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Hi Guys

I have an issue which my coolant spills after a hard ride. Normally this thing happen when in sport mode and on trackdays.

What actually happen and any guide to troubleshoot this issue ?

Is the coolant volume more than the max level causing this issue ?

Its normally start spills from the reserve area to the frame area...

thanks in advance :f4:
 

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Its a known problem.
Search in the forum. There is much written about this problem.

But keep the level in the expansion tank at the minimum level.
It is important to get all the air out from the cooling system. I raise the bike up in the front so radiator cap is the highest point and leave it so for a day or two (without the cap) to get the last air out.
 

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As Racerman has stated; When the bike is cold, the coolant level should be at the very minimum mark.
 

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I had this problem on mine and the coolant in the overflow bottle was on the minimum mark when cold. It would overflow when hot but looked like the levels were ok. This was obviously not right as if you lose fluid and dont top up the level has to drop. I found that although the level in the expansion tank was ok the level in the radiator was low. Turned out to be a dodgy radiator cap. It was allowing water under pressure to exit the radiator and fill the expansion tank which was then venting but not allowing water to flow back into the radiator from the tank. I found the centre pin in the cap was seized. Freed it up and now alls well.
 

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Yup, that system should be tight. Any air will expand at a rate that pushes coolant out.
 

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when you going onto the track, just replace the original radiator-cap with a one that holds up to 1.8 or 2 bar. The original one is made for 1.2 bar and maybe it's not the best quality as this happens to many 800 riders.

I replaced the cap with a 2 bar cap from that german online-store (I'm fom Germany) and this one fits well and worked well. It's made for KTM and Husaberg radiators but fits perfect. No more gushing coolant during racing ;)
 

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when you going onto the track, just replace the original radiator-cap with a one that holds up to 1.8 or 2 bar. The original one is made for 1.2 bar and maybe it's not the best quality as this happens to many 800 riders.

I replaced the cap with a 2 bar cap from that german online-store (I'm fom Germany) and this one fits well and worked well. It's made for KTM and Husaberg radiators but fits perfect. No more gushing coolant during racing ;)
Are there any dangers associated with doing this? For either track or road use?
 

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Are there any dangers associated with doing this? For either track or road use?
I just know, that many other riders and tuners upgrate this to an 2 bar cap. So I did the same and it worked for one weekend. I think, the radiator will held 2 bar and the engine, too. That would be not a problem. But the original installed 1.2 bar cap is just too weak. So this is my solution so far. If I have more input, I will post it.
 

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I just know, that many other riders and tuners upgrate this to an 2 bar cap. So I did the same and it worked for one weekend. I think, the radiator will held 2 bar and the engine, too. That would be not a problem. But the original installed 1.2 bar cap is just too weak. So this is my solution so far. If I have more input, I will post it.
ok, cool

Thanks
 

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when you going onto the track, just replace the original radiator-cap with a one that holds up to 1.8 or 2 bar. The original one is made for 1.2 bar and maybe it's not the best quality as this happens to many 800 riders.

I replaced the cap with a 2 bar cap from that german online-store (I'm fom Germany) and this one fits well and worked well. It's made for KTM and Husaberg radiators but fits perfect. No more gushing coolant during racing ;)
Now this is good info, thanks.

Will it hurt the engine or anything just leaving this 2 bar cap on permanently? I mean specifically after I'm done with track for the day and going back to street riding.
 

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that's a good question. you've increased the cap rating from 17 psi to 29 psi. 80%. but everyday use your not likly to see the elevated system pressure like track day use. are you using regular OEM coolant or water wetter ? good luck
 

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Spark not sure how changing the cap rating will affect a warranty claim if something goes wrong but might be worth keeping in mind. if you have a warranty!
 

