Chops banana is dead

[GregMember]

So Chops banana stopped 6kms from Hillend after not missing a beat, it left him looking like

Even an old pro like boulder couldnt massage some life into it which surprised me some

So I took it to fatheads today and we proceeded to diagnose the non starting banana and even after removing the carby and a stripping, cleaning and a rejet whilst apart no joy. The plug was remaining dry? Fathead and I both looked at one another and said valves!
Yes it had closed up one inlet, and done a job on it to boot, the valve is sharp enough to shave with, we dont know why, its only one of the two inlets and it is rooted. The pictures dont do it justice but you can see how sharp the edge is if you look hard enough

You can see the top left valve is sitting further into the head

Sharp edges

Evan after the cones lol

Fatheads head man has broken ribs so how long it will be we are unsure

Why one has worn so much we dont know, there is no dust in the intake or the carby nothing, he looks after any banana that has done 50,000kms + and no dramas

TB

[Eric SmithMember]

I wondered about valves, given there was spark and no fuel. Bit of an odd thing to happen. Any other damage?

[GregMember]

Fixed the pictures ECKS, no other damage, I did the valves when he got it 1100kms before this and the same inlet was tight and I re shimmed it, must have been on the way out and was already into the valve face and seat

TB

[john pavkovicMember]

Sad to hear mate:(

Was Chopper using the Valve addative in his fuel ???

[Eric SmithMember]

Could have been worse then. I have heard of banana’s self destructing, although not usually from valves.

[BillMember]

Got a few ideas why the valves wear out on one side same as the CRF250 (they do it in a short time)I will have to tell you my theory over a few drinks when I see you

[Eric SmithMember]

Nah nah Bull, post em up here!

Are bikes left or right handed? Is that the problem? Left handed bikes don’t last?

[GregMember]

I will look forward to it bull, I have an idea as well, well I know why would like o see if we have the same idea, bet we do :laugh:

TB

[Nick AgainMember]

Care to share said theory/theories?? it’s all interesting ( well i think so in any case??) I’m a tad curious to hear BOTH theories on it? have a mate or two riding these….could be worth the knowledge?

[GregMember]

These dont do valves Husky, dont worry your friends about it, just make sure they do their air filter all the time.

TB

[BillMember]

The problem I believe is that the coolant exits from the r/h front of the cylinder head and there is a large exhaust port blocking the coolant path around the l/h side of the head and this causes a hot spot around l/h exhaust valve which causes core shift and moves the inlet boss off centre and causes the valve to scrape on the valve seat and wear itself out faster
this is just my theory
I have some very simple and cheap ways to test this

[GregMember]

Mine is more direction of air flow based when looking at the flow paths in the head

TB

[DavidMember]

KTM Bull wrote:

Quote:

The problem I believe is that the coolant exits from the r/h front of the cylinder head and there is a large exhaust port blocking the coolant path around the l/h side of the head and this causes a hot spot around l/h exhaust valve which causes core shift and moves the inlet boss off centre and causes the valve to scrape on the valve seat and wear itself out faster
this is just my theory
I have some very simple and cheap ways to test this

No how many people will I have to kill , Bull the words will blow their minds

[Anonymous]

Sorry to hear the flying bannana isn’t a quick fix. It looks like it could have been worse though.

TB is the valve stem okay?

[Anonymous]

What about the the big red beast ?
Had any chance to look at it..

[Author]

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