bikerpet

I've recently bought a low hour 2017 Evo 300. Pretty happy with the purchase. Currently the weather is mild and I don't see any particular issue, but moving into summer I'm wondering if it's worth fitting the Costa Special Parts hi flow water pump for 40 UK quid? I've read a couple of posts where people have commented that they think the bike tends to run a bit hot and the CSP pump keeps it cooler. Not sure if it's actually an issue or not. Where I ride it's fairly hilly with climbs of 1000' on fairly steep terrain being not uncommon. I mostly play around on obstacles, but do go for singletrack rides sometimes and travel about on forestry roads and steep firebreaks a bit to get to different areas. Our summer temps climb into high 30's / low 40's (celsius). I'm planning keeping the bike for a fair time so want to make it last as best I can. Anyone have any comments on the standard cooling system in hot weather and long climbs, or their experience with the CSP pump?

An old topic, but we never heard back from Pavloszx and I have just finished (I hope!) sorting out a very similar problem. 2013 Sherco 290. Over a week or so of almost daily riding it started to develop issues. Ran fine cold. Once hot it would start to run lean & not idle, better with choke to an extent. Sprayed WD40 over the crankcase joints etc. No result. Cleaned the carb and drilled the LH vent nipple while I was in there. Trimmed the slightly ragged end of the fuel pump pulse pipe at the manifold nipple and checked the nipple seal. Replaced the LH crank seal with viton (forgot I'd done this not so long ago when I had a similar issue. In that one when I went to replace the seal I found a couple of the crankcase bolts inside the flywheel area were slightly loose - easy fix). Waited a week or so for a new RH crank seal and replaced it. Tightened a slightly loose exhaust manifold bolt. Checked fuel breather. All to no avail. Thought for some time. Figured it seemed like fuel starvation more than air leak so started at the simple bits: Tank breather again. Check. Fuel tap flow. Check Fuel out of end of hose to carby. BINGO. No flow. Remove the Mann filter - blocked. Backflush it with syringe and compressed air. Lots of very fine grey bits. Reassemble and all is good. The correlation with Hot vs Cold must have been that when cold I never drive it hard. Once warm and giving it some throttle the carby starved. Hope that helps someone else

That makes sense. I'm not sure the age of the tyre, I felt the tread and it felt as soft as a recent tyre so figured it worth a go. I'll see if wd40 makes any difference, if not I'll put it back on the GG. Heating is something I hadn't thought of, might give it a go out of interest. On MTB ghetto tubeless setups a wrap or two of tape on the rim seat can work wonders, I may try that too. No doubt longer term the solution is simply a new tyre ?, still if I can get this one to work reliably I don't mind saving a couple of hundred dollars! I suspect the adhesive would be ok getting off, it's not a huge area being peeled at any one time, and alloy typically doesn't stick that well.

I've just swapped around some tyres between bikes and now find that one rear X11 is loose on the rim and spins and pops the bead. The tyre was on an older style rim with rubber strip (GasGas '05), now it's on a Morad tubeless rim (Sherco '13). It popped the bead on very easily compared to all other X11's I've done, and now pops it off equally easily! I'll probably just put it back on the original rim which it worked on, but I'm wondering if there are any good tricks to get the bead to grip a bit better? I mounted it with soapy water as per my usual technique, but have now mounted it using WD40 having read that WD40 tends to make the rubber go a bit sticky. I'll leave it a day or so before trying it again. I wondered about using a bit of conveyor belt adhesive on the rim as a mounting lube (a rubber contact cement), might try that next if the WD doesn't work. The tyre is older, but very little wear, maybe newer tyres are tighter? Cheers.

An update on my homemade stainless frame protector/stops. I sent the bike for a fairly significant un-piloted flight today - got off lightly with a dented tank and forks needing a re-alignment. The protector/stop in the photo above now looks like this: The frame underneath it looks to have sustained no damage (there was a small dent from when it had the useless factory plastic stops, but it looks the same to me). I had a couple of mm of silicone holding it on and acting as padding, that was split and peeled under the impact area. Only a few minutes to peel the old stainless off and silicone on another, this time I think I've done a better job getting the stainless sitting squarely on the fork clamp chamfer (as you can see this one still got hit hard by the sharp bottom edge of the clamp) hopefully should work even better next time.

