Katana Owners Club U.K.

Hi All

So I was riding my 550 Katana today with the mrs on the back cruising down the a3 at about 80-90 (Yes it dose go that fast ) (Even 2 up)
(Oh and I also set a milestone today and pegged out the stand as we went round a corner )

I can keep this speed up for about 2 miles then It starts to loose power (All the cars that I pass then pass me !.
Oh I think
The throttle has no affect apart from make it worse .I have a moment of clarity and pull the choke out and now it keeps on going but when I touch the throttle it dies again .Then all of a sudden it springs to life and off we go up to 80-90 again .And again it happens .
Now If i Stay at 70 its fine (But that's just to boring and to slow )
So after many miles of trying different variations I finally get a balance .80-90 for 2 miles and then slow down to 70 for a mile and then back up to 80-90 .
But my question is what can cause this ?
My Idea is that the float chamber is running out of fuel before it can be filled up again .This will explain why it can idle but not respond to throttle .But a second opinion on an actual cause of the problem or if someone has had a simile problem

So any help would be gratefully recieved

Bruce 550 katana

check breather in the tank/cap or if you've not got a kinked fuel line... vacuum pipe maybe letting a lil air past and not holding the vacuum.... fuel tap flowing ok?

I would say fuel tap not supplying enough fuel. Do you have a filter inline?


Pete

Fuel supply from tank, not letting enough fuel for flat out riding, that's why racers fit high flow taps.

Just keep it to the speed limit of 70?

Check what sparki says.

check the filter in the fuel tap isnt clogged up..........

as fuel runs out, then air needs to get in, if the breather in the filler is blocked or partly blocked then the fuel just cant get out of the tank. if you can try a diferent cap then just give it a go, or try it with the filler cap loose and see what happens. float heights would mean it loses one cylinder, unlikely to happen on all 4. as has been said the fuel filter in the tap might be clogged, but id check the stuff thats easiest first.

I had the same thing happen to me all the way and back to EuroKat 5. It was the fuel cap. There are two ball bearings (large and small) in side the cap which get bunged up. You can take the inner of the cap too bits very easy and clean it.

I tried with the filler cap open, but It made no difference. Cleaning the cap solved the problem.

Keith

Hi All

Thanks for all the guidance on this .I have inspected this some more an their is a vacuum that is being created in the petrol tank .I have dismantled the fuel cap and removed the ball bearing and the mechanism and blown out the very small hole that is where the ball bearing any needle assemble sit (It was bunged up ). I then left the ball bearing and associated mechanism out and re assembled the fuel can then went for a run .

The first run was perfect 80-90 no problems .2nd run which was a lot longer and faster 90-95 then the same thing happened again .
Home again now and refitted the ball bearing mechanism again and can hear the air pressure being equalized .

Question ? I f i ride the bike without a fuel cap on it or even just over it will i get covered in fuel ?
The pressure equalization hole seems very small .Could I make it bigger ?

Any help will be gratefully received

Thanks

Bruce

The hole in the cap is small, but it should do the job as it did so for 30 years. There's a kinda labyrinth just beneath the black brass cover of the cap which leads the breathing air to the small hole. Saw a cap which was blocked there.
For testriding without a cap I'd go for little fuel maybe just reserve, that should be a safe thing to do.

...and avoid bumby roads, haha.