www.zxrworld.co.uk

Hi all I have an L9 zxr400 that as soon as I put it in gear and try and pull off it bogs and cuts out. It will rev freely in neutral.
So far its had
-new battery
-new coils and leads
-new plugs
-tank cleaned and sealed with an epoxy rust sealant
-new fuel filter
-new fuel pump
-cleaned carburetors and rebuilt with new orings, floats set to 11mm, mixture screws all 2 turns out and all butterflies balanced.
Bit lost as to why it wont work, there is a slight hesitation on the revs and a they hang very slightly though it will rev freely through the rest of the range after 2k rpm when out of gear and stationary. Main problem when I put it in gear and try and pull off it will only rev to 4k and after I hit that it will bog badly and slowly die off.
If there's anybody can help or give advice it would be much appreciated.

Just a suggestion. Measure the compression figures for the four cylinders. They should be reasonably similar, and above 120 psi. Any significant discrepancy between cylinders, or a lower figure could explain why there is insufficient power to move the bike above 4K revs. Under no-load conditions it will rev freely even with poor or indifferent compression figures. Do post your findings as other ideas might be suggested. The bike is now 25 years old and, dependent on mileage, may need an overhaul.

Read the post "Bogging when in gear" for more suggestions.

Sorry. The post I meant to suggest was "Bike stopped revving after sitting for two weeks". It has similar symptoms to your situation.

Thank you, hopefully shouldn't need an engine rebuild as its only got 3k miles on it but im going to double check the petcock and then do a compression test and ill post the results from that.