Need Help Bad News. Figured out today I have blown my headgasket....

R

rcrider

New Member
Country flag
So.. a blown headgasket..
I was riding on the highway stopped to refuel and afterwards bike wouldn't start. Battery voltage was fine, starter motor was spinning but not engaging. Got it started and after 2 minutes check engine light came on. Got home riding over backroads not going over 70. When I got home and inspecting the check engine light and the coolant was very low. Topped it up and started again. (I think starter wasn't engaging due to overheating in hindsight) saw some.faint white smoke and could smell something was off, this paired witht the low coolant level lead me to the conclusion of a blown headgasket.

Bike has 21000 km on it

Now the question is:

Get a garage to rebuild my top end and replace my headgasket. (Does anyone have an indication of how much this might cost?)

Get a DIY gasket kit and do it myself.

I have experience working on 2 stroke engine. I have replaced the pistons and cylinders on my Piaggio APE 50 two times now

(once for performance increase 50cc to 102cc and once because of the 102cc piston overheated as I had driven 250 km that day and the air cooling wasn't sufficient and a piece of it broke off 102cc to 102cc)

however no experience with valves and cams.

Further questions:

-Does anyone have a repair manual for a RC 390?
-What tools would be required for a top end rebuild?
-Does anyone have experience with this and tips to share?

All help is very much appreciated!!
 
Last edited:
1JZSupra

1JZSupra

Active Member
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Mine went at 23500 miles. I did the DIY method. Feel free to hit me up if you want to chat about it.
 
KTMLaos

KTMLaos

Member
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Hi rcrider,

In my experience having repairs done in NL can be an expensive event as labour costs are so high.

My first line of action though is determining if indeed it is the head gasket of perhaps any other cause.

As you have worked on engines before I would also go the DIY way.
It is not too hard, pay attention to what you do and take pictures of the camshaft settings before taking them out, measure and note the 2 in- and outlet valve shims and where they sit.

To make it easier (and if space) take the complete engine off the bike, this gives you plenty of space to work.

Good luck.

Oh b.t.w. Gray Area (US) has Black Friday discounts so a very good opportunity to order the parts you need during their discounting period.

rcrider said:
So.. a blown headgasket..
I was riding on the highway stopped to refuel and afterwards bike wouldn't start. Battery voltage was fine, starter motor was spinning but not engaging. Got it started and after 2 minutes check engine light came on. Got home riding over backroads not going over 70. When I got home and inspecting the check engine light and the coolant was very low. Topped it up and started again. (I think starter wasn't engaging due to overheating in hindsight) saw some.faint white smoke and could smell something was off, this paired witht the low coolant level lead me to the conclusion of a blown headgasket.

Bike has 21000 km on it

Now the question is:

Get a garage to rebuild my top end and replace my headgasket. (Does anyone have an indication of how much this might cost?)

Get a DIY gasket kit and do it myself.

I have experience working on 2 stroke engine. I have replaced the pistons and cylinders on my Piaggio APE 50 two times now

(once for performance increase 50cc to 102cc and once because of the 102cc piston overheated as I had driven 250 km that day and the air cooling wasn't sufficient and a piece of it broke off 102cc to 102cc)

however no experience with valves and cams.

Further questions:

-Does anyone have a repair manual for a RC 390?
-What tools would be required for a top end rebuild?
-Does anyone have experience with this and tips to share?

All help is very much appreciated!!
Click to expand...
 
S

StuffinThings

New Member
Country flag
grayareaktm.store

OEM Cylinder with Fire Ring

KTM OEM cylinder and piston complete with circlip and OEM piston preinstalled. This has thicker cylinder walls then the earlier production equivalent for more durability. Plus we machine a fire ring into the cylinder to prevent head gaskets from blowing ever again!
grayareaktm.store
if you go this route you will never blow a head gasket again
 
R

rcrider

New Member
Country flag
Drianed the bike of it's oil and coolant today first drained the oil it was definitely ready for a change I'm going to order a new filter set for it right away aswell. Put some paper towel in the filter housing and drained the coolant.

Coolant definitely has oil in it, does someone know how I can determine if it's the waterpomp or somewhere else before I crack open the head?

I have attached pictures of the massacre
 

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KTMLaos

KTMLaos

Member
Country flag
To determine if the head gasket is responsible do a leak-down test.
In my experience, it will be more likely the water pump seals have gone rather than the head gasket at 21,000 km but I do not say it can't be the head gasket.
 
