GL1000 Getting hot or Temp Gauge?

[Pinball]

Well we can now take flushing the radiator off of the list. My son did that with little improvement. The bike runs right by the hot mark but not into the red and doesn't boil over but something is not right. He has his headers wrapped...would that make the bike run hotter? I guess the next thing to look at is the water pump. I also want him to try and run the bike without the thermostat just to see if the new one might be bad. This seems like it is just something simple as there aren't many parts in the cooling system to go wrong. Any other ideas other than the pump...as that is next on our list. Thanks again for all the help

[Pinball]

Well I just got back from working on his bike. He flushed the cooling system last week and it didn't seem to help much. We replaced the right head gasket today because it started smoking and had some coolant in the #3 cylinder. It seemed to help some as the bike will idle now without over heating but I think the head gasket was caused by the overheating problem not the cause of it as he took it for a ride and it got hot again. I took the cover off for the lower hose and the pump didn't have any play in it. I am going to take an extra radiator to a shop to have them clean and pressure test it. If I replace that and the overheating problem is still there I guess we will try replacing the pump. How do you know if the lines on the reservoir are reversed? Sometime soon...there is not much left to replace or check

[Sidecar Bob]

The line from the rad neck should be connected to the bottom of the reservoir and the overflow line should be connected t the top. If the overflow line was connected to the bottom all the coolant in the tank would drain out.

[Pinball]

Well I went and picked the bike up this weekend so that I could work on it in person and not over the phone. I let it idle in the workshop and it stayed in the normal range. The only time the bike would move to the upper end of the normal area is when you would rev it up...but as soon as you just let it idle the temp would come back down. I thought I would start with some basic things today and decided to check the resistance on the plug caps. The caps tested #1 - 9.4K, #2 - 11.8K, #3 - 9.9K and #4 - 90K that is not a typo. I left my multimeter on the cap and it kept dropping but stopped at 60K! I took the plugs and caps off of my bike and replaced them and it seemed to run a lot better. I guess it is time to order some new cap and plug. Mine all tested about 4.7K as I had replaced them last year. The strange thing is I was checking the temp of each cylinder with my HF infrared thermometer when I had it idling in the normal range #1 165 deg. #2 185 deg. #3 170 deg. and #4 230 deg. so the cylinder with the super high cap also had a very high temp. I took the bike for a quick ride to put some gas in it and to see what would happen. It got just out of the normal range after ten minutes so I pulled over and within two minutes with it just idling it was back into the normal range so I took off again...same thing five minutes down the road. I let it cool down by idling on the side of the road and brought it home. The test ride was all on the highway 55 mph plus. I forgot to check the temperature right after my ride but did check it after I got my helmet and jacket off and all of the cylinders seemed to be around 145 to 160 so I am hoping that at least #4 will be running cooler now. I am going to change the radiator and thermostat (again) to see it that helps. If it doesn't I think I might put my carbs on his bike to see if that helps. I would think that on the highway the bike would be running cool with the air being forced through the radiator. I will post back after the radiator switch. Thanks

[OCR]

Have you checked the output of the 7v regulator?
If it produces more than 7vdc at any rpm range then you may also have an issue with the main regulator over charging.

[robin1731]

Well I went and picked the bike up this weekend so that I could work on it in person and not over the phone. I let it idle in the workshop and it stayed in the normal range. The only time the bike would move to the upper end of the normal area is when you would rev it up...but as soon as you just let it idle the temp would come back down. I thought I would start with some basic things today and decided to check the resistance on the plug caps. The caps tested #1 - 9.4K, #2 - 11.8K, #3 - 9.9K and #4 - 90K that is not a typo. I left my multimeter on the cap and it kept dropping but stopped at 60K! I took the plugs and caps off of my bike and replaced them and it seemed to run a lot better. I guess it is time to order some new cap and plug. Mine all tested about 4.7K as I had replaced them last year. The strange thing is I was checking the temp of each cylinder with my HF infrared thermometer when I had it idling in the normal range #1 165 deg. #2 185 deg. #3 170 deg. and #4 230 deg. so the cylinder with the super high cap also had a very high temp. I took the bike for a quick ride to put some gas in it and to see what would happen. It got just out of the normal range after ten minutes so I pulled over and within two minutes with it just idling it was back into the normal range so I took off again...same thing five minutes down the road. I let it cool down by idling on the side of the road and brought it home. The test ride was all on the highway 55 mph plus. I forgot to check the temperature right after my ride but did check it after I got my helmet and jacket off and all of the cylinders seemed to be around 145 to 160 so I am hoping that at least #4 will be running cooler now. I am going to change the radiator and thermostat (again) to see it that helps. If it doesn't I think I might put my carbs on his bike to see if that helps. I would think that on the highway the bike would be running cool with the air being forced through the radiator. I will post back after the radiator switch. Thanks

