dadof2

Pat #20. Interesting comments those and exactly the same as my experience. I used to race a CR500, blueprinted and slightly tuned engine with Schlecten works pipe. Could steer and slide it on the throttle with as you say no nasty surprises. I could also ride a 125 pretty well, just wind it on all the time. 250s on the other hand were tricky beasts, not much go then you wanted it then all of a sudden in comes the power. The only way I could ride a 250 was in a gear lower than it really should have been and rev the ar?e of the fu??er. I reckon the reason Hildo beats the CBR is because on the HD he can pretty well dump the clutch and wind on the throttle whereas on the CBR it is much more difficult to keep the revs and clutch bite well matched.

Billy Bolt, Nigel are you now implying that EFI can't cope with a hard riding style?

Fascinating, can't wait for the next instalment, keep me posted The 2014 frames are hydroformed rather than welded from preformed sections / extrusions but this should have no effect on the gasoline. Gasoline + air always pressurises a tank when shaken so that is normal. But the pressure should vent through the breather with the petrol being separated by the mechanism in the cap I would examine the filler cap area of the tank and as much of the inside that I can see and compare it with a tank that is not giving problems. Could there be a catalyst in the tank, pre paint treatments or even something completely unrelated to the bikes manufacture. Pop a Nuttalls Minto into a bottle of Coke, lightly shake it and you will see what I mean by catalyst. http://en.wikipedia.org/wiki/Diet_Coke_and_Mentos_eruption Ultrasound (high frequency vibration) can turn 1 gallon of petrol into well over 100 gallons of petrol vapour, but where would such vibration come from on a non running bike If you drain the tank can you hear anything rattling about, a small battery perhaps like the ones use in electric speedometers.

Thanks for that Neil. I feel It is difficult to discuss quite complex issues in brief posts, and it is the case that at first some may seem to have very opposite views when in fact there opinions are very similar. Look at the way Nigel "jumps on" bits of my posts, I give them as an example and he treats them as if they are the key exhibit in a murder trial. I am fully aware of the way Billy Bolt rides, one of my friends practices with him occasionally and at a section in the Scott this year he launched the bike out of his hands and up the bank into my sons legs, my son caught it to stop it tumbling back down the section over BB who was on his back. Atomant, I am not against new technology and I like working with electronics and up to date diagnostics. What I do like for my sport is reliable proven technology that meets my budget. At this time I believe the overall balance of advantage on a 2T trials bike is with carburation, not EFI. That is a judgement, not anti technology. I recently did some work on a "carburated" Suzuki "jeep". It had a downdraft carburettor but also a lambda controlled air inlet valve in an attempt to provide closed loop fuelling. What a pig to work on, give me EFI anytime compared to that set up. Also when it comes to trolling, I have had more success from the bank. Do I know more than Vertigo about EFI?, like I said I do not know but (based on over 35 years FI experience) I do know there are a lot of potential drawbacks with it and there are a lot of competent EFI technicians who will tell you EFI and water don't mix. Take the Honda EFI CBR600. A while ago I diagnosed one of these that would not consistently run right despite supposedly having been fixed by several dealers. The owner had dropped it and rather than replace the plastics turned it into a streetfighter. The problem was water ingress on the electrics when parked due to the removal of the plastics.

Ty 250 mono, never rode a 350 as there were not any in this area. Biggest I ever rode was a friends bike of about 270 (overbored 250) in 94 but I don't think it was running right (suspect carburation too weak)

#13 Richmond is pretty well northern UK, but its only about 1/2 way up The Disunited Kingdom Brings the words of the Clash song "should I stay or should I go" to mind PS we use to tease one of our work colleagues from the Dumfries area that he would shortly be needing his passport to get to work.

Dave Thorpe world MX champion was (putting it as reasonably as I can) much more impressive on the bike than in front of the microphone. Prior to his recent TV appearances Foggy was already a celebrity and used to being a celebrity and the attention of large numbers of people and PR. With the exception of Bou in front of a Spanish audience I think it is fair to say no trials rider falls into that category no matter how brilliant their riding.

I have seen that video before but I bet if I'd posted than an old HD could out accelerate a CBR1000 I would have taken some stick. I can remember Cal Rayborn out accelerating quite a number of more powerful bikes out of Mallory Park hairpin in the early 1970s

Good for chainsaws and occasional use equipment, a bit pricey for bikes. My local Husqvarna dealer sells it in 5 litre cans

