engine stutter!!!

[2VRoy]

It feels like loss of spark, power wise she seems to fly. The faster you go the smoother it gets, but go slow and it is like a bad case of the hichups. Any ideas!!

[Tiger]

 ??? Roy...at around 4 to 5,000 RPM..... ??? ...or....

[2VRoy]

4000 and fadding out a bit around 6500.

[h2olawyer]

Dirty / misadjusted carbs & maybe leaking YICS.  Those are the most likely culprits.  What you are describing sounds a lot like "Vision Stumble".  That was one of the main reasons the 82 bikes were so detested by the dealers & didn't sell well when new.

H₂O

[Extent]

It's in the right rpm band, but the stumble usually happens when you throttle on fast, and it smooths out when you roll on really slow.  It sounds like his is doing the opposite if I understand right.

[2VRoy]

Carburators were just cleaned, changed several vacuum lines and YICS seems to work fine. RPM drops back pretty good. This stutter is pretty constant all through 1st and 2nd gear, speeding up or slowing down. Fads out around 80 to 90 and stays that way speeding up or slowing along that range. Also just disconected the yellow/black wire off the TCI, for a much better start and idle. Spark plugs are fairly new, less than 100 kilometers, coils are the original 1983's.

This stutter is like a sharp break and not a smooth fad in and out.

[Lucky]

as much as you may hate to hear it, your carbs are still dirty...
did you disasemble them & DIP them? spraying them out won't do it...
the pilot (low speed) jet is at the very bottom of the carb where all the crap ends up. sometimes cleaning the carbs only loosens up some of the crud, the vibration from running the bike later makes the scale come loose reclogging the carbs. often a second (& rarely a 3rd) cleaning may need to be done.

other possabilities:
--crap/water in the tank clogging the petcock/filter/fuel pump/carbs.  a clean carb is of no use if the tank hasn't been cleaned & sealed.
--re-do the synq & pilot screws, they may want an extra 1/4-3/4 turns out (adjust & ride in 1/4 turn increments.)

--Lucky

--Lucky

[Extent]

I'll just tag on to the end of Lucky here, you say the YICS seems to be working fine, but how did you test it?  A leak won't always be very obvious.

[2VRoy]

Thanks, I will take things apart for another look. Trying to get this sorted out, as the "Ride For Sight" is next weekend and I would like to make it the first official ride for this one.

[big_champ]

my friend im having the same problem, from what i have been researching it could be a valve clearance issue. I havent gotten along to try and fix it because I havent done that job before so i wanna be careful and ready before i do.  Let me know if you have checked your valve clearance and i can X that option.  One question i have for you is, does your idle increase after the bikes been warmed up for sometime, up to 2000rpm?

[2VRoy]

My engines valve clearance was checked before I mounted the engine in the frame a year ago. This project has been an on going one, including a relocation. One of my bottom jet was cloged solid and I had a line leak at 25 psi going to the YICS. RPM is now spot on along with the rest of the engine.

[Tiger]

 :) Well done Roy.....another satisfied ROV customer... ;D ;D ;D :D :D ;)

[d0n]

I have the same issue with my 83 V now. Hopefully a carb rebuild will help.

I'm also wondering about putting real quality auromotive type hose clamps on the yics lines. The stock spring clamps don't seem to be the best things for the job.

[Night Vision]

I'm also wondering about putting real quality auromotive type hose clamps on the yics lines. The stock spring clamps don't seem to be the best things for the job.

when I replaced my yikes hoses, the only hose that i.d. size I could find was windshield wiper hose. The rear oem hose had molded angles which are tough to duplicate in a short length without kinking....

....so.... what i did was get a stout spring from home depot that was about the same inside diameter as the hose, had to stretch it slightly.... inserted into hose...

viola... no kink     and the smallest auto hose clamp works nicely too.