dadof2

Circlips for gads sake? I never new these were produced for his use, but as everyone should know God rides a Harley so presumably he will have had use for circlips at some time. http://simplybearings.co.uk/shop/index.html

Take a look at the above video and it is clear many riders are stopping yet probably getting threes. ianw #38 makes the comment that globally the majority of riders do not want no stop. I can't comment globally and I don't think anyone else can without a proper poll. What I can state with certainty is that in Northern England entries were in decline under stop allowed and are showing a useful recovery under no stop rules. Also traditional no stop trials always continued to be well supported. Bike sales also were in severe decline under stop allowed. If so many riders support stop permitted why are they not turning their backs on no stop trials and running their own stop permitted events? We all know what Raga's view of non stop was, if a number of other top line riders and manufacturers shared his view why did they not go on strike from FIM non stop trials in protest? I never intended this topic to be about stop or no stop, it was intended to be a discussion on hard or easy sections and marking stringency. If a trial is run under no stop, it must be ridden and marked as such. Recently a long time trials enthusiast expressed with some contempt the view that today's riders are cheats. the By enthusiast I mean someone who has travelled extensively to trials of all levels including WTC for many many years and is known to most trials central members and held in high regard. I can enjoy watching both stop and no stop trials and it would be a great shame if Bou, Raga etc did not have somewhere to show their skills but the fact is (in my area at least) the great majority do not have the time nor the inclination to learn stop permitted skills and if stop permitted returns they will turn their backs on organised trials.

Most exhaust "fires" are not inside the exhaust. All that is in there is a very hot flammable mixture. As soon as it touches fresh air which pulsates in and out of the last section of the exhaust it can catch fire. A standard 2 stroke carburettor if correctly jetted for normal use, will run weak when wide open at high revs leaving excess oxygen in the exhaust. That is one of the reasons why fixed gear karts, which run at full throttle and high rpm much of the time use pump type carburettors.

When its dirty. Might be after a 2 hour practice or 2 or 3 trials, depends entirely on the type of use.

Try 10 weight. Take the fork springs out, fully compress the forks and fill until the oil is 110mm from the top.

Sorry to put a bit of a dampener on things as I know what fun big off road bikes can be. In Northern UK and probably many other regions I suggest for green laning the best thing to use is a small quiet 4 stroke. Anything large, noisy and powerful just upsets people and risks too much damage to the surface.

I have just read, to my considerable dismay (I could use much stronger words) John Shirt Jnrs account of the SSDT. He introduces 2 new "definitions" of a stop, these being a "so called stop" and a "supposed stop". Rather than disrespecting observers in this way he out to be thankful there are people willing to sit out in all weathers so that he and his works riders don't have to mark themselves. Can you imagine the uproar if it had been someone from the same team that had given an advantageous mark contrary to video evidence? I am aware of 2 notable issues in the last few days regarding observer availability, in one case when the organiser was asked how many observers have you got, his reply was none yet, in the second instance the organiser said we still need a lot. Both these organisers are very well respected within the sport and have been organising or deeply involved in trials since the 1970s.

Thanks b40rt for finding such a superb clip to illustrate my point, I wonder if the rider was awarded a "spanish 3" for his multiple 5s.

I would be inclined to have someone who is fully familiar with these engines investigate this further. I have never had a 4RT apart but I have quite a few Honda 4 strokes. From what I know would expect the valve clearance should be the same on the TDC and F marks as I would not expect the lobe / lift part of the cam to be anywhere near at these angles. It sounds as if the timing between the camshaft and crankshaft may be out. Possible causes are a partially sheared woodruff key on the flywheel or the camchain may have jumped a tooth or 2 on the sprockets. I have even seen cam timing out when the crank had twisted due to hydraulic lock in the cylinder, because the engine sucked in water. It is perfectly possible for an engine to run with the valve timing quite a bit out.

Johnnyboxer. Thanks for clarification. I have helped set out trials and acted as C of C at centre championship level. Also occasionally other tasks such as trailing round the paddock begging for observers, making flags and section marking tape (try splitting fertilizer bags in a continuous spiral to make long tapes for a fun activity) and copying maps so observers can find sections I will probably observe twice this month. At 2 of the last 3 trials I have ridden only about 50 to 70% of the sections have had permanent observers, the other sections being marked by riders taking turns at observing, myself included. I have a number of friends who will no longer observe (one an ex WTC and BTC observer) because they are fed up with riders expecting and arguing for a 3 when they have clearly had a five. What prompted me to start this post as not so much the DL issue but the number of riders in SSDT videos struggling with a lot of legging, and the appearance of dangerous sections on clubmans (or even beginners / easy) courses, e.g. being perched on top of large rocks or with dangerous falls to one or both sides. I get no pleasure from legging or fiveing myself nor from seeing others do the same. What I like and like to see is riding. I think a move to more ridable sections and marking by the book would be better than having sections that are likely to cause stops and then bend the rules to give 3s.

I think the number of hours is dependant on so many factors, not least air filter maintenance and whether you ride in dust or not. I have some bikes from 1970s and 80s that have never been bored or piston replaced but I have been told one British youth Championship rider is on his third 125 this season because they wear out so fast.

http://uk-motoplat.com/testing.html may be of help just for info, not expecting you to send stator to uk.