Unless you know its had a really competent mechanic as an owner, once a bike is more than a year old it really needs a thorough strip down and all defects put right. This gives you a good base to work on and keep on top of things. Difficult to estimate an exact figure or parts list but I would think to ensure a bike that looks ok really is in good nick a spend of £150 to £250 is not far off. A few years ago I bought a bike several years old, was cheap, looked a bit uncared for and had a bit of engine noise, it needed: New main bearings and seals A gearbox bearing - probably unnecessary, just felt a bit tight Engine gasket set Wear marks filing off clutch basket Swinging arm bearings Some shock linkage bearings Welding on exhaust Air filter Front and rear brake pads All fluids changed Chain tensioner Stripped tread on yolks helicoiling Footrests and hangers welding The steering head bearings were rusty but after a few cleans and regreasing workedfine The bike then did several years light use without needing anything

I actually like all the Yam engines including the TY80, TY 175 and the 75 250. My favourites are the last of the air cooled as fitted to the TYR and pinkie. I would have liked to see them watercooled and maybe a few more CC for a little bit more power and bore / piston longevity. Although the watercooled variant as fitted to TYZ and Scorpa were good reliable engines I just did not feel quite at home with the power characteristics and found the TYZ riding position did not suit me.

Milky oil - the gearbox has a breather pipe, when you plunge the bike into cold water it cooled the air in the gearbox creating a vacuum that sucks water in through the breather. Could also be a corroded primary drive case / water pump housing allowing coolant to leak into transmission oil. Bikes tend to cut out in deep water, can be a splash shorting the HT spark, water in carb or on air filter. You need to repeatedly flush gearbox with clean oil, fit a dry air filter and thoroughly warm the bike up. Leave water in and it could wreck your main or gearbox bearings.

Fuel quality. The branded stuff is in most cases the same base fuel as the supermarket stuff, comes out of the same tanks at the refinery and is carried on the same tankers. Difference is the additive package that is added just before despatch from "refinery". Quite a few years ago many karters reckoned Shell was best. A few weeks ago I was talking to a multiple British champion (4 wheels) and BP Ultimate was presently giving best HP on dyno. About 3 years ago a mechanic for a WRC team told me the same.

Nigel #201 Not answering questions again but just turning them round? Give me a straight question and I will try to answer it. you think jeff smiths bsa (when did they fold?) scrambler has a direct relation to 2015 trials? Yes insofar as both have chassis stiffness as a discussion issue. Glad to get your feelings on DL great insight. The fact that my feelings are the opposite, having seen him up close in the wtc quite a few times, are the opposite, ie when under pressure be it either injury or adversity is when hes performed best. I agree that he can dig deep when under pressure etc, but my comments on ankle injury and change of bike are at least as valid. It should be also noted you have failed to address the questions above, ie why do YOU think efi is not an advantage and why do you know more than vertigo? You have slightly misquoted me but here goes. I said EFI has not yet demonstrated a competitive advantage, meaning with regards to 2T trials engines. For example BBs Ossa was running crap at the section in AGs back garden (you can look back at my post on this) and there is hardly an ossa rider who has not had fuelling / starting issues and had to have the bike remapped sometimes several times. Do I know more than Vertigo? I don't know but I have been working on EFI since DL was running round in shorts and am am well aware of its drawbacks. My perspective is that of a club rider who has to run bikes on a budget, DL and Vertigo backed by a multimillionaire will have a different perspective. Again if you look at another post I made I said I would rather carry a 50 pence screwdriver than a £500 laptop and leads. A Dellorto PHBL is something like £120 / £140 very reliably and easily adjusted. EFI needs an injector, TPS and various other sensors, high pressure pump, pressure regulator, ECU and extra wiring loom and power, larger alternator + rectifier + capacitors (or battery). All this adds cost and complexity (more to go wrong), EFI is more sensitive to fuel and oil quality. One of EFIs advantages (on 4T) is its ability to respond to Lambda output. Lambda sensors are expensive and not suitable for 2T nor the environment in which a trial bike is used. If fuel spill from carbs becomes an environmental issue a catch tank on the drain tubes and a simple diaphragm pump to return it to the tank is a simple cheap solution.

Neil # 208. Putting specific in front of density was just a typing error, I was going to type something else, changed my mind and missed deleting specific. I did mean density. I do know plenty about steel, Titanium and Aluminium, having machined, punched pressed and welded them all and been involved in design of items from them. In another post I mentioned I was involved in machine tool design, well we never used titanium for that but we did switch from cast iron and steel to Duraluminium to reduce reciprocating mass. I fully accept what you and others have posted regarding the physical properties but there is more to it than that. Because titanium is so light you can increase section size, this means it is the increased section that gives the stiffness not the material properties, same comment goes for adding bracing. Cycle frames in Al and Ti compared to Fe are a clear example of light larger sections. Ti and Al are the preferred material or aerospace despite being much more expensive than Fe. My info on Jeff Smith / BSA was based on an interview he gave many years ago, not a technical analysis. The BSA titanium frame despite being lighter and stiffer did not handle as well and was subject to cracking.

http://www.venhill.co.uk/Hoses_&_Cables_-_Motorcycle http://www.speedycables.com/

Hot and a flat spot sounds like weak mixture or retarded timing, possibly both. Does the bike lack torque from just over tickover to near half max RPM? as this can be a sign of retarded timing.