On the principle of "leave no stone unturned" I dismantled the whole thing - not looking forward to reassembling it, but it went together once so it will go together again!

Thanks lineaway. Wouldn't a broken top hat effect all gears similarly? This only effects 3rd to 4th. 1, 2 & 3 have always been perfect. And even if the top hat was completely removed the gears will still change, just the shifter won't return correctly. I'm now wondering if a stray piece of metal from the starter gears was somehow caught in the shift drum stopping the internal roller from engaging for 4th. Clutching at straws. I'll inspect the roller plates again. Hopefully I'll get the bearings in today and see how it all works after a thorough clean.

Thanks everyone for the replies. I now have everything apart and am replacing bearings seals (probably not the mains as they feel good and I'm getting shy of spending yet more $$$). It looks to me like a couple of things might have contributed. The common kickstart quadrant/idler damage - both have bits missing. There is evidence of bits going into the box and damaging the boss that holds the RH end of the rear shift fork shaft (17) and slight damage to the face of the fork in that area (20). Other than that things look undamaged in the gearbox luckily. The fall onto the shifter. Which is the real cause of the shift problem I don't know. My problem lies in working out what's not right. I've inspected the top hat (10x magnifying glass) and the weld is definitely intact, and the bar is also absolutely undamaged. Even if this was damaged I believe the gears would still shift, just not recentre correctly and need manual repositioning. This was confirmed by Hell Team. In my case the gears would not shift 3rd to 4th whatever I did, 1st to 3rd where fine, suggesting this isn't the culprit anyway. Inspected the shift drum (magnifying glass again) it appears perfect, no visible wear on tracks. Slight polish to the internal and external stars, but nothing that looks like wear. Bearings smooth and good. Shift drum shaft (28) has about .05 - .07 mm runout (clocked between centres in lathe) toward the shift lever end. Rolling it on a surface table shows no perceptible bend through the main length. The measurement in the lathe is a bit iffy - there was .05mm wobble right at the top-hat end of the shaft, running on a centre. I decided it wasn't worth trying to nail this down as I reckon it's probably what I'd call straight in this application. Perhaps an incorrect assumption. Inspected the forks - neither fork is absolutely dead flat back to back. I've had them on the surface table and both have some small deviations, but nothing that really looks significant. Again the Hell Team advised that unless they are badly damaged they would not effect the shifting. The pins show no sign of wear. The surfaces of the forks that engage the discs have differing wear patterns - RH rear fork (20) only has polish at the tips. (19) & (16) have polish along much of the surfaces. None of them look scored, just polished. Inspected the fork shafts (17 & 18) - straight and smooth. Inspected the internal rollers, carriers and springs - no sign of anything worn, bent or damaged. Both rollers sit symmetrically out from the shaft. Cavity the internal rollers run in has very slight wear at the corners the rollers run over as they move in and out, but it is very minimal - only slightly more than "polished". External roller (23) also appears fine. Selector discs all move freely and no signs of damage. The most puzzling thing to me is that after disassembling and inspecting everything and checking each component's function (including moving the selector drum up and down the positions) I put it back together in the RH side case and tried changing gears. 1st to 3rd where good but then 3rd to 4th was as if the internal rollers just weren't engaging in the star, the lever just moved up with very little resistance. Obviously impossible to see what was going on in there. This felt about like it did when the bike was together. The difficulty is that after gradually removing each shift fork one at a time again, it started shifting and continues to do so if I put everything back together! I'm waiting on the replacement bearings. Once I have them I'll put it all together in the RH case again and see what happens. I'm very reluctant to re-assemble it without actually finding the root of the problem though. I'd hate to put it back together and have the same thing re-appear! I can't decide if the lack of movement of the drum is caused by something going on with the roller/star, or something up around the forks that's jamming the drum. I haven't yet found anything that would obviously effect either. Certainly the movement of the forks as the selector drum rotates isn't frictionless, but given the shafts and gears aren't supported both ends, there is no oil bath and the gears aren't constantly rotating it's hard to tell if it's more than should be expected or not. Lineaway, you said "10,11 and 12 is probably the cause ". That would be top hat assembly and the internal rollers. What would you expect to be wrong with them? I'm suspicious about that shaft assembly but reluctant to spend nearly $200 on a suspicion. Puzzled. Peter

