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Motorcycle News (UK) - - Garage -

Q Why has my trusty FZR400RR packed up?

I have an of­fi­cial UK 1992 Yamaha FZR400RR which was my road bike in the 90s and then a track bike for the last 15 years. The en­gine is com­pletely stan­dard and up un­til six months ago started and ran with no is­sues. Now, when I turn the ig­ni­tion on, it primes the pump and fills the carbs, starts af­ter a cou­ple of turns and runs fan­tas­ti­cally un­til the carbs empty (around a mile of rid­ing) then runs out of fuel. I have changed the fuel fil­ter, pump, re­lay, wiring and checked the float cham­bers are free of de­bris.

Stuart Mur­ray, email

An­swered by Charles Marvell, Fl­itwick Mo­tor­cy­cles If this is a stock RR then the fuel pump is pow­ered from the re­lay via the blue/black wire (the black wire is to earth). The re­lay is switched via the ECU us­ing this blue/black wire so try earth­ing it; if the pump now runs, it sounds like an ECU is­sue, if not the next step is to check for power at the re­lay, but I’d guess this is good, as the pump primes. My thoughts would be a faulty ECU not recog­nis­ing the en­gine is crank­ing and sup­ply­ing an earth to the re­lay. Bear­ing in mind this is a 24-year-old bike, poor con­di­tion wiring con­nec­tors could also be a fac­tor. There are quite a few of th­ese ex-race bikes ap­pear­ing lately, mas­querad­ing as ‘orig­i­nal’. Most of them are hor­ror sto­ries. We’ve got one here at the mo­ment; the carbs were as­sem­bled with sil­i­cone, which dis­solves in petrol and one of the pi­lot jets was miss­ing all to­gether. It was sold to the bloke as a min­ter.

Watch out for du­bi­ous ‘mint con­di­tion’ FZR400RRS

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