Please help with Airlock in cooling

[jaysinet]

My father recently purchased a Komoto 248cc K1 Sport from MotoXtremes. It arrived and had the usual loose screws and minor setup. As we were first filling the fluids we discovered a leak in the radiator that sits below the seat right in front of the engine. The company offered to send a replacement radiator in a short time, but they are "backordered" right now. Rather than waiting, I removed the radiator and took it to a shop to have it soldered. I have since re-installed the radiator and verified all is hooked back up. Now I refilled the system with antifreeze, but it will only run for about for a short while before the temp gauge goes up to the top. I attempted to drain the coolant at the water pump, the lowest point I could find, and then refilling the system. It was a little better but still got hot. I am under the impression I have an airlock in the cooling system from coolant being in the lines when I removed the radiator. Is there a right way to remove any potential airlocks in the cooling system if they are on the lower end on the engine? Please help. Oh and by the way the Komoto appears to be basically a Roketa Bali type setup, body, engine and all. Thanks

[donroketa]

I am having the same overheating problems with my new Roketa Bali 250, and suspect an air bubble.
Air will always travel upwards, so perhaps cracking a hose connection might release trapped air someplace, some eariler cars had that problem. I am about to drain mine and refill it, hoping to "burp" the air out in the process.

[jaysinet]

Thanks for the reply. That is the problem, I have drained it at the lowest point, but if you look at the enging there are two lines that go to the engine block, one goes up and one comes back down. I suspect this part of the cooling system to be where the air is trapped, because as I drain, this is appearing to be the hardest part to get the coolant out in it's entirety. I was going to crack hose clamp off alittle too and see if I could get some to release and possibly eliminate the airlock. Is there a better way to do this with this particular setup though? I know some snowmobiles have an actualy bleeder type valve for this exact problem.

[scooterollie]

Jaysinet;
Welcome to the "Dawg Pound"!

I am not familiar with that model. Is it a scooter? Can you post a link directly to it?

Below is a link to Stan Jessup's website and information from Baron on how to fill the cooling system on a scoot with a CFMoto engine.

www.oregonvintage.com/Coolant.pdf

[jaysinet]

Thanks Scooterollie, the link you provided is exactly how I have tried to do it....the problem is, no matter how far or long I run it and refill it, it still only runs a short bit and then begins to get very hot on the guage to the point of the light coming on. The CF Moto engine looks similar but does not appear to be the exact same. I bought it at MotoXtremes.com and they have the pics on their site. It is the K1 Sport 250 cc.

[monty57]

I have not read the web site listed so this may be a dumb questions but you say "no matter how far or how long i run it". The way I did mine was with the soot on the center stand I started the engine with the radiator cap off. When the engine warmed up a revved it a bit and the water level goes down in the radiator fill. I topped it off and repeated the process until it no longer went down when I revved it.

Maybe this will help (I hope).

[jaysinet]

Yep, that is exactly how I have been trying to do it. I rev it up and it goes down, do it again, and again until it no longer goes down. Then we run it and after a very short time of driving it the temp gauge goes way up and the light comes on. I then bring it back and check the coolant level and it shows full. I have to believe this is an airlock issue, but I am open to suggestions. Thanks

[jaysinet]

Oh and by the way, the site is actually www.motorxtremes.com not the other one. I didn't realize there are two with almost the same name.

[MLN]

I've worked on some difficult to bleed dirt bikes and street bikes. Here is something that is very simple and will usually net progress.

With the engine off lean the scooter over to the side slowly. Sometimes you have to nearly lay it down. Do that in both directions. You may hear the water rush around inside the lines/engine. Burp it and refill a couple times until it is full.

If it doesn't work with the engine off try it again with the engine running. BE CAREFUL if doing it with the engine running. It would be easy to twist the throttle and launch your scooter. Two people would be best. Obviously you won't be able to hear the burp if the engine is running. You'll just have to check the level to see if it helped.

[90GTVert]

It sounds like you have tried all of the common methods of getting the air out of the system, but with limited results. So, at this point, I would remove the thermostat and put it in boiling water to make sure it's opening. Sounds like you might have a bad one. Still could be air, but that's pretty unusual given what you have tried. Also, make sure your fan is actually cycling on like it should when the temp gets up. The fans they use aren't always the best, so you may also have a problem there. Stan

[scooterollie]

jaysinet;
Have you ever heard the cooling fan come on? If so, where is the heat gauge when the fan comes on. Does the fan run for a period of time, with the gauge dropping some, then go off? You may just have a heat gauge that is not calibrated properly - a common malady on Chinese scoots.

