smokinjoe73

So I am trying to track down a cooling (or lack therof) issue.

I still want to bleed the oil cooler but I drained the coolant, flushed the radiator, refilled with new distilled including purple ice.

I am running no thermostat. I opened the waterpump housing and it looks immaculate.

Should I turn the engine over with the waterpump housing off to check impeller movement?

What else could cause it to run hot even in cool (40*) temps.

msethhunter

The lack of a t-stat comes to mind. I know it seems counter-intuitive. But the t-stat is in there for a reason. The coolant needs time in the radiators to actually cool. So with it running wide open, it's just moving to quickly.

A while back, I had a '71 El Camino. It made about 600hp on the motor(Small Block Chevy with 11.5 to 1 compression), and another 250 on a bottle. I started off with a 160 t-stat when I finished it in the summer. It would run at 200-210. Then winter came, and it would run at 160, which is to cold. So I put a 180 thermostat in it. Mind you, I had a 4 core radiator in it(MONSTER radiator). It would run at 180/185. Then summer came, and it ran at the same 180/185 in the summer. What I found out was the coolant was actually doing it's thing and staying in the radiator long enough to cool the coolant off.

Put a new thermostat in and see if it helps.

smokinjoe73

I will try that and am ordering a new rad cap. My confusion with it is that the previous motor ran cooler on the same setup.

Is it possible that an '05 motor has different temp signals and the guage is misreading it? The old motor was 98.

msethhunter

It could be a lot of different things. Remember that the coolant temp sensor works off of resistance. You could have a resistance issue somewhere. I wouldn't worry about it to much unless the fans come on, and never go off.

saige

if you used all the sensors from the 98 on the new motor,it should be correct,and the brain should be from the 98 too,not the 2005,i believe there it would read different,i may be wrong.
im sure some knows about the brains on the bike.

at the moment,im having cooling problems,tomorrow i will be able to run it and found out if i fixed the problem.i changed the thermo and sensors,but while i was doing this,i found the carb lines for the cooling system was heavily clogged.this may had something to do with the system,but i dont think entirely.

if i were you,i would turn the motor over and see that the impeller is spinning.when its off,check it by hand too to see if it has play or anything.

zmaniv

Could also be running too lean

smokinjoe73

Like I said everything is the same as with the old motor, jetting is spot on and carbs have been cleaned.

msethhunter

I doubt it. Without looking to see where the coolant for the carbs comes from that is just a guess though. I can't see such a small diameter hose causing problems. But I do know that the main reason why 99% of manufacturers rub coolant through carbs and throttle bodies is to prevent carb/throttle body icing. When you drop the pressure (venturi effect, remember JR High science), you also drop the temperature. Thats why every airplane with a carb also has a way to introduce carb heat. Typically you see a 200-300 rpm drop by pulling on the carb heat. I have thought about bypassing the carb coolant in my bike, but don't feel like messing with it that much. I know it would gain a small amount of power, but I don't think it's worth the hassle.

8541Hawk

Common misconception about the coolant lines going to the carbs.....

It has nothing to do with "icing" or anything like that.

They are there to aid in fuel atomization which gives better fuel economy, smoother running engine and more power.

It is one of those counter intuitive things for most people.

Of course you will get the group that says you need a cold, dense air\fuel mixture and all that. Well that is only half correct. Yes you want cold air but cold fuel is not good.

So what the lines do is flow coolant while the thermostat is in the "closed" position.

The coolant heats the float bowls. If they were there for "icing" then the water jacket would wrap around the venturi. As they don't do that, it pretty much proves that they are for preheating the fuel. This is also why they "They heat the air going into the engine, so you lose power" argument doesn't hold water.

Then when the thermostat opens, the coolant is bypassed from the carbs and the radiant engine heat does the job from there.

If you want we can start a new thread to discuss this once again.

Just let me know as you know I do have a "slight" interest in the carbs on this bike....

Also here is a little reading for you. While this bike doesn't use a complete adiabatic system, you can see where part of the system is used on this bike and where they got the technology or idea to run it the way they do.


