Finding conflicting info on jet needle type, main jet size and float level for 1976 DT400. One example is float level, an all inclusive manual says 17.3, specific manual says 23. Pretty big differences and thought I would inquire to see if anyone has a solid answer on all of the above. All manuals and info obtained from this sight and Yamaha dealer parts breakdown online. Thanks in advance for any help.

Yamaha Service Bulletin also says 23. Lots of errors and discrepancies in Yamaha literature.

Float arms should be parallel to float bowl gasket surface when the needle just closes no matter what the spec says... I learned that a long time ago.

Yes, my head was spinning so badly from the conflicting DT400 carb info I created a chart to keep track of the discrepancies.

I second what Mark T says about the float arm being parallel to the gasket surface, which is close to 23mm.

Hi there Silo7 I have just read your post about conflicting information on your DT 400 1976 bike, I am in the UK and have a DT 400 B 1975 bike imported from the US and I have almost finished a total restoration on it .The bike is sound good engine plenty of compression ,new reeds ,new crank seals, new air filter every part that I could replace I have. I have also fitted a 12 volt conversion from Rex speed shop .The bike now fires up first kick but I am having some issues with trying to get a nice even idle, so I am looking at the carb but like yourself have come across conflicting information regarding float settings and jetting. At the moment the float is set at 23 I have not touched the jets other than giving them a good clean with carb cleaner ,I am not sure what size jets are fitted but I would like to fit the standard jets so that I know where I am at, then hopefully I can obtain a much better idle. Any advice would be great . Many Thanks Peter Wells.

If you do need to replace any jets, make sure you buy genuine and not the rebuild kits. Original ones should still be available from Yamaha or a Mikuni stockist.

Sometimes if the two readings are so far out it could be one of them is float level and one is fuel level. I just hook up a remote fuel tank, like one off a garden trimmer, and connect to carby off the bike and adjust until it is as high as possible turning the carb on an angle each way to see where it overflows. It should be able to not overflow at an angle just more than that when it would be on the side stand.