950A with a blown headgasket?

So before I get into this any further, I need some sage advice. A few months ago during an 800 mile day my 05 950 started blowing coolant. I didn't realize it at first, only when I got stuck trying to make my way around Atlanta and the temp started climbing did I know something was up.

I nursed it through that trip keeping the revs down and adding coolant each morning; made it back to RVA without any other issues.

So... I was really hoping a radiator cap is all she needed.. new cap and the same problem; blows coolant from the overflow, into the bottle, then all over my leg. Nursed it through another (shorter) trip, but now she's coming apart for repair.

I'm assuming I have a weak head gasket, but I won't know for sure until I pull it apart. So before I pull the heads - Any words of wisdom? If the heads come off new rings and valves will go back in. Does Kibblewhite make valves and guides for the 950?

TIA

Start simple and cheap. Put a new radiator cap on it. If that doesn't work, go from there.

I had an oil leak on the inner clutch cover that caused water to pump into the oil. It was a minor thing, but I ended up doing the top end to find it. New head gaskets require a resurfacing of the heads to do it properly. It can be done without replacing rings if you are careful and leave the piston heads in the cylinders. Some mechanics just pull the cylinders off of the pistons, and then you need new rings. Replace chains, chain guides, and tensioners while you are in there. Some of your plastic chain guides will be worn.

Orangecicle, why would you think that new head gaskets REQUIRE resurfacing of the heads, and why would you think that removing the piston/rings from the cylinders then REQUIREs ring replacement?

As for the OP's question, a compression and/or leakdown test will tell you if you have a blown head gasket, but I'd be sure the water pump seals have not let go, and that the cooling system's integrity has not been compromised first. A leak will allow the system to depressurize, not to mention things like a bubble forming in the rear head due to low levels. Due to the design of the engine, if the coolant level drops low enough, an air pocket is formed in the rear head, which when it gets hot enough, expands and pushes fluid out of the radiator.

Run the bike for a few minutes then pull the outer clutch cover. Got milkshake? Rebuild the water pump. Also, check the oil filter. Wavy pleats could mean water contamination in the oil.

New rings are only needed if the old ones are worn; you can check ring gap for that. That said, if you have high mileage, it's usually a good idea to replace them because they can lose their tension after (quite) a while. The heads/jugs don't need to be resurfaced unless something is warped or has some fairly severe surface damage to it. I think people have a little bit of a misconception when it comes to how delicate a head gasket is, and how perfect everything actually needs to be, this coming from experience as being a mechanic.

How many miles on the bike? I also would look for cooling system problems. You tried the cap. I also find that the symptoms of a leaking water pump (much more common than head gasket failure) are best detected by removing the clutch cover. I'd bet a beer or 2 that the WP is the problem....

First, I said, "New head gaskets require a resurfacing of the heads to do it properly." I stand behind that. If you remove the heads, you will have indentations in the aluminum where the old head gaskets cut into the aluminum. The right thing to do is to just "lightly" resurface those heads. It can be done in any motorcycle shop. Just a light resurfacing to get rid of that indentation is appropriate.

I didn't say that. I said, "Some mechanics just pull the cylinders off of the pistons, and then you need new rings." I stand behind that as well. If you leave the pistons in the cylinders, you can get by without changing the rings. You pull the cylinders (leaving the pistons) and then remove the allen bolts holding the head on. From there, you can change head gaskets without changing rings. If you pull the cylinders off of the pistons by yanking the cylinders off of the pistons (a common mistake), then you need new rings. The bottom edge of the cylinders are sharp and can damage the rings. This I know because I had to buy new rings after a mechanic pulled my cylinders off the wrong way:

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Guys, explain to me how the water pump can over-pressurize the cooling system and blow coolant out the overflow. The bike isn't overheating, just blowing coolant. Mileage is just under 45,000.

What about a Super Duke engine? Drop in and go with some jetting tweaks?

