[CrowdedTrousers]

Spraying a garden hose couldn’t hurt. Try it and see what and where it comes out.
The internal coolant passages and water jackets, I believe, are large enough that the stop leak won’t bother them but you got to get any remaining stop leak out to reduce the risk of clogging the radiator in the future.
Youll be ok.

Also, while garden hosing, there’s usually a bolt somewhere in the system meant for bleeding air out of the system while filling. Flush that out too. And the thermostat if it’s not too much trouble.

Thanks Zed, last night I ran the garden hose and performed this - looking at the service manual, I couldn't find any mention of a bleed bolt or similar. I left the engine-side/thermostat-side hose on, and ran water through the passages with the garden hose. When doing this, water did successfully run through and come out the top of the water pump (see images below).

I ran about 2 to 2.5 gallons through it in this manner over a course of ~15 minutes. Everything that came out was - totally clear. No chunks or anything like that. (see picture). A couple specks of dirt but not much at all. I was not able to get great pressure through it, as I couldn't seal the garden hose to coolant hose connection, but the coolant hose effectively made a column of water that then went through. I did not take the thermostat off - but, the water went through the thermostat, yeah?

So - I think this is good news?

Also, I had to use my drain pan again to catch the water; I tried to cut you a nice slice of the tofu pie Zed for scientific purposes, but couldn't get it out cleanly. I put a bunch of what I could get out in a dish which we'll save for monitoring.

Water after flushing through passages:

Tofu pie - this is after 8-9 days of sitting in the garage:

 

[Zed7]

That looks like good news. I think all the non-solidified stop leak came out with the original coolant drain then finally solidified when exposed to the air in the pan.
Id still do a flush. You’ll be good to go.

 

[CrowdedTrousers]

That looks like good news. I think all the non-solidified stop leak came out with the original coolant drain then finally solidified when exposed to the air in the pan.
Id still do a flush. You’ll be good to go.

Thanks Zed and moto, I appreciate all the help.

Given what I've done so far, and no evidence of further stop-leak in the system... I am hesitant to use the Thoroflush product in that video given its suggested harshness. Doing some googling, it seems most people use 50/50 vinegar and distilled water in motorcycles for flushing - which I expect would be less harsh. Think this would be adequate? I don't see many other products recommended.

 

[Zed7]

Thanks Zed and moto, I appreciate all the help.

Given what I've done so far, and no evidence of further stop-leak in the system... I am hesitant to use the Thoroflush product in that video given its suggested harshness. Doing some googling, it seems most people use 50/50 vinegar and distilled water in motorcycles for flushing - which I expect would be less harsh. Think this would be adequate? I don't see many other products recommended.

I was thinking the same. Before you run the vinegar, make a 50/50 mix and see if it dissolves the gunk you have saved. If it does dissolve it then run it in the bike for ten minutes.
If it the vinegar doesn’t dissolve it, in other words, has no effect, then I’d just run straight water in the system and take it for a ride for an hour or so before switching back to coolant.

Vinegar is pretty harsh too, guys use it to de-rust gas tanks.

 

[CrowdedTrousers]

I was thinking the same. Before you run the vinegar, make a 50/50 mix and see if it dissolves the gunk you have saved. If it does dissolve it then run it in the bike for ten minutes.
If it the vinegar doesn’t dissolve it, in other words, has no effect, then I’d just run straight water in the system and take it for a ride for an hour or so before switching back to coolant.

Vinegar is pretty harsh too, guys use it to de-rust gas tanks.

Sounds like a plan, thanks!

 

[CrowdedTrousers]

Hi Zed and folks, update -

First if anyone finds this thread in the future, I want to loudly thank bluesentra for his excellent walkthrough on how to easily replace the mechanical water seal without a press, using hardware and an $8 pipe from Home Depot. He also thoroughly explains the whole process of taking the water pump apart and putting it back together, with torque values. THANK YOU!!