R

rcrider

New Member
Country flag
Thanks for the tips @KTMLaos !!
going to start with opening up the water pump

I ordered a bunch of stuff today:

Oil filter and strainer kit
Waterpump seals kit
Front Head Lift Paddock Stand V5 (already had a rear paddock stand)
Motorbike Scissor Lift ConStands Mid-Lift M (for possibly dropping the engine)
feeler gauge set
Torque wrench
Long hex socket set
a new snap ring plier
4L of Motul 7100 15W50
OBD2 Reader
OBD2 to KTM connector
new snap connectors for the bodywork (broke 2 during disassembly)
242 Loctite

The OBD2 reader and connector should arrive by the end of this week. Going to hook it up and see what it says before dropping the engine. Will definitely have a look at the water pump when the kit arrives. Check if it can be the cause of the coolant and oil mixing.

If it's not the water pump ill see what the OBD2 says and keep this thread updated!

I hope I can find out this weekend to use the discount at Gray area if I need to buy more parts.

gonna be ordering the
airbox + injector + air filter
precision Axle blocks
high compression gasket kit (if I need a new head gasket)

The things I would be missing for a head gasket replacement are Loctite sealant for the cylinder gasket and a valve shim set (if I missed anything please tell me!)
 
R

rcrider

New Member
Country flag
Another question:

Is it possible to run the high-compression gasket without any other internal engine upgrades (except the included head bolts)? Or should I just install an OEM head gasket?
 
Kanaloa

Kanaloa

New Member
Country flag
1JZSupra said:
That kind of depends to be honest. Some people advise against running the HC head gasket as it means you run the risk of blowing your HG again. I went ahead and installed it and I haven't had any issues. In fact, it has been running great with the Dynojet WBC2 installed. Here is my build so far:

https://www.ktmduke390forum.com/threads/1jzs-build-documentation-thread.47254/
Click to expand...
That link is a fantastic thread. The pics, lists of parts, steps taken, etc. It’s invaluable for someone like me. Good stuff and very much appreciated. Now how about a link to the Supra?
😉 👍🏼
 
R

rcrider

New Member
Country flag
Back woth another update

I opened up the waterpump and didn't see too much out of the ordinary seals seemed ok and the grease was still there. Ordered some replacement high viscous high heat etc grease before I install the new water kit.

The turbine also looked fine no excessive where or anything like that.

I also hooked up the OBD2 Today and got this message.

Anyone know any details about a P0335 code?

Does this relate to my coolant having some oil in it?

I saw some videos talking about a possible cause being relay no 4 or loose connectors.
Does someone know what connectors this might be?

Will the error dissappear once its fixed or do I need to delete it and run the bike to see if it comes back?


Oil and coolant are still drained and waiting on the grease for the waterpump for reassembly.

I was looking through other threads regarding broken headgaskets and noticed that my engine oil isn't light brown can someone tell me why this might be?

Thanks again for all the replies!
 

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R

rcrider

New Member
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update.....

I was cleaning up and put the coolant in a different container...
It does not look as bad (don't use a blue bucket)

Should be ok then if I reassemble the waterpump refill the system and keep an eye on the level

This is a big fail on my part but also a big relief regarding not disassembling the engine
 

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KTMLaos

KTMLaos

Member
Country flag
I have no experience with a higher compression cylinder head gasket and would like to think that if you are not modifying anything else, as in tuning the engine, it wouldn't make too much sense other than a higher risk of blowing the gasket again.

The code P0335 refers to the crankshaft position sensor and indicates that the OBDII reader could not detect a signal from the sensor.
Not too much to worry about.
Not sure if the code will resolve itself once it detects the sensor but why not delete it as you have the OBDII connected anyway.
If the issue remains it will just pop up again in the next OBDII reading ;)

When your drained oil isn't contaminated with coolant/water you probably have no head gasket issue (although still possible) BUT
- this will mean that oil has been forced through the water pump seals into the coolant.
- you should check your engine case vent to see if this is not blocked, building up (too much) pressure in the oil side of the engine.

If I were you I would drain the coolant again, fill her with distilled water 50/50% and white vinegar and run the engine till the thermostat is open. Let it cool down and sit for a couple of hours then run again till the thermostat is open, let it cool off and drain the distilled water/vinegar solution.
Now fill the fresh coolant (make sure there is no air bubble by opening the purge screw on the top left side of the radiator) and you should be okay now with most of the contaminants flushed out of the cooling system.

I hope the new water pump seals have resolved your issue.
 
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