So, my 08 6th Gen has reached 72,000 miles and is due her service. Whilst she's on the ramp, I'm going to swap in a new thermostat as she is taking too long to warm up still.
I've just cleaned up the Fast Idle Wax Unit joints and started her up and the fast idle seemed to work better than previously so hopefully that will improve cold idle. Time will tell whether I need to go deeper into it or if this will suffice.
So along with oil, oil & air filter change and coolant change (just as well as it has to be drained to replace the thermostat) I'll balance the Starter Valves. I've also bought new seals for the front calipers. They've not been touched, other than occasional cleaning of the exposed piston surfaces and after fitting the braided hoses last year, I thought giving them a good overhaul should keep the brakes working well for many miles to come.
Another issue I will try to resolve is my RH heated grip which stopped working quite a while ago. The controller is fine so with winter on the horizon, I will try to swap in a new one I got cheap when Hein Gericke went bust. Hopefully, connection will be simple enough.
Photo of the new thermostat awaiting connection - I'm just having a coffee and some toast before pressing on!
[image: IMAG0714[1].jpg]
Did you ever check her valve clearances?
I don't have the correct tool to access them and as I've only ever completed a 5th Gen valve clearance (every 16k up to 130k miles) in the past and so am unsure of the exact procedure, so previously I have given her to a dealer to do just that part. I shall probably do the same again this time.
That was a long day.
Engine all done, front brake calipers removed, stripped and cleaned. Will refit them both tomorrow then, if I have time, I'll do the rear caliper.
Not had as much time today as I hoped. Also underestimated the number of banjo bolt copper washers I'd need so only finished the fronts. The rears will have to wait until new washers arrive as will the RH grip as the assembly wont arrive until Tue.
Shame, I'll have to take the 1200 to work tomorrow. :cheerleader:
Bugger!
Bike is still running too cold despite the fitting of a brand new thermostat from David Silver Spares. That's the 3rd; original which failed open, a 2nd-hand replacement I bought off ebay still in its housing which was failed open and now this brand new one.
So what could I have done wrong? Is there a way to install it incorrectly so that it doesn't close and allows too much coolant through?
Or is there any other way anyone knows of that causes the bike to run too cold? Even after 15 miles it's not warm enough to activate the Vtec.
Maybe the sensor is giving inaccurate readings?
Does it feel like it warms up?
That's difficult to answer. But it should be warm as it spends 45mins at 6k rpm!
I'll be honest, I'm not sure what sensor the ECU reads from for the coolant [and/or] oil temperature. I'll need to look in the manual, but it may be a good starting point imo since you already swapped the t-stat.
26 minutes ago, thtanner
I'll be honest, I'm not sure what sensor the ECU reads from for the coolant [and/or] oil temperature. I'll need to look in the manual, but it may be a good starting point imo since you already swapped the t-stat.
I was thinking along those lines but have no knowledge either.
1 hour ago, Skids
I was thinking along those lines but have no knowledge either.
It is the coolant temp that is read. What coolant are you using?
It's a Halfords one....here. Ethylene Glycol based mixed with equal amounts of distilled water.
My basic thermostat test is to start the engine from cold, and keep a hand on the right radiator. If the thermostat is working properly it should hold the coolant in the engine block until around 78C; up to that point no hot coolant gets to the radiator so it stays cold. Once the thermostat opens, you will get a rapid rise in radiator temperature so you can't keep your hand on it. If on the other hand the radiator slowly warms from the time the engine is turned on, the thermostat is open or leaking.
The ECU reads temperature from the thermosensor at the back of the front head just under the #3 intake port. This can be easily extracted while you have the throttle bodies out and checked for operation, should read 2.1-2.6 kOhms at 80C and 0.65-0.73 at 120C. Or use an IR thermometer and compare to the digital reading on the dash when the bike is running.
