Coolant

[cladoo]

I have ordered the impeller and will change the fluid also when I get the impeller. I will try that before I try the KTM cap. I use Motul MotoCool for fluid, maybe I will get some WW also. Thanks for the tips guys!
Claude

[Brian VT]

FYI: The impeller can be changed without draining the coolant.
Just lay the bike on it's left side (turn the gas off 1st).
This way you could determine if the impeller was the fix. Then you could change the coolant, if desired.

[iancp5]

Originally Posted by cladoo

I rode yesterday, 3.5 hr- 74km ride very technical and lots of climbing. A couple of long climbs my rad overflow was spewing. The other bikes didn't do this at all. Why would mine?

It shouldn't - was it unusually hot? Mine has never overheated or vented more than a drop when I've overfilled but the UK is quite a temperate climate and I've never ridden it over 30 deg. I do run the LTR impeller though.

[cladoo]

No it wasn't hot at all, about 23 C. I hope to get the impeller this week. I have bunch of buddies(8-10) from out of town coming to ride here this weekend so it should be a good test on the impeller.
Claude

[cladoo]

Well I tried the impeller and went on the same trail with the same uphill and it boiled over. The impeller was the only thing I changed so that was not the problem. I am not sure what to try next. Ideas?

[cdn280]

I just changed the coolant on my 300, and it was the easiest change I've done on any bike I've worked on. I did find that leaning the bike over almost 45degrees to the right, and pouring slowly waiting for the burping and bubbles really helped in getting the air bleeded out of the right rad. I first filled it up while upright, then leaned it over right and left and quite a bit of air came out, necessitating a re-fill a couple times. Went for a 40km ride after and the level was fine.
For the record, I used some premixed Honda coolant I had.

[iancp5]

Originally Posted by cladoo

No it wasn't hot at all, about 23 C. I hope to get the impeller this week. I have bunch of buddies(8-10) from out of town coming to ride here this weekend so it should be a good test on the impeller.
Claude

I think you have a more serious problem.

Check the mixture via plug chops. Make sure you haven't blown a gasket or o-ring. If that's ok you must have some sort of blockage in the cooling system - I guess that's a laborious job of stripping the head and all the bits off and checking. Small point before - the impeller is turning ok isn't it? Check it isn't slipping for some reason.

[Eric K]

Claude,

The 2 key things to sort out are 1) adequate coolant flow and 2) adequate airflow through the rads.

1) verify adequate coolant flow - see if the radiators warm up quickly when first warming up the engine. If not, then you proabaly have a coolant flow restriction.

2) adequate airflow – I suggest that you remove the Flatland guards and try it without them. Install the stock louvers. I do not run flatland radiator guards for 2 reasons - they notably reduce radiator airflow compared to stock and they do not provide me adequate crash protection (I badly tweaked both rads in crashes on my ’01 while using Flatland guards in conjunction with GP braces). I now use modified CRD braces and custom sized GP braces. For more details on my radiator protection set up see my reply in…
http://www.gasgasrider.org/forum/showthread.php?t=131

If you really want to keep running Flatland guards, then you could use Evans NPGR coolant. The engine will not run cooler, but you will most likely prevent the coolant loss since the boiling point of Evans NPGR is 400F.

[GMP]

Claude,

I just realized something, you run a Clarke tank correct? Does this tank in any way restrict airflow on the back side of the radiators? Also, what cap do you run? If you don't have the KTM cap get one, unless you go with the Evans coolant then it doesn't matter.

I have had two GGs, and ridden with a number of others in some very technical terrain without problems. Standard coolant, rad guards, stock impellers, stock and KTM caps. 125s to 300s. Mud, steep hills, deep sand. The bikes just aren't prone to overheating. There is something more to this.

[Eric K]

Claude,

Glenn's post triggered a question - what is the altitude where you are experiencing the problem?

I agree with Glenn that the GG 2T are resistant to overheating. However, the only time I had mine overheat with conventional coolant was at 6k ft elevation in hot weather on a steep climb with many tight switchbacks. At this high elevation there is less air density which means less cooling.