Teamwork prevailed. I used Loctite 620 high strength/temp bearing mount to fix my home-made collet extractor into the bearing. I then put a plate across the top of the case with the thread of the extractor through it. Plenty of heat then tighten a nut down onto the plate and out it came. Thanks.

I'm struggling to get the input shaft support bearing out on my '07 250 Pro. It's in the blind housing under the breather nipple. Tried a collet and slide hammer - no go. Machined up a shaft with spigot to plug the breather hole, filled behind bearing with grease and drove in the shaft to hydraulically force it out - just blew out the seals. I'm now waiting for some high strength loctite bearing mount to cure on the collet before having another go, this time with some more heat. Anyone have a good solution to this one? I figure I just haven't sworn at it enough yet - a few more curses and I'm sure it'll just pop out easily Or maybe I'm just not applying enough heat?

I think they are OK, probably just the rider. I've replaced LH seal and oil, still need to do RH and replace bushes. They feel pretty free, and my results are pretty similar on the other two bikes I've tried in it. I will take a careful look at them though and see if they are at all sticky, thanks. It has made a pretty quick difference to my hopping. Still rubbish, but in 3 short sessions I've got better faster than in the previous weeks of effort out riding. It just saves the hop-foot down-step up-repeat. I can now do several hops left or right before completely loosing balance. As Cleanorbust suggested, I tried the back wheel against a wall - complete fail. With back brake on the wheel has to be able to roll backwards in order for the bike to rotate, With brake off it just moves away from the wall and you're no better off and also not learning to hold the brake on throughout.

Glad to provide amusement The wall might well work, maybe I'll give it a shot. One thing I found with my dodgy stand was that if the bike is held rigidly upright it's nearly impossible to hop the wheel sideways. With the straps a bit loose I can move the wheel sideways a bit and learn that technique. Another few hundred hours and I'll have it.

I've been trying to learn to front wheel hop. I can do reasonable beginner hops on my bicycle, but the moto eludes me. A timing thing and also the bigger leg movements needed I think. So I was thinking how I could help the process along. I knocked up a very rough and ready jig to hold the bike up so I could hop without continually having to stop after every attempt. It has a few problems being so rough, but it works. In just two short sessions my hops have improved more than they have in the past few weeks (still absolute garbage, the video certainly isn't a how-to!) https://www.youtube.com/watch?v=-PCeKD7R8Qs

I've been mucking about with zaps and what I'd love to see is a really good side view zap video with Picture-in-Picture like you've done, but with the inset video being an action cam mounted on the bars looking at the clutch, or ideally clutch and throttle. This would really show the timing of throttle clutch and jump. Any takers. If you shoot the video I'll sync and edit it (just need a hand clap or similar in both videos to sync them on).

I'm pretty sure I know the answer to this one but am hoping to shorten the time taken trouble shooting/repairing. GasGas TXT Pro 2007. Stopped shifting after being dropped (not hard and in soft ground, but dropped nonetheless) Adjusted the eccentric until it shifted up and down (full up rotation on the eccentric), but when we went riding realised only shifts as far as third gear. Lever moves up full range but nothing happens going to fourth. 1st, neutral, 2nd and 3rd are fine both directions. Took out clutch and checked eccentric. Tried giving the lever a little extra move down to get the internal "click", but no dice. My guess without any real appreciation of the internals of these things is that a shift fork is bent? I've seen mention of the "shift pawl" being a problem, but it seems like that problem is consistent through the whole range of gears? Cheers Peter

