Dies after full throttle run

[The_Hamster]

83 GS450ED

This little guy needs about full throttle to keep up in 130kph traffic on the highway, if there is any sort of hill.

After 30 or so seconds of full throttle the engine dies, no fuel. Let off the throttle for a few seconds and it runs again and stays running as long as you aren't at open throttle.

Is this because of a lack of flow (clogged filter, lines etc), or lack of vacuum at full throttle closing the petcock?

Previous owner added an inline fuel filter. Small plastic UFO shaped one. Anybody know what the stock fuel line size would be on this little guy? I would like to replace that clear yellow stuff with something nicer, and without the extra filter.

Filter and such are in this picture.

[tkent02]

That filter needs to flow enough fuel for full throttle, test it by running it into a bucket. If it doesn't put out a steady stream, it's not enough.
Is the tank clean?
Is the petcock screen in place?
You really don't need a filter if the tank is clean and the screen is still on the petcock.
You could also have a partially clogged vent in the fuel filler cap.

[hzoltaan]

I had similar problem on a old Jawa350. Yhe fuel tank was dirty and I had to unscrew the filter (built together with the cock) and clean it. So it well might be your filter, and I'd test the vacuum screen by riding with opened cock. (mine on '87 GS450 has a stat (maybe PRI) when the screen does not control it. Try it. And I agree with tken02, if the tank is clean, you don't really need a filter.