rich, lean - how do you check it?

[oldgreyandslow]

sorry to be thick but what is WOT?

[hardnutdvd]

Wide Open Throttle maybe.....

[porndoguk]

Wide Open Throttle maybe.....

[Neosophist]

Well, if you're only getting 25mpg then it will be Rich (using more fuel) rather than lean (not using enough).

I'm surprised it isn't running like total arse that rich though!! (It should be clean and crisp through the throttle range, maybe a slight hole around 6800rpm, but apart from that smooth and sleak)

So firstly.

These bikes are all getting on 20+ years... many numptys have had them over the years who don't have a clue what to do and try to perform 'performance mods' to the bikes engine system, if you want more power get a bigger bike.. these were designed to produce 60hp and anything significantly more is going to cost you lots to achieve... anyhow.. lets not digress too much.

Whip the airbox off, check the airfilter and subfilters are there, that there clean (will cause it to drink fuel) and there standard. Make sure all parts of the airbox including the rubber flap are present, if you head on over to http://www.cmsnl.com you can type in vfr400r3 and find the microfiches to check your bike against (or take some pics if your unsure and people will help!)

When you've checked all this get the carbs off and clean everything and reset them to factory specs as per cammos guide, while working on them work on each one individually to start with (dont' split the 4 carbs, just only open 1 float bowl at a time) check the jets, needles and emulsion tubes are all correct and not worn. Set the float heights too (all of this is easy)

When you have a nicely setup bank of carbs and verfied everything is correct and not missing put it all back together and see how it runs.. people on here will be able to advise you on where to go from there but if you follow cammos guide and everything is correct you won't be far away from spot on, plus it will drink a lot less fuel!

Also check for fuel leaks from around the fuel tap and carbs when your disassembling it, because if it is running that rich and not leaking fuel then it must be runnign like arse.

Anyhow. after you've got it all mint if you want to dial it in fuly take it to any decent dyno (again peopel will recommend) and they'll do the final adjustements and verify fuelling (you will save lots of money and time by having done most of the work youself)

Hope that helps