88 Running hot

[Hawg]

Alright guys I changed the coolant Thursday evening ran it with the drain vale set to on for awhile topped off the coolant and set drain valve back to off. I rode it about 40 miles and the temperature gauge remained about 1/3 of the way from lowest mark on gauge with the temperatures in the mid 40's. I went to ride it today and within 5-6 miles gauge was up in the red. Temperature only in the low 40's here, so I pulled over and set the valve back to on to get it back to the shop. Thermostat stuck or what else could cause this? I don't believe there is any air in the system as it ran fine the day before

[Flyinfool]

Did you check the obvious? I there still coolant in the system? How about the overflow tank?

[dingy]

The bypass valve wording is rotated to the 5:00 o'clock position when it is turned to normal flow.

 

Don't ask me why Yammy decided on this orientation.

 

You should feel the ball detent drop into the hole when it is a correct alignment.

 

Gary

[Hawg]

there is coolant in both the radiator and coolant reservoir. The drain valve is in the correct off position when it was running hot....

[bkuhr]

I had a clogged reservoir hose. rad pressure allowed coolant into & overfill reservoir, but would not flow back into rad.- Rad ended up low and hot. If you pull rad cap, reservoir should drain out the open rad cap- if not you have a problem.

[Hawg]

both the reservoir and the radiator are full. The coolant reservoir was not overfull when running, It's puzzling me since it ran fine the day before but it didn't today

[Squidley]

This is just some damage control questions, did you "burp" the system when you filled it back up. Meaning let it run with the cap off so that it could push any air through the coolant passages and come out the radiator opening?

 

I have found that even if you think you have it all out, some times it's not that way. I have had to do it a couple times on troublesome systems.

 

Another mention I want to throw in here is that the gauges on a 1st gen are low quality, they are not that accurate. Did you hear any boiling in the engine when it got hot? I know that when I replaced the hoses on my '86 I took the temp sensor apart and sandblasted it and cleaned it very well. I noticed that after I did that, my temp gauge would stay at the bottom of the gauge, instead of closer to the red line which is somewhat normal on a 1st gen....

[Hawg]

Yes I did that, and no I didnt hear any boiling. It could be a gauge problem not sure of that. It did get in the red. Before that it was fluctuating down and up. If I rolled off the throttle it would come down some, but if I held a steady throttle it would rise.

[Squidley]

Just for some clarification, the temp gauge probe is on the right side of the bike on the frame above the top corner of the radiator. If that connection is dirty or loose it might give you some erroneous readings. You might want to think about burping it again, just to be sure that it really is in good shape....

[Hawg]

I went back out to the shop today and ran the bike for about 20 minutes at an idle and the temp never went up above the middle of the gauge. Rode it for about another 20 minutes and the gauge stayed at the line between the lower green and the upper green or about 1/4. Dont know why it was running hot yesterday? My RF900 Suzuki on days like today and yesterday the temp gauge barely moves from the C... Don't have to worry about it on my Harley's lol

[Venturous Randy]

Dont know why it was running hot yesterday?

 

You may have got the bubble cleared out and now the coolant is flowing correctly.

RandyA

[pmelah]

that's cause Hardleys need more wrenchin then ridin just sayin most of my PGR friends ride actually all my PGR friends ride Hardleys and they always rag me for my metric i show them i only carry SAE tools just for them :rotf: seriously check the sensor like Squidley said mine is doing the same and i haven't changed the coolant found a loose connection helped some now i will take it out and sand it clean with 1100 grit