Up here in Lochaber we've recorded temperatures dropping to just above -16 Celcius, some thermometers in the garden recording lows of -20 celcius. Bloody cold, got about 10 inches of snow on the ground still, sitting on about half inch of polished ice.
Estate manager has resorted to driving round in a tracked digger, and and argo cat with chains on.
Half of our gritters have gone off the road since this cold spell began, leaving many roads uncleared and untreated.
I'm not complaining though, conditions up Nevis Range are amazing...
Okay 2k8 man, let's get serious for a moment. I do not want to overshadow any one elses advice. Tony mentioned a good point by looking for air bubbles in the cooling system. This is a good sign of compression leaking into the coolant, but impellers can cavitate causing air bubbles, it's important to tell the difference. Shellman also mentioned filling to mfg's specks to be sure you have the proper amount to begin with. With cracks in the head, they are usually minute, and often not seen with the human eye, as often they only open when the engine warms up enough to make them expand. There is a process called magnaflux, which can be perfomed by a machine shop. Some times a little history of how or when this began is helpful. You mentioned falling over in the snow, I doubt this would have any effect as hot engines plow through water all the time. Keep in mind your engine may NOT have a serious problem, sometimes it just takes a little time to
diagnose it properly. remember, don't panic. Also, did it have enough anti freeze content in it to begin with? This of course could crack a head or cylinder overnight by freezing.
Yes, air bubbles and locks in the cooling system is a good place to begin, and has been checked, system flushed right through and filled slowly, allowing air to escape back up the funnel as coolant went in, then gave all the pipes a quick squeeze as reccomded with the silicone pipes. I didn't just brush past this advice, I took it in and will try it, just wasnt anything to discuss about it so didn't get a mention. But thanks tony!
Cracks in the head are hopefully going to be my last place to look if im honest with you. As it's the most expensive part of the whole job... and if I sort everything else out, and it does turn out to be this, it's all just gonna last a bit longer. I'm not saying it's not the head, i'm just saying i'll check all the cheaper parts, and parts I have to hand first.
History - Bike was sat in garage, average temperature of around 5 degrees C when it was put away in the garage. I then went away for a few days, so the bike didn't get ran everyday as it usually does. Come back to find an average daytime temperature of around -5 degrees C, with temperatures dropping to -15 at nights. I ran it, and it spat a little bit of coolant out, as the fan didnt cycle, but that turned out to be a loose connection, sorted with silicone spray and new spade connectors, sorted.. Didn't do it again that day, and fan cycled seemingly normally. Fitted titanium frontpipe and compression insert on christmas day, the day after I sorted the connections. I started the bike up that day, fan cycled on once or twice, seemingly not as often as normal, but I put that down to cold weather, and then she spat a few more mls of coolant out. I filled the rad up to the bottom of the neck the other night, ran it, it spat out a load more, obviously setting it's own levels. Stopped, and the fan cycled.
Went to run it again day before yesterday, and the thing ran right up, overheated, sprayed a lot of coolant out without me realising, and then I killed the engine. It seems to cut the engine of its own accord when it gets too hot to run, so no damage done I wouldnt of thought. Reason behind me testing and finding out before I run it again.
Coolant is an antifreeze coolant, rated down to -30 degrees C, and the radiator was full when issues started, and has been flushed and filled again since.
If I wired the fan on permanantly, and ran it... No coolant lost, and no overheating, this means that there's no pressurisation of the coolant, and that its circulating fine? Basically saying that the issue is the stat?
If I then unwire the fan, so the job is down to the the thermostat, and again it overheats, and sprays coolant. With the fan cycling, or not cycling, it's the stat at fault?
If the fan is on permanantly, and it sprays coolant, yet doesnt overheat, the coolant is circulating, but under pressure?
If the fan is on permanantly, and it doesn't spray coolant, yet seems to overheat, the coolant is not circulating, not allowing heat to get to the radiator?
Stat at fault, new stat, report back?
Under pressure, head gasket and o-rings, report back? Still faulty, try different head?
Not under pressure, but not circulating, check impeller and flush system and report back?
O-ring in the head gone bad..........my 2 cents.
Start storing bike in house, temperature controlled environment your bike will thank you................other humans in the house will hate you.
But hey fair trade as far as I'm concerned.
What I was thinking. At a tenner to do the job, i'd be willing to try this without troubleshooting, but i'd prefer to narrow it down to all the different areas before I go wasting money, incase I need a new head, or stat instead.
I have seen the nut break free from the impeller so it doesn't spin thus doesnt circulate the coolant
I had an "invisible"; crack in the head of a gasser once .......was similar symptoms...i.e pressure in the coolant system.. took ages to find it it really was invisible but the heat & pressure in there at Xthousand times a minute!!!!!!!!!!!!!!!
Hi 2k8, I tend to agree with chewy. It sounds like compression building up in the cooling system. It may not be a crack, but possibly a cylinder head gasket or seal. I'm not sure yet if these have thermostats! Another possibility stuck causing pressure to rise. The main thing is, Don't Panic. Keep checking the forum.
Impeller could be a possibility. Will check that last as its an expensive one if I remember correctly. Did water pump seals ages ago.
