section swept

???‍♂️?too late....TOO LATE???

As sprinter27 suggests this could be your answer, note down every adjustment so that you can go back exactly if needed.

I didn't miss your very valid point, but wanted to describe a potential causal effect. Almost ‘pinging’ must indicate that the owner has heard a noise, otherwise why would he mention it? By describing what might be the causal effect can better help in any diagnosis....one mans pinging could be another mans ticking sound....all very difficult when diagnosing at a distance, or dog nosing as it is referred to in some trade circles.

Well if you want a really heavy constructed gearbox case able to deal with neutral and then first etc start thinking in terms of extra weight as not only will the cases have to be stronger, but also the shafts will need to be thicker and the bearings much larger to cope with torque wind up forcing the two gears of first apart and forcing the shafts to try and splay away from each other. Bike transmissions have always had a tendency to ‘pop’ or ‘slip’ or ‘jump’ out of gear and thats without hunting down all those ‘false’ neutrals that some boxes appear to have. Nine times out of ten its the riders that miss the gear by prodding the gear lever which in most cases is set at a higher position on the splines to avoid rocks and branches that are deciding on a new gear lever shape for you! everything on a competition bike is short in the foot operated lever department and thats the rub....make the detent overly strong and you will have selection issues, tame the detent plungers tension and then you get gears jumping out of selection. Thats my experience on the subject, but I take issue with your comparison between carburettors and transmission designs. Trials bike transmissions are almost as small as they can be designed unlike carburettors that may well have started out life intended for a scooter ot industrial engine plant, thats why there are so many about and options to swap are readily available.....unlike transmissions for specific motor cycles ie Trials bikes. As an aside I can tell you that a certain Formula One race car maker actually copied the transmission sequential change from a motorcycle. in conversation with the designer, when I asked what bike did you get the transmission from, he reached under his desk and pulled out a Honda CG 125 engine and transmission. His stated words were, it works perfectly and why re-invent the wheel when some one has already done it for you! Neutral was still in between first and second gear too!

Er they are OZO shocks

You say that you have overhauled engines before but dont know if a big end overhaul is a big job??? Crankshaft out is a big job if you have little experience. To an experienced person its still a big job but not that challenging. Yes you will need to use not only a powerful press bur also some good alignment tooling and press tools, together with dti’s and vee blocks on a surface table.

Pinking is actually detonation and is a really bad thing as it can cause piston damage. If pinging is your interpretation then it needs to be sorted. Poor fuel can cause detonation, ignition timing also. Altitude will also have an effect so if you are riding up a mountain so to speak the higher you go the more chances of ‘pinking’. The detonation makes the piston rattle against the cylinder walls and the sudden explosion creates a shockwave across the piston crown, too many and goodbye piston. An air leak in the intake can also weaken the mixture and cause this. Combustion is a rapid burning and not as a lot of people describe ‘an explosion’!

Two feet of snow.....here in the UK it only takes the threat of snow to clog the railways and create a run on the staples of life....and thats before its sctually snowed!!! Get out there in the snow....its the best place to practice balance control....better than mud??

The real reason for 1st then neutral and then 2nd is this: As 1st gear is the lowest ratio in the gearbox, it is the gear set that creates the most torque and therefore will try to force both gear shafts apart. To prevent this happening to the detriment of the support bearings and the gears, 1st is placed as close to the gearbox case and its bearings. Imagine if you will two shafts about 7 inches long inserted into two holes drilled into a steel block, the shafts are a nice sliding fit in the holes...almost a perfec fit. Now you put your hands on the ends of the shaft and try to push/pull them apart, due to the length of these shafts at their top you would feel movement but slide you hands down to the base where the shafts go into the block and you will be hard pressed to make any movement sideways at all. Thats why first gear is where it is as its the strongest place to locate it. Kawasaki used a neutral indexing system that meant when going down the box the gear lever stopped at neutral, first was then selectable after either coming to a standstill or double clicking the gear lever....nice but only good for the road. There were some gear boxes made where neutral was the lowest position for the selector mechanism and all other gears were 1,2,3,4, etc. The same scenario is found in nearly all car and lorry gearboxes of the manual variety, that is 1st neutral 2nd etc.

