The Mystery Of The Missing Coolant (Sherco 2.9)

my bike has started doing this great new trick and I thought I'd share this bike is losing engine coolant and I have no idea why or how and seeing as we're all here where when what and even who for good measure just to put it out there losing coolant is a bad thing the engine could overheat and blow it stopped up until now I've tried absolutely nothing and it still hasn't worked so I've decided not just to do something but to do everything full disclosure it hasn't been a lot meaning the problem isn't so bad I can't ride the bike so I've been putting up with it adding coolant as needed but the weather is warming up and it's high time I sort it out it's only gonna get worse if not worser I realize we're getting a little bit out of the machining comfort zone so fair warning this video contains greasemonkey content not to worry they'll be right here the whole time right by your side if it gets to be too much I'll throw in some machining though I may have just jinxed myself now I just know I'll brake a bolt off in the head god I think it's the head gasket not positive it might be the head gasket though let's take this a step at a time cowboy also if you haven't noticed this is a sure co2 92.9 though it doesn't really matter let me get some grief for this but modern trials bikes are all more or less the same aren't that many companies that even make these and their relationship at times can be a bit incestuous at the risk of insulting your intelligence iziz let's quick recap what we're looking at so we're all on the same page this is a two-stroke thermonuclear engine just idling there's something like 25 or 30 explosions per second inside that little cylinder gets pretty toasty to keep from burning that toast it has a liquid cooling system most two-stroke engines some two-stroke engines I guess I don't know if it's most but like your lawnmower chainsaw or weed eater or air-cooled a small fan usually built onto the engines flywheel pushes air across the engine keeping it cool well not hot not that hot okay fine it keeps it from liquefying maybe you can just see it down in there as I pull the cool those are fan blades maybe impeller bleeds and this is water cool just like your car there's a water circuit in there and it's water taking the heat away from the engine instead of air as far as engines go in trials bikes like this one the use case is rather harsh bikes like these usually creep around quite slowly and see bursts of high revs and clutch dumps all day long perhaps you can make the case that dirt bikes have it worse it's something insane like 10,000 rpms from the minute they're started until they run out of gas maybe but at least they're moving the whole time now what was I even talking these engines get hot and they have a cooling system to help deal with that the entire engine or most of it anyway is shrouded in a water jacket there's a second cavity in there full of water or coolant and that coolant takes heat away from the engine it's like putting an ice pack on your swollen head hot coolant from the engine is then pushed to the radiator that hot coolant makes the radiator hot a fan blows on the radiator to cool it down like you'd blow on that hot soup you're eating after having busted your head blowing on hot things is scientifically proven to cool them down crazy huh that now cooler coolant is then routed back to the engine to pick up more heat or as in my case it's fired right out the top of the radiator cap I really should have washed this bike before doing this video my apologies as I mentioned the coolant is moved between the engine and the radiator by a little pump and it lives right in here cutest little water pump that ever could break into that in a moment and have a look the water pump runs the whole time the engine is running it's geared right into the engine the fan on the other hand doesn't start doing its thing until the coolant gets hot when the cooling cools down the fan stops I'll show you the thermostat that turns the fan on and off when we get there consequently you shouldn't turn your bike off while the fan is running give it time to do its thing should only take like a minute so the problem could be anyone or a combination of the cooling system components we just talked about anything from not enough coolant to a bad radiator radiator cap or pump maybe you have a hole in one of your hoses where the thermostat isn't working right not telling the fan to go when it should or the fan itself for that matter given my symptoms the fan seems to be coming on and off I know there's coolant in there the fact that it's shooting out the radiator cap I don't know my money is either on a bad radiator cap which I'll change for they're cheap and yes I checked my radiator cap with a multimeter seems okay but still not positive or it could be a blown head gasket I'm not seeing coolant in the engine oil the engine oils coming out not milky not frothy but the fact that I'm seeing so much pressure in the radiator seems to point to the cylinder head of course it could be just as simple as loose cylinder head bolts maybe I just work those bolts down and problem solved or it could be as bad as a cracked head itself which would stink oh now ain't that rich ignore all the carbon deposits for now I think I see the culprit I'm no expert but I spy with my one good eye a weak spot in the inner seal right about that area there there are two seals here this engine uses o-rings not a gasket but same thing the outer gasket keeps stuff from getting out or into the engine the inner gasket separates the combustion chamber from the coolant passages there are also some small overhangs around each