1986 SEI overheating after PoorBoy Installation

[syringa]

Installed a poorboy conversion (from Don) a while back. works perfect except.... The bike always ran 3 lines on the temp gauge,sometimes 4 when outside temps over 90.. Now if its really hot outside i can't idle for long or do slow speed without the temp going to 5 plus lines.. I have got the rad cleaned and have wired the fan on a switch, it's ok on the highway but not in town. Has anybody else had this problem after doing a poorboy conversion??

[Saintjude33]

I did mine a while back, but no issues with overheating- possibly an air-pocket in the system? I did have an issue with leaking where the bottom hose didn't fit on too well, but as long as I keep an eye on it, it goes fine. My fan beat against the other parts for a bit, but eventually they wore down enough to clear.

[syringa]

I have also changed the thermostat, drained and refilled the system with 50/50 a few times so i don't think a air pocket. has anybody used that Evans no boil coolant?? Maybe it would give a bit more safety factor. I know it won't stop the overheating but presumably will raise the boiling point. thks

[syringa]

sorry it's Evans WATERLESS Coolanr

[Rednaxs60]

Did the alt mod on my '85 LTD last July and initially had what I thought was a heating problem as well. I had a new rad core put in, and changed the thermostat (OEM). Still ran hotter than I thought it should. I also had to think about when I bought the bike which was in October of 2015. Rode it over the winter months and of course it ran cool, slightly different when summer hit.

The bike normally operates at the 4 bar level when solo, and 4-5 bars when two up. Around town routinely at 6 bars but the fan comes on and keeps everything in check.

Did some research and found that the rad is a high efficiency rad that is intended to keep the bike at approximately 4 bars when at speed, other wise the bike engine temp will rise. The Owner's manual mentions that any temp up to 8 bars is fine, after which shut down and investigate.

Have checked the temperatures at the various temp bar levels and the fan kicks in when the bike is at the 6th bar. The fan drops the temps 10 deg C. The bike goes back to 4 bars quite quickly after being at 6 bars when back up to highway speed(s).

I have installed a manual switch and fan on indicator light and monitor it. System works as it should.

I would let it heat up until the fan comes on and monitor after that. If the fan does not come on when the temp gauge is at 6-7 bars - investigate the issue. Could be the connector to the fan temp sensor or the fan temp sensor is bad.

Hope this helps. Cheers

[Krazywolf8169]

50/50 mix of antifeeze raises the boiling point also so does the presssurized radiator cap. For every pound of pressure it raises the boiling point of plain water 3°(think of a pressure cooker) But i am curious as to why the fan is on a switch and not on the thermostatic switch? If its because it has failed maybe you never realized how often the fan actually ran? It also could just be the cores in the radiator are partially plugged. Also the impeller of the waterpump may have corrosion on it. Another thing is that the fins between the cores may have built up dirt and road grime impeeding air flow. And then there is the possibility of the fan being moved to clear the belt may of decreased the pull that the fan is capable of also dirt on the fan blades itself can greatly reduce effectiveness. It could be the sensor for the gauge or just the fact the bike now runs at full voltage and the sensor reads correctly?

[syringa]

Your question about the fan being on a switch.. I changed it but the fan would come on when it reached 5-6 bars.. I just don't like it getting that hot so when it gets 4-5 I switch onn the fan manually

[Krazywolf8169]

Well as mentioned the fan is designed to come on at 6-7 bars not sure what that is equivalent to in °F but it would definitely be above the thermostat opening temp. I mean hell my pickup i run a 195° and normal operating temps range from 200-220°

[Rednaxs60]

The temperatures I took with a therm imaging temp pistol are:

1 Bar: 41.6 deg C (106.9 deg F)
2 Bar: 46.8 deg C (116.2 deg F)
3 Bar: 55.3 deg C (131.4 deg F)
4 Bar: 68.1 deg C (154.6 deg F)
5 Bar: 90.5 deg C (194.9 deg F)
6 Bar: 98.1 deg C (208.6 deg F)

Fan on at 103.3 deg C (217.9 deg F)
Fan off at 92.7 deg C (198.6 deg F)

Timing to catch events is probably a bit off but the temps recorded are well within normal operating parameters.

Have no issue with operating the bike and letting the system do the work. As with all indicators, these are a guide and as long as the events such as the fan coming on is consistent, I do not worry. It's when the same event happens outside of what I expect and have been seeing that I become more engaged and start to keep a closer eye on what is happening.

Cheers

[syringa]

Thanks Ernest... Puts my mind at ease.. but it still puzzles me what changed after the poorboy install thks for your input

[paneled]

I did a por boy alt kit on my 86 sei and have not noticed any change
in the operating temp at all runs 3 bars till I sit at lights then it goes
to 4 and sometimes 5 bars then the fan comes on and cools it down.
check to see if your fan is running and make sure the air flow is moving
the correct direction if fan gets wired backwards it will push air toward the
front of the bike instead of to the rear. easy mistake to make

[Rednaxs60]

I don't think anything changed from pre and post poorboy. I find that when I do maintenance of a major item, or fix an issue, something else comes to the fore to catch my attention. I had the same inclination as well when I did the alt mod. Noticed a higher operating temp and thought it was because of the alt mod. Did a lot of work on the cooling system, researched it to no end, and came to a good understanding of how the bike was designed and supposed to operate.

I'd recommend letting your bike heat up and take note of when the fan comes on. You can use a small thermo temp heat gun such as this:

Got mine on sale for half price - approx $20.00. A small temp survey of your bike at the water pump inlet can put your mind to rest, after which it is on to the next mystery that needs solved.

Cheers

[mikeanw]

Sorry for being late to the show.

Did you find anything else out??

I ask because I did the poor boy to my 85 Aspy. It's now regularly running 7-8 bars. The fan kicks in but she keeps getting hotter. Has not jumped to 9.

Just seems too hot. Will pull and clean the rad and change the thermostat. Something is not right (no I don't have any bubbles)

[Charlie1Horse]

I don't know much about the Poor-Boy conversion but, my thought is, are they really running hotter or just registering hotter? Seems quite a few are posting so but, I am wondering if they really are. Could it be some kind of feedback loop on the wiring attached to the bike like a change in the amount of ground, or, higher amount of charge at an inappropriate circuit that makes the instruments read higher than they should. Just a thought.
Russell

Those who say it cannot be done should try not to interrupt those who are doing it.

[Rednaxs60]

I agree with Charle1Horse. Sometimes we do work then another issue crops up, we second guess ourselves on what we did and is it the reason for this new issue. Ultimately the issue is not related, and I submit that your bike operating the way it is is not because of the alt conversion. Went through this as well, did the alt conversion, saw a possible temp problem and second guessed my work. Alt conversion had nothing to do with what I was seeing.

As I mention in my other posts, I did a temp check to get an indication of what the operating temp is at each "Bar" on the temp scale. Gives me a good indication of what I can expect. Also know when the fan comes on and that it drops the temp 10 degree C then stops.

Recommend doing the same on your bike. Gauges are an indication and consistency from the gauge is what you want. When something changes from what you are seeing, then there is a need to investigate.

If the fan is coming on and the engine temp still increases, you need to find out why.

Good luck.

Cheers

[mikeanw]

Did some work this weekend. A good flush. Twice. Thermostat works well in hot water.

Measured rad temp while running. Fan comes on between 195-205. Immediately drops to 170ish at the top.

Shows 6-7 bars on the gauge.

I will try it on the road tomorrow. If its at 170 or better on the road I’m good.

As described, consistency in the gauge is most important, not the # of bars.

Thanks all for the guidance and feedback.

M