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Have a look at the Sherco specific site on TC. They are not difficult to work on if you know what you are doing technique wise, straight forward really. But you say you are going to do a top end rebuild and change the main bearings. What about the big end? You need to decide if you are going to take the engine completely apart....or fudge around. ?

Well it wont be the Beeb or Channel 5/24 or Eurosport so another opportunity missed by the media. Be down to our intrepid photographers and video...ists to capture the action...again!

Wish that I could live in the US....wide open spaces.....bliss?

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Quite right? but I thought I would give some information in case our man is new to buying parts.

so chroming doesn’t make the frame more brittle then!

Oh so you bought it!?

Hmm now which one shall I wear..ooops ride today?

You need to make sure the exhaust system is not bunged up, this will cause the same issue. The same for the air filter, needs to be nice and clean?

Proper jetting is a debatable subject when you are well above sea level. At sea level atmospheric pressure is 14.7psi so you need to be able to adequately adjust for the reducing pressure at your current height. Even two identical bikes at sea level might need (by an experts opinion) slightly different jetting in both pilot, main and needle position. You have to compensate for less oxygen in the thinning air, to best achieve the right transitioning from pilot to main and needle a number of running tests need to be done. Spark plug colour at the centre electrode and surrounding nose need to studied to ascertain each jet change etc. But first the engine needs to be in good order with air filtration and as oni nou quite rightly suggests the airbox needs to be properly sealed otherwise your adjustments will be too random for reliability. Whatever anyone says to use will be immediately out the door when you decide to ride at a lower level in height terms. So you will need a number of alternative jets so that you get the best from your engine, it’s no wonder that many a two stroke rider struggles with an engine that is also struggling to breathe with overrich or weak settings. Establish a base setting this will be the standard carb set up according to your manufacturers specs. That’s jet sizes, needle position and very importantly fuel/oil mix ratio, that in itself can mess with your settings. I will assume you run 70:1(crystal ball gazing)! Idle jet, go up in whatever incremental jet stages are available eg 25, 30 etc these will not cost much. If your current idle jet is a 35 then you might try a 45. Again as oni nou rightly points out experimentation will be needed .....at this someone else who runs a bike at high level will say to use this that or the other jet but it won’t be your bikes set up if you see what I mean....? Main jet, with the needle clip in the manufacturers specified position go up at least 15% in jet size as a starting point. Now run the engine and with out putting loads of revs on see how the engine reacts, crisp clean blips. If the engine boggs down its probably too rich on the idle jet....this is why you are going to need more than one of each jet. You can work it out mathmatically by using the percentage difference between sea level pressure and your positions atmospheric pressure. Once you have this you can increase the idle, main jets by that proportion. I don’t know your atm pressure but if it were 15% different then that’s the figure to increase jets by. Needle positions a plug chop test. As oni nou points out the squish band may not have the desired effect at your atm pressure. Whatever you do, my suggestions are purely that so I accept no responsibility for any damage or accidents. I know that some one will pick holes in my post but it’s there in the spirit of helping you to increase your knowledge and gain a good result with your bike. KMT should be able to supply jets.......www.kmtproducts.co.uk ?

