Changing radiator fluid

[Acton67]

So I posted in another thread about how I leaked radiator fluid by mistake on 2 different occasions while working on my bike this winter. The first was when I mistakenly started to remove the water pump when I meant to remove the clutch slave cylinder cover. I had a small amount of radiator fluid leak at that point.

The second time was when I mistakenly had a ratchet strap across the pipe crossing over the starter motor cover that caused a decent leak.





Today I was working on the bike and I had to run it a few times to diagnose another issue I was having. No spark/engine running g on one cylinder which I figured out. I noticed the temp light was on so I killed the bike immediately. I did top off the radiator fluid with aluminum friendly radiator fluid. After doing more research in the Clymer manual it suggest replacing the fluid completely. I had the fluid replaced last year so I figured it wasn't necessary to so a complete change again. Now I really want to make sure I do it right.

The manual suggest doing a 50:50 ratio of antifreeze and distilled water with "two packs of bars leak anti leak material". The concern is that when I leaked fluid I introduced air into the system right?

Any suggestions on what I can do to ensure the radiator is functioning correctly after I change the fluid? The manual mentioned partially kicking the line that's behind the right cover and then to check for a "pressure release " when the kinks released. The thermostat and water pump was fine last fall and I didn't touch those. How does the fan work and how can I check it to make sure it's working right? I also plan to do an oil change tomorrow too.

[Lechy]

When using Bars Leaks, only use the liquid version as the powder version blocks the cooling fins.

[navigator]

When using Bars Leaks, only use the liquid version as the powder version blocks the cooling fins.

Yup, use the liquid stuff and only add about an ounce. It helps to stop leaks and lubricates the water pump.
The drain for the fluid is on the left lower frame rail, obscured by the exhaust.
When filling it, crack loose the bleeder screw on the frame rail up near the neck cover, to purge the air.
Do not remove the breather screw, just crack it loose, and be careful, it is a hollow bolt and can break easily...soak it with penetrating oil first
The left frame rail is the water passage.
The pipe you tweaked with the ratchet strap has gaskets or O-rings on each end.
If you raise the front of the bike slightly, it also helps to purge air while filling it.

[Designer]

If you raise the front of the bike slightly, it also helps to purge air while filling it.

Wouldn't doing Wheelies work also?

Just a little levity, guys.

[Acton67]

When using Bars Leaks, only use the liquid version as the powder version blocks the cooling fins.

Yup, use the liquid stuff and only add about an ounce. It helps to stop leaks and lubricates the water pump.
The drain for the fluid is on the left lower frame rail, obscured by the exhaust.
When filling it, crack loose the bleeder screw on the frame rail up near the neck cover, to purge the air.
Do not remove the breather screw, just crack it loose, and be careful, it is a hollow bolt and can break easily...soak it with penetrating oil first
The left frame rail is the water passage.
The pipe you tweaked with the ratchet strap has gaskets or O-rings on each end.
If you raise the front of the bike slightly, it also helps to purge air while filling it.

Well you pretty much called it! Tried to remove the air bleeder screw today and it snapped off. Not sure how I'm going to fix it. Glued the bolt head back on with loctite. If I need to remove the bolt and loctite I'm sure I can pry it back off of there. Is it possible to drill another hole directly on the other side of the frame from it, tap that hole and make a new air bleeder valve hole? Then I could seal off the other bolt? There's not enough clearance to try to drill the old bolt out or to get an easy out on there. Is it possible to somehow purge air from the system without this air bleeder valve? Wish I had seen your post before I did this. Tried following everything the manual said to do, it didn't mention anything about being careful with the bolt.

Tried bleeding the system with just the radiator cap off and the bleeder valve down near the exhaust like you said. The Clymer manual says that the system should take 1.7L when fully drained. I was only able to add about 1.1L before the radiator topped off. I rocked the bike back and forth and turned it on. It looked like the fluid was moving around in the radiator with the cap off, but when I kinked the hose crossing I mentioned earlier, I didn't really feel a "pressure release" that I mentioned the manual talking about before. Think I have about 500mLs of air in the system. Now the temp light keeps popping on and off. Have not run the bike for any extended period of time.

