Coolant Loss

[GMP]

OK guys, I've been around these bikes and others for a long time and this is a first for me.

Quarry Run in Hancock Sunday, lots of big hills, mud, what I would call high intermittant engine loading. Bike ran great most of the day, pulled the hills clean and kept ahead of a friends KTM 300. Jetting is good, no issues. After about 85 miles bike starts to rattle and surge a bit when throttle chopped, like its going lean. I think fuel so I check, crack tank cap for vent, tweak air screw, all to no avail. Now I think maybe clogged pilot but odd because of filter I added, or maybe bad gas at last stop(station). Hit the road and head back to the truck, bike seems hot but runs OK on the throttle, and will settle into an idle after surging a bit. Shut it down, get changed, let it cool, and check coolant. Almost NONE! WTF?? Never saw/smelled any coolant steam, neither did friends close behind me. A KTM250 in our group boiled and the cloud was obvious as you would expect. Now I'm concerned that the new motor is damaged, being run 5 - 10 miles with no coolant. Scrubbed it down good last night. Compression tests like it did after break in, 180 PSI, good! Pull the top end, looks like new! Lots of red Amsoil over everything and no evidence of coolant in the crankcase. Inner head oring just a little sticky and distorted from heat but not bad. Trans oil fine, no coolant. No evidence of all the coolant blowing out the line on the front of the cylinder, like you can usually see, as glycol leaves a residue. Just dry here like nothing happened. So, this leaves an external leak somewhere. Everything looks fine on the rads and hoses, plus the rads are well protected. Now I'm thinking maybe the cap is bad and just leaked slow all day rather than dumped alot at once. Has anyone ever seen this? I'm going to pressure test everything, and send the head to Ron while its off. I don't want to put this together and ride it without an answer.

 

[Neil E.]

The only way a leak would go unseen is if it was one of the factory hose clamps low down on the motor. It could weep steadily and lose coolant on a hard ride. Might not show up when covered in mud.

Any air trapped in the motor might give you a false read on the coolant level. Did you have a look at the impeller yet to see if it's OK?

 

[GMP]

One of my thoughts exactly on the clamps. I always change them to worm clamps first time the hoses are off. Will check pump tonight, better not be a left over old stock plastic impeller. Just grabbed everything I need to pressure test rads, hoses, and motor itself, but I doubt it leaked into motor. Crossover tube welded through frame is another question, but it didn't leak a drop during the national a couple weeks ago.

 

[Jakobi]

Spooky. It did have coolant when you started the day right?? hehe cheap shot!

If its an external leak it'll become well obvious as soon as you pressure test the system. I'm surprised someone of your caliber doesn't have a leak down tester made up Glenn.

 

[GasGas]

I had a clamp let go at the water pump on my 125. New piston and a hone and all was well with the world. Did it stick a ring Glen? If it didn't seize. hopefully all will be fine. I wonder if the washer on the coolant drain bolt failed? Very easy to over tighten and split.

 

[Simmo737]

I had a similar issue that was a capillary leak from damage that pushed the rad rearward causing rubbing of left bottom tank on the starter. The guy whom fixed the rad (vv knowlefdgeable biker type dude covered in tats, always confidence inspiring....?!) said they are a good rad unit but press fit can have problems occasionally. He was confident after a pressure test that mine was purely the rubbed capillary leak and it's been good after being burped. Hope that helps in some way.

 

[GMP]

Ok guys get this. Configured a pressure test setup to test the motor (with cyl removed) and each rad including hoses separately. For the motor I plugged the two cylinder coolant ports, the water pump inlet, and pressurized the other side. It would hold 2 bar forever, so far so good. For the rads/hoses I plugged the engine/head side hose ends with 3/4" pipe caps, and pressurized through the frame tube side of the crossover. Right side rad fine. Left side rad would not hold any pressure, and would bleed to zero through coolant drain/vent line. Removed and reinstalled cap, a little better but still no good. Tried known good cap from the '07, better but still a slight leak. WTF? Inspected the rad neck surface and found that the coating they use was very rough in this area, like speckel paint. Fine for the outside but no place on a sealing surface. Cleaned it up with a flat blade screwdriver and buffed out with Scotchbrite, easy. Tried again with stock cap, problem solved! I will change cap anyway as you can see where the rubber has taken a set over the irregularites. It leakes at different rates depending on how the cap is positioned. So, my thought was right, it must have leaked out slow over the ride, never building pressure or steam, so it went undetected with the mud and rain during the day. The bike got hot from lack of coolant, it did not puke its coolant from getting hot.