[jaysinet]

yes, the cooling fans do both come on, they don't come on until the gauge is right at the top and run a short bit and eventually cool it back down to the light going off. But it is constantly getting hot and staying near the top of the gauge. Is there a way to calibrate the heat gauge or do you have to buy a whole new heat gauge and this one is just dysfunctional?

[90GTVert]

You need to determine if the gauge is actually the problem before messing with it, but who's to say a replacement is any better than what you have now since this is a common issue. Test the thermostat, then see if you can get some actual temps at the cylinder and at the radiator surface. This is easy to do if you know someone with a laser thermometer. Your cylinder temp may be just above 200* which is normal. If it is, you can adjust the needle on the gauge, just like with a speedo, but, make sure there is no cooling problem first. Stan

jaysinet said:

yes, the cooling fans do both come on, they don't come on until the gauge is right at the top and run a short bit and eventually cool it back down to the light going off. But it is constantly getting hot and staying near the top of the gauge. Is there a way to calibrate the heat gauge or do you have to buy a whole new heat gauge and this one is just dysfunctional?

[jaysinet]

okay, I'll keep tinkering with it....For what it's worth my temp gauge is digital at the dash, I assume since you said to adjust the needle if necessary that there is another gauge related to temp, or at the motor end of the temp gauge cable/wiring is there an adjustment??? Thanks for all the help and suggestions.

[scooterollie]

Jaysinet;
On a digital gauge, no adjustment. Sorry, in your original post I missed the mention that it was like the Bali. Is it a CFMoto/Honda engine or a Linhai/Yamaha engine? The CFMoto has the water pump on the lower right side of the engine and the cylinder is vertical, with a slight rearward slant. The Linhai engine has the water pump on the lower left side of the engine and the cylinder is more horizontal, facing the front of the scoot.

[monty57]

Those infrared temp gages are available at Sears for about $80. You simple aim it at the engine and it will read the temp. If you find your temps are OK you may correct the problem by changing the temp gage sending unit.

[donroketa]

I have one of the Craftsman ones, but Harbor Freight has theirs on sale usually for
$9.99, works just as well as my Craftsman one.

[jaysinet]

it has the water pump on the right side with a vertical cylinder

[scooterollie]

Jaysinet;
Guess you need to do the spot check with an infrared thermometer to determine whether or not temperatures are within range. If so, you could try replacing the gauge or just living with the problem, knowing temps. are really OK in the cooling system and engine.

[jaysinet]

okay, I will continue with my efforts. Thanks to all that have responded.

[donroketa]

I think my heating problem may be fixing itself. I have about 60 miles on it now, and it seems to be running cooler each time I take it out for a drive. The coolant has not gone down any, and I have not got it changed yet either. Could be just a tightly assembled engine needing to be broken in some. I know it sure is running smoother in that short amount of driving it.

[scooterollie]

Don;
I would drain, flush and replace that coolant right away. The stuff they put in there doesn't seem to have any corrosion inhibitors and corrosion may already have started, partially blocking passages or causing the thermostat to stick. The scoot doesn't have to sit for many weeks before the damage begins. I have experienced this problem in both of my water cooled Chinese scoots, including my newest, the Linhai SS300.

I add 2 ounces of a product by Royal Purple called "Purple Ice'. This product and one called "Water Wetter" are widely used in the racing industry to improve heat transfer between the engine and coolant. You know the bubbles that form on the bottom of a pan of water when it starts to boil? These products reduce the bubble formation resulting in more surface area of contact between the coolant and engine and better heat transfer.

[monty57]

Don,

Rollie is right on the money again. I changed my coolant after about only 30km and it looked like rusty water. There was a fair amount of solid contaminates that had formed also. I flushed the system with fresh water for about 10 minutes until it ran perfectly clear and put in some 50/50 pre-mixed coolant for aluminum engines. I changed again at about 550km and it was still as clean as when I installed it. That leads me to believe the original coolant had no corrosion inhibitors or they are using some pretty nasty water. In any case I would take the time and change your coolant ASAP. It will probably prevent some pretty serious headaches down the line.