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After doing a little more research into this, I've decided there's simply no way in hell I'll put a 2.0 bar cap on the radiator. Like lefin said, this is an 80% increase over what the stock engine is rated at. Increasing pressure will put additional wear on the weaker parts of the cooling system, namely hoses. Can you say for certain that the constant tension clamps used to hold the hoses in place are rated for this higher pressure? Can you also say for certain that you won't experience premature failure of cooling components like your radiator?

I won't deny that based on what you've said that increasing the pressure has eliminated the spillage, but a 2.0 bar cap is excessive to me. I did find that the same manufacturer also has a 1.8 bar cap available but for me this is still too high. If I had this issue, I might be willing to increase the pressure just a bit to maybe 1.4 bar, but I think that would be it for me. Let's not also forget that when you increase the pressure on your cooling system that you are essentially allowing the engine to be able to run hotter, and many people here seem to agree that MV engines like to run hot already.
 

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How is it that you are "allowing the engine to be able to run hotter"?
Your cooling system (should not be) is not boiling, therefore raising the boiling point by raising the system pressure does not affect your running temperature......
 

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when you going onto the track, just replace the original radiator-cap with a one that holds up to 1.8 or 2 bar. The original one is made for 1.2 bar and maybe it's not the best quality as this happens to many 800 riders.

I replaced the cap with a 2 bar cap from that german online-store (I'm fom Germany) and this one fits well and worked well. It's made for KTM and Husaberg radiators but fits perfect. No more gushing coolant during racing ;)
This man knows!! Yep this will work and was often done when i raced

The rad cap is normally the first bit to go and the rads, pipes etc will take a fair bit more

My 800 had this issue on a fast track here in England in the summer. I'm not worried as i don't track it much and have a track bike to kill now anyways
 

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After doing a little more research into this, I've decided there's simply no way in hell I'll put a 2.0 bar cap on the radiator. Like lefin said, this is an 80% increase over what the stock engine is rated at. Increasing pressure will put additional wear on the weaker parts of the cooling system, namely hoses. Can you say for certain that the constant tension clamps used to hold the hoses in place are rated for this higher pressure? Can you also say for certain that you won't experience premature failure of cooling components like your radiator?

I won't deny that based on what you've said that increasing the pressure has eliminated the spillage, but a 2.0 bar cap is excessive to me. I did find that the same manufacturer also has a 1.8 bar cap available but for me this is still too high. If I had this issue, I might be willing to increase the pressure just a bit to maybe 1.4 bar, but I think that would be it for me. Let's not also forget that when you increase the pressure on your cooling system that you are essentially allowing the engine to be able to run hotter, and many people here seem to agree that MV engines like to run hot already.
Spark , Silentservice is correct raising the system pressure will also raise the boiling point.the engine shoudn't run hotter because of this. if the others are right and the OEM caps are weak I'd wonder how it would work with a good quality cap slightly increased like the 1.4. sounds like a good place to start
 

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Right..... back to the original problem first.
Your bike should not be pissing out coolant on a regular track day, if it is then either you had the level too high, or your rad cap was faulty in the first place. I've done a track day in close to 40degC temps with Gregostini's F3, and no coolant pissing problems at all.

I would not go from 1.2 to 2 bar, but I have gone from 1.2 to 1.6 on my bike a few years ago, and my bike often sits on the grid at 110-115 degC in summer if we have a race restart.

Although it is true what Chuck said about your bike not running at a higher temp, but if it does overheat at some stage, that's a lot of extra pressure on the system to worry about.
 

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Sort out what is causing the issue. Be it ignition timing, air in the system, or a faulty cap.

I'd rather replace a cap than a radiator.

Learn how the system works.

What you propose is like putting a copper pipe in place of a fuse.....
 

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+1

Sort out what is causing the issue. Be it ignition timing, air in the system, or a faulty cap.

I'd rather replace a cap than a radiator.

Learn how the system works.

What you propose is like putting a copper pipe in place of a fuse.....
Well said, and so true.:)
 

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Thought you'd like that refeerence, Sparky!
 
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