dan williams

The problem is usually air trapped in the system. Air is an elastic medium (or at least much more than the brake fluid, Gas vs. liquid distance between molecules type of stuff) so when the pedal is depressed some of that fluid displacement is taken up compressing the air bubbles and doesn't generate the same force on the pads. Remove the gas from the fluid and you remove most of the problem. The only possible effect I can think of from putting a weight on the pedal to keep the fluid under pressure forces the gas in the system into solution with the brake fluid. Like CO2 in a bottle of soda. Once the pressure is released the gas will come out of solution. Try the bleeding from the top banjo bolt at the master cylinder. It's fast, it's easy and my guess is it will help. Since I just rebuilt the rear system on my '13 EVO (rear master and caliper) a month ago I can tell you it was the last step that finally got my brakes back to where they belong. Another issue could be contaminated pads/rotor. It's fairly common to get chain lube over spray or just finger grease on the pads and they lose a lot of their grip. Brake cleaner helps as does heating the pads to burn off any organics that may contaminate them. You can really heat up the metallic pads and they'll still be good. Just don't do it on the bike as you'll damage the seals in the caliper. I took a MAPP torch to mine and they were fine but I eventually told myself to cut loose with a buck and buy some new ones. The reason I don't recommend the pressure on any of the hydraulic systems on a bike is simply they are not designed for it. They are designed for short term application and it is possible to cause long term plastic deformation of the seals which will wear them faster. Fluid will weep past seals every time there is a pressure differential. In normal usage the amount of fluid that gets past the seals is so small that it will evaporate long before you would ever notice it. So a small amount of leakage from a seal under constant pressure that isn't designed for such duty is not surprising but it won't hurt to keep an eye on it. So I think it best that you start with the cheap (free) and easy bleed the caliper first with the bleed nipple just to be sure there is no air hiding in that high spot then bleed by cracking the banjo bolt at the top of the master cylinder. I think that will cure the majority of your problem. If that doesn't work then go ahead and try the other guy's tricks. I promise I won't have a tantrum.

Oh that hurts Heather.

Rear brakes on the Beta are a pain to bleed as the air gets trapped in the highest part of the system in the banjo bolt at the top of the master cylinder. Hanging weight on the pedal will only force fluid under pressure past the piston seal and possibly damage the seal. Try bleeding the rear by pressurizing the system and while holding the pedal down crack the banjo bolt. Tighten the bolt, repressurize and repeat. It usually takes four or five repeats to chase the air out. Refill the resevior and it should be better. There really should be a bleeder valve at the top of the master cylinder.

Except if you try an EVO you are going to wonder how you ever rode the Techno?

A last place, 3 DNFs and a win I might have a problem with consistency. I'm quite happy in the bunny class thank you.

Ordered a 2018 EVO 300. Got tired of waiting for the electric bikes.

25:1?! Might as well be a diesel.

Well somebody must like them since we're hip deep in Beta's in New England. Quite a few riders have come back to a Beta after switching. As long as the bikes are selling why make a major change?

0.003" shim seems to have sorted it but I haven't really put any hard riding (if what I do can be called hard) on it yet. I'll have a much better idea after tomorrows event. Anybody want some brass shim? I have a whole roll of it that I only used about a square inch of.

The two seem at odds. Sounds like two issues that are unrelated. Things we need to know assuming this is a two stroke, How does the bike run? Pinging or knocking on run up under load? Smoky and bogging? What plug do you have? Have you tried a fresh plug? Black oily plug is usually jetting, oil mixture, incorrect plug, blocked exhaust, crank seal/case leak allowing gear oil into crankcase. What are you using for premix oil and ratio? Typically I run 100:1 Bel-Ray H1R. Most guys run between 80:1 > 100:1. Depends on how you ride. Fast trail riding is much different than plonking through sections. Is your coolant topped off? Best to use a propylene glycol mixture like Silkolene Pro-Cool or Engine Ice. NO TAP WATER!!! Only use deionized water. Have you checked your water pump housing/rotor? Betas tend to corrode the pump housing and the plastic rotor gets easily stripped. Jitsie makes a larger metal water pump kit. Highly recommended.