Henry "Smokey" Yunick -- Fuel vaporizing carburetor system
Henry "Smokey" Yunick -- Fuel vaporizing carburetor system -- USP # 4862859

PappySmears

IMO, Japan has fuked up with the radiator location, air flow is at a mininum and the rads struggle to keep these things cool. I have mounted a front rad , but my bike has been heavily modded. If you can increase air flow through your rads , you will instantly find your cooling problems disappear.

saige

i was having the same problems as you smokingjoe,i changed out the thermo and unclogged some small hoses and fixed the cooling issues i was having,besides a small leak im fixing now,it runs good,gets hot and cools down like its suppose to do.i would look into thermo and make sure no hoses are clogged.

smokinjoe73

Yeah I am going to replace the thermostat (begrudgingly) but I have always had the carb coolant lines clamped off.

Beyond those 2 little ones I cant see the big 1"+ hoses being clogged. I am also going to replace the rad cap.

Saige you just cleaned out the carb hoses right? I dont think they make a diff, like I said mine have been clamped for years.

saige

yea,just the small hoses,i had everything apart and realized they were clogged,so i cleaned everything out to do with the carbs.
im sure they have been clogged for a long while and most likely had nothing to do with the overheating,but it was good peace of mind.

and my small leak is fixed due to not clamping one little tiny hose clamp
oopppsssss lol

msethhunter

I know this is going to start a **** storm, but I am not all that sure of what you are saying here. I have been looking for a while now to find a cut away of a CV carb to see exactly where the coolant may pass through. But, I am fairly certain that (even after reading your bit with Smokey Yunick), that is not why Honda has plumbed coolant into the carbs. You have a cutaway of s SHawk carb?

Fire up that new thread if you want. I'm am busy doing research.

smokinjoe73

So I got a new rad cap. Almost stupidly bought the bikebandit/ronayers one for $40.

I found that a million cars use the same cap, like mustangs, explorers etc. Its stant #10233 or equivelant.
Anyway, there is a snowstorm raging here now but I hope to try the cap soon.

Oh yeah and does it really matter what exactly the carb coolant hoses do? Cmon lets rally around my problems.

saige

lol,i was just saying my particular problem and it blew into this,sorry if i started something.i didn't think a comment would cause all this.
but im still leaning towards a good flush and change the thermostat.
i dont remember,but will your fan come on at all.

ohhh and thanks for the info on the rad cap.

smokinjoe73

Yeah fan comes on but the temp needle climbs slowly to like 2/3ds before it does.

On the last motor (and my other vtr) a stint over 60mph will bring it back to half but on this it stays at the 2/3 spot.

I am going to have to plumb in a temp guage (digital) so I know more of the story. For all I know now the guage could be the culprit.

8541Hawk

No **** storm. I was just trying to keep it short as to not upset Joe...

Start a new thread on the topic if you like. I would think by now that most would think I have a pretty good understanding of the carbs on this bike.

The only other thing to add is, if you have removed the lines, my challenge is reattach them and take the bike for a ride.

Then tell me which way has the "crisper" throttle response.

Sorry to go off topic..... I really am trying.......

8541Hawk

As for Joe's issue. Did the later models use a different sensor for the digital read out?

So yeah the first thing would be to make sure you have all the original sensors on the bike and then go from there.

As for the oil cooler, there really should be no need to ever "purge" it.
The way the system is designed and set up, it is self priming and it either works or it doesn't. If it doesn't work check the relief valve by the pump, as that is the only "failure" point.

smokinjoe73

Ok PROBLEM SOLVED crisis averted.........

Of course it was the first thing I would've advised anyone to do first......Radiator cap.

If anyone reads this in the future just remember an autoparts store will have it as a stant 10233 or equivalent.
(ford escort 97-02,explorer 97-05,mustang 97-02,ranger 95-11 to name a few for cross ref)

She has her old personality back. Nice & cool....(needle @ 1/2 way)

Thanks for all the help guys

mboe794

I had a bad radiator cap once. Tried deionized water for a short period and I think the seal under the cap did not like the PH. Went back to distilled and no more problems.

The only symptoms my bike displayed was a tendency to boil over prematurely. I don't recall seeing abnormally high temps on the gauge. And now that I think about it, the lack of pressure should physically limit the temp to somewhere just above 212 (I think water wetter adds a little, could be wrong). Now this is not to say that cylender temps weren't higher than normal. I imagine they were. The gauge just has no way to recognize it.

Around here the auto parts stores carry a brand called motorad. I just bring in the bad one and match it up to one from their selection. No need to cross reference part numbers.

smokinjoe73

Yeah thats the brand I got. Its just easier to tell them one of the cars listed & have them hand it to you. These guys werent willing to dig for it.