fastbob

Slight change of tack here but this advice is based on a lesson I learned the hard way . DO AN OIL CHANGE ! I don't care what the seller has told you , just do yourself a massive favour and change the oil . And use proper bike oil . Enjoy your new toy ! By the way , it does have a mechanical speedo driven by an old fashioned cable , here's a link , not a difficult job to replace . https://m.ebay.co.uk/itm/Honda-CBF-125-Speedo-Cable-NEW-2009-2012/262584092930?_mwBanner=1&_rdt=1 Oh yeah, welcome to the forum .

It's a pain in the arse for one! I wonder how long a sprocket with Teflon liners on the teeth would last... When you've paid £120 for a chain surely its no hardship to look after it .

Leaving the chain unlubricated is NOT an option and it is irresponsible to suggest that it is . Please bear in mind that people with zero experience and occasionally no common sense browse this forum seeking advice . I am also puzzled as to why enclosing the chain has been suggested. The only bikes I know of , and presumably there are others , are MZ ( no longer made ) and CG 125s . So are you suggesting that we start hacking up bits of pipe and welding brackets to swinging arms ? Sounds bloody dangerous to me . As for over lubricating the chain , why waste chain lube ? What's wrong with cleaning and lubricating the chain on a regular basis . Little and often seems like a better strategy and it works for me .

I'll pass your suggestion on . I haven't heard from the owner since the weekend. The chap wasn't too well and he's got a bit on his plate right now apart from motorbikes . i hadn't realised it was you who had posted the original post .... thought it was one of those bloody fly by night newbies That's alright, I was just trying to help out a fellow member of the ER5 Forum who happens to live not far away from me . As I say , give me a week with this bike and I'm pretty sure I could sort it out but in a few hours I could only guess . It's the tremendous heat that this engine generates that was the biggest surprise. Regardless of whether the cooling system works or not this thing is like a blast furnace .

I'll pass your suggestion on . I haven't heard from the owner since the weekend. The chap wasn't too well and he's got a bit on his plate right now apart from motorbikes .

Yep , my first thought too . Maybe its missed out altogether. You didn't accidentally loosen the wrong bolts when you removed the calliper by any chance ?

That's a very good question, I think he bought the new cap AFTER the over heating problem so that he could monitor the temperature. Up until he balanced the carbs he had been riding it without being aware of the over heating problem. He only noticed it spewing coolant when he was running it stationary.

He's after a cylinder head .

Are you going to fit a 150 cc kit ? ( I won't tell anyone )

No difference, see other thread.

No difference at all.The tappet covers were a slightly more angular shape on the Brazilian models but everything is interchangeable . I've built engines from a mixture of models in the past with no problems. If you need any bits let me know. I know CGs inside out so I'm happy to help with any advice as well . Here's few I made earlier.

It's was certainly on my list of possibilities and you're quite right, any small object dropped into the filler cap would quickly find it's way to the impeller . As far as I could tell though the coolant was circulating . As I say , the guy was really just seeking reassurance that he hadn't missed anything obvious. He did have reasonably good grasp of what was going on so its pretty much up to him now .

I quite agree, the only way to get this thing sorted would be an investigative strip down . I am more than capable of carrying out the work and my knowledge of the ER5 is excellent but it is not my bike . I was just paying a visit to an ER5 forum member in the hope that I could spot something more obvious.

Thanks once again, I reckon it all points to a leaking head gasket. If anyone's that interested, this is a good read with a happy ending . The symptoms are very similar to what I saw today anyway. https://www.perthstreetbikes.com/forum/showthread.php?t=180046

Oh please don't remind me , that one mushroomed out of all proportion once the nit pickers got their little claws into it .

I'll go along with that because its the only connection I can imagine between a nudge up the rear and difficulty changing gear .

I'm sure it would but I was genuinely shocked at how much heat this thing was producing especially out of the tail pipe . Bear in mind that an ER5 does have cooling fins as well . The owner told me that he had the exhaust glowing red so that's not caused by a cooling failure. I can't imagine what I would have to do to get an ER5 to run that hot . The main needles are not adjustable and the pilot air screws being a bit out would surely not cause this . He said the bike was doing 100 mph so surely the cam chain can't be out by a tooth. The trouble is ,I could probably figure this all out if it was my bike and i had a week or two but I was just dropping by in case I could spot something obviously wrong.