The fan isn't turning on either. I checked the wiring going from the main harness to the radiator switch and then to the fan. When I bypass the radiator switch the fan runs fine. When I hook the wiring up like its supposed to be hooked up and the temp light comes on the fan isn't coming on. . .

[Herb]

Never having messed with the 800 I am not sure of the layout. Is the temp switch at one of the higher points that might not be getting water flow by it and is the fan switch and the temp light the same sensor?

I had a car that the fan switch was at the top of the engine and the gauge/idiot light sensor was much lower. When it got low on coolant the fan switch would not turn on the fan but the temp indicator and the light would indicate the overheat.

[Acton67]

Never having messed with the 800 I am not sure of the layout. Is the temp switch at one of the higher points that might not be getting water flow by it and is the fan switch and the temp light the same sensor?

I had a car that the fan switch was at the top of the engine and the gauge/idiot light sensor was much lower. When it got low on coolant the fan switch would not turn on the fan but the temp indicator and the light would indicate the overheat.

Good question. I tried looking in the manual, online and in the wiring diagram to give me a clue as to where the temp indicator switch is but I couldn't figure it out. I thought maybe that the temp switch is the radiator switch right next to the air bleeder valve I screwed up but even when the light comes on the fan dosen't come on.

[Herb]

What manual do you have?

I looked through the One I have and it is not real specific on the location of the fan sensor or the temp indicator sensor. It does say that the fan controller is on the radiator and it provides a ground for the fan. The temp indicator sensor is under the fuel tank, it doesn't say where. Both Sensors only provide a ground to the systems. The manual gives a procedure for testing them off the bike.

not sure of the bleed valve situation, if there is a high point that you could drill, tap and put a valve in it it would be good, maybe just a bolt or plug. Never having worked on the 800 I am not sure of the clearance available

[navigator]

Shit...too bad it broke.
I wouldn't drill a new hole. the tubing is very thin.
The original location has a nut welded to the tube to accommodate the bleeder screw. If you welded a new nut, it may work.
Does water weep out of the broken bleeder?
If so you need to weld or plug that hole, then perhaps a new welded nut is the answer.

The fan switch is on the radiator, the temp light switch is on the left head, where the upper radiator hose connects.
You could try loosening the temp sensor on the head to burb air there.
The fan rarely runs, only in extreme heat with no airflow, like in stopped traffic. If you can direct wire the fan and it runs, you are probably ok.

An easy out is probably the only recourse, you may need to shorten the tool and get creative. Jam it in there and use vice-grips to turn it...But if it is not leaking, it's probably best left alone.
Running the bike will eventually purge enough air to operat properly.
Good Luck.

[Acton67]

Shit...too bad it broke.
I wouldn't drill a new hole. the tubing is very thin.
The original location has a nut welded to the tube to accommodate the bleeder screw. If you welded a new nut, it may work.
Does water weep out of the broken bleeder?
If so you need to weld or plug that hole, then perhaps a new welded nut is the answer.

The fan switch is on the radiator, the temp light switch is on the left head, where the upper radiator hose connects.
You could try loosening the temp sensor on the head to burb air there.
The fan rarely runs, only in extreme heat with no airflow, like in stopped traffic. If you can direct wire the fan and it runs, you are probably ok.

An easy out is probably the only recourse, you may need to shorten the tool and get creative. Jam it in there and use vice-grips to turn it...But if it is not leaking, it's probably best left alone.
Running the bike will eventually purge enough air to operat properly.
Good Luck.

Water does not leak out of the broken air bleeder bolt hole. I do not know how to weld, I have loctite glue on there for a temp fix. Should I use some jb weld or another product to seal it off?

Direct wiring the fan does cause it to run. When I start the hike when it's cold the light isn't on so I suspect there's no issue with the temp switch, it's just air in the line causing an issue.

In another thread from last year I saw the OP had the same issue with the broken air bleeder valve bolt that was welded shut by a previous owner. Elevating the front of his bike did the trick.

I'm going to seal off the bolt and then leave it alone like you advised, elevate the front of the bike, run it and then see how much air I can purge that way. I figure I have 600mls of air in the system at this point since I was only able to add 1.1L of coolant and the manual said the system takes 1.7L.

[Acton67]

So I tried to to bleed the air from the system by raising the front of the bike with limited success. Had the front of the bike elevated about 2ft with my bike table at one point.

