VFR runninh hot/drinking coolant

Sabre · Post by **Sabre** » Tue Oct 13, 2009 10:48 am

Hey guys my mate has a VFR 400 and its giving a bit of hassle.
It overheats really badly and its basically burning off the coolant.
We drove to Fermanagh and had to pull over a few times to top up the coolant and on the way back from a spin on Sunday there was what looked like steam coming from the overflow pipe.
Any ideas what it is?
Bikes not down on power and runs flawlessly but noone has been able to point us in right direction

Cheers

Post by **CMSMJ1** » Tue Oct 13, 2009 11:30 am

rad cap not sealing...

Sabre · Post by **Sabre** » Tue Oct 13, 2009 11:35 am

You reckon simple as that yeah?
He wants to sell it but this is really wreckinh his head,he was told it might be head gaskets etc etc

Post by **CMSMJ1** » Tue Oct 13, 2009 11:41 am

yep - my FZR racebike was doing the same...I could ont figure it out so got round to swapping the rad cap and it sorted it out.

If the cap does ont work properly the system bols over as the water is not under pressure..hence the constant steam out the overflow even when ti is not even showing as too hot...

get a new cap and it will be sorted..if not, I am a twunt and know nothing...

Post by **abrmoto** » Tue Oct 13, 2009 12:10 pm

I have had a RVF race bike do the sam eas well, worth try on the rad cap, yours sounds extreme but worth a try before try anything else more expensive.

have to agree with make the he is a Twunt.

Sabre · Post by **Sabre** » Tue Oct 13, 2009 12:18 pm

Thanks for all the help lads they said they had put on 3 but the other 2 were off CBR250s so they may not have been good enough to begin with.
Loads of wanna-be mechanics beeen giving him some awful advice on another forum i figured this is the place to be askin such a question!

MexicanGringo · Post by **MexicanGringo** » Tue Oct 13, 2009 5:03 pm

If it were a leaking head gasket youd probably see steam out the exhaust as well

Post by **Neosophist** » Tue Oct 13, 2009 5:19 pm

Sabre wrote:Thanks for all the help lads they said they had put on 3 but the other 2 were off CBR250s so they may not have been good enough to begin with.
Loads of wanna-be mechanics beeen giving him some awful advice on another forum i figured this is the place to be askin such a question!

Pressure Cap Opening;
CBR250(F) + CBR250R(H) : 0.75 – 1.05kg/cm2
CBR250R(J+K) : 0.95 – 1.25 kg/cm2
CBR250RR(L+N+R) : 1.10 – 1.40kg/cm2

The NC30 is 1.1 I believe, eitherway I think the caps were probablly ok. However, it doesn't hurt to try one designed for the bike first.

You'll find a metal tube sealed with 2 o-rings that runs between the V. I had a hairline crack in one of those, only leaked when the engine was warm and the spray was that fine it was very hard to track down.

The part is discontinued too so I had to make my own out of copper tube :)

Worth a check

Dimple · Post by **Dimple** » Tue Oct 13, 2009 7:10 pm

Sorry to just come in but what is the normal temp for the Bike to run in traffice as mine heats up to half and the seat get so hot i feel like my

is on fire

MexicanGringo · Post by **MexicanGringo** » Tue Oct 13, 2009 9:35 pm

Dimple wrote:Re: VFR runninh hot/drinking coolant
Sorry to just come in but what is the normal temp for the Bike to run in traffice as mine heats up to half and the seat get so hot i feel like my is on fire

The rad fan comes on at 98 - 102, so in the 90's is normal operating temp.. "Traffice"... you must be an afrikaans ou then...