly radiused and polished. On the original bike I did the fix too (guinea pig1) I had a friend replace the main bearings (I didn't have the time) and he, being a Gas Gas dealer, stuck in ATF. The clutch is not working quite as good as before so I may have to crack it open and have a look. In my experiance ATF is not great in a Beta. Not sure about the hypoid gear oils as they are not really meant for a wet clutch if I remember trading friction characteristics for shear strength under load. Oh yeah one other note, too much oil in the gearbox will give you that creeping drag. Not sure why but I've heard it from some of the top mechanics and noticed it myself.

They are supposed to move. Do NOT try to tighten them to stop them from moving. You will bung up your brakes and possibly break your hub. Yes I've seen both happen. The float allows the brakes to be self adjusting which helps them be very strong with minimal throw and much more consistant.

Needs a set of rings. It may seem to run OK once it's going but throw a set of rings in and it will seem like a whole new bike.

It seems to be two opposite methods here but people are really in agreement. When they say put the naughty bits on the tank they really mean to lower your center of gravity to help keep the front wheel down on climbs. Think about the angle of your center of gravity vs the contact patch of the rear tire. When you move forward you increase that angle but it tends to unweight the rear wheel which causes spin. Sqatting down allows you to increase that angle while keeping pressure on the rear wheel.

The clutch fix does help but Beta's are notchy as a matter of course and neutral is always elusive.

Well there are a million ways to do this but you only need one since you only have to do a set of clutch plates once. I thought of lots of methods and they were good mental exercises but in the end picking up a set of files and just going at it got the job done faster/cheaper.

Sorry but the only way to get rid of a stupid rule is to enforce it exactly as written. Just like the only way to get rid of a bad law is to enforce it. When something like this is let slide by most then the people who do try to follow the rule are considered jerks.

Brilliant!

I remember reading about Ossa having titanium frames for some of the factory bikes.

Have a look at your reeds as well. You may have a damaged one. If they are just slightly open though it's not a problem as they are forced shut by air pressure not the springyness of the material. Is springyness even a word? Actually I should add the question does it rev properly when slowly brought up to full throttle?

Basically the bearings sit flush in the hub and the spacer should be an exact fit between the inner races. The spacer is really just a bare tube. I haven't had the wheel apart on a Beta in a long time but I don't remember it looking like what you found. It almost looks like what was in your wheel was some random piece of tubing just stuffed in the wheel. The sole purpose of the spacer is to allow you to torque the axle without any side force being absorbed by the bearing.

The Beta Mikuni is a VM26-208. It's sort of a special setup so you won't find any parts places stocking parts for that particular model outside of a Beta dealer. I don't remember if that particular year had the "noodle" on top. Basically a right angle tube held into the top of the carb with a snap ring sort of deal so the cable doesn't foul coming out the top of the carb. This is a good place to start. Remember some parts are not specific to a certain carb so they may have very generic part numbers. http://www.motorcyclecarbs.com/VM26-VM44_Spigot_Mount_Parts_W192C1420.cfm

The Bernie book is rare as hen's teeth these days. I had an autographed copy but gave it to a lad I thought had potential. He quit after a year. Dammit I want my book back!