bolt to keep coolant from squirting out from around the head bolts it looks to me like pressure from the engine was pushing past that inner seal and pressurizing my coolant system and then blowing out the radiator cap by the looks of the build-up it may have been sucking some coolant in - but I wasn't getting a lot of smoke or any smoke out the tailpipe anyway before I can replace the seals I'll need to clean this mess up ideally I'd break the engine down give this cylinder a light honing change the piston rings but other than the coolant problem this engine was running perfect ton of power great compression and quite honestly I just want to be able to ride it we could get into trying to read the tea leaves here it does look like it's spent a little time running which makes sense I suppose but for now I just want to do my best to clean it and if I'm feeling it order some parts and save the rest for a rainy day here's what I plan to do you don't need to do all this yourself if you're having similar problem reason through it fix just the part that needs fixing but in my case I'm going to change almost everything head gaskets water pump seals the water pump itself pump bearing shaft and pinion gear radiator cap maybe even the thermostat my bike is over ten years old now and while I'm in there I might as well compared to being stranded all alone in the middle of nowhere parts for these bikes are cheap at least these parts that I plan to change anyway there's a maybe a better look at the impeller the water pump it's mounted to a shaft that comes through the cover there's a bearing and there should be two seals in there is attached to this unfortunately plastic pinion that interfaces with the gearing on the motor in the bike again this is always turning when the bike is running it looks like coolant is ported through here so there is a gasket of course oil on this side coolant on this side that impeller would throw coolant yeah there's a hole on the side so coolant is coming from the radiator into the face of the impeller impellers spins pumps it out the back and into the rest of the engine can't see any real way to get a hold of this I'm gonna squeeze this in some soft inserts in the vise this side has what looks to be a 10 millimeter hex built right into the hub of the impeller let me try to break that down and we'll see what these seals look like came off surprisingly easy plastic impeller molded in brass insert that seal has seen better days there's a weep hole on the bottom of this casting I did see a little bit of water coming out of there not a ton that tipped me off to a bad seal in the water pump it almost looks like maybe someone put some sealant on there see if I can get this out not sure what that is there's the bearing that shaft has seen better days I'm guessing that's what tore up the seal see if that seal won't come out I'll be careful not this scratch the counter board that this seal is sitting in it sure is in there this thing may have been glued in place I guess somebody who's worried about losing it sorry about that I had to stop the camera the whole thing got not very family-friendly I managed to dig all that junk out of there clean the inside up pretty good the bearing is also shot maybe what led to all these problems it's very wobbly anyway I got some new parts the new seals the bearing you saw I also got what they call a high flow pump high flow impeller see maybe it's taller sure if this is marketing gimmick I see this pop-up a lot so I thought I'd give it a try because this is taller it's obviously not gonna fit on the cover like it did before it comes with a bit of a spacer and it's blue so it must be better I mean no offense to the people that make and sell these things I've just never tried one so I don't know how legit of a modification this is hopefully my fan comes on less often or comes on for less time when it is on although it is true that for the same RPMs a taller impeller will move more water more fluid it doesn't depend on just the impeller and the rest of the system might not be able to handle it meaning we might have just the same flow rate as before maybe the system can handle it you have a higher flow rate now the fluid is spending less time in the radiator I don't know what I'm getting at is this is a system but we'll see I'll let you know and again it's blue also comes in red I figured red would probably run hotter the only thing of note is that cups heels are directional so there are two unless I lost the other one and they'd be installed back-to-back cups heels works sort of like parachutes or umbrellas pressure on this sort of empty side causes them to open up and seal you put them in the wrong way then water or oil whatever pressure you have on the outside can squeeze its way by that went together surprisingly well new seals new bearing I feel much better about that cleaned up this gasket surface gasket scraper and a very light stoning I don't want to put this on just yet I don't install it just yet because they think as I put the cover on I'll want to be able to turn the impeller so I can get this to mesh with the bike just using a bit of light Oh ring Lube silicone grease just to help you stay in place maybe two drops cover that up head over to the bike since I won't be able to get in here with the angle grinder I'm just going to use some wd-40 and scotch brite these things are cooked probably be smart to cover the coolant passages I want to clean around those things pretty good too I have the side of the bike open the water pump is off and the coolant port is exposed so I should be able to flush this out any of this junk that gets done there I think I can wash it out once this is back together