trapezeartist

After a phone call to Beta UK, I believe I have the only B size piston in the country heading my way. Great service from them, and also South West Trials.

I understand your point, and partially agree. Of course no top rider rides a 200 or 250 2T either, although they are only variations on the theme and a 4T is a totally different animal. No doubt ROI was the reason Gasgas never got their 4T to production. It would have been a unique trials engine whereas all the other 4Ts (Montesa, Beta, Sherco or Scorpa?) are parts bin specials.

I see it now. Not keen on using a C but if that’s all I can get. Thanks. I’ll ring them tomorrow.

What can I say? I went through agonies on the back brake too. I tried every method anyone could come up with, and now I can't actually remember which method finally worked. However I did finally get it working and hopefully won't have to touch it again for a couple of years. The squeal seems a bit odd. The only time I've heard them squeal is when they are wet and muddy. And that goes with the territory on a trials bike.

My Evo service manual (probably the same on a Techno) says 0.6mm max, but that's maximum acceptable wear. Not what it should be when new.

So I settled on using a 0.5mm base gasket (subject to measuring when it's all installed) and then I find there are no pistons to be had anywhere in the country.???

When Gasgas were developing their side-valve 4T, I thought that was such a good example of lateral thinking. We're so locked into thinking that OHC is the only way, but side-valve would (I think) be perfect for a trials engine.

A thick gasket raises the port heights but also lowers the compression ratio and increases the squish clearance. I’m generally happy with the engine characteristics as they are (were) so don’t really want to move away from Beta’s recommended settings.

I agree with you on both points. I wouldn't expect the gasket to crush to half it's thickness, but I would expect some reduction and the only thickness above 0.5 is 1.0. The point about the '40' being the thickness in thou was grasping at straws. There is absolutely no other way of identifying it. As I have time, I think I'll reassemble with the old gasket and measure the squish. Then order and fit the appropriate new gasket.

489,300 hospital admissions per year. 77,800 deaths per year. Guess the cause.

As Boris has stopped me riding, I decided to investigate the piston slap noise emanating from my 250 Evo. The bore is a bit scruffy but no serious problems. It will go to Langcourt for replating, honing and matching to a new piston. I'm just trying to identify the thickness of the base gasket that has just come off. It measures 0.5mm, but of course it has spent the last 4 years squashed under the barrel so it may be thinner than nominal. The only marking on it that gives a clue is a "40" printed in one place. Could this mean 40 thou ie 1.0mm? Unfortunately I didn't measure the piston height while stripping it so I don't know how close to spec it was before. Which gasket thickness should I order? I'm not a scrooge (despite what my wife says ? ) but I would really like to get it right first time as I'm dreading compressing the rings correctly and guiding it all into the barrel, and I don't want to have to do it twice.

Yes, and they've got it out so quick too!! Normally it takes years to develop a new drug. The pharma companies have to determine: What is the correct dosage? How does the dosage vary with age, sex, weight, race and any other variables? Is it effective? Is it safe? What are the contra-indications? What are the long-term effects? And many more questions too. I think I might wait a little while before having the vaccine.

I use a Citroen Berlingo car with the back seat removed. The bike fits fairly easily and there are even lashing eyes as standard. Secondhand, car versions are better value than vans, and I can use it for going to the local dump where vans aren’t allowed.

Interesting. I've noticed that the clutch bite point changes with gearbox temperature. As the bike warms up, the bite point moves away from the grip. (Beta Evo 250). I'm going to set it a bit over-close to the grip when cold, in the hope that it will be more to my liking when it warms up.

I started on a Beta 300 4T. It was too much for me, as a raw novice. I have a 250 2T now which is great, but If I could have found a secondhand 250 4T I would have gone for that. Having said that, the main attraction is the sound of the 4T, which shouldn't really be a factor.

My grand daughter: “Nana, where did you grow up?” My wife: “In a town in the Midlands, called Loughborough.” My grand daughter: “And where did Grandad grow up?” My wife: “He hasn’t yet.” (I think most of us older riders can relate to that.)

Possibly piston slap. Mine does it. Rather offensive on the ears but everyone I’ve asked about it just says “I’ve heard worse.” I’m learning to live with it.

Thanks guys. I think I might try Bostik.

Button head screw: that’s a good idea ?. With a copper washer, of course.

We may be misunderstanding each other. Agreed, taking the airbox off is easy. I had to take off a lot more than that to remove the entire brake system in one piece. But if you fit a banjo with a bleed nipple, it has to stay there when the airbox goes back on, and that is where i saw the problem.

How are the air intake grilles on an Evo supposed to be fixed? On both of my bikes they were stuck on with hot melt glue so I had assumed that was the factory method. But having just removed them in order to re-fix them properly, they look more like a bodged repair.

I don’t want to be too negative too soon, but will it fit? The one I tried fouled the air box. If you get a success, please give a reference to the part. I’ll be keen to get one myself. I eventually got the air out of mine by removing the complete system from the bike a creating a straight uphill run for the air. A fair bit of dismantling, but worth it.

Having just damaged my helmet by throwing myself backwards onto some rocks, I concur. Better a damaged helmet than a damaged head. I can't remember the exact quote but Martin Brundle said something along the lines of, "If you've got a £20 head, buy a £20 helmet."

Dan, that’s interesting. I have been toying with doing the same. I’ve lost a few stickers and some others are beginning to peel. There’s something seems all wrong about paying to advertise someone else’s business so I’m reluctant to buy a new sticker kit. Unfortunately my bike has a black frame, black rear mudguard, white front mudguard and frame cover, so may not look quite so handsome as yours.

My thoughts too. "Nose weight" or "Nose load" is a parameter of a trailer. A bike rack doesn't have a nose so I don't see how the law or an insurance company could claim you were exceeding a specified nose load. Just going at it from first principles, the issues are the strength of the tow bar mountings and the effect of the weight on the vehicle dynamics. The latter is likely to be the point of most concern. Having the bike overhung well behind the rear axle means that it adds more than its own weight to the rear axle and takes some weight off the front. I just ran through some typical figures and a car that start unladen with 45% of its weight on the rear axle would have 55% when fully laden and 61% with the bike rack and not much else apart from the driver. With a vehicle engineering hat on, I would say that takes the loading outside of design limits. With a pragmatic hat on, I would say the drive needs to be a bit extra careful when using the bike rack.