86 vfr750 RC24 performance dropped / timing pickup bumped? clutch slipping & part throttle surge

Hi all. Just got bike back together last week after splitting case to investigate 4th slipping/grinding etc. Found a fork eaten away on one side. Replaced fork and gears from donor bike.

1: Clutch:
I polished and cleaned the clutch slave assembley - everything works well.. I micd the clutch plates and they were well withing spec - So the clutch is still slipping although MUCH less, ive even adjusted the lever to have a tiny bit of play before engaging.. should I change to a mineral oil? Also - is it possible to put a washer underneath the clutch springs to give them more strength?

2: Crank Pickup:
I noticed i must have slightly knocked one of the crank pick ups while doing the job (it was connecting with the round knobs while turning by hand) so gently bent it back, if this is out by a few hairs would it effect timing? If so - is there a way to check the timing somehow? to make sure the spark is occurring at the right time or does the computer somehow do this/correct it somehow?

I will do the valves after a few rides, i didnt even bother really - bike still starts well, but seems to idle worse until warmed up, where prev the rpms between hot and cold seemed alot less..

At part throttle the bike seems to surge slightly, as if there is either a timing, valve and or fuel issue -

3: Also - I have a k&n filter and a bigger exhaust - possible I need to re-jet? And am i correct in noting there are no mixture screws, only the ones that basically open the butterflies?



Any info wd be appreciated thanks!

 

#1 Probably just a bandaid to the real problem, and those 4 bolts can f*up quick if over-tightened and break !

#2 Unlikely a timing prob. If mixture screw passages opr idle jets are partly-clogged, that might be responsible for the surging. Experiment by opening idle mix screws 1/2 turn at a time (3 turns is max) to see if you can reduce surging at part and low throttle.

#3 Idle mixture adjustment screws are inside the middle of the set covered by L-shaped grey plastic caps that shouldn't be removed. Probably can't turn them until float bowl cover is off.

 

hey squirrel, tx fo the reply. I mentioned cleaning the clutch slave as a elimination of a sticking assembley - since it was leaking super slowly as well.. the discs measured correct, no play on basket or side play on shafts, clutch lever not over adjusted and ive read alot of places that using either a (very pricey) dedicated motorbike oil OR a mineral (NOT full synth oil) has eliminated clutch slip for lots of riders. My suggestion for slightly shimming the springs would stiffen them u as many have installed pricey after market springs that are stiffer and thought this could be a cheap mans upgrade - ???

What else do u think would cause clutch slip?

I assembled the carbs without paying att to the mix screws, yikes how do u get in there with bike running? gonna be a tight fit. Ill have to do valves before anything. Can I test the timing with a timing light thru hole?

 

Check that your clutch master is bleed properly, Mine took 4 times to get to work properly. and like squirrel said
be very careful with the slave bolts they strip easier than Kim K.

 

my clutch seems to be pumping fine.. very firm and releases plates. Had cover off yesterday, I think my surging is not perhaps clutch slip after all but perhaps a carb circuit thats possibly blocked which explains why the power keeps coming on and off like the clutch is being half engaged, and why there are some severe backfires on coasting/deceleration -

Set valves yesterday after 200 miles and boy were they tight, poor lady!! Starts and sounds so much better now.

Ill pop em off today/2moro and poke holes with fishing line and spray some stuff thru there to see whats happening and let u all know -

cheers

 

So i shimmed the clutch springs with 5 washers, still feels like its 'slipping'.. Decided to haul carbs out for a second check and of the small jets 3 were blocked so bad I have to brush it out with soft electical wires twisted (3 of them), bike ROARS now and has all her power and performance back. Im still blown away by the power of these bikes - wow,and that gear howl and thump thump idle, everything a man wants imo!

tx for all the input. Ill be removing the washers in due course.

 

good to hear you got it all sorted out