Here in Northern UK Richmond MC always (as far as I know) kept to the non stop rules, runs 2 of the most popular trials (Scott and Reeth 3 day) and has good entries at other events. In North Lancs ad Northern centre the expert / hard courses have very very few riders and it is this category of entrants that would possibly learn stop permitted skills. The vast majority of entrants ride the easy and clubman courses and a lot of these riders are in their 40s and 50s and have no desire to learn stop permitted Couple the above with the difficulty getting observers who would have to put in an even longer day if stop were permitted an I don't see this area going stop permitted any time soon. Obviously some areas / countries seem to favour stop permitted despite WTC being nominally no stop. Time for the sport to split? My feeling is and always gas been that it would have been far better if stop permitted had started as a separate discipline linked to arena / x type trial rather than hijacking traditional no stop. Perhaps some clubs (if there is demand from riders) will run trials with stop and no stop sections rather than easy / green / hard.

Sherpa 325, I am a bit surprised at your dislike of the Yam engine, in various forms it powered the Scott trial winner 11 times in between 1984 and 1998, a pretty good record by any measure. It may not have been the best engine for top flight riders but for the clubman it provided extremely reliable service and hardly even needed the oil changing. Back to split bearings - Vehicle bearing manufacturers have tried many times to make split rolling element bearings as they have better friction characteristics than plain bearings, but so far no split rolling element bearing has been produced that can match the performance of non split bearings. For example on a Suzuki 1100 GSX they went to the trouble of pressing together all the crankshaft parts so they could use non split roller bearings. The Burman gearbox of the 1950s used cageless crowded roller bearing and these were very robust despite being lubricated with a mix of grease and paraffin. Perhaps GG should slightly redesign the shaft and use crowded instead of caged rollers. Crowded rollers have the advantage of spreading the load over a greater area, but have less space for lubricant ingress so may not work as well at higher RPM. It is very difficult to know why these bearings fail on a GG. When they fail it makes such a mess you can't tell how the failure initiated and when you strip a gearbox to sort the selector failure you don't see any obvious precursors to the split bearing failure.

The Vertigo is expected to give about 30 HP, 300s from Beta, Sherco and Gasgas are reckoned to give in region of 25 / 27 HP. These sort of power outputs may be what a few top riders need for firing the bike up big steps and very steep slopes on dry grippy terrain, but is is needed or even desirable for 99% of riders?

The pads should retract slightly from the disc when the lever is released, the slave cylinder seals and seal grooves are profiled / designed to give a specific amount of retraction. Worn or ageing seals or build up of corrosion in the seal grooves or on the piston are common causes of insufficient retraction and pads rubbing on disc.

Zippy - Its a fair cop as they say, I won't mention it again

Just to clarify the titanium vs steel / CrMo situation. Yes size for size steel and CrMo are stronger and stiffer than Ti, but because Ti has a specific density just over half that of steel / CrMo, for a given weight of frame Ti is far stronger and stiffer. But as Jeff smith / BSA found out that extra stiffness did not prove to be an advantage. Atomant - what do you feel is individually new on the Vertigo? Regarding DL. My feeling is that the most detrimental thing to his career was the crash where he hurt his ankles, but changing to a bike (almost certainly underdeveloped at that stage) with significantly different characteristics and back again can't have helped either. DL has stated that the trellis frame on the Vertigo is to increase rigidity. This it will almost certainly do. What I question is whether increased rigidity is necessarily an advantage, and at this time I do not know. What I do know is that in car racing increased chassis rigidity does improve performance but on motorcycles this has not necessarily been the case. Jeff Smiths BSA is an early example, but over stiff frames have proven to be detrimental in both MotoGP and WSB. I did not say EFI on 2T had or had not given more power, I said it had not demonstrated any competitive advantage, can anyone give an example of where it has? Is more power what most riders need? I will start another topic on this so as not to clog this Vertigo topic. If EFI and advanced design were what most riders wanted, Ossa would be selling a lot more, but in fact the best selling 2T bikes are carburated and 2 out of the 3 have simple ferrous metal based frames.

Quite a few years since I have looked at one but I think what you are calling a brass insert is like a large thin washer that holds (or should hold) a rubber seal in place. The rubber seal used to soften and thin with age, as this seal gets thinner and thinner the pressure at which coolant boils out gets lower and lower. You can make a temporary fix by cutting a rubber washer from an inner tube

Does it have a measure inside the cap/ I had a 175 bantam (road bike not trials) and it had the measure as part of the filler cap. I think it worked out at 16 or 20:1. I would be inclined to use something like Gulf pride 2T at 24:1 rather than a synthetic at a lean ratio.