if it even starts I'll write it for half an hour an hour or so check the spark plug again I'm starting to wonder if my carb set a little too rich I did notice the gap on the spark plug was quite a bit bigger than it should have been I think that can result in incomplete burns and leaving carbon behind but with coolant getting in here I know I'll put it back together write it again and check the spark plug resist the urge to use any abrasives on this thing don't try to stone the ceiling surface flat I mean you can or you could want to do that when the entire engine is broken down where you can wash it meticulously don't want any abrasives getting inside this combustion chamber any tough spots you can try to hit with a fingernail if you've got them it's probably as good as I'm willing to get it now I realize the other day when I ordered all of the gaskets I neglected to get new head bolts I don't know if technically this size engine warrants changing head bolts when you take out the old ones but it sounds like one of those best practices kind of thing I'm just using two of the old ones until the FedEx guy shows up in the meantime I think I can get the side cover back on it's a very squirrely gasket I'm gonna use some jet Lube anti-seize on all the fasteners anything that gets torqued including the head bolts that's probably too much here's my trusty husky torque wrench these cover bolts just outside the bottom end range of this thing but it's the best I got I call that my shooting star pattern for torquing when you store this style of torque wrench you put it away be sure to completely unload the spring according to my YouTube analytics over three quarters of a percent of my viewers look up to me and to those misguided men and women I have something to fess up to I had to borrow a torque wrench to finish putting the head bolts and pump cover on although the dubious bottom end of my faithful husky was probably fine for the engine case these smaller fasteners in the head and ear on the pump well they're just too small torque wrench is too big trying to run my wrench that far below scale the numbers would have been meaningless and I would have run a high risk of snapping these fasteners off in the block not to make us think about this but if you don't have a torque wrench it's not the end of the world close but not the end of the world probably tens of thousands of bikes are rebuilt and garages every day without them and work just fine use your common sense when tightening or in a pinch a box end wrench a spring scale and a calculator if you don't have common sense or a spring scale buy torque wrench if you don't have a calculator you should re-evaluate your priorities a little something I didn't see coming with just the factory pump the radiator hose had very little clearance to the exhaust in fact on close inspection that tube had some heat damage not a lot but some not enough to warrant a new hose at any rate but with the spacer to accommodate the high flow pump that radiator tube has been pulled out closer to the exhaust so I've had the stuff in a little bit of that heat-resistant woven fabric fiberglass stuff keep that in mind if maybe you're considering adding this to your bike as I work my way through I've also been changing these stupid hose clamps I've hated these things from day one hate I tell you I don't know how many street signs the previous owner had to vandalize to get his hands on these why would you put something so ugly on such a pretty bike especially with all these pokey bits all sticking out not that I'm doing much better with my clamps but these are all I have I'm gonna regret installing these the only way to get these crimp-on clamps off is to cut them the factory uses these nice I never remember what they're called like Bob Odenkirk clamps but hopefully these hoses and clamps don't leak and they're on there a long long time before I've got to order the right ones I also think I need to tighten those more you know what I've always really liked about these shortcodes it's just how easy and convenient it is to get to the radiator I use a funnel just pour the coolant in until my socks feel and back off a couple ounces bending over backwards with a flashlight and an inspection mirror gives you a clear line of sight to check the level and that's the new cap easy as that that yellow thing you see is just a wrap of old apron leather is to keep the wires in the cables off of a potentially hot radiator that down there by the way is the thermostat I just probably fixed this insulation while I'm here I thought I was gonna change it but I'm gonna leave it I figured innocent until proven guilty that and I have this sinking feeling in the pit of my stomach that if I try to pull that out I'm gonna break something else that I don't have this is just a switch in the coolant path when the coin gets to a certain temperature it closes and that sends 12 volts to the fan turning the fan on okay all back together I think that's about it I believe I put all the parts back inside yes I'll find out tomorrow I know this content was maybe a little different if you like this motorhead kind of stuff let me know maybe we'll do some more but for now I'm really curious see if this thing starts

Channel: This Old Tony

Views: 626,565

Rating: 4.964263 out of 5

Keywords: sherco, sherco 2.9, sherco 290, cabestany, water pump, head gasket, compression, radiator, CSP pump, high flow pump, engine, subscribe

Id: s0-0KTa2Olg

Length: 18min 30sec (1110 seconds)

Published: Sun Jun 30 2019

Reddit Comments

[u/calculaterror]

I gotta know how it ran! What is this cliffhanger ending tony? I like these videos, kind of a one off of the kart build series.