Guest Posted February 15, 2014 Posted February 15, 2014 just finished rebuilding my old cbx750,passed mot [no adv] on the way to mot station bike pulled freely until I hit the 5k rev,struggles like hell to pass this mark.doesn't seem to have the umph,after 5k,anybody got any ideas? Quote
rennie Posted February 15, 2014 Posted February 15, 2014 Hello and welcome please say hello in the newbies sectionand put your location in your profile some sort of fuel or air restriction?spark plugs breaking down?Could be almost anything really! Quote
Tango Posted February 15, 2014 Posted February 15, 2014 Welcome to TMBF mate.......as rennie says, please go to the newbies section and introduce yourself to the guys..... Yeah....check that there's no restrictions around the airbox.......especially the air inlet..... Quote
cockercas Posted February 17, 2014 Posted February 17, 2014 You havent got half choke on have you? Quote
Stu Posted February 17, 2014 Posted February 17, 2014 I would be tempted to strip the carbs for a clean up and make sure the jets are clear and also make sure the choke isnt sticking Quote
GazzyG Posted February 17, 2014 Posted February 17, 2014 How are the air inlet rubbers looking? Quote
Guest Posted February 19, 2014 Posted February 19, 2014 ta guys for the info,have checked and double checked the inlet side,no sign of leakage,the carbs I rebuilt with new internals.took the old girl out last sunday[it was sunny and I have the pics, to prove] still the same as first post,back in my bolt-hole found that the two sprockets where new but not original.ie, 14 front 46 rear,will change to Honda:s original and see if that improves??????????? Quote
eastanglianbiker Posted February 19, 2014 Posted February 19, 2014 sprockets shouldnt make that much difference if its not revving into the red line in each gear its not imported from usa or japan is it as they had restrictors built into cdi box check out the numbers on the side of the cdi and if it has 2 plugs both with 4 pins in then i have one here also have the fuse panel that goes over handlebars and coils plus few odd brackets Quote
Mr Fro Posted February 19, 2014 Posted February 19, 2014 If you've checked everything else (don't worry about the sprockets for now) and you've still got the problem then your carbs will be iffy.What does it feel like after 5k? If it's boggy then you're running rich and if it runs out of puff then you're lean. Also, is there any difference from cold to warm?5k+ will be main jets or needle height depending on your red line.Before you start fiddling with jets and such, just double check that they're really clean and dunk them in a sonicator if you can.Ooh, check that you're getting full range of movement on the throttle and that the butterflies are opening all the way (made that mistake before!). Quote
Guest Posted February 21, 2014 Posted February 21, 2014 much appreciation to you all for replying and some ace advice,the bugger is running lean. [ thanks mr .fro ] will put my nose to the grindstone after we beat the French??????????.come on you welsh boyo"s.remember...REALITY IS AN ILLUSION,CAUSED BY A LACK OF ALCOHOL.!!!!!!!!!!!!!!!!!!!!!!! Quote
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