1 hour ago, Terry
My basic thermostat test is to start the engine from cold, and keep a hand on the right radiator. If the thermostat is working properly it should hold the coolant in the engine block until around 78C; up to that point no hot coolant gets to the radiator so it stays cold. Once the thermostat opens, you will get a rapid rise in radiator temperature so you can't keep your hand on it. If on the other hand the radiator slowly warms from the time the engine is turned on, the thermostat is open or leaking.
The ECU reads temperature from the thermosensor at the back of the front head just under the #3 intake port. This can be easily extracted while you have the throttle bodies out and checked for operation, should read 2.1-2.6 kOhms at 80C and 0.65-0.73 at 120C. Or use an IR thermometer and compare to the digital reading on the dash when the bike is running.
Thanks Terry, I'll try the hands-on approach. :beer:
Keep in mind the right hand side radiator won't remain completely cold as there is some communication with the left hand side, and therefore the motor. There's a small line which does allow a reduced flow through to the right hand side radiator, but it's minimal.
You're quite right, there is a tiny air bleed line that comes off the thermostat and joins to the back of the RHS radiator, so you might get a little hot flow through that, but I've never felt a detectable rise in the radiator from it. On the other hand, when the thermostat opens and dumps 80C water into the cold radiator system, it is very noticeable.
This morning, on my journey to work, I managed to give this a go. Whilst I was getting changed, I started the bike and kept checking the RH rad. It stayed at the same temp, except for a small slightly warmer patch near the filler cap, right up to 44 deg C when I had to leave or be late for work. The LH rad felt pretty similar, perhaps a smidge warmer. Neither got what I would call warm at all.
I'll try & do this later with the temp rising to 78+ and see what happens.
I think warming her up at a standstill helps alleviate the problem cos she was >64 deg C (Vtec op temp) before I hit the freeway and she maintained 68 deg C at a steady 6k rpm which though 10 deg or so lower than normal is still better than yesterday where she struggled to get to 60 deg C.
As a reference, with a stuck open thermostat, my 5th gen would hit 38C in say 3 minutes on a 75°F day at 3,000 RPM. That is slow because it had to warm up all of the water in the rads. You did not give times but I get the impression (correct me) that your engine runs a lot longer to get to 44-64C, and the rads are still ambient temperature, correct? This sounds different from the typical stuck-open thermostat problem, which would warm up the rads. This sounds like the temperature sensor is heating up due to the conduction of heat through non-moving coolant. So the temp reading only reflects the localized temperature at the sensor, but the rads are cool and the engine head is extremely hot.
This sounds like air is trapped, the thermostat is stuck closed, or the pump is not moving coolant.
A theory: If there is no flow or the thermostat is filled with air, the overheating could have seized up the prior thermostats. AKA replacing the thermostat was treating the symptom, but the the root cause remains.
Are there flow tests (pump/thermostat) in the factory service manual?
Is it possible for a radiator to be completely blocked?
Hmmmm....yr pushing (or have pushed) the limits of my engineering & understanding there but I don't recall thinking it's over-heating. I will check.
There is a possibility that air is stuck but I did the throttle blips and tipped the bike on its side to release the trapped air so I'm not sure what more I could do other than repeat those.
I can't say what the rads are doing once she gets up to, or close to, normal operating temps. I'll have to check on the way home tonight.
Thanks for the inputs. :beer:
Got home from my 52 mile commute. Running temp was ~70°C, so about 8°C below normal. Both rads were hot but I could easily touch the plastic screen covering the rads. The RH rad was ever so slightly warmer than the left. It still took longer than normal to get to that temp, but idling for a few mins really helped.
I have no previous experience to be able to judge whether the rad temp was normal.
Rads are hot - oh okay it sounds like flow is normal. So, short of an infra red thermometer, perhaps a meat thermometer would reach the radiators through the screen? I would try that with Terry's test. Only this can tell you if another stuck thermostat is keeping it too cool, or otherwise if this is how this bike wants to run (on the freeway I presume?) during 17°C weather.
