Fuel Starvation ??

[mysticzed]

I've got a Z900 with a 1075 conversion (400 miles since rebuild), standard carbs, bell mouths and Pingel tap.

Fuel pipes from Pingel to carbs have air bubbles which seem reluctant to depart. Some 'light' black smoke from Vance and Hines at low revs.

Bike pulls like a train to 5.5-6k then starts to die.

It feels like:
i) Fuek starvation
ii) Or a tight engine

Any suggestions, additional diagnostics would be appreciated.
Any observations re use of standard carbs vs alternatives also welcome.

Thanks.

[Pigford]

Mysticzed, are carbs on std jetting/set-up
The whisps of black smoke means its running RICH. If it runs OK up to 5/6k rpm, is this on a constant run (over some distance) or just acceleration When you throttle back from6k, does she run OK again, straight way or after a while
Try going at it until it starts to die then slowly wind throttle back & see if she picks up again. Does she clear 6k rpm with part throttle, in other words is it WOT (wide open throttle) that kills her?

[mysticzed]

Hi Pigford, unfortunately haven't had time today to take it out....I haven't pushed it as I don't want to create any problems....will rev freely in neutral.

Always pulls like a train up to 5.5.-6k revs even if you back off the throttle, doesn't matter if its constant or under acceleration.

Get where you are coming from re throttle opening, unfortunately won't be in a position to try this out until later this week

What is the rich running likley to be from...flooding in a carb ?

Thanks for the help

[Pigford]

Could be many things

Hows the electrical side, points? std coils? recently timed, plugs etc. This stuff needs to be spot on first.

[Garn 1]

Myst', when you step up from 900 to 1075, it is usually mandatory that your "standard" carbs are re-jetted, particularly with ram tubes and your V&H 4 into 1. Running on normal setting would conform with your title "starving for fuel".
RegardZ.

[Pigford]

Yeah, what changes since kast running right, are bell mouths new & 4:1

[mysticzed]

Guy's bought bike like this, done 75 miles, haven't taken carbs off yet...will do so this w'end, to check jets, if they are standard how much bigger should I go ?

[rickman CRR]

The bellmouths will be sucking so much air, 130's should do it.

[mysticzed]

Thanks Colin