I suspect the JTR Gasgas 320s of the late 1990s may be about the most powerful production trials bikes made, the newer 250s and 300s are certainly softer and easier to ride.

Johnnyboxer and Greeves, is there earlier threads on this or is it this years SSDT you have in mind when saying "not this again"?

Where do you live?

I don't know for sure, looks like it may be a 32.5, see http://www.motocarb.com/mikuni-pilot--air-jets.html

http://simplybearings.co.uk/shop/advanced_search_result.php?categories_id_src=4478&only_in_cat=1&inc_subcat=1&search_in_description=0&Two_Teds_1=32005&x=35&y=9&sort=2a

I would probably have put this in SSDT 3 or 5 post had Andy not locked it. Watching the SSDT videos, other trials videos and my experience at quite a few trials it seems to be common practice to have sections on the hardish side which cause momentary stops and then mark them leniently as a 3. On the SSDT videos (thanks they are excellent) there seemed to be a lot of riders legging or stopping rather than riding. What do riders favour - hard sections with lenient (strictly incorrect) marking, or Easier sections marked stringently. I favour the latter

http://www.trialscentral.com/forums/topic/48320-oil-mixture/?hl=%20dadof2%20%20oil%20%20mix%20%20ratio

I think the earlier Evos up to and including 2011s tend to be soft at the back end, the 2012 on bikes seem to be a bit stiffer.

We are not talking 4 stroke here. I was referring to typical 2 stroke mixes of between 100:1 and 15:1 and in that range in a correctly tuned engine more oil gives more power and this is based on far more recent research than the original Gordon Jennings / Yamaha work. That manufacturers are working towards lean mixes for emissions reasons does not alter that. Some reasons more oil gives more power are, less friction, higher compression due to better piston / bore sealing and less blowby which contaminates incoming mixture and reduces crankcase pumping efficiency. I use pump gas but avoid the cheaper and unbranded stuff. The cheaper stuff contains less cleaning agents and is more prone to pinking. That a lot of oil causes build up on the piston and ring sticking is a common myth (all to frequently quoted by those promoting lean ratios). Ring sticking and carbon build up (if oil related) is caused by poor quality oil or blowby accompanied by high piston temperatures. With plenty of oil heat is conducted out of the piston to the cylinder walls and cooling system via the oil film. With lean mixes this oil film just is not there. Plenty of oil seals the rings, and piston to bore clearance better preventing blowby. It is hot blowby gases getting down the side of the piston that cause most carbon build up and ring sticking. I have seen plenty of engines run on quality fully synthetic at bewtween 60 and 80:1. The piston sides and crankcases are full of brown gum build up. Engines run at between 25 and 30:1 even on horticultural semi synthetics and mineral 2T are frequently completely clean or only have light honey coloured deposits. Wear - If you you use a lean mix of even the best synthetic the oil film is very thin say 2 micon. This means that particles over 2 micron cause wear when they are rubbed between piston and barrel. Up that oil film (by using rich mix ratio) and you can increase the oil film to say 8 to 12 micon. This increase of the film thickness greatly reduces the number of particles that have the potential to cause wear whilst passing through the engine. I use a fully synthetic oil from a leading manufacturer. The oil meets both JASO FD and ISO EGD specification. At 100cc oil to 3 litre petrol there is virtually no smoke, less smoke than from some bikes on well known oil running at 75cc oil to 5 litre petrol.

http://www.splatshop.co.uk/catalogsearch/result/?q=Mikuni+pilot Try the above link for jets or Beta UK. You could also try Yamaha dealers like Nigel Birkett.( Birkett Motorsport) When I replied to your earlier post about jets I was thinking you had a 125 with a Dellorto. Carb on an 07 250 should be Mikuni VM26-208 with a 150 main jet and 30 idle / pilot jet.

Get a bit of tube that slips over the stem down to the bearing. Weld a washer and an M12 (or similar) nut onto the end of the tube.But a bolt through the M12 Nut and something on the end of the stem for it to push up against. Tack weld the tube to the bearing race with a 10mm long tack on each side. Immediately after welding (so welds do not have time to cool and contract) tighten the M12 bolt and it will pull the bearing race off.

http://www.trialscentral.com/forums/topic/50825-2-stroke-premix-help-300-evo/page-2#entry365995

Don't worry at all about coming last. Best way to learn is to find some friends who are just a bit better than you and practice together. Also best to flag your practice sections, then you can tighten them up as you clean them. If you don't have much room try the following, circles and figure of 8s in your drive. Gently run your front wheel straight into a wall, pulling your clutch in as you approach, then tug bike back and turn right and left until you can do it without footing. Get a plank 6 inch wide, 2 inch thick an 12 to 16 ft long, lay it on the ground and ride along it. Get a 40 gallon drum and bolt 2 logs or bits of sleeper to it so it does not roll away. Practice riding over it in a tighter circle as possible. Also practice just running your front wheel onto the top of it then pivot away to left or right on rear wheel. Ride over the drum and stop the front wheel with the brake when the back wheel is on top of the drum, by pushing on the bars and bouncing the rear suspension swing the rear wheel sideways off the drum whilst holding the front wheel stopped or barely moving.