Chewy & Rockyrider;
Crack in the head, will check if and when I do the o-rings. Could be quite possible as a lot of snow got around the head when I went for a ride just before christmas, dropped bike and landed in deep snow, head was cooled pretty much instantly.
Going to check the o-rings in the head if rad cap doesnt do it, will wire the fan to be on constantly and check for pressurisation. Got a spare head here also. But will need new one, maybe oppurtunity to go high compression.
Speaking as Cope's witchdoctor apprentice ,I would go for the easy-peasy stuff first..replace the rad cap,then... let us know so we can rule that out
Yeah, got a rad cap here, off my 06. Would try everything else off that, but the stats buggered on it. Fan was on all the time on that, even with the fan not bypassed. Bit late to go start it up now, so will change that and test tommorow afternoon.
Until I get round to doing that, keep imput coming.
Right guys, what the hell is it with this bike? I'm sure it's determined to drive me to the mental instution and nowhere else!
Started off after the bike was sat for a bit, in the garage. Two or three days possibly, with temperatures dropping to about -10 at night. I took it for a spin, and it was spitting a bit of coolant out, not much, and the fan did cycle... But it did continue to spit, for the whole ride. Didn't think much of it, just thought possibly there was a loose connection somewhere. Shoved her back into the garage, stripped her down, sorted all the wires, waterproofed them, and sprayed silicone on the connections.
Started the bike up on the paddock stand, took a long time to warm up, but when it did... It continued to spit coolant, but again, the fan cycled. Stopped the bike, put her back away. Started her up again on the stand the next day, let her warm up, revved it a few times, and then the idle went really slow and lumpy, had to turn the tickover right up for it to even run. Lack of power and dribbling coolant out of the overflow.
So, clearly overheating and the fan didnt come on. I've tested the fan directly off a 9 volt battery, it spun fine. Off a 12 volt battery, spun fine. So, the fan works fine. Bypass the stat, works fine. So it isnt the regulator.
Maybe there was a loose connection again? Ran it all up, and the fan cycled as normal... odd.
With the help of a member on the forum it's been narrowed down to the following;
Rad Cap - Loose connection on the stat, causing the fan to not cycle properly. The coolant spits when it runs at the correct temperature anyway... So is the cap releasing coolant before it should?
Thermostat - Dodgy stat, only sending current occasionaly. This would explain the occasional overheating, the occasional spitting, and the occasional normal running. When it sends at correct times, and wrong times. Maybe it's sending at the wrong temperature?
Cylinder head o-rings - More than possible? Sat for a while, in cold weather, o-rings possibly went hard in the cold, and when I fitted the titanium frontpipe and high compression insert the extra pressure's caused them to go finally? This allowing pressure into the cooling system = inneficient cooling and the constant spitting of coolant. And if extra pressure is getting in, the impeller wont be circulating as it should, right?
Then the extra compression with the new insert and pipe. The cold weather causing it to run lean and the ignition advance on the paxau causing all that little more heat, and it cant cope?
Running decent fuel, 80:1 fully synthetic and 98octane fuel.
Cooling system is standard, apart from silicone hoses.
Any more ideas?
Give me your thoughts guys, before I go and strip it down... Any ways to identify if the o-rings really have gone?
Hi Shercoman. cooling systems are designed to run under some pressure. This keeps the coolant from boiling even above the temperature it would boil at in open air. That's why the temp guage in your car can show 230 degrees and the water's not spewing out everywhere. It's also why a pinhole screws up the whole system. The cap acts to regulate that pressure. Too much and the cap is supposed to vent if the system pressure gets too high. That's why the cap has a tube on it. Just like your car it's intended to dump into a reservoir but on trials bike they don't bother with the reservoir.
It could be your cap is venting at too low a pressure but the cap could be fine and something else in the system is causing the pressure to spike.
Check your cold fluid level and make sure you are using the proper coolant. I now use propylene glycol based like Engine Ice or Silkolene Pro-Cool. That way I don't feel bad for destroying the planet when I screw up working on the bike and pour half the cooling system on my shoes. Actually the real reason is it's premixed with distilled water which is critical on the newer bikes with magnesium cases. Tap water and bottled water will do only if necessary but they contain ionic contaminants which act as electrolytes turning your cooling system into one big electroplate tank. Unfortunately the magnesium cases become the sacrificial electrode. If you use tap water flush that stuff out ASAP.
Ron Commo Sr. who is the big dog in the US on all things Beta used to tell me to not completely fill the cooling system and I was always having to put more fluid in. One day I decided to challenge the conventional wisdom and just fill it to the top. I haven't lost coolant yet. That alone defies logic as the expansion of hot fluid alone should displace some.
Does your bike only do this under certain conditions like really hot weather (weakness in cooling system like a blocked radiator) or really cold weather (lean mixture because of denser air) or after a long slow climb (heats up all bikes)? Is your radiator clean? Gotta have air flow or the fan's just a party noise maker. Is your ignition advanced to give a little extra "snap". Are you running good fuel? Low octane fuel that causes minor pre-ignition will spike engine temperature.
