RC51 Forums banner

1 - 20 of 22 Posts

·
Premium Member
Joined
·
1,108 Posts
Discussion Starter #1
So, my projects finished, its just passed its MOT too, so Im well chuffed. Its now taxed, Insured and on a full tank of fuel.

So i thought, time to take this bad boy out. Stayed pretty local, everything fine, running sweet, temperature fine.

Then, I come to a nice long stretch and decide to put the beast through its paces. Next thing i know, the more the revs build up, the wetter my right leg gets!! Pissed off man. The higher up the rev range i went, the coolant was spraying out everywhere! Just like last year!

For those of you who didnt fall asleep during my winter project, I took off both rads and and the overflow pipe, ran a power hose through them to check for blockages.........there were none.

Im at my wits end man!
 

·
Registered
Joined
·
2,186 Posts
That sucks. It isn't too surprising unfortunately. It had symptoms of a blockage/constriction, but no blockage was found in when you checked the rads and overflow. That would indicate there appeared to be a blockage/constriction somewhere else in the system. Since it is on the right side, perhaps some people with good knowledge of the coolant system setup can give some advice. I don't know those details.

Good luck and hope you get it sorted.
 

·
Premium Member
Joined
·
1,108 Posts
Discussion Starter #3
Thanks man, but its leaking out of the coolant lid, which is on the right side. Thats why my right leg got wet, lol.

B4 anyone asks, the lid is the right pressure bar
 

·
Premium Member
Joined
·
4,617 Posts
Could be a bad head gasket causing pressurising of the coolant system? I've seen this before on a car that was badly overheated and losing coolant / Pressurising the coolant system.

Do a pressure test - a special cap is put onto the radiator and pressurised with a pump.
Then look to see if there's any coolant seeping into one of the cylinders.
 

·
Registered
Joined
·
2,246 Posts
Could be a bad head gasket causing pressurising of the coolant system? I've seen this before on a car that was badly overheated and losing coolant / Pressurising the coolant system.

Do a pressure test - a special cap is put onto the radiator and pressurised with a pump.
Then look to see if there's any coolant seeping into one of the cylinders.
Yup seen the exact same thing from the blown head gasket allowing exhaust gases into the cooling system

Can sometimes be hard to detect with a pressure test as it is difficult to replicate the same conditions as a hot engine combined with exhaust pulse through what is sometimes a very tiny break in the head gasket
 

·
Registered
Joined
·
2,246 Posts
Not necessarily. I blew the headgasket on my 1000RR at NSS on a day when it was 105° INSIDE the garages in the shade. On the banking at 160 mph it felt like I was riding in a blast furnace and the engine temp was a steady 245-252°.

I finished that day then went to Barber the very next weekend where it was 135° just standing in the paddock and I completed that day by adding a liter of water to the radiator in between track sessions. The bike ran awesome the entire time and I posted some of my fastest times ever that weekend at both tracks. I just had to make sure I kept an eye on the temp gauge and prayed to the god of gription that I didn't fill a cylinder with water at some point and hydrolock it :D
 

·
Premium Member
Joined
·
346 Posts
Like others have said, it sounds like a classic head gasket weep, I have seen it many times before. Best way to test for it is do a leakdown test on a hot engine. Doesn't always pick it up but most times it will.

Just one other thing to check before that, is the rad cap. You said it is the right pressure, but is it sealing? I have seen ones before which were too short to seal, or had damaged rubber seals. Also just because it is stamped the right pressure, doesn't mean it is. You can check it the same way you pressure test the cooling system; with a special adapter the cap fits into, then pump it up and see what pressure it releases at. Having said that for the cost of a new one, I would by a genuine Honda one and just replace it. Even if it turns out to be a head gasket, I always recommend changing the pressure cap as it will have been overheated and over worked with the gasket failure.

Hope it turns out to be just the cap.

If I wasn't at the opposite end of the country I would be able to help hands on.
 

·
Premium Member
Joined
·
1,108 Posts
Discussion Starter #9
Ok, thanks lads, il start with replacing the cap, cos TBH I've just got it all back together and it's time to ride, defo don't have the time or energy to take it all apart again. If it is the gasket it'll need to wait till the next winter project. Will report back when the cap is replaced
 

·
Registered
Joined
·
729 Posts
If you have an old cap, take the seal off it and use it in addition to the one you are using
it has the effect of increasing the preload on the spring a little, just make sure it is all burped properly and the expansion tank isn't overfilled
 

·
Registered
Joined
·
81 Posts
I've had this on my racecar. Embarrassing as it is, turned out I didn't put the cap on correctly. TWICE.

Check the cap is completely seated and secured properly. Often, it is the simple things that get us.
 

·
Registered
Joined
·
8,663 Posts
If you have an old cap, take the seal off it and use it in addition to the one you are using
it has the effect of increasing the preload on the spring a little, just make sure it is all burped properly and the expansion tank isn't overfilled
That was my initial thought at the beginning of this thread.
Once properly burped, and healthy rad cap, if the overflow bottle is filled past the halfway point, it will leak out while riding.

I sure hope Polarbear doesn't have to dive into the head gasket, but maybe that's it...
 

·
Premium Member
Joined
·
4,617 Posts
Reminds me...I once had the top of a slightly leaky radiator explode on the highway (in a V-Tec CRX). I filled it back up with a 2 litre bottle of drinking water, cruised to the nearest home centre, bought a fibreglass kit and repaired it on the spot, then went to work. :D

Polarbear, I'd keep an eye on your temp gauge. Don't let it overheat and see how much coolant you're losing by topping up. If it's leaking externally, it should be visible with the side fairings off and the bike running (At normal operating temp).
 

·
Premium Member
Joined
·
1,108 Posts
Discussion Starter #16
Looks buggered to me. anyway,will take this rubber off,put it on the old Honda cap and will take it for a ride. Gonna go back to the fast road that it originally gushed out on, cos I can give it full power there. wish me luck
 

·
Premium Member
Joined
·
346 Posts
That doesn't look good!

Good luck with the ride, hope this cures it. I would get a new OEM one if this works.
 

·
Premium Member
Joined
·
736 Posts
Cant tell ya how many bikes i have seen or heard of overheating/losing coolant...and the culprit was the cap. Even when new, they can have just enough of a flaw to cause fits and a new one fixes her right up ;)
 

·
Premium Member
Joined
·
1,108 Posts
Discussion Starter #19
Right, got the rubber seal on the old honda cap and went for a ride. Long story short, i throttled the pants off the RC along the fast road (122MPH). slowed down for the turn off and took a peak at where there should have been a load of pink fluid skooshing out.....................nothing. Squeaky clean, so it worked. Well chuffed cos i never hammer the bike at those speeds normally, so if it doesnt leak when its pushed that hard, then itll never leak.
 
1 - 20 of 22 Posts
Top