The Story Of The Resurrection of Blitsie….

[ClimbingTurtle]

I am not sure if it was mentioned, but have you replaced the radiator cap?

Yup - did that, as well as the seal and the thermostat....

Anyway, rode 10km yesterday before it started leaking water from the overflow....

So, Justin at Motorradtech is getting a call just now.....

[ClimbingTurtle]

Right - after a short 10km ride yesterday, the problem is still prevailing....

So, after a chat with Justin at MotorradTech a few minutes ago - he has offered a exceptionally possible explination - and that is that there is blow-by on the water-jacket at the exhaust valve area, as a result of the head having a microscopic bulge as a result of overheating.....

This would also explain why the coolant is looking "milky" after 85km of riding - its getting pressurised fuel/exhaust fumes pushed into it.....

Now, i did have the head checked originally, and it was found to be OK, so it wasnt skimmed - live & learn I suppose hey?

Anyway - head is coming off tonight.....

Wish me luck!!

[Piet]

Wish me luck!!

Good luck!

[ktmmer]

Silverton radiators can do a test where they can ascertain whether exhaust gas enters your cooling system.

[ClimbingTurtle]

Silverton radiators can do a test where they can ascertain whether exhaust gas enters your cooling system.

Thanks - I will ask them about this too - will post results here!

I just got back from MotorradTech, Justin is pretty confident this is the issue, he showed me another barrel & head of a bike that he has at his shop currently with the same problem.....

If this sorts the problem, I am happy.....

[katana]

I had a warped head on my Rotax powered Pegasso a number of times, but they thinned the head out when they fitted 5 valves in there.  Same symptoms though.  I think you might be on to something.

[Superkazy]

@katana yes he has. Start the bike and ride it a little bit then put on stand and play with your hose 's and wipe it off. Might have a stress fracture. Are those hoses new or used? Are the clamps new or used? Are the hoses placed onto connectors far enough? Are you using the right hose clamps? Are the hoses original or aftermarket?

[ClimbingTurtle]

@katana yes he has. Start the bike and ride it a little bit then put on stand and play with your hose 's and wipe it off. Might have a stress fracture. Are those hoses new or used? Are the clamps new or used? Are the hoses placed onto connectors far enough? Are you using the right hose clamps? Are the hoses original or aftermarket?

Cheers - yes, we went through this process, @Halfdaft and I for about 4 hours last Saturday - the coolant is definitely "leaving" when the engine is under stress ie: when its being ridden (not hard, just up & down the road a couple of times will do it) - it does not happen when its idling on the bench.....
Hoses - we prodded, pulled & wiggled them - they are all in good condition, nice & flexible and have no build-up inside them - used torches to examine for leaks/splits etc.
Clamps - mostly new, some re-used hose clamps, situated correctly and tightened properly - no leaks around he end of the hoses.
Rad has been cleaned of scale, but according to Silverton it wasnt necessary as the rad was pretty clean anyway.

The most probable cause is a warped head, as far as I can tell - we have checked, re-checked & triple-checked everything else for hours!

Off to Silverton later this morning to see about checking the coolant for fuel contamination.....

[ClimbingTurtle]

They need to have the bike running to check the gas levels in the coolant - and as this only happens when the bike is actually being ridden, under "load" and not static on a bench. this isnt going to work - but they were certainly able to advise that the pressure being created in the radiator was 99% likely to be caused by a leaky head-gasket - so this is the route we are going down...

Blitsie as of last night - back on the bench.....

[LoopSoosStroop]

For what it's worth, when my Forester leaked between the combustion chamber and water jackets a fine grey residue could be seen floating in the coolant and at the top of the overflow bottle. Looks almost like flat ash flakes. None of that visible? Maybe because I did a lot of km's like that and it gave it time to form.

[raffie]

CT, the gas check method is very subjective, and often gives a false no fault return.

An old, easy DIY and very reliable trick I use to check head gaskets, is to force compressed air into the cylinder while the engine is at TDC firing stroke. So piston TDC and all valves closed.
If the gasket is blown, even very slightly, air will be forced past the "blow" into the cooling system, displacing a bit of coolant. If the head gasket is blown, coolant will be forced out at the radiator / filler neck. If the "blow" is very slight, the level at the radiator neck will rise / overflow very slowly, leave the pressure on the cylinder for a few minutes, to be sure.

It can be a bit tricky to get it exactly TDC, so try to allow the compressed air into the cylinder gradually, as if the engine is not 100% TDC the compressed air will spin it. Don't leave the tool used to turn the engine on the bolt.....

Fill the radiator to the brim, its best if the system is bled properly as well.
I use a made up pipe with a modified compression tester fitting to force 8 bar into the cylinder.

If the engine is hot when doing the test, the level may drop slightly as it cools.

Hope this make sense...

[ClimbingTurtle]

CT, the gas check method is very subjective, and often gives a false no fault return.

An old, easy DIY and very reliable trick I use to check head gaskets, is to force compressed air into the cylinder while the engine is at TDC firing stroke. So piston TDC and all valves closed.
If the gasket is blown, even very slightly, air will be forced past the "blow" into the cooling system, displacing a bit of coolant. If the head gasket is blown, coolant will be forced out at the radiator / filler neck. If the "blow" is very slight, the level at the radiator neck will rise / overflow very slowly, leave the pressure on the cylinder for a few minutes, to be sure.

It can be a bit tricky to get it exactly TDC, so try to allow the compressed air into the cylinder gradually, as if the engine is not 100% TDC the compressed air will spin it. Don't leave the tool used to turn the engine on the bolt.....