I am trying to resist the urge to say "Right, change the motor out or pull the heads off before you check the WP". WP rebuilds are a well known maintenance item--and 45k miles would be a near record without a pump rebuild. Are you sure the bike is not overheating? You said bike was overheating on your 800 mile ride day. Checked for signs of water in the oil?

WP was done around 36'ish. No water in the oil, no oil in the water. It never overheated, just heated up higher than normal, maybe one bar more.

It's due for an overhaul, it's started puffing a little oil smoke when I open her up (or so my slower GS riding friends tell me ) before the coolant issue.

If I can get away with a SD engine I might go that route. Adding this up in my head with pistons, valves, gaskets, machine work, etc, has me coming close to the cost of a used engine.

Anywhere to look for a used engine other than fleabay? thx

Think I am beating a dead horse here, but....45k miles not typical for a rebuild. Water in oil is what you need to check. Best place is in the clutch cover. Could be a bad WP rebuild, scored shaft causing bad seal...

It's due for a rebuild, no question about that. Two different issues here that are getting mixed 1. engine needs overhaul 2. blowing coolant. I was putting off the overhaul until the 'off' season, but if the heads are coming off, the overhaul will happen.

I'll pull the clutch cover and check the pump before I go any further. If nothing else, we'll make sure the horse is dead.

So here is my water pump shaft. No signs of the seal eating away at it.



No moisture hiding behind the clutch cover. Very small amount of water from the oil tank. Looked more like condensation than a cooling issue.

Any other ideas before I pull the heads?

I just wanna ride. My R50 isn't happy standing in for the KTM.

Did you run the bike for a bit before pulling the outer clutch cover? Reason I ask is if you simply pulled it after the bike cooled down, the "milkshake" won't be there. the water separates back out of the oil and sits at the bottom of the sump.

How's the oil filter look? What about the oil itself?

Classic symptoms of a failed head gasket are bubbles in the coolant with motor running and cap off. Sweet smell of coolant in exhaust. If pump is good, flow should be good looking through the filler. Got time to do a compression check before you tear it down? I am sure it happens, but I don't recall hearing of an LC8 head gasket failure. Did you get it super hot?

My '07 has 35k miles on it. Runs good, no oil used. I won't even be thinking about a rebuild for a long time.

Another thought- better equipped auto shops can test your coolant for the presence of combustion gases. Might be worth a phone call or two.

I just did a head gasket job on my 06 just under 30k. I was on a trip in Baja. Running at sustaind triple digets for hours on end. Coolent started to puke on my right leg. I found a small amount of greyish slugs in my expantion tank. I re routed the over flow line into a coke bottle filled with water. So the over flow tube is submerged. Start bike, see bubbles? Head gasket blown!
I pulled the jugs and head and had them resurfaced, new rings and gaskets.
One cylinder defiantly had a low spot.
Good luck and have fun. The 950 motors are fun and easy to work on once out of bike.

If the cap is removed it's normal to have bubbles in there - as the coolant can boil -> introducing bubbles. So the only easy way to test a blown head gasket is the way CRW mentiones in the post above. BUT: You have to have the cap on the radiator and you have to be sure the cap isn't failing (if it is, it's almost the same as you didn't have a cap on the radiator, as the coolant will start boiling without the pressure valve - which would be the cap)

As it's a 950, it's worth checking that trhe cylinder head nut TSB has been performed. On the early engines there was no washer under the head nuts - the TSB was to fit a washer and a different nut.

When my 950 had a blowing head gasket, the act of replacing and retorquing the nuts cured it.

Some people go as far as to recommend retorquing the nuts at every major service - I'm not sure about that one.

It would be nice to think a re-torque would cure it. I'd be worried the gasket would be compromised and start to leak again when I'm in the middle of nowhere.

I'll pull the motor later today and see what I find. Timing marks on the crank and cams apparent?

Cycletech, pm me your email address I will email you a present(service manual) if you don't have one....