Cooling system mod ideas

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joedrum

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I’m looking at ways to add more cooling capacity to hooch ...like adding more radiator to the stock system ...and where to do it at and how ...you can see the bike in the pic ...it basically the same now ...do I have to just scrap stock radiator and just go bigger ...looking for imput thanks
 
I’m thinking it cools okay because when it overflows, it isn’t hot. Just more volume or a bigger reservoir or a radiator that will flow as fast as the pump pushes it at high rpm. If the rpms went up rapidly when the thermostat was still closed, the thermostat is slow to open. There is a bypass which should help, but I’m thinking it just isn’t enough.

I’ve never seen any data on the speed or volume of the water pump of the 1200, but I remember Old Fogey saying the oil pump would be driven slightly faster. Would the water pump be driven the same amount? I think it would. If so, it’s driven a few thousand rpm higher rpm and gets a boost from gear differences. It is a different animal.

I always thought it would be neat to have two radiators like 15-1800’s and lots of smaller Honda bikes which could be utilized for heat on cooler days.

Too cold for any experiments here. Be glad you’re down there where you can enjoy riding and wrenching most of the time.
 

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Interesting pic ...on the overflow bypass ...might try blocking that as an experiment...not sure what that would do ...but with no thermostat in place it’s not needed ...yes the coolant and the oil flow through motor is like 12% more on 1200s over 1000 and 1100s ...
 
I’m trying to remember why it was greater and I think it was from using the 1000 or 1100 output shaft?? If so my current is an 87 and output shaft can’t be swapped, so my current setup is stock 1200 as far as the oil and water go.

I think I had the water pushing out on this motor too with the 1000 heads. Just can’t remember for sure.

No thermostat removes that from the mix.
 
Clutch basket spocket that drives the oil pump shaft ...only thing you could do to change that is put a 1000 clutch spocket and chain setup in the 1200 motor this drive also drives the water pump also....I’d say it was done to supply more oil to the hydro 1200 heads ..
 
From what I remember, the ratio of the sprockets on the clutch basket and the oil/water pump shaft are about 1:1, so both pumps turn at or near crankshaft speed. The oil pump on the 1200 is slightly larger to output more oil.

Also, one of the functions of the thermostat is to control the flow of coolant through the radiator, allowing it enough time to transfer the heat to the fins.
 
The clutch bracket sprockets are different by on tooth and so is the oil drive sprocket ..I think all the other parts ...including the chain are the same ....yes I know all about the thermostat purpose ...I’m not suggesting others try it ...it’s just what I’m doing ....at the moment ...
 
If I'm following, what is being suggested here is somehow the coolant flow or heat is increased so much faster (in bursts?) that the stock cooling system can't handle it, which makes coolant leak out the cap?

I call bullshit. There's something else going on.

Joe, I think you're looking for a problem that doesn't exist in a properly running stock system.
If the engine isn't overheating, why would more cooling capacity be needed?
 
Well,when it would spit out it seemed not hot ..of course at speed it gets cooled fast ...I could have cracked head maybe but if I do it’s hidden ...waiting for the rain to stop ..to look more into it ...
 
[url=https://www.classicgoldwings.com/forum/viewtopic.php?p=214429#p214429:1kvnvho9 said:
joedrum » 8 minutes ago[/url]":1kvnvho9]
Well,when it would spit out it seemed not hot ..of course at speed it gets cooled fast ...I could have cracked head maybe but if I do it’s hidden ...waiting for the rain to stop ..to look more into it ...
Exactly my point.

If there was a lack of cooling capacity/ability, and overheating caused the system to pressurize past the cap rating and spit out, the coolant would have been steaming hot at least.
The radiator cap is both a temperature and a pressure relief. I'm betting the problem is pressure related and has nothing to do with temperature.
If you've got a situation where combustion pressure is blowing past the head gasket only when you get on it, the head gasket seal isn't going to last long, and will start leaking at lower rpm's also.
 
That’s the road I went down. Assumed I must have a leak, so pulled the heads and found no evidence of it on the copper gaskets or heads. I think I did that three times. Two times were with thinner head gaskets (0.010” under) and I did have my pistons kissing the heads slightly. So I went to a stock thickness copper gasket. Same issue until I enlarged the overflow tank. Then I could see through the clear plastic tubing a surge of coolant almost always when really loading the bike rpm. With the larger reservoir it would not overflow. Sometimes you would see a s the bike warmed up, but then it was a slower movement of the coolant through the tube.

I don’t know the volume of my reservoir but I think it’s a liter. Not sure of stock size.

I put the 1200 heads back on just to see how well they perform compared to the 1000 heads. They’re pretty close to the same, maybe better down low but give up a bit around 7000.

There are others who have done this mod, (1000/1100 heads/cams) but they don’t report much.

