Loosing all my coolent

[banoffee]

was it a brand new OEM NC30 rad cap?

[GCD]

Thanks Kav. Oil looks fine, but there could be some wear on the radiator neck. I just figure it is the low pressure caps as it only starts playing up when its being asked to work a bit harder.

Cheers
Glenn

[jacknell]

Thanks Kav. Oil looks fine, but there could be some wear on the radiator neck. I just figure it is the low pressure caps as it only starts playing up when its being asked to work a bit harder.

Cheers
Glenn

Try this...
One crude way of trying to solve the cap and radiator fit is to bend up the lips a little bit on the cap. this will make the cap a tighter fit. Hopefully it might solve the problem of a worn radiator filler neck.

Also dont over fill the radiator as the water expands when it get hot.

[Neosophist]

Thanks Kav. Oil looks fine, but there could be some wear on the radiator neck. I just figure it is the low pressure caps as it only starts playing up when its being asked to work a bit harder.

Cheers
Glenn

Try this...
One crude way of trying to solve the cap and radiator fit is to bend up the lips a little bit on the cap. this will make the cap a tighter fit. Hopefully it might solve the problem of a worn radiator filler neck.

Also dont over fill the radiator as the water expands when it get hot.

Your supposed to fill the radiator to the very top.

Water boils at a higher point when under pressure, when it does expand, that is what the expansion bottle is for.

Standard Nc caps are 1.1 bar rated. On the race NC30 we raced last year we ended up using TZ or KTM radiator caps as they were rated to 1.2 bar preasure. Also check that the radiator cap seat is clean.

fingers crossed

Did this solve the problem for you on the track?

That sounds like a very bad idea for your situation.


1. Have you checked the water-pump is working ok?
2. Did you bleed the air out of the system to correct way?

You need to fill the radiator to the top, run it on the side-stand with the cap off until the bike gets upto temp.

Snap the throttle to 5000rpm and let it settle, do this 3 more times.

Kill the engine and allow it to cool, then fill the rad upto the very top and replace the cap. (you need to make sure the water pump works first)


Spitting coolant on these is usually either (in commonest to rarest order.)

1. air in system
2. faulty rad cap
3 water pump failure
4. head-gasket failure

[GCD]

Thanks Kav. Oil looks fine, but there could be some wear on the radiator neck. I just figure it is the low pressure caps as it only starts playing up when its being asked to work a bit harder.

Cheers
Glenn

Try this...
One crude way of trying to solve the cap and radiator fit is to bend up the lips a little bit on the cap. this will make the cap a tighter fit. Hopefully it might solve the problem of a worn radiator filler neck.

Also dont over fill the radiator as the water expands when it get hot.

Your supposed to fill the radiator to the very top.

Water boils at a higher point when under pressure, when it does expand, that is what the expansion bottle is for.

Standard Nc caps are 1.1 bar rated. On the race NC30 we raced last year we ended up using TZ or KTM radiator caps as they were rated to 1.2 bar preasure. Also check that the radiator cap seat is clean.

fingers crossed

Did this solve the problem for you on the track?

That sounds like a very bad idea for your situation.


1. Have you checked the water-pump is working ok?
2. Did you bleed the air out of the system to correct way?

You need to fill the radiator to the top, run it on the side-stand with the cap off until the bike gets upto temp.

Snap the throttle to 5000rpm and let it settle, do this 3 more times.

Kill the engine and allow it to cool, then fill the rad upto the very top and replace the cap. (you need to make sure the water pump works first)


Spitting coolant on these is usually either (in commonest to rarest order.)

1. air in system
2. faulty rad cap
3 water pump failure
4. head-gasket failure

Thanks a heap for all the info. I'll work through the list. The oil is clean with no signs of moisture, so fingers crossed on that one. I'll begin by checking the water pump, then the air.

[karl BKK]

i have this same problem (HRC expansion bottle fitted) I have replaced the rad cap but the bike still spits a small amount of coolant when running high RPM's for a lengthy period.
First time round, it spat alot but that's because i wasn't running the HRC bottle dry, so i ran the unit dry and occasionally it will spit some water out.
I have put this down to a faulty water pump now, as i can see the unit's noticeably moist after a lengthy run, so water is escaping from the uni and being replaced with air, thus allowing the system to boil and pushing out some water at high RPMs.

Only problem is finding a water pump out here in Thailand, i assume these unit aren't serviceable?

[GCD]

Hmmm, maybe we will both be looking for a waterpump in bangkok. I do not think it will be difficult to get one, there are plenty of VFR parts around. Try Red Barron, I'll try my guy and let you know how I get on.

I am pretty much loosing all my coolent though. Checked the oil again, there in no water in there, a small oil sepage from the right hand side front cyclinder, but very small. I doubt it is the cause of anything.

[karl BKK]

YEah Red Barron is fairly close to my house, their work is good but too pricey for my regualr pit stops.
I take mine to a big bike shop on the way to Seacon Square, the guys there a pretty switched on and build VFR's from their chassis up on a daily bassis, being an ex mechanic myself i sit and watch them repair my bike for peace of mind.
I know for a fact that these guys will have a water pump or 10.
My bike is going in for new water pipes, a fork ovehaul, head bearings, skimming the front discs, front and rear BT092's (090 are far too soft for my commuting) ouil change and to fix small oil leak from the cam cover after the valve clearances were adjusted last month.
while it's in for that little lot i'll ask them to whip out the water pump and check it, at red barron that little lot would cost at least 5k in labour, i don't expect this shop to charge much more than 13k and that includes labour and parts (260 English pounds for those back home)
Valve clearances, speedo drive and quick tune up on the carbs set me back 800baht last month too (about 16 English pounds) :D

[tayto94]

Just out of interest, are you sure the rad fan is working (could be thermostat or fan motor). . . same issue was happening on a trials bike of mine, bike would boil the colant and spit out the overflow, turned out the armature in the fan motor was knackerd. . . new fan fixed it all. Just something to check before buying new caps

[karl BKK]

Spitting coolant on these is usually either (in commonest to rarest order.)

1. air in system
2. faulty rad cap
3 water pump failure
4. head-gasket failure

5. Cracked radiator core / chaffed water pipe / leaking water seal between the 'V'

Found out my problem was a cracked upper radiator core, it only weeped water when hot and at high rpm's, only then was there enough heat and pressure to expand the crack.
At this point water had expanded to my HRC expansion bottle but instead of the cooling system drawing back the expanded water it was drawing in air from the cracked core, lowering the pressure of the system and thus boiling and spitting water out of the expansion tank.
I'll replace the rad tomorrow and hope that sorts the problem, i'm sure it will because the symptoms i have marry up with this fault i have found......... fingers crossed :)