Rings are fine, piston fine. I removed the rings and there was no burned oil deposits in the lands. It really is amazing, the moly coating is still all there and it almost looks like it came from the box! My belief in Amsoil Dominator, and at a 36:1 ratio which many scoff at as being too much, is highly reinforced. That oil did not burn, it was coating everything. The hell with spooge, let it spooge, spooge is good. Change silencers not oil ratios and jetting.

The head is going out to Ron today while its off, 2mm(edge) - 3mm(center) squish. Really? Maybe this has a lot to do with my jetting being different than my '07. And this is with the stock single .5mm base gasket, a new metalized type I have never seen before.

 

[gasgasman]

And this is with the stock single .5mm base gasket, a new metalized type I have never seen before.

The PV covers and clutch side cover replacement gaskets are the those also, even for the older bikes. I did a top end on mine last week and got the metal sandwiched gaskets.
Way better IMO. Won't squish out of position.

 

[GMP]

It looks like you could almost reuse it, no distortion or compression lines.

 

[GasGas]

Let us know how the head mods work out. I would like to get mine done this winter.

 

[Jakobi]

Nice find Glenn! Love seeing threads where an issue is presented and a conclusion is posted. This site is filled with them and is what keeps me coming back for more!

Great news that the piston and rings have come out fine. A true testiment to the quality of the lubes and durability of the engine. Things could have been much worse although it would be fair to consider that would be covered by warranty, its still a pain.

That sounds like a pretty typical squish measurement for these bikes. I don't know if I've heard of anyone having one under 2mm from the factory yet. My RHS pri drive gasket is one of these metal gaskets, but rest have always been paper.

 

[GMP]

So tonight I put the top end back on minus head, and figure I'd check the pump impeller. God Damn white plastic impeller! Is this '02 again? We didn't learn? What is in your bikes guys?

 

[Jakobi]

Green plastic one in my 2010.. Shiny metal one sitting in my spares basket.

 

[GMP]

What you may not know is back in '00 - '02, there were failures of the plastic impellers. They softened and separated from the brass hub. There are two kinds of plastic ones used, the greenish is the older kind and the white the newer kind. This was changed to alloy soon after, in '03/'04 I beleive, and it was one of the improvements noted for that model year. This prompted Les at LTR to start modifying Honda CR250 impellers as prototypes and then had a CNC pgm made for a run or two of a GG specific impeller. Now there is the Checkpoint impeller which I suspect is the same, I ordered one for $50. So, why are we back to using these old parts that have proven to be unreliable? Whats in my '12 is EXACTLY what I pulled from an old bike years ago that I still have in a parts box. I have ZERO faith in this part especially since it got hot. Jake, your impellers are backwards, the alloy one should be in the bike not the box.

As far as the squish, it was 2mm at best, just hit 3mm at the edge of the band/dome, so the MSV (mean squish volume) is huge. My '07 was not this loose, in fact neither was my '03. I'm expecting a noticable improvement.

 

[blitz11]

So, why are we back to using these old parts that have proven to be unreliable?

Accountants. How much more to cast up an aluminum impeller vs. molding a polymeric impeller? Very little. I don't get it either, but at least Checkpoint will make some money.

 

[GMP]

The stupidity in this is the lack of consideration how much damage in reputation will be done if one of these things fails and toasts a guys bike. Its not a known good or even an unknown, its a part that has been known to fail and was replaced. This is the kind of crap that makes them take a step back for every two foward.

Notice the edges of the vanes, they were contacting the cover. Heat distortion, expansion maybe, in any case its outta there.

 

[mcnut]

In a former career I was a Quality Engineer. From my recent experiences, it looks like they could use one.
Coincidently, I am looking for the right job.

 

[gasser]

My 07 bike came with the white plastic impeller which I changed out. I haven't checked to see what my 11 bike has.

 

[Jakobi]

I know mine are backwards I noticed the plastic impellor last time I had the cover off. I had also noticed it had made contact with the cover. I'm pretty sure the dealer had this off when they repaired my kick start shaft as the gasket was not there and they had used liquid gasket instead. When I noticed I had a plastic impellor I then ordered the checkpoint item. It'll be changed out next time the coolants dropped.

 

[GMP]

Its more than that. I've done five and only one came off easy. You should pull the whole primary side cover and retain the shaft from the rear. The drive gear is plastic with slot/pin through the shaft driving it. The bolt can be rusted in the shaft and tough to get out unless its a new bike. Sometimes you have to pull the shaft/impeller and hold it in a vise with soft jaws. One I had to drill off and heat the shaft a bit. Too much potential torque on that drive gear. Hopefully it was loctited, that will keep water out of the threads. Use a stainless button head bolt and loctite for easier removal next time.