I just aquired a 86 vfr750 and am toatly stoked my dad came through with the toatal hook up. My question is this, the bike idle would stick at about 5-6000 rpm when comming to a stop after ridding, well we thought it might be a vacuum leak so we went through and replace the rubber nipples that the previous owner had put on after removing the smog equipment. After doing that we started the bike and let it get up to temperature, we would twist the thottle getting rpm up to 5500 - 6000 rpm then let off and the thottle would hang at 4000 rpm for a couple seconds then return to 1200 idle. Sorry if this is long and jumbled i am trying to describe the best i can, if I can get any thoughts as to what might be causing this that would be greatly appreciated thanks in advance.
3 things come to mind 1 Sticking cables (lube them) 2 leak at carb insulator boots. (spray WD 40 or starter fluid around see if idle changes) 3. Sticking throttle linkage. (clean and lube)
Thanks for the suggestions i will try those and go from there. Total newb follow up question, but what would make that happen only after the bike has warmed up?
Never done it, but I've heard that when you are checking for vacuum leaks you can open a propane tank slightly (one of the small ones) and hold it near any suspected leaks and the engine should idle up if any propane gets sucked in. Just an idea. Obviously attempt at your own risk.
Bad carb sync. Stuck Choke valve. With the choke off, see if you can push down on the Brass choke valves. If you can, readjust cable. If still happens, clean valves with 0000 steel wool and WD-40.