They could be silicon nitride but really no big whoop. The bold new graphics are basically, "Screw it, let's not paint it." As for the diaphragm clutch I see just as many people complaining about setting up the diaphragm clutch as the old style so...

Could be fuel leaking into the intake manifold then into cylinder. When it does start is it running very rich? This is fairly common on all bikes except on two stokes the fuel gets into the crankcase and so it doesn't raise the apparent compression.

OK that made me spit coffee.

Bold new graphics, improved clutch. New crankcase volume for make the improved power immediate..... Of course there's always the chance they will redesign the whole thing. Fuel injection anyone? I guess we'll just have to wait and see.

Hmmm sounds like a way to save a few ounces on the factory bike. Not sure I like the implications for long term reliability. I've seen designs where the bearing cap has an extension and the top clamp slides onto the cap. More than one way to skin a cat(fish). My brass shim stock has arrived so I'll give that a go first. Nice find on the Parker "shaft saver"

No clamping force. The fit between the spindle and the top triple clamp shouldn't be an interference fit but close. It should be tight enough that a few mild taps are required to slide the top clamp on. On this and my past few Betas it's been absolutely floppy once the top nut is removed. The top nut is meant to hold the clamp on not fix it in place relative to the spindle. The leverage of the forks is sufficient to force the clamp to slide on the spindle and clunk no matter how tight the nut. Looking at the spindle it seems Paioli ran the thread for the bearing cap too high and just plain got the clearance wrong to speed up assembly. Another thing that is a bit odd is there is a relief about 3mm wide around the bottom of the clamp almost as if there was supposed to be an insert there possibly to allow for manufacturing tolerances.

So after a complete disassembly of my forks to chase another noise I figured I'd throw a caliper on the top triple clamp as the head has started clunking again and I'm getting tired of repacking the space with Teflon tape every couple of months. The difference between the spindle and the hole in the clamp is a good 0.006 of an inch. I've ordered a sheet of 0.003" brass shim stock. We'll see if that works but I was wondering if anybody else has measured the clearance between these two parts as it seems to be a fairly common issue. I'm wondering if it would be worth having shims machined? Not worth it for one bike but might be worth it if there is demand. Still tempted to just buy a new top clamp since they now have a pinch bolt.

I don't think WD40 will work anymore. I think they stopped using propane as a propellant. Starting fluid will work.

I think Peter's suggestion is the O-ring that seals the shaft to spacer my need replacement. Not sure how that is to do. I would imagine pull the spacer then remove O-ring with something like a dental pick then cover splines with tape to protect O-ring and slip on new O-ring, remove tape, make sure spacer end that seals against O-ring is smooth, throw in spacer and sprocket.

People are always surprised by the compression of a trials bike and to be honest I've never been able to properly start a GasGas. I suspect there is a big difference in the kick start ratio compared to my Beta. If it's running good and starts well then just ride it.

Yup what they said above. The good news is you did this to yourself which means it's something you can fix fairly easily. Everyone on here who's taken a carb off to clean or adjust has been in the same situation where we put the carb back on and realized something ain't right.

Welcome to the pub puzzle of the modern trials bike where you have to disassemble half the bike to get to what first appears to be easily accessable. I don't know about the Scorpa but I suspect it's the same as the Beta and it'll become apparent that there's some little twist to getting it apart. You'll discover this after dropping the exhaust and the chain and the front motor mount to rotate the engine case so something else interferes with what you're trying to do. Take your time and think your way through the problem. Any time working on the bike is a learning experiance. Might as well get the most out of it. Why are you pulling the head?

Ahhhh good point. Next year maybe if they are modifying production frames.

We are glad to have you. Hope you enjoyed Berwick. We have rocks.

https://www.pegasusautoracing.com/group.asp?GroupID=BLEEDER http://www.probolt-usa.com/titanium/ti-motorcycle-special-parts/titanium-banjo-bolts.html Just google "banjo bolt bleeder" and a bunch of vendors show up. If you use the correct wrench you won't round off the flats but it sounds a bit late for that.