Yes , apparently so .

Thanks for all the replies. I've been to see this ER5 this morning. I've had a good look with the tank off and there was nothing obviously wrong such as coolant pipes wrongly connected. Interestingly, the owner had fitted a rad cap with a temperature gauge. Anyway, we started the engine and warmed it up . It didn't like having the choke taken off but when I put it back on the revs went really high so I couldn't find a sweet spot where the bike was at a medium fast ( ish ) idle . Eventually it settled down to a idle without choke . After only two minutes the coolant temperature had climbed to 100 ° . I removed the rad cap and there were no bubbles but then the level began to rise rapidly so we shut it off . Then we started it again with the rad cap back on while keeping an eye on the coolant level in the expansion tank . After another two minutes of normal idle speed the tank filled right up and over flowed . Ok so there are two possibilities here to my mind . A. The coolant is boiling B. The heat has opened up a warp in the head allowing combustion gasses to seep past the head gasket and pressurise the cooling system . I guess that only a proper top end strip down would answer this for sure .NOW here's the bit that puzzles me . Bearing in mind that this engine was only running for 5 minutes at the most the heat coming off it was tremendous . The owner had told me that he had had the exhausts glowing red in the dark just from balancing the carbs . When I put my hand a foot away from the tail pipe it was like a blow lamp . ( we compared it to my ER5and mine is only luke warm after five minutes ) So regardless of what's going on with the head gasket, what on earth would cause an ER5 to generate such tremendous heat so quickly ? What I'm trying to do is work out the order of cause and effect here . Sorry for the long post but I've never felt so much heat coming off an engine in my life .

Can anyone suggest the best way to confirm that a liquid cooled bike has a blown cylinder head gasket ? The bike is an ER5, but thankfully it isn't mine . My current thinking is that combustion gasses are pressurising the cooling system which is causing coolant to spew out of the reservoir overflow. BUT , I haven't actually seen the bike yet so it might just be connected up all wrong . Thoughts welcome.

Are you certain that this is actually whole frame as produced by a bike manufacturer or could this be a hybrid left over from the 60s and 70s craze for trying to turn anything into a chopper ? In other words does the hardtail actually belong to the original frame ? The single front down tube is not unusual but the way it remains as a single tube under the engine is . What are you planning to do with it ?

Hi fastbob. I'm not worried about flattening the battery as I use the bike 365 days a year, what I was wondering about was is it indeed meant to flash when ignition off, and if so what could have gone wrong to stop it flashing Oh , I see , sorry I didn't read it properly. So it has stopped flashing . HERE YOU GO, found it , try this.

I would have thought that it would flash when the ignition is off as a warning to potential thieves and also flash once when the ignition is turned on as an indication that it recognises that the bike is no longer immobilised. It's probably an LED so I wouldn't be concerned about draining the battery.

No. dont do any of this. This specific problem you are experiencing is well known to owners of this particular bike and is nearly always caused by letting the side panels and indicators hang off the side of the bike with only the indicator cable supporting it... and what happens? the connector comes loose and eventually - off... or the bare wire is pulled out of the connector. either/or. less likely... but possible a wire that is under the headstock has had its insulation rubbed off as the handlebars have been turned left and right over time. As the MOT went fine.. I'm assuming the engine started and ran perfectly.. as well as the headlamp, brake-light and horn. So, its a fault at the very front end of the bike.. nothing to do with the Battery. leave THAT alone. Ok , I get what you are saying but nonetheless quickly eliminating the battery terminals as a possible cause wouldn't do any harm .

Disconnect the battery, give the terminals a quick sandpaper and reconnect. Could be as simple as that . Strangely enough I've been seen bad battery connections where everything seems fine until you apply some load then everything dies . As previously mentioned, this sounds like a connection problem , so if it isn't the battery then its worth checking all your block connectors looking for signs of melting or oxidisation .