All in all it doesn't sound like too big of an issue.
Very good post, thank you!
I've only really noticed it recently, after replacing the crank seals... It ran fine for a week or so, but with an air lock developed in the pipe from the water pump. I cleared this and its ran fine since. Just recently though we've had a major cold snap, temperatures dropping to -20 Degrees Celcius at nights, and not going much higher than -5 in the daytime. Snow on the ground has stopped me taking it for a proper blast though.
The coolant I use is rated to -30 degrees, and upto 270. Valvoline stuff I beleive, so it's not icing up in the pipes or anything. Using an 80:1 mix of 98 octane fuel. Advanced a bit I beleive, but never had problems before. It's a Paxau Sherco, if you were wondering or if it's of any help.
Now, after running it today, I dont think I saw the fan come on once, within thirty minutes of it being on the paddock stand. Maybe before it was just intermittent and causing it to occasionaly overheat, and then kick in? It's lost A LOT of coolant though.
Thinking about it actually, it only seems to be since i've fitted the titanium frontpipe?
I keep thinking it could be running lean, but my exhaust is more full of gunk than ever, and even spraying carbon laced crap out the end of the muff! Could it just be the cold causing the oil to go all thick?
Will take this to the sherco forum, and let Mr Manny here get his own thread back. I'll catch you over there as you seem to be a great help.
Seems to always be this way, best you can do is fill it right up with cheapest gearbox oil of the right type you can find, open the drain screw for a few seconds... Run the engine for a minute or so, going through all the gears a few times with the bike on the stand. Make sure to get them revs high in 6th!
Straight off and dump the oil through a very fine filter, re-flush with the filtered fluid, using the same technuique. After using this technuique for a while, if the oil doesnt run clear, then it probably wont anytime soon.
Dont worry about it though, black/grey oil is normal, normally. It's only milky oil you need to worry about!
Well, I changed the thermostat and the fan still runs as much as it did before. I would estimate it runs 60-70% of the time. It might be normal for it to run that much. I'll keep riding the bike for now.
Sorry to hijack your topic but I'm having a simillar problem with my sherco, cooling systems fine, fan cycles in and out as normal, bike doesnt overheat, no loss of power but occasionaly it'll spit out a few ml's of coolant, maybe every 15 minutes or so? Dodgy cap?
I seem to beleive its not the o-rings, as it would be more constant?
Got some new boots yesterday after months of riding around in shot boots, as they weren't cheap I'm obviously trying to prolong the life of them by as much as possible. Few questions for you!
Best way to clean them? Fine brush and hosepipe alright? I guess I shouldnt use chemicals on them?
Best way to dry insides without drying out the outer material?
Aftercare - Dubbing all over, working as much into the stitching whilst still moist, yeah? Maybe best to do this before drying, then go over quickly after again?
Donts;
Guessing not to put them on or near the boiler or wood burner to dry?
No chemicals?
Dont leave mud on there when possible, our mud is peaty acidic crap
Do's;
Please add/remove from both lists, and give me much advice as possible please.
Boots are the White Gaerne Balance Classics, like the oiled leather but made from Lorica instead.
Hi there my son was out practising on Sunday in the snow & ice.
He has a 08 Sherco 125. When we got home I was washing his bike to find the swinging arm had snapped just in front of the rear brake anchor point on the right hand side. This was a clean brake no signs of discolouring at all. I was just wondering if any one else has had this problem & will it weld or is it best to get a replacement swing arm.
Any chance of pictures?
Should be weldable though depending on the state of it, like Mark said, best off finding some kind of speciality welder to do the job!
Lifted straight from a defence bulletin Jamie, new missile delivery vehicle test that went wrong. You saw my initial response right back at the start I didn't think possible either but......
Hmm... Still all seems a bit strange to me, Russia were denying it when the reports came flying in, why the change I wonder?
Sorry Donald mate, but can you please explain to me where you have seen a perfect spiral like that in cloud formations before? Or has Mr rocket man thrown a rope out the window and turned the rocket into a giant catherine wheel?
If this was a failed rocket it wouldn't be just sitting in one spot in the sky spinning, would it?
There were no reports of any kind of noise, no loud bangs, nothing. A rocket, even a small firework would make a rather large bang at that point in the sky
Debris, Unless the russians scampered straight out there and picked up all the debris, there would be small bits lying around, the area has been searched and nothing found.
right then i did as advised and cleaned it to an inch of its life! then topped up the oil and changed the O ring on the filler plug, checked the clutch cover as well , all good. just back after an hour's fairly hard riding and nothing is leaking at all so maybe it was just the O ring on the filler. fingers crossed thats all that it was. many thanks for the help guys and thank god its a simple one!
No bother... it's just little tricks like these we learn, living in the Scottish Highlands with the most unreliable postal service ever, you want to make sure its the correct part for sure before you order!
Kinell, you out there? Where is the old bugger these days anyway? 
so maybe it was just the O ring on the filler. fingers crossed thats all that it was. many thanks for the help guys and thank god its a simple one!
Overheating Again
in Sherco
Posted
Still not resolved, no progression due to no garage time and snow.
Thanks anyway.
Jamie