Your engine may just be one of those where the production tolerances have collided. Like all manufacturers they have production tolerances, otherwise you’d be into ‘blue printing’ this is where all measurements are exactly as on the designers blue print drawing/computer. So some engines have parts that are very close to the specifications and are known as ‘rogue engines’ very often producing slightly more than specified power eg an increase of as an example 3-4+ bhp. Whereas another engine might unfortunately end up being built from parts that are on the edge of specification positive and some parts on the negative side of acceptable, these would be your normal production engines. Then of course it is entirely feasible for an engine to be assembled where the mass of parts are all on the limit of acceptable and you end up with either a tight engine or a loose engine. That’s why no two bikes are the same, identical to look at, identical in the way they work....but wholely different in their sound when idling. One of the differences between a works bike and a standard one is that all of the transmission, gears, clutch, shafts etc will be measured, polished to remove stress lines that may turn into cracks etc. The engine will have been dimensioned so that it is as close to if not exactly as the blue print specifications.....a nice smooth, quietish engine producing nigh on max power..! After reading what you have done to the bikes engine, listened to your video I have to say ( bearing in mind I’m not next to the actual bike) the engine sounds really good, not too noisy or rattling...in other words fine. I’ve heard thousands of engines and as many other experienced people may agree it’s not too difficult to recognise a running engine that has a fault or faults? You need to remember that the transmission is being driven while the engine is running so other components will be adding to the overall sound. Be aware that overloading the cam chain tensioner puts extra stress and strain on the tension guides, the tensioner it’s self and the drive sprockets, then there is the cam bearing and the crank bearings that will all be loaded if you overdo the tensioner loading. I would reset the tensioner exactly as The manual stipulates. Then get on and ride the thing. Your very first video.....that’s valve clearances opened up, probably not set at pdi or after initial break in period. After setting those clearances, paranoia has set in and you can tune in to more noises, bit like a new car, nice and quiet for the first few days then the creaks and rattles develop......? Last video, sounds like the majority of four stroke engines....wouldn’t put me off buying it if it were on offer to me?

Thought I might not mention that as a bit obscure, I bet is was well built?

You have been singularly lucky, people have wrecked the camcovers using your and other methods of wriggling and levering. Coca Cola works quite well at eating the carbonised crude that works its way up from the combustion chamber/injector passageway. The electronic injectors don’t take kindly to any sort of brutalisation. Yep, once you’ve got the engine cover off, the job if straightforward is about 20 mins per injector. The MB UU owners club forum is littered with injector removal issues. Once repaired it’s a good idea to dose the outside of the injector with a suitable lubricant, also good idea to check for signs of the dreaded carbonisation, that stuff can ruin the wiring harness for the injectors. How did prevent abrasive material getting into the cylinder head injector hole. At Mercedes we remove the glow plug, that’s tricky as well as they tend to snap off as they have very long bodies, into the glow plug hole goes a compressed air line adaptor blowing air into, up and out of the injector hole. This way when we recut the seat any debri is ejected. The whole area is thoroughy vacuumed to remove any other small pieces of scarf. The injector face has to be resurfaced otherwise the seal will fail again, the escaping combustion burns a tiny trail approx 0.005mm through both the seal and the injector sealing face...very often the injector cannot be saved the overall length of the injector allied to the depth of the injector passageway equates to the clamping force between injector and seal. After cleaning up the seat face and the injector sealing face the clamping force are reduced. The whole design thing is over complicated, but the same faults occur on Ford, Honda and most of the Vauxhall and French stuff....nightmare when you consider Toyota use a belt and braces approach to there direct injection injector clamping method. Apparently Honda CRV injector seals will fit down the MB injector passageway(hole) ? Once the injectors are ready to be refitted we smear a special grease onto the injector outer sleeve to try and prevent seizure. An owner going apoplectic after being told he needs 5 new injectors at £200+ each plus labour at £135 +vat is not a pretty site I can tell you. Take too much out of that injector hole seat face and the cylinder heads scrap. It’s enough to make you buy a petrol powered vehicle. I like your approach but wonder about debris getting into the combustion chamber through the injector nozzle whole. There are those that say it doesn’t matter as it will all go out through the exhaust on initial start up, yep all those tiny pieces of abrasive and swarf getting squashed between valve seat and valve face, ready for burning the valve and seat.

Wasp.....side cars I know.

Sounds as though the mountings are rose type joints, more than likely held in by circlips or snap rings. You specify the size of mounting or they tell you the size.