dombush

Sherco 34 a much discussed topic!! I personally use 75:1 also on a Sherco 125. You will find people running as much as 40:1 and as little as 100:1 Opinion warning!! That 100:1 with a high quality synthetic oil is probably ok but i dont want to risk it.... 40:1 - 60:1 creates decreasing amounts of spooge (exhaust dribble) risking clogging the silencer wadding. 75:1 seemed to keep the wadding clear and didnt choke the engine even with prolonged low rev running. Engine dissasembly also showed good distribution of oil in key areas (piston skirt, big end, mains etc) So, with no negative effects at 75:1 i figured that saving some pennies on oil by pushing it further wasnt worth risking. Dom

Ben http://www.splatshop.co.uk/gasgas-pro-water-pump-shaft.html For the effort involved in replacing the seal, its worth doing the job right. There's a strange satisfaction to be had from selling something that you know to be "good". Also, trials is a relatively small world... Dom

You may possibly have the wrong idea about oil life. Whilst it might be possible to feel when your oil has deteriorated, the other properties of the oil may (will) have long since significantly deteriorated. Oil life is limited by a number of factors; contamination, particulate build up, deterioration (loss of viscosity), deterioration (loss of film strength), corrosion resistance and more besides. Its likely that the "feel" of an oil might be related to the viscosity (clutch action) or its film strength (ease of gear selection) BUT by this time the particulate build up or contamination is high and bearing life is suffering. Bearing life is calculated in 1000's of hours and assumes "good" lubrication. You wont know that you've accelerated the wear in your gearbox until long after the damage is done. Its also worth noting that mechanical wear doesn't occur at a steady rate. As component wear increases it accelerates for a number of reasons.... therefore you want to slow the early stages as much as possible. Cutting to the chase... change it often because:- ATF and gearbox oil is cheap A trials bike doesn't hold much oil anyway. Contamination (clutch particles, dirt, gear particles, water etc.) limit its service life. Gearbox rebuilds are expensive and time consuming. Its easy to do. This reminds me of a mate that raced bike engine race cars. The engine cost £4,000 and tuning work a further £8,000. The engine spent most of its life between 9000 and 13000 RPM. If we were forced to strip the engine before the perceived the oil life was up he would strain the oil through some ladies tights and put it back in...... even race oil was only £60!!! Doh!!!!!! Dom

Malcolm Not knowing where you are its difficult to be specific, but assuming your in the UK, Europe or the USA, then any KTM dealer will help you. I take it you've tried the Beta importer for your area. In the UK its John Lampkin, link here:- http://www.beta-uk.com/index.php?option=com_content&view=article&id=216&Itemid=160 Dom

That Copey, was the information I was hoping to hear. I imagine that loosening some of the surrounding good spokes may involve putting a grinder through them!! Thanks both. Dom

Hi This weekend we broke a spoke on the front wheel of our Sherco 125. My question is how to get the spoke out of the hub as the remaining good spokes in the hub appear to prevent the "head" of the broken spoke getting past. This means extracting a single spoke is difficult / impossible?? Tomorrow I'll post a photo to make it clear but anyone who has done this will understand what I mean. I'm hoping there's a simple "trick" to it...... Any ideas??

Malcolm The bottom end of the engine is the same as the KTM 65 (might also share with the 85 as already stated above). KTM used Beta to manufacture their small 2 stroke engines from 2002 - 2009 before they introduced their own power-valve engine. Dom

Two thoughts (assuming that you've checked there isn't any other more simple reason its not moving, this is quite unusual) Use an aluminium dolly instead of wood to transfer more of the shock load (wood is a good shock absorber) if that doesn't work..... Get some local targeted heat onto the inner race of the bearing as the resulting expansion breaks the seizure, use some penetrating oil before it fully cools. Dom

At least 2 of those kicks should have started it (or would have started mine) If it were me, next steps:- Compression check, cold, wide open throttle, 5 kicks... expect something around 150 - 170 psi Check the ignition timing is std Dom

Sawtooth I dont doubt that the technique is working, but you've just described the quickest way to damage the kickstart mechanism. The manner that you describe puts shock load on the gear / teeth / ratchet (e.g. your instinct is correct) Not owning a 280 personally i'm happy to be told otherwise, but a video speaks a thousand words. Credit to Jim Snell for this http://www.youtube.com/watch?v=QdM4qkAqywk If this is the case the question might be why do you need to do this?

