Wr 400 only starts with hot start and also wont idle at all
Posted July 09, 2015 - 03:30 AM
Posted July 09, 2015 - 04:04 AM
Posted July 09, 2015 - 06:10 AM
It could be something as simple as your starting procedure, or you could have corrosion in the carb creating a rich condition.
Did it ever run will with the jetting you now have?
Posted July 09, 2015 - 07:13 AM
I wouldn't expect the bike to idle particularly well with the hot start pulled, but it should stay running. The single most common reason the older YZF/WRF models start hard is an improperly tuned carb, whether it's set up wrong in the first place, or just worn or dirty. The most likely suspect within the carb is the pilot jet. The metering orifice is extremely small; a #45 pilot meters fuel through a hole only 0.0177" in diameter. If you develop even a .001" film of dried fuel varnish in that orifice, it reduces the effective size of the jet to that of a #39, which is enough difference to have a definite negative effect on idle and starting.
I would start there. Something else that can come up suddenly is a crack or a broken off corner on the vacuum release plate on the engine side of the slide. When that happens the degree and nature of the symptoms the engine will have can be difficult to predict exactly, and they can act in all kinds of odd ways.
Posted July 09, 2015 - 10:03 AM
Posted July 09, 2015 - 11:55 AM
Hi thanks for the replys the bike wasnt getting no fuel at untill I pulled the hot start and it started and then I had too keep the throttle on to keep it running?
All the hot start does is add air.
You need to do a complete service on your carb.
Posted July 10, 2015 - 10:39 AM
The hot start is simply a clean air bleed that bypasses the slide, and isn't any different than very slightly opening the throttle. On the left side of the carb, there is a black plastic thumbscrew knob that raises or lowers the idle speed. Turn it in (clockwise) to increase the speed and see if that helps.
You do very likely have either an internal leak, a damaged VR plate, or a partially blocked fuel or fuel/air passage in the carb, however.
Posted July 10, 2015 - 11:54 PM
Posted July 13, 2015 - 08:30 AM
Not immediately, but here's the actual part number: 3TJ-14562-40-00