garyc

I've seen this happen before, but not recently. When the bike splutters the engine stops briefly before the piston has reached the top, the ignited gas then pushes the piston back the other way. In 2 strokes there is no reason why the engine can't run in reverse, but it tends to stay running forward because that's how it was started and the flywheel keeps it going. So any 2 stroke that splutters significantly can run backwards, but what really makes this more likely to happen is over-advanced ignition timing. This means the spark plug is sparking too early and before the piston is at the top. (the factory settings are usually a little bit of spark advance though because this helps make more power). Over-advanced ignition timing will cause knock and splutter, which causes the engine to slow down and then the over-advanced spark helps push the piston back down before it reaches the top. So check your timing. I don't mean check that it's at the factory settings, sometimes they make mistakes. Measure it as per these instructions found here: http://www.sherco.com/wayne_corner.html If the timing looks right, it might be that it's just the splutter, so clean your carb and change your spark plug. If that doesn't work it might be your electrics, in which case see if you can find a mate with the same bike who's willing to let you swap bits over to see if you can diagnose which bit of the electrics has gone faulty.

New bikes every year are not really necessary, just look at what Wiggy and Sam Haslam made bikes from the 90s do in Jersey! A 2 year old bike can win center championship trials and score points in the Novogar/S3 rounds and the lower classes of the British Championship if it is kept in good condition and the rear shock gets refurbed/replaced when it's gone. For me the biggest problem is time. Time spent travelling, washing and maintaning. I also live in a city and so garages are hard to come by, and places to wash a trials bike are non existent. To start from scratch there are a lot of things that need to be in place, which probably puts people off a bit. Once you've got yourself set up with bike, license, van, helmet, boots, garage, spares, tools, insurance, floodlit washing facility? things tick over nicely, but that's a lot of stuff to think about for a beginner! Compare that to a mountain bike, a bike lock and a cycle helmet and you can begin to see why many potential off road motorcyclists stick to pedal power.

I've never had the chance to ride in a gate trial, but they sound interesting and i'd like to have a go. I can definitely see the benefit for an average rider who just wants to enjoy themselves, but perhaps it might be frustrating for riders who want to push themselves? As an Expert level rider I really like the feeling when you conquer a hard obstacle that you weren't sure about and I would perhaps get frustrated that I would have to choose between attacking those hard obstacles or getting a good result. When you try to improve as a rider you need to push your boundaries, but getting penalized for doing so may slow this down. Perhaps some tweaking could be done so the rewards for trying the harder gates are greater? - so that there is more incentive to give it a go and less penalty for taking the risk? For example, perhaps there could be a doubling rule so the values for gate severity could be 1,2,4,8,16? I like the dabbing rule described, (i.e. a dab is a 1 point penalty rather than a failure) this will definitely help. I think there is a big difference in riders who ride purely for fun and riders that ride to push themselves and so ideally the format needs to cater for both. I guess the normal scoring system caters more for riders who want to push themselves? Maybe this is due to the modern bikes? back in the 60s the bikes were so big and heavy that everyone could ride one course, which had no super large obstacles and more emphasis on turns and momentum. I guess back then the old no-stop scoring system catered better for both types of rider.

Electrical tape has always worked for me. double it over so it's sticky on both sides and wrap it round the handle from the middle outwards, slightly overlapping the tape you've already put on. put some petrol (preferably without 2 stroke oil) in the grip and shake. empty the petrol and quickly push the grip on. Petrol is better than carb/brake cleaner as it doesn't evaporate as fast, giving you more time. never use WD40. super sticky with no wires and no mess and easy to remove and clean up for next time!

I think maybe they are considering the moment (or torque) due to the bikes weight about the rear wheel? This is the weight of the bike multiplied by the distance of the center of gravity from the rear wheel axle. To keep the moment constant as the bike gets lighter, the center of gravity is shifted forward. This moment is important, because it determines how easily the front wheel lifts off the ground, but I really don't know what the best setup would be is. I'm guessing Ossa are assuming it's currently about right and so making the bike lighter would indeed need the centre of gravity shifted forward.

Trials marking it not always black and white. An obvious five should always be marked a five no matter how good the attempt is. Observers have the right, however, to make their own interpretation of the rules and also of the events that occur in the section, they then have the right to use their discretion and make a judgment on the mark the rider deserves. I'm only suggesting that it might help to take a more rider-friendly judgement on hard sections and a harsher judgement on easier sections, but ultimately it's completely their choice and riders have to accept that. I'm in no way suggesting the observer gets more lenient throughout the day, this really musn't happen and ideally observers shouldn't be switched mid-event either so that consistency is not lost.

The most important thing is the observer is consitent and fair over the entire marking of a particular section. The marking will vary from observer to observer and there's no reason why it can't vary from event to event with the same observer. The point is that a section that sees nothing but fives, despite some extremly good rides, because the observer does not use his/her discretion appropriately achieves nothing and is frustrating for the riders, the organisers and the spectators. and yes backward is a five, but we're talking about the real marginal cases here, for example, when a rider sets off from a standstill, the bike make rock back a cm or so as he transfers his weight over the rear wheel and engages the clutch, would you honestly mark that as a five?