I mentioned in another thread the mod I have done to my 2013 rear mudguard attachment to reduce breakages. Thought it better to make a new thread rather than hijack the suspension repair one. I drilled a couple of small holes in the guard and put a couple of washers and a spacer sleeve onto the bolt that connects the inner guard, tank and muffler at the rear of the bike. I then take a cable tie and pass it through the holes, over the top of the guard then down beneath the bolt. Now when I flip the bike the cable tie breaks instead of the guard. I found a 5mm cable tie was a bit strong and 2mm a bit weak. I've settled on 2mm for now. I carry several spares poked through the handlebar pad attachment points. I've used a soldering iron and a piece of the plastic cut from the rib under the guard (visible in photo) to repair a couple of cracks caused before this mod.

Nice videos you make Cascao, simple but effective. Is the white plastic protector on the back of the dog bones a standard part on newer bikes, or an aftermarket piece? My addition is that I got rid of the two rear bolts holding the rear of the mudguard. I drilled two small holes in the guard so I can pass a thin cable tie through the holes and around the bolt (spaced out a little) that holds the "interior fender". Now when I flip the bike the cable tie breaks, not so much the mudguard.

Today I finally replaced the spring with one I modified to match the broken original (minus the break). Eureka - it is still working after an hour riding so I'm going to say it's fixed. So if you buy a replacement spring for your Sherco carefully compare it to the original working one and modify it to match if it isn't the same. In the photo I've attached here the original is in the centre, the new incorrect one is on the left and a new one modified to match the original is on the right. Now to fix the stripped clutch housing bolt from all this on-again off-again - it didn't get close to torque before it stripped, strange as it spun in easily. Am I impressed with Sherco quality do you think?

How often do I damage my bike? - Not often at all. I fit handguards (plastics largely or completely removed) to avoid busting levers. I replace rear mudguard bolts with cable ties that break before the guard does. I'm old enough and have enough imagination to be somewhat cautious. Repairs - generally pretty easy with some reasonable mechanical knowledge, and for a motor-sport fairly infrequent. Do I hurt myself - yes, but not often or badly so far. Bruises and sprains. Rider safety - I wear good quality MTB knee guards and protective shirt (chest, back & shoulder pads). Sometimes elbow pads as well if it's rocky and I'm planning on extending myself. Magnetic kill switches are a great thing - yes sometimes they cause problems but mostly they save things. Clutches & brakes do the same but I'd not like to ride without them either. Not carrying a spare magnet (they grab onto any spare bit of steel) and having to walk is operator choice. I sometimes think boots could be improved with impact absorbing insoles for when we jump off onto hard ground from a height. Bike safety features - they have very few really. Guards on the discs & sprockets and sometimes a magnetic kill switch. Perhaps a pad on the handlebars. For the most part they have few sharp edges on "body work". Exposed headers are a potential hazard that could be better guarded on many bikes. On the whole it's not bad for an inherently hazardous activity.

Well, another failure. About 3 shifts before the lever went floppy again. I'm at a loss how to fix this without resorting to somewhat desperate measures. My current plan failing any other good suggestions is to re-bend the spring so it sits further back on the boss. The only other thing I can think off is to screw a thin flange onto the end of the boss to retain the spring - not sure if there's room to do that. Or build up some weld to form a flange, but that becomes a big job for a stupid little spring. Getting really good but sick of the process of removing the clutch and shift shaft! EDIT: I hunted out the remnant of the original broken spring to compare the shape and voila - the new spring has legs almost straight inline with the coils, the original has a significant kick out to the side. This fits perfectly with what's happening. I've now reshaped my second spare spring to match and am looking forward to installing it later in the week perhaps. Sherco really needs a new spring manufacturer - poorly made with obvious stress raisers and not even able to match a consistent form apparently. So beware - if you get a replacement shift spring, compare it carefully with an known-good one!

