▁was ▁returned ▁to ▁a ▁more ▁traditional ▁five - speed . ▁An ▁all - new ▁al umin um ▁single ▁back bone ▁frame ▁sh aved ▁another ▁ 1 0 ▁pounds ▁off ▁the ▁weight . ▁ ▁The ▁ 2 0 0 6 ▁saw ▁K Y B ▁S SS ▁for ks . ▁▁ 2 0 0 7 ▁saw ▁cam sh aft ▁and ▁exhaust ▁changes , ▁moving ▁power ▁from ▁low - R PM s ▁to ▁mid - R PM s . ▁▁ 2 0 0 8 - 2 0 0 9 ▁further ed ▁pushed ▁the ▁power band ▁to ▁mid - R PM s . ▁ ▁Fif th ▁generation ▁Y Z 4 5 0 F ▁ 2 0 1 0 - 2 0 1 3 ▁▁ ▁September ▁ 8 , ▁ 2 0 0 9 , ▁Yam aha ▁introduced ▁its ▁all - new ▁Y Z 4 5 0 F ▁with ▁fuel ▁injection . ▁The ▁engine ▁cyl inder ▁is ▁rear ward ▁sl anted , ▁the ▁c rank ▁rod ▁angle ▁has ▁been ▁changed ▁to ▁provide ▁a ▁more ▁complete ▁comb ust ion , ▁the ▁ 5 - val ve ▁head ▁is ▁now ▁a ▁ 4 - val ve ▁head , ▁the ▁gas ▁tank ▁is ▁located ▁under ▁the ▁seat , ▁the ▁exhaust ▁pipe ▁ex its ▁the ▁rear ▁of ▁the ▁cyl inder , ▁and ▁the ▁air ▁int ake ▁is ▁now ▁in ▁the ▁front ▁of ▁the ▁bi ke . ▁They ▁have ▁a ▁new ▁bi - l ater al ▁frame ▁which ▁allows ▁for ▁new ▁improved ▁ste ering ▁and ▁the ▁new ▁engine ▁components . ▁The ▁entire ▁package