Anybody know how the fuel system works on an old tzr?

[simon1221]

Its not as dumb as it sounds.

Fuel tank >> Carb >> Engine

But the problem is that after running for a while at average revs (7 - 8000rpm) the bike just dies and bogs down if you open the throttle.

If you wait a few seconds it will pick back up again but then I just give up and ride slower.

It sounds like fuel starvation but Im curious as to whether it could be something to do with the tank (breather pipes?) and possibly the carb as I raised the tang a little to stop fuel leaking out but it wouldnt cause this completely?

I wuold love to take it apart and see but Im not really sure where to look and its cold in my garage. Any ideas?
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DNA50 (sorry) ->> TZR125l >> GPZ500S

[Barry_M2]

Blocked fuel filter (if you have one fitted)?

Low float height?

[www.125power.com]

Think they are gravity fed, look on your petrol tank tap if theres two pipes on the tap chances are its gravity fed, one will go to carb other will go to cylinder, give the one that goes to the cylinder a suck and petrol should "piss" out of the other one for as long as you suck (use for checking petrol tap works)

Check the float does not stick, and jet jets are clear

Also on some carbs (not sure if this applies to yours) just above the overflow pipe there will be a small screw that controls how fast or slow the carb will "empty" itself if it overfills check it isnt just dumping all your petrol as you wind it on
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[stinkwheel]

[Kickstart]

Hi

If it runs for a while then starts to die I would doubt it is the floats (they just keep the fuel height in the float bowls constant so the problem would occur however long it has been running).

Fairly certain the TZR doesn't have a vacuum fuel tap.

That leaves the fuel tank breather and any filters in the system. You can try riding with the fuel cap loose to confirm / eliminate the breather and see it it solves the problem, but be careful that you do not spill fuel all over the place.

Also consider draining the fuel tank and cleaning out the filter built into the fuel tap (generally a piece of gauze tube the shape and size of a cigarette). Also gives you a chance to check the contents of the fuel tank (and see just how much water has accumulated in there).

All the best

Keith
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[simon1221]

It will run fine at lower revs all day without any problems, its only the higher revs that are the problem.

Il have to wait a while before testing it thought as I only just filled up yesterday

This carb has some sort of drain screw but it is stuck solid so thats a no go.

Cheers for the help I will test it in a week or so when there is less fuel in there.
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DNA50 (sorry) ->> TZR125l >> GPZ500S