I was absolutely fastidious following the Splatshop pictures - measured both flanges of the bush it rides in, held the assembled spring and shaft in front of the photos. It just didn't work. Today I finally pulled the clutch out yet again and studied everything carefully. The original wear marks on the cast boss look like the spring was assembled the other way around, with the ends of the legs kicking out from the shifter. So I've now flipped the spring over and also ground a very slight groove into the boss for the spring to ride in. We'll see what happens this time. I'm not removing the "external return spring" I fitted yet though (a length of bungy through the bash guard that loops over the shift lever - doesn't work perfectly, but certainly helps), just hooking it out of the way until I see if this time it stays fixed.

The funny thing is the Formula Seal Change manual indicates to always replace the lower bush, however for me the lower bush remained in good condition, it was the upper that got damaged. Maybe best to have both on hand!

I'm definitely no expert at this, a bit of a beginner indeed. However as I've been working on the same skills a few things have helped me, maybe they'll help others. 1. This video talks of a "touch up". Probably what might be called a double blip more than a zap, but I consider that if I use clutch it's a zap (rightly or wrongly, I don't care - works for me). I found that rather than dropping the front wheel into the obstacle it was easier to get the timing together if I hit the obstacle on the rise. Interestingly after watching this then watching Trials GP this actually looks more like what the pro's do most of the time rather than dropping the wheel onto the obstacle. 2. I spent a bit of time doing stationary zaps on a tiny obstacle - maybe 150 - 200mm (6-8") high. Gave me the confidence to really drop the clutch and have a few revs, and also get the movement and timing dialled in a bit better without any significant consequences. I had a tiny rocky step, a large curb would be similar. 3. As the Ryan Young/Pat Smage zap video above says, I find it easier to ride into it with the clutch slipping, then drop the clutch for the zap. Heaps easier for bumbly's like me to get the timing compared to clutch out/in/out. 4. As also mentioned above, closing the throttle when dropping the clutch makes a big difference to the pop/lift. It does however rely on having enough revs up to carry the bike up to the top. Point 2. gave me the confidence to actually bring the revs up a bit closer to what's needed. Still a bit scared of too many revs, but getting better bit by bit. EDIT: Out of interest I took sample out of the Young/Smage Zap video and tracked the front axle path to check that what I think happens actually does happen. And yes, the front wheel hits the object whilst on the rise.

Beware that at least on the steel forks removing the upper bushing as shown will destroy the teflon lining. The lower bush slips up inside the edge of the upper and scrapes the teflon off. The lower bush does not appear to get damaged.

So I got a new spring and fitted it. 15 shifts later it was the same as before Assuming it was the terrible manufacture of the spring at fault (there is a significant crimp at the inside of the bends, one leg consistently worse than the other) and the new spring was busted, I ordered another. Meanwhile I jury rigged a bungy from the bash guard slots to the lever as a temp. return spring - worked pretty well really. New spring arrived and yesterday I tore down again only to find the spring intact. Hmmm. It seems it had just jumped off the boss in the case. The boss is in good condition, I can see a slight groove toward the back corner from where I assume the spring has been the past years. Double checking the Splatshop and Tear Down PDF pictures I decided I had the bushing on the shaft the wrong way around, there is a very slightly thicker flange one side that appears to go toward the shift arm. Swapped that around, held it up in front of the splatshop pic to check it looked the same, reinstalled everything, new fluids again, checked it was all working nicely in the shed and away we go. Got at least 8 shifts out of it this time The boss looks nice and absolutely undamaged except perhaps for these slight grooves down near the back of it - they look as if they would be an advantage if anything. There is no end play to mention in the shift shaft, so I don't think there's any problem there - the stop on the clutch housing that prevents the shaft moving right is in good condition, barely a mark where the shift shaft touches. I read in another thread that someone had trouble when they used a thinner clutch housing gasket and it caused the shaft to bind, I'm using the original still and the lever feels free moving, so I don't think this is the case here. Can't really think of anything else to look for. So before I get into it for the third time has anyone got any particular experience they might share to enlighten me how to make the b-----y thing stay where it's supposed to be? All I can think is that I need to somehow push the spring to the back of the boss in the hope that the slight grooves there hold it in place. TIA