That ryan young dvd sounds similar to the way I try to do it. The most important thing to remember is if the back wheel is spinning it's not gripping! To take off in mud from a standstill I select 3rd, Let go of the front brake and overgrip the throttle to make sure you can comfortably wind all the way on.This is important make sure you feel it hit the stop, otherwise the revs will build and as soon as you get going they'll drop again. Look up to where you are heading. Now wind the throttle on and wait for the revs to build, once it's at full revs you need to simultaneously start to feed out the clutch, push the bike forward and sink your weight over the rear wheel. You then need to feed the clutch out over the next 5 metres or so, but keeping the wheel hooked up. If you watch the top guys they tend not to spray much mud about and really accelerate fast.

I would have to disagree with the rider not being aloud to carry on. I've always known it that the rider is allowed to finish the section, after all they've paid their entry and should be entitled to ride the full course laid out. It's not an unfair advantage provided they only try each bit once. Obviously if there is a queue and time is short the rider should not take the mickey, but I'm sure they are entitled to finish the course. I think rocking backward slightly should be down to the observer to decide how to mark it for the particular section in question, but going backward significantly should always be a five. Sections are there to grade ability. So if it is a really hard section and nearly everyone fives it hopelessly, but one or two make a very skilled attempt and, except for a slight rock backward, clean it or dab it, then most would argue they deserve better than a five and definiely rode the section better than most of the others. An easy section on the other hand should be marked harder so a clean rewards a faultless ride and any small mishap is marked to the book.

Raphly is not entirely right. Too much damping and you'll lose grip. Too little damping and you'll also loose grip. To get the most grip as the wheel goes over a bump, it has to stay stuck to the ground and the force from your weigth needs to stay as constant as possible. If the damping is too high (or too slow) the shock won't contract fast enough and you'll unweight after the bump and loose grip. The shock won't rebound fast enough either so this will make the effect worse. If the damping is too low or the shock is knackered it will feel springy and when you hit a bump the shock will shorten too fast and rebound too fast and make the bike unstable which will loose you grip as well becuase the force on the tyre is changing. I'm not sure it's all down to the suspension though, chewey is right about michelins in the mud, they are mediocre when new and absolutley awful once the edge is worn compared to a reasonably used IRC. Your mate might have had a lot less pressure too, you can get away with very low pressures in mud. The flywheel weight would definitely make a difference, if your struggling to bring in the throttle without the wheel spinning then it could be that. The slow action throttle might help, but I don't like them because it's hard to wind it on fully and it doesn't really change anything, just means your throttle control can be sloppier. If you want actual engine mods then you can look into carb inlet spacers or longer front pipes to shift the torque curve down the rev range, but don't go too far or it will be hard to bring in the throttle off tick over without it spinning. Lastly it could also be the ride front/back heights. If your mates bike was set up with a lower rear and higher front it will grip better as more of your weight will naturally be over the rear. you can adjust the spring preloads or slide the forks in the clamps to set this. Hope this helps and dispells some of the myths!

I've cleaned and put new oil in using the heights given and they're much better. It took a long while to work the air out of the damper though! I wonder if before, as well as there being too little oil, some air got trapped because the damper rod never got pumped it's full range in normal use. I've found though to stop them oscillating a bit on rebound I've had to wind the damper screw all the way in. I'm pretty sure it's set to nearly all the way out as standard, but this gives too little damping for my forks. Is this what other people have found? I've also upped the preload to stop them sagging, but I guess this is common in older forks that the springs have got a bit shorter over time? Cheers Gary

I think the keihins are temperamental because of the 28mm diameter throat. The bigger throat means the air speed is slower for the same volumetric flow rate. Carbs need the air to speed up at the throat to create the pressure difference needed to draw the fuel up through the jets. the bigger throat causes a lower pressure difference, which the jets are adjusted set for, but it means it's more sensitive. The 200 having a lower capacity draws in less air than the bigger bikes, which I reckon is why they've used a smaller carb. It could have been a keihin if they made a 26mm version. I think a lot of riders would ride better on a 200, it's only the top experts that dare overgrip the throttle to make sure they're holding it absolutely flat out!

Thanks, I'll try that and see what happens. I did think it was strange that the quantities were the same as for the old style fork. Where did you find the correct amounts? I'm guessing that the height mesurement is from the oil surface to flush with the top of the fork with the cap off? Cheers Gary

Thanks I'll check the height when I refill it. The Sherco manual, http://www.sherco.com/service/2009manual_ST-2T.pdf says 330cc and 150mm air vol. is this incorrect? should it be 60mm? that could be the issue. I took out a little over 300cc so I expect the air vol. was around 150mm. Also I was wondering if it is possible there was an air lock in the damper rod? When I refilled it I measured out 330cc and just poored it in the top, assuming that with a bit of use the oil and air would get to where they should be. Is this the correct way to fill them? The oil I used was new, but had been sat in the bottle for a few years on my shelf, can new oil degrade over time all by itself? Cheers Gary

hello, I have recently noticed that my front forks are quite springy. They are clearly underdamped compared to other newer forks on other bikes. They're the standard paioli forks on a 07 Sherco 290 and have separate compression and damping legs. I put new 5 wt. oil in it 4 or 5 months ago and I took out just over 300 ml from the damping leg when I checked just now with the oil looking ok. The damping adjuster seems to make little difference. Has anyone experienced with any modern trials forks before? Does anyone have any ideas why they seem to have lost there damping? Is there some internal seal or valve that might need replacing? Thanks Gary