Ben often 2 strokes don't rev out initially due to oil / fuel build-up in the crankcases being thrown into the combustion chamber (all that low revs running). With that gradient, he needed full revs (power) immediately. If you've ever watched the supercross (2 stroke days) you'll have seen them red lining the motor for 2-3 seconds (clouds of smoke) before the gate dropped.... same reason. Dom

Yes, frustrating isnt it!! Autosol on my 06 chrome frame recovered most of the damage. Dom

Southwester Trials bikes / Motocross bikes are chalk and cheese, as are the riding styles (I'm sure you know this). I can truly say that riding my mountain bike in Wales is more relevant than the two years I spent riding Enduro. Opinion warning!! As you're a big lad I wouldn't buy a 125. They're very capable but need a committed approach, 15 stone will exacerbate this. 250's have a wider spread of power, meaning they're more forgiving to ride. All capacities power delivery can be adjusted by more / less compression, flywheels, etc. All models (125's - 300's) require the same good throttle / clutch control. I don't find the bigger cc bikes any harder to ride. Like riding a big road bike they can be pussycats until you get sloppy. £2000 buys you a 3 or 4 year old bike from the most common 3 manufacturers (Beta / Sherco / GasGas) Buy on condition rather than age because spares are expensive. As a beginner a good condition 2005 bike will see you through your first year without much performance penalty. Watch a good rider win on a 1990 TY mono to understand trials is more rider than bike. There.... got that off my chest Good Luck Dom

b40rt I couldn't say that its "industry standard" but its true of every bike that I've worked on (Japanese, Italian, Spanish in multiple bike disciplines). Dom

mccarro the side with the etched letters at the ring "ends" face upwards. Dom

Glad your sorted!

I came the other way Enduro - Trials Please understand that like most things in life its horses for courses. For me the following swung it towards trials. Enduro wasn't unfriendly (far from it), but trials was friendlier, mostly because its more relaxed. Trials starts at 10:30am, Enduro earlier. Lots of trials are closer to my home. I can ride trials alongside my son. Enduro we have to ride separate days. Trials I can be competitive on a 7 year old bike, Enduro not so much so. I can afford to compete in trials for 3 years for every 1 year racing Enduro. Crashes in Trials tend to have less serious consequences. My wife worries less = more passes out! I was destroying my knees in Enduro. 2 keyhole surgeries, 1 broken collar bone, 2 concussions. Riding trials I realised that I had a lot to learn about riding, even after 20 years on road bikes and motocross / Enduro for 5 years. Having said that though if your young, need adrenaline, love jumps, need speed, power drifting, want to train to be competitive, can afford the bikes (and more importantly the spares)... there's nothing like Enduro. Dom

Me Tarzan, you Jane. Copey, you are a ninny!!

Ben as lineaway says talk to your dealer first, then the importer. although issues are worrying, give them a chance to help... this could be your lucky day :-) Cant see from the photo, but be sure its a crack? Sometimes at the edge of a weld a thin "valley" is created. This sometimes doesn't fill with paint so can look like a crack if it goes rusty. either way, have a chat with them. Dom

toman Whilst not certain of the Sherco, engine fans normally cut in at a water temperature around 90 - 95 degrees. If we assume that there is a temperature differential from the inside to the outside of the cyl head of 5 to 10 degrees. Then yes, this sounds reasonably normal to me. More to the point though... have you had a problem when actually riding the bike? If you were adjusting idle mixture (??) then its possible that if set slightly weak, the tick over would rise slightly at higher temps. Careful that you're not looking for a problem that doesn't exist. Dom

Does it cut out instantly? or does it die gradually? Dom

+1 on all of those suggestions also just check the slide is returning positively. Check that the jetting values and needle type and clip position is somewhere close to standard. Dom

Squish (compression) is a very personal thing. Originally I had mine at 1.1mm and the bike was very (very) urgent in its throttle response. I liked this but the trade-off was lack of smoothness at steady revs. Now at 1.3mm its a happy medium, good (not electric) throttle response but smoother. I can imagine that 1.5mm is very subtle indeed. Worn big end or little end bearings would have been very evident with significant rattling during running. Did it rattle badly? Dom

The slightly bigger squish (1.5mm vs. 1.3mm) could explain the lower compression. Yes, this could be a crank seal but crank seals normaly cause erratic higher tickover due to weak mixture. Do you have this? The degree of emulsified oil on the cotton bud isnt huge for a blown crank seal either. Ive opened up the flywheel cover and found oil / mess all around the bottom of the cover and the bike was still basicaly running (although eratically). Do you think this could just be residue grease from the original assembly? Going back to your sometimes lack of compression when hot..... mine could never be acused of this (hefty kick required always). Although your squish is larger (lower compression), as a guide i cant kick mine without hoisting myself to put full body weight through the kick. The idea of kicking mine over with a simple jab of my right leg is a dream. Dom

ok 170 PSI cold, 5 kicks, wide open throttle. 2006 250 Pro, std compression.. Piston and rings 4 years old but in good condition. that's quite a bit more. If I were you I would :- Measure the squish with soft solder before dismantling anything. Check against Std (1.3mm) if its considerably more this may be reason for low compression. If the squish is ~std you need to look further, e.g. take the barrel off Measure the ring end gap vs. Std normally around 0.5 - 0.8mm .Worn can be considerably more. Measure the ring width around at 6/8 places to see what wear there is. (should be within 0.05mm) Measure the piston to bore clearance (need the tools) Dom