If the system is pressurized and there is sudden expansion from heat, it has to go somewhere, either it increases the pressure or the cap releases it. You’re probably right that it has nothing to do with pump speed, because the system is closed and the pump would help draw the coolant through the radiator. Cavitation??

On mine it did not continue spewing coolant. It would stop. But if you didn’t replace what was lost, and did that a few times more, your level would be too low, and then you start running hot.

I have to add a little coolant now and then because my cross tubes leak occasionally.
 
Ok ..rain stoped ...ran the bike at idle for about thirty minutes with the fan running ....during this time the bike ran cool most of the time till the end ...I had the false tank panel off so I could observe all the time ... I noticed and noticed before that one intake runner was warmer than the rest on the right side of bike in the back ...my manifold is insulated quite well from the head heat with wood gaskets ...ive also notice in the past the back cylinders get the coolant last cause it feeds the heads from the front of the motor ...so in general the back intake runners would always be a bit warmer than the front ones ...but this one runner was getting warmer faster ....anyway when the expansion tank started working and pushing water back and forth ..I could see it working ..I stut the bike down and letting it cool ...I’m starting to think the back cylinder head on the right side is cracked in the intake runner port ..I’m fixing to check this out when all things cool down ...
 
Ok no sign of water in intake or cylinders ....I have noticed that the runner that gets the warmest is the cylinder the furthest away from the water pump ....hmmm ...all the plugs look great in color .. the argument of the expansion tank being to small or radiator in general is a good one ...I watched it push out and pull back in Ike it was fluttering there every second or two ...will fasten down manifold and put plugs back in and test ride it again ....it for sure stays cooler with thermostat out it seems .....
 
Ok the mod I’ve done so far is I put on about 5ft of overflow line from expansion tank ran it all high above tank ...with over flow up above around the triple tree so I could see it...over flow should go back in expansion tank ...ran it 50 miles hitting hard twice ...second Time really hard ...all things seemed great and seen no blow out from hose ...motor seemed to run very cool ..I’m encouraged so far ...
 
The very first thing to do, Joe, is put a red light up on your triple-tree that is wired into your cooling fan relay. When the fan is on, that light should be on.

Next is to put on a temporary (or permanent, if you desire) coolant temp gauge.

IF your cooling fan is on for less than 80% of the time, there is no reason to add more radiator capacity.
If the coolant temperature is above 260F for more than 2 minutes at a time with the fan running, then you need either a new thermostat, or more cooling capacity.

You do NOT want to 'overcool' the engine under ANY circumstances, especially not in Florida- you'll wind up with considerable condensation in the crankcase and transmission.
 
It was to cool today to ride high 60s lol....I did run it for awhile ...seemed fine ...with long hose mod above expansion tank it basically makes the expansion tank bigger...we will see how all this works in coming days ....Dave myfan is set up both ways temp switch and manual ...I have no temp gauge at all right now...and as far as my motor goes I run it as cool as I can get to run ...also like cool gas charge in my manifold ...I get plenty condensation on the intake runners and outside of the weber carb and mount ......I had a super charge intercool car for a couple decades ...and know the power that comes air to air intercooler set up ...the motor was set up for boosting and would hardly run with belt off ....the hooch bike is not boosted and doesn’t need to be ...but the cool gas charge I’m a firm believer in ...and I want the motor running cool as I can ...fingers crossed on the work that’s been done ...
 
I think everyone is missing the simple, obvious solution to fix the overheating problem:

Move to Fairbanks.

;)
 
Dan, you noted that the cap is both temperature and pressure... unless there's something REALLY odd about it, the cap should simply have a pressure relief point, as there's no thermal element... but the cooling system is designed as a pressure-regulated-for-temperature reasons, and the thermostat and radiator are temperature-regulated-for-pressure-reasons.

The other note about 'flowing too fast for the radiator to cool it' is a misnomer. When cooling systems fail to cool, it's not because coolant is moving too fast in either the radiator or the engine, it's because the coolant PUMP is cavitating under differential pressure... meaning, the pump is developing such a high pressure differential between outlet and inlet, that the coolant boils (under extreme low pressure at the impeller), resulting in the impeller losing effectiveness. Typically this happens when you're running a coolant pump WAY faster than it's design speed, or when you have a blockage (unintentional restriction) in the return TO the pump, or insufficient restriction at the pump outlet (like... a missing thermostat). Proper coolant flow path is simple- a circle coming out of the engine, circling back into the engine. The thermostat's wax motor element is in this loop, and when temperature of coolant rises, the wax expands, and allows diversion of engine coolant through the radiator. The thermostat has a small bypass that 'always' flows a little engine coolant through the radiator, so that any air bubbles have a rapid path to the top of the radiator tank.

Joe... is this cylinder head the right side? Is it one that was recently replaced, or one that you've been using for some time?
 
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