Pretty sure he should see 78-79c, even with 17c freeway rides.
Yes I agree with thtanner; the purpose of the thermostat is to keep the temperature at least around 78C, it should stay closed below that and keep the coolant in the block when the air temperature is low enough. On my 5th gen it usually hits 40C in the time it takes me to fit earplugs, helmet, glasses and gloves, and hits 78 after 2 km gentle riding, and at 17 it would normally sit between 79 and 82 whilst moving, never lower.
If your bike is running in the 60's, I'd suggest you either need a new thermostat or possibly the temperature sensor is in poor health. Skids. Either way I hope you enjoy pulling throttle bodies out! As you will have seen, it is easy to spot if a thermostat is jammed open. I guess you could install a thermostat upside down but I'm not sure if that is physically possible given the housing size. You can test a thermostat by dunking it in a pot of near boiling water (when Mrs Skids is at the shops); you should see the plate move open by 5 mm or more, then close up when you pull it out of the water.
If the thermostat was working but the ECT sensor was reading low, I would expect the temperature reading while riding would be consistent. I imagine that you could remotely test the ECT sensor resistance at the connector; the same connector services the sidestand switch and neutral switch, so you should be able to trace back from one of those to find the connector. I think you want to check the resistance across the green/orange and yellow/blue wires.
[image: IMG_1387.JPG]
Thanks Terry, Knight & thtanner. :beer:
At idle from cold this morning, whilst putting on my helmet etc, by the time the gauge read 36° (which took several minutes, longer than to don my kit and longer than normal), both rads were warm with the RH rad slightly warmer. So I guess this confirms the t'stat is open when it shouldn't be.
Trouble is, this is the 3rd t'stat to fail in the last month and a brand new one too.
Prior to these issues, the bike ran high 70s/low 80s so I know current running temp is not normal.
I'll wait until Mrs Skids is out on Sat and check the t'stat - don't worry, I'm used to removing the throttle bodies so no big issue. I'll be well-miffed if I have to fork out another £55 for a 2nd brand new replacement.
72k miles on your 08 hey, very nice. I'm curious to know what sort of issues you have had in that time, anything electrical?
1 hour ago, vfr_steve
72k miles on your 08 hey, very nice. I'm curious to know what sort of issues you have had in that time, anything electrical?
The stator went...I think there's a thread on here (edit: here it is) about it, but it's simple enough to replace.
Otherwise the electrics have been pretty solid, it's usually my messing about that causes issues!
I'm currently having issues with the thermostat following the 72k service I did last week and I also solved a small caliper bleed issue where I hadn't bled them fully and still had air trapped in the rear after I overhauled the calipers last week as well.
Like I said, any issues I've had are generally of my own making, but it makes for greater understanding and luckily I have a 2nd bike which I can use if the Vtec is off the road.
Cheers for the info Skids :) I wondered whether Honda might have updated some of the electrics on the later models (particularly the wiring harness and blue connector issues) - But that's great to know, not bad at all really. How does the 800 compare to the VFR12? Which one do you feel the urge to ride the most or are they used for different roles? Sorry for all the questions ;)
7 hours ago, vfr_steve
Cheers for the info Skids :) I wondered whether Honda might have updated some of the electrics on the later models (particularly the wiring harness and blue connector issues) - But that's great to know, not bad at all really. How does the 800 compare to the VFR12? Which one do you feel the urge to ride the most or are they used for different roles? Sorry for all the questions ;)
Hah, that's not a question I like to ask myself or there'd only be one answer!
The 800 used to be my #1 bike; I took her to Italy twice but now I use her for my 105 mile round trip daily commute. The 1200 is my weekend/holiday bike.
Terry, 9/28/2016 at 8:47 AM
Yes I agree with thtanner; the purpose of the thermostat is to keep the temperature at least around 78C, it should stay closed below that and keep the coolant in the block when the air temperature is low enough. On my 5th gen it usually hits 40C in the time it takes me to fit earplugs, helmet, glasses and gloves, and hits 78 after 2 km gentle riding, and at 17 it would normally sit between 79 and 82 whilst moving, never lower.