It's your new baby, treat her good!

[donroketa]

Well, I finally got tired of hearing it, so went out and drained the coolant - WOW WHAT A MESS OF CRAP IN THERE!!!!
Mine had no rusty element in it, it was more like black ink! LOTS of sediment, some even grainy black stuff. I suspect left over stuff from the casting or milling processes. I flushed it for 10 minutes or so, then put in fresh stuff and went for a ride. The jury is still out on how much it helped, still getting all the air bubbles out.
I am going to flush it again in a fre more miles, just to make sure it is all gone.
Thanks for keeping after me til I did it!

[scooterollie]

Don;
For both you and your scoot, I am glad you did! When flushing, be certain to run the scoot at idle long enough for the temp. to rise to the point where the thermostat opens, circulating coolant or flushing water through the entire system.

Generally, I change coolant in my vehicles often enough to not need a special flushing chemical. Wonder if there are good ones out there we could use to be certain we have gotten all the corrosion out of our systems?

[jaysinet]

I can concur, that when I first filled it and my father began having problems with it, I drained it and it looked like it had a large amount of black sediment in the coolant. I have since drained it two more times and refilled with fresh antifreeze and now the last time the coolant was clear and green.

By the way for all those interested...Last night I drained at the water pump again. Then I unhooked the top hose on the lower radiator under the seat. I then filled from the front radiator until I had antifreeze coming from both ways. I then continued pouring while a friend reattached the hose and we let any residual bubbles bleed out before we secured the clamp. Last night my father and I went for a ride and the temp did get to the hot side a few times, but the fans would kick in and drop the temp a couple notches and then be okay again. I am beginning to think, either A) i had an airlock and it is better now , or B) as DonRoketa says his has been getting better as he is putting more miles on it. Time will tell I guess. Thanks alot everybody.

[scooterollie]

Almost every one of these water cooled scoots, when working properly, display a different "normal" range on the gauge between when the fan cuts in and cuts out. My Bali CFMoto 250 does so at + or - the 1/2 mark. My Linhai SS300 does so at + or - the 3/4 mark. Others may display as high as the "RED" zone but still be operating at normal temps. You have to do a little sleuthing to be certain.

[donroketa]

On mine the fan comes on at about the 2/3 mark, and stays on until it is almost to the 1/2 mark.
Mine does an interesting thing, as I initially take out, it is normal, and very slowly climbs as I ride, takes 3-4 miles of road driving to slowly creep up to near top of scale. I still got to carry my infared temp gun with me to see what it is ACTUALLY doing.
I am just going to ride it some more for the time being since it seems to be working itself out. Besides, I still got to tighten the steering head bearing before I get it up to any more speed, be sure to check yours, with it on center stand, grab the front wheel and try to shake it from front to rear. A little bit of looseness will create a movement at the tire, and lots of steering slop feeling.
Another cooling issue, does everyones belt drive cover get hotter than heck when driving? Mine does.

[jennings813]

Snap-on sells a coolant system bleeding kit. It contains a cap and funnel system that you attach to the top of your rad filler neck. You add coolant (always use a 50/50 mix) and fill to where the funnel is holding about a pint, start your scooter and let it run. You should have the scooter on level and on the main stand. As the water circulates the air will bleed out and the reserve fluid in funnel will replace it. It work well on my Roketa MC 54 - 250.

[monty57]

I am not sure if I was just lucky or what but after the soolant system was flushed (early) I did not have any of the the issues talked about here with cooling. Even when riding two-up the gage would go the middle and stay there. I never noticed much fluctuation at all. The only time I ever had an issue is when i let it idle for a very long time in the garage. Then the tem p went quite high before the fan finally kicked on. Other than that one time it has always seemed to do the job correctly. The thing that may be a clue here is the radiator location. The Roadrunner rediator is located directly behind the front wheel. i have heard that some of the radiators are located elsewhere under the scoot.

The Majesty I recenly purchased also has the radiator located behind the front wheel. Even in the 104+ temps we have had recenly it goes to the middle and stay there. I rode the Roadrunner for a short distance over the weekend in the 100+ heat and it did well also. Right to the middle of the gage and there it stayed even under some pretty hard riding.

I guess what all this leading too is there a dependabilyt issue with the Thermostat, fan switch or sending units that are causing the iractic issues some guys are having?