Bluesentra's post here


So - all my parts arrived; a friend and I put everything back together. Took quite a bit of time to clean up the engine-side water pump housing and shaft - it had a lot of the hardened gunk on it. We carefully used acetone and brake cleaner on rags to try and dissolve all that we could; ended up getting almost everything off.

The radiator I had left soaking in water for ~2 weeks - this seems like it was a good idea, as when I opened the tub it sat in, I found lots of little specks of the gelatinous stuff floating around in its water. I'm guessing it was in the radiator and worked its way out.

After putting it back together, I flushed the system - four times by running the bike for 10-15 minutes:

1. First time with plain distilled water, let it cool, drained. Saw nothing, came out clean and clear.
   (then realized - probably a better chance at getting anything out by draining it hot, before any solids can settle)
   
   
2. Second time, also plain distilled water (forgot the vinegar), drained it HOT within 2 minutes after shutting off. This time, I saw tiny bits of gelatinous stuff in the drain pan, see below. Concerning - but seems the hot drain was effective.
   
   
   
   
   
3. Third time, I remembered and did 50/50 distilled water and white distilled vinegar. I put my hands on the radiator to feel if it evenly heated - as far as I could tell, it felt even. Did another HOT drain (will shoot 7-8 feet out the drain plug if you don't catch it), this time came out clear, no chunks.
   
   
4. Fourth time, to be safe - plain distilled water. Another HOT drain, came out clear, no chunks.

After all this - I figured it should be all gone. Filled it up with non-silicate coolant, and I think... we're done? Still thinking it wouldn't be a bad idea to check the coolant in a month or so of riding.

Really appreciate all the help from @Zed7 and others, thanks so much guys. Let me know if you have any other thoughts.

 

[Zed7]

You went through the whole PITA process but now you can rest easy. 👍
As long as your bike runs at the proper temperature you can ride it a season then check. I would guess that the process of the coolant running through the water pump impeller would tend to beat any remaining gunk into smaller pieces. On your next coolant change just try to get it out as hot as possible.

 

[CrowdedTrousers]

You went through the whole PITA process but now you can rest easy. 👍
As long as your bike runs at the proper temperature you can ride it a season then check. I would guess that the process of the coolant running through the water pump impeller would tend to beat any remaining gunk into smaller pieces. On your next coolant change just try to get it out as hot as possible.

Thanks Zed - I forgot to mention also, I did a test leaving some of the chunks in 50/50 vinegar and water; after 2 weeks there is no change. It doesn't seem that breaks it down - as such yes, think I'm relying on mechanical movement to dislodge anything else.

What is the best way to ensure the bike runs at proper temperature, since there is no temp gauge on these bikes?

 

[motocopter]

Yep, nice work there!

Maybe keep an awareness of when the radiator cooling fan is running. You can determine when the fan should be doing it's thing.

 

[Zed7]

I had a 650 Versys for a few years. I don’t ever recall the fan coming on.
You can pick up a non-contact thermometer at Harbor Fright on sale for ten bucks sometimes.

 

[CrowdedTrousers]

I had a 650 Versys for a few years. I don’t ever recall the fan coming on.
You can pick up a non-contact thermometer at Harbor Fright on sale for ten bucks sometimes.

Thanks, didn't even think of it but - I do have an infrared thermometer. Mainly as a laser cat toy. 🐈
Google says - healthy liquid cooled bike coolant temp is 155F - 220F. I can point it at the radiator and see if it ever exceeds this.

 

[Zed7]

Thanks, didn't even think of it but - I do have an infrared thermometer. Mainly as a laser cat toy. 🐈
Google says - healthy liquid cooled bike coolant temp is 155F - 220F. I can point it at the radiator and see if it ever exceeds this.

Hahaha, my IR thermometer was over my brother's house because he needed it to determine the temperature of a pizza oven he built but I found out for the last few years they had been using it to play with their puppie. 🐶