Fill the radiator to the brim, its best if the system is bled properly as well.
I use a made up pipe with a modified compression tester fitting to force 8 bar into the cylinder.

If the engine is hot when doing the test, the level may drop slightly as it cools.

Hope this make sense...

makes perfect sense - and I will see if I can make up something to screw into the spark-plug hole to do this - a good call.

TDC on the Rotax motor is dead easy - there is a bolt-hole at the bottom of the engine casing, once removed and the motor is at TDC, there is a slot in the crank that a pointed bolt fits into and locks the crank in place - so no movement and you know that its exactly TDC to set the cam-chain sprockets.

[ClimbingTurtle]

For what it's worth, when my Forester leaked between the combustion chamber and water jackets a fine grey residue could be seen floating in the coolant and at the top of the overflow bottle. Looks almost like flat ash flakes. None of that visible? Maybe because I did a lot of km's like that and it gave it time to form.

Nothing visible - but then I have only put around 80km on the bike so far - a little over 2 hours riding.
The one thing is that the coolant seems to me to be a little "milky" when compared to fresh coolant, like its a little opaque - initially i assumed this was just calcification coming off the inside of the motor, but now i am leaning towards exhaust/compression gasses mixing in with the coolant......

[Jacobsroodt]

Ai toggie broer, dat jy so moet sukkel! At least you are getting to the bottom of the initial problem.

And I felt despondent when the CRF230F I partly stripped, greased and rebuilt overflows petrol from the carburettor...
I just have to take off the carb and reset the float - I should be lucky...

[ClimbingTurtle]

Ai toggie broer, dat jy so moet sukkel! At least you are getting to the bottom of the initial problem.

And I felt despondent when the CRF230F I partly stripped, greased and rebuilt overflows petrol from the carburettor...
I just have to take off the carb and reset the float - I should be lucky...

yes indeed - it is a sukkel, but tbh, I dont actually mind, as when its sorted, its sorted, and I will have gained a wealth of knowledge that may or may not be useful in the future! I was under no illusions when I started this, but the reward of riding it, even for only 80km, has been a wonderful payoff - the bike is brilliant! Its so light and nimble and easy to use on the tight & twisty single-tracks - I really need to sell the GSA so that I can keep this!

The 2nd aspect is that there are a few niggles that I discovered when riding, that I want to sort out, so if he bike is in pieces, I will get those done at the same time - all small, non-critical things, but stuff i want done.

[Jacobsroodt]

 . So you are still enjoying it.  As much as we enjoy reading and learning from your project

Yes, there is a case to be made for light bikes. I rode a 403kg Harley Davidson cruiser and could hardly keep it upright. Is an adventure bike approaching 300kg still an adventure bike? If you have ridden a GSA in strange places, a blitsie becomes a gift from heaven!

[Superkazy]

@ClimbingTurtle I take it you had the engine apart, have you maybe not properly installed the head gasket? Did you sand both mating surfaces clean and checked the gasket itself before installing as the gaskets can get damaged in shipping. Also used bikes leave the coolant discolored as there is filth/corrosion in the system depending on age and mileage of the bike. But you did say you cleaned the system out. Generally if I rebuild a motorcycle I get the head engineered and is super cheap for the peace of mind and I know for a fact then that the head is perfect before installing. If you are taking the head off check the gasket and both mating surfaces you will see blow by if the gasket has failed or did not properly seal. If you are going to send the head in send the block housing in also with so they both can be decked flat, but you will need a thicker gasket after that as to keep to stock values. But first make sure that this is the issue since this is a lot of PT and cost involved.

[ClimbingTurtle]

@ClimbingTurtle I take it you had the engine apart, have you maybe not properly installed the head gasket? Did you sand both mating surfaces clean and checked the gasket itself before installing as the gaskets can get damaged in shipping. Also used bikes leave the coolant discolored as there is filth/corrosion in the system depending on age and mileage of the bike. But you did say you cleaned the system out. Generally if I rebuild a motorcycle I get the head engineered and is super cheap for the peace of mind and I know for a fact then that the head is perfect before installing. If you are taking the head off check the gasket and both mating surfaces you will see blow by if the gasket has failed or did not properly seal. If you are going to send the head in send the block housing in also with so they both can be decked flat, but you will need a thicker gasket after that as to keep to stock values. But first make sure that this is the issue since this is a lot of PT and cost involved.

I cleaned and sanded (P800 on a pane of glass) the mating surfaces when I originally assembled the motor - but I did whip the head & barrel off yesterday anyway as we are running out of options - results will follow in pictorial format, but i do think there is blow-by on the narrow band between the barrel & the water-jacket, so i ma getting it machined, both the barrel & the head....

[Jughead]

I cleaned and sanded (P800 on a pane of glass)

I have rarely seen that work!  People do not realize how flexible glass is.  It would basically boil down to how flat the surface was that the glass was on.  Any pressure on the glass would have made it conform to whatever it was resting on.

If you used a piece of 50mm thick bullet proof glass you may have better success, but quite honestly, for the cost and time saving, get it skimmed professionally.

[Superkazy]

I'd have agree with jughead on this. This would only work perfectly on certified AAA flat lab Granite used for hand scraping on machinery. Only then would would there be no deflection of the glass when you put pressure on it. By to that extent might as well just send in the head and block. Getting those 2 machined on motorcycles is relatively cheap since the surface being done is small. Since you are sending them in check if you can get a thicker gasket otherwise you will push your values out of whack and can get higher compression or less cc's.