If your bike is running in the 60's, I'd suggest you either need a new thermostat or possibly the temperature sensor is in poor health. Skids. Either way I hope you enjoy pulling throttle bodies out! As you will have seen, it is easy to spot if a thermostat is jammed open. I guess you could install a thermostat upside down but I'm not sure if that is physically possible given the housing size. You can test a thermostat by dunking it in a pot of near boiling water (when Mrs Skids is at the shops); you should see the plate move open by 5 mm or more, then close up when you pull it out of the water.
If the thermostat was working but the ECT sensor was reading low, I would expect the temperature reading while riding would be consistent. I imagine that you could remotely test the ECT sensor resistance at the connector; the same connector services the sidestand switch and neutral switch, so you should be able to trace back from one of those to find the connector. I think you want to check the resistance across the green/orange and yellow/blue wires.
[image: IMG_1387.JPG]
I removed the thermostat tonight....looks closed to me. Also did the boiling water test and lo and behold it opened the best part of 1cm at about 85 deg C. So within spec.
So how on earth is it running cold? Struggled to get over 64 deg C coming home this afternoon.
It has to be the temperature sensor then, doesn't it? Where is it located? And is it easily replaced? I'll have to check the manual tomorrow as it's nearly 1am now and I'm bed-bound. Would a malfunctioning temp sensor affect the ECU and fuelling as the fuel consumption has increased quite a bit this week?
Cheers.
Morning all.
Seems the ECT Sensor is just screwed into the back of the front cylinder bank so hopefully easy to replace. The Haynes manual has a complex method using oil on a stove to test it which I wont do so I'll change it on spec as the 3rd/new thermostat appears to working normally. It'll be Tuesday next week before the part arrives so the 1200 will have to be my commuter!
New coolant temperature sensor arrived & fitted today but I don't have time until the weekend to put her back together.
[image: IMAG0728[1].jpg]
Skids... When you purged the air, were you able to see the coolant flowing or surging when looking down the filler spout on the rhs rad? You should be able to see the current or flow once the thermostat opens, so if the dash displays temps at which it would normally be open and it isn't flowing it could be the water pump, if you're sure the thermostat is good.
Anyway, you must only make one change at a time in a process of elimination so first finish checking whether it's the temp sender unit (sensor)...
Just for reference' sake I recorded the following behavior with a known good thermostat:
At 12ºC ambient temp it took 6 minutes to get to 64ºC (minimum temperature required for VTEC to function). Within those 6 minutes it took 2 minutes 30 seconds for the temp to come up on the display (36ºC, which is the lowest it will display)....
Thanks Aus....
Surely, if the pump is fooked, the bike will overheat rather than under?
I need to get this sorted as I plan to sell her now as I have another bike coming this weekend.
5 hours ago, Skids
I need to get this sorted as I plan to sell her now as I have another bike coming this weekend.
After 72k miles of loyal service. *sheds a tear*
Skids Thanks Aus....
Surely, if the pump is fooked, the bike will overheat rather than under?
I need to get this sorted as I plan to sell her now as I have another bike coming this weekend.
Yes of course... Faux pas moi
16 hours ago, thtanner
After 72k miles of loyal service. *sheds a tear*
Her predecessor did 130k.
I shed a flood of tears!
6 hours ago, Skids
Her predecessor did 130k.
I shed a flood of tears!
I feel the need to put on a memorial service
thtanner, 10/7/2016 at 4:56 PM
I feel the need to put on a memorial service
I'm just prepping her for sale now. Taken the luggage & racks off, fitted the grab rails back on. Surprised to find the tank paint in excellent condition despite the Bagster cover being on it for nearly 70k miles.
Looks a little strange without the rack.