Went and bought some easy outs as suggested with no luck there either. I noticed that the bolt broke halfway down the thread and I had some thread left on the hole. Was able to use a nail to make a hole through the old bolt. Didn't realize that I was successful until I took the cap off the radiator and radiator fluid started coming out of the bleeder bolt. I was able to put a new bolt in and torque it down enough to stop fluid coming out.



I guess this should work as an effective replacement for the bleeder bolt right? If I don't take the cap off the radiator no fluid escapes even with the bleeder bolt off. I'm guessing this is because the radiator cap has a vacuum seal right? So unless I take the radiator cap off I don't have to worry much about the air bleeder bolt leaking since fluid isn't traveling past the bolt normally?

Figure I'll just use some thread lock to seal it on there when I'm done.

It definitely made a difference after. Now I rev the bike and the temp light dimly flutters at high rpm then immediately turns off. It stayed on solid before. This must mean I have a little air left in the system or?

[navigator]

If you got water to dribble out of the bleeder, you have removed all of the air that you can.
You do need to seal off the bleeder though because when the bike gets hot, the entire system is under pressure.
It will leak there until you seal it.

[Acton67]

If you got water to dribble out of the bleeder, you have removed all of the air that you can.
You do need to seal off the bleeder though because when the bike gets hot, the entire system is under pressure.
It will leak there until you seal it.

Was able to use teflon tape on the bolt. Had the bike running for a decent amount of time tuning the carb with no leak. The temp light still comes on though. On Monday a decent amount of radiator fluid came out of the bleeder bolt hole when I started warming the bike up. When I drained the system I wasn't able to open up the aid bleeder bolt. Should I drain the system and start from scratch again or?

[navigator]

No need to start from scratch.
With the bike cold, top off the radiator.
Then run it.
The light coming on may be related to your shorting issue elsewhere in the harness.
If you unplug the wire on the temperature sending unit, the light should go out.
If you ground that wire to the engine or frame, the light should come back on.
If the light stays on, you have that wire touching ground at some point...either to B/W or to the frame.

[Acton67]

No need to start from scratch.
With the bike cold, top off the radiator.
Then run it.
The light coming on may be related to your shorting issue elsewhere in the harness.
If you unplug the wire on the temperature sending unit, the light should go out.
If you ground that wire to the engine or frame, the light should come back on.
If the light stays on, you have that wire touching ground at some point...either to B/W or to the frame.

The radiator is full when cold. When the bikes cold and I first turn on the bike it's off. As I start to warm up the bike it starts to flicker, especially when I rev the bike. After 5 minutes of running the bike it comes on solid and stays on. I'd suspect a short if the light was just stuck on like it is with my neutral switch but it doesn't seem to come on immediately and starts to flicker when the bike warms up then stays on solid after the bike has been run for a few minutes. Seems like it's functioning appropriately. I've tried jigling the wire with no effect. I could take a video if you want.

[navigator]

That light should not come on after running 5 minutes.
It rarely comes on, The fan should cycle first if it is hot enough for the light.
I suspect you may have air trapped there. try loosening the sender until water trickles out, then tighten it back up.

[Acton67]

That light should not come on after running 5 minutes.
It rarely comes on, The fan should cycle first if it is hot enough for the light.
I suspect you may have air trapped there. try loosening the sender until water trickles out, then tighten it back up.

The sender unit? I know you talked about possibly loosening the temp switch before to bleed air on the left head. There's some adhesive on the switch, I can take pictures when I get home. That's what you want me to crack open right?

[navigator]

Correct.
Sending unit = Temp switch.
It is threaded and probably has thread sealer on it.

[navigator]

You could also have a pinched wire where the harness enters the instrument light cluster. It is rather tight there.
You could also have an issue with #3 here:
https://www.partsoutlaw.com/oemparts/a/ ... peedometer

[Acton67]

You could also have a pinched wire where the harness enters the instrument light cluster. It is rather tight there.
You could also have an issue with #3 here:
https://www.partsoutlaw.com/oemparts/a/ ... peedometer

Your right it's a short, but somewhere in the main harness again it looks like. Just like with the neutral switch.

https://youtube.com/shorts/6TkWMsjnCfY?feature=share