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Massive Overheating


Paulie B

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I had a job cancel on me today so I decided to take the shee out for a blast.

It never overheats but today after about a 5 minute ride it was massively overheating. I heard water boiling inside the radiator and steam coming out my overflow tube.

I'm about to break her all down for some new carbs and take the head off to mill it down some more.

Anybody wanna take a stab at what just happened? I have a billet impeller and oversize radiator.

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I had a job cancel on me today so I decided to take the shee out for a blast.

It never overheats but today after about a 5 minute ride it was massively overheating. I heard water boiling inside the radiator and steam coming out my overflow tube.

I'm about to break her all down for some new carbs and take the head off to mill it down some more.

Anybody wanna take a stab at what just happened? I have a billet impeller and oversize radiator.

 

Do you still have that plastic water pump gear. Sounds like the flow has slowed down to almost nothing if it was boiling over in such a short amount of time.

 

You said about 5 minutes, is that total time including warm up time? My bike probably takes about 5 minutes to get up to operating temp just idling.

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Do you still have that plastic water pump gear. Sounds like the flow has slowed down to almost nothing if it was boiling over in such a short amount of time.

 

You said about 5 minutes, is that total time including warm up time? My bike probably takes about 5 minutes to get up to operating temp just idling.

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Yes I'm still running the plastic impeller gear.

No that was not including warm up time. Warm up time for me is a short ride until I feel heat in the pipes and the head getting warm.

 

I got it broke down real fast. The radiator was missing alot of water. I can't find a leak in it and the head gasket looks to be intact.

I did a compression test still 142psi on both sides. The cylinders and pistons still look new- I was worried about it seizing up some from all that heat.

The plugs look lean and I just noticed my left side pipe o-ring has blown out.

 

I took a few pics

 

P1260020.jpg

 

P1260022.jpg

 

P1260024.jpg

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you still runing the stocker carbs?? maybe lean,obstructed pipe?what coolant u use?looks like straight water.thats a nono.;) ..goodluck

i got some pj's if your still looking for carbs..

Yes sir I still got the stocker carbs, that was the last ride on them. RJATV has some new ones on order for me.

I jetted it not 2 weeks ago if anything the mains (370) are a tad rich? The low and midrange has always been too rich.

Thats straight distilled water with redline water wetter in it.

aw man I hope I don't have an air leak somewhere. I need to check that stupid plastic impeller gear too apparently....

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I'd say while your in there to replace the plastic gear... but i don't think that is your problem seeing as you lost coolant. Sure it was actually overheating not just being pressurized by a leak in the combustion camber somewhere?? Is there coolant in your pipes?? I'd be leaning toward a bad cap at this point. Hope that helps.

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I got the side cover off and the impeller gear looks fine.

I put the stock cap back on over the china one that came with the radiator. How does the cap have anything to do with all this just curious.

I put a new exhaust o-ring on the left side pipe.

I filled the rad. and it looks to pumpin just fine. I shut her down and re-filled almost to the top.

Ride report says everythings back to normal. Now I just need them new carbs!

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Radiator caps have psi ratings...... Usually 16psi is what is found. That being said.....when pressure gets involved with a fluid that takes heat such as coolant it will actually cause the liquids boiling point to rise. Biling liquids are never good in cooling systems. When coolant getsut under pressure your coolant will raise the boiling point (make it harder to boil) 3 degrees for every 1 psi that you put to the coolant. So 16psi cap......let's say regular boiling point of 50/50 coolant to be 230.....plus the 48 extra degrees.....

 

Now you have coolant that will not boil until it hits 278 degrees.

 

Also a lot of older style radiator caps have that mid way clamp down on it when you tighten it.....you know its where it's on but it's floppy as hell and doesn't seal? That is actually a cap setting also. Say you have a coolant leak that's is formed from the pressure.....you can actually leave your cap half on and eliminate the pressure buildup in your cooling system.....however your coolant does not get that pressure to help eliminate boiling.

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I got the side cover off and the impeller gear looks fine.

I put the stock cap back on over the china one that came with the radiator. How does the cap have anything to do with all this just curious.

I put a new exhaust o-ring on the left side pipe.

I filled the rad. and it looks to pumpin just fine. I shut her down and re-filled almost to the top.

Ride report says everythings back to normal. Now I just need them new carbs!

 

sounds like you had an air pocket in the cooling system, with that bad cap and just water it got hot and boiledover. a waterpump won't move an air bubble, so the water just boiled.

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I will note a few things. Anti freeze should really be regarded only as such. Boil over protection mostly comes from the watr pressure by way of the rad cap. What you have to consider inside an engine is localized heat. This just means though your average water temp holds a certain temp, there are hot spots in the engine that will try to boil the water. This would turn to steam and try to escape the system if not condensed. This can be a mode of water loss that you never really see. It just slowly loses water due to local heat.

 

I will also discuss coolants. Ethelyne Glycol does not have the heat absorption ability of straight water. For this reason, we always recommend running the least amount you can get by with from the freeze table. 30% will usually do. Not only does EP reduce freeze temp, it also help as a corrosion additive and lubricates seals and such. When you buy a product such as water wetter, all you are basically getting is lube and additive to maximize the water content. They advertise this as "better cooling" but tht cooling is really only coming from the increased water amount.

 

You must also consider fluid viscocity. ANY real pump designer (not just someone with a CAD program) knows that pump design and fluid viscocity are closely related. the number one design factor for any pump is cavitation. It can destroy pumps as well as cause localized steaming of the water right at the pump. This steam can them move through the system and escape. For anyone that cares, when water turns to steam, it will expand approx """1700 times!""" What does this mean? it means if you have a cap set to blow off at 15psi and steam being created by the pump, you are going to vent water in the way of steam.... A simple CFD model would prove that many billet pumps on the market are prone to this condition.

 

 

From my reading so far, I kind of wonder if you have been losing water via steaming and level finally got too low. Unless you check it every ride, I would be inclined to add coolant and see what it does.

 

brandon

Mull Engineering

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