That sounds like a restriction in the system. Usually radiator but could be in the engine too. Have you flushed the cooling system? Changing the radiator sounds good if you have another known good one. But a good flushing/cleaning may be all it needs.

.

[ericheath]

After or while you’re doing the radiator, spark plug color might give an indication of what’s happening on number 4. Another item to cross off the list is the bulging inner header possibility. Drop the header and look in the elbow for a bulge in the tubing.

[dontwantapickle]

Another item to cross off the list is the bulging inner header possibility. Drop the header and look in the elbow for a bulge in the tubing.

what? why?

[Track T 2411]

Another item to cross off the list is the bulging inner header possibility. Drop the header and look in the elbow for a bulge in the tubing.

what? why?

I don't recall which years, but some of the 1000's headers are doubled walled, and the inner wall has been known to 'bulge' inward, restricting the exhaust flow...

[Pinball]

GOOD news BAD news kind of a day. I believe I found the problem...the bad news is it looks to be the water pump. I took the radiator out and it looked a lot cleaner then the one I was going to replace it with (Jake did add a flushing agent and ran it for three days like the instructions said) so I dug a little deeper. I removed the pump cover to get a good look at the pump as I had only seen it when I removed the lower hose cover. The pump looked great and had no play in it at all but I couldn't get it to move AT ALL when I grabbed it. I turned the kill switch off and cranked the bike over and the pump doesn't even try to spin. Looks like I will be digging into the engine a little further then I wanted to. I guess I should be happy that I found the problem. This would make sense for the way the bike was heating up. I will let you know what I find when I get a little deeper into this. Time to do a bunch of reading on how to do this. Thanks again for everyone"s help on this.

[Pinball]

I don't think I would have been able to sleep tonight if I had not a least looked Once again I am happy to know what the problem is. The bearings on the pump were frozen up as tight as a drum...I guess that 35 years of sitting didn't do it any good. Now I guess it is time to start looking for all the parts to put this beast back together. Here is a picture of the pump shaft and the tang that drives it...boy was I happy to see that tang in one piece!

[Pinball]

One last thing before I order my parts...a lot of the K & L gasket kits on eBay are saying that the mechanical seal is not included...is this the press in seal that goes around the shaft of the pump? If that is what they are saying is not included with the kit that seems a bit of a kick in the pants. Just checking so I can have all of my parts here at the same time. I believe I will get a Honda pump so that this is not something I will be redoing in the near future.

[Sidecar Bob]

The mechanical seal is what you would use (along with 2 bearings) to rebuild the pump itself https://www.ngwclub.com/forum/viewtopic ... 90#p723193

The oil seal for the oil pump shaft probably isn't included in their kit either, though...

[sunnbobb]

I sure appreciate you keeping this thread going and updating it. What I learned: The mysterious overheat after everything has been changed and cleaned is likely the water pump. Going to head out and change mine this weekend. Ive been chasing the same devil and was waiting for this thread to come to a conclusion...

[Pinball]

I got the parts in the mail today and got everything back together this afternoon. I just got back from a 50+ mile ride and it never got above half way in the normal zone!!!! It was not as bad as I was thinking it was going to be to put the new water pump in...just time consuming. Thanks again for all of the help through this and thanks for letting me use you as a sounding board as I worked through this mess. Here is a picture of the bike after my ride today and one of it when we first rolled it into my workshop. Thanks, Scott