Make your guess

[GT @ oh.]

Alright some of you know the deal with my 82 but for those who don't here it is.    The bike sat for awhile(4yrs.) :-[....... wouldn't start :(........ so I took it to a shop (before I found this site)...... to have carbs cleaned....... they got it running..... but not great......it starts with the greatest of ease and runs fine unless....... you want to romp on it...... then it has nearly nothing above half throttle.....soooo. I would like you all to take a guess as to what is the problem.....and you can't just say dirty carb.....be more percise..ie plugged mains,airs,accel pump,yics leak,boot leak.....one guess per person please ;)......I will be tearing into carbs real soon because I can't take it anymore........not being able to rip it up the tach like before >:(.....now it takes for ever to climb up the r's >:(......and never really gets to the top >:(.....goes up to about 6-7000 r's "ok" but from there it would take a 1/4 mile or more to get it to climb to say 10,000r's >:(....... all at half throttle.     If the bike is in neutral idling it will take full throttle and rev right up to 7'000r's  :o(don't like to take it higher than that at idle)....but as I said when riding it will not take full throttle.....it seems to launch ok..... as I've tried launching it at about 3000r's and it seems if I gave it more it would wheelly for me soooo..... I'd like to hear your guesses and once I tear into carbs I will let you know who guessed right. ;D If you would like more info before taking a guess let me know.... but thats really about all there is to say.... everything is original except spark plugs and oil for the most part.

[Lucky]

your not playing fair, on a 25 year old bike it's often a combination of small things that eat at performance & mask other symptoms.  it's not usually one thing, so your now commited to check each of our guesses & not dicount any of them   ;D

that said, i'm guessing carb synq & pilot setting (as one item, because they are inter-related tuning procedures)

i'd have more advice to add, but i'm only allowed one guess.. 8)

--Lucky

[zore]

Could be anything.  Airbox flapper could be closed and not opening would be one of my guesses. 

[Brian Moffet]

emulsion tubes in the carbs are dirty.  (what the heck, it worked for me  :D )

[Night Vision]

your big fat 120 tire in the rear is squatting down at higher speeds and rubbing against your swingarm which is slowing you down  :o

might as well guess against the main stream so I can win the pool  ;)

[inanecathode]

Plugged mains.

[Lucky]

if his mains were plugged he'd never get into the upper rpms...

[GT @ oh.]

 semi-Plugged mains was my guess too. :-\...which is what I will check second when I start because I can do that without removing tank or carb if I'm not mistaken ???.....Lucky ...I am going to try to see if tweaking the pilot setting does any good.. what a 1/2 turn at a time??? .......but it idles and starts to good for me to filddle to much with the synq plus.... the mech seemed to know about synqing and the pilot settings.....what he didn't seem to know was where the mains and the air jets were :o.....so blocked or replaced wrong air jets ....like what Dave experienced would have been my second guess and is what I would look at next if the tank needs to come off ....then check synq and pilot settings.......but if bike runs differently after one of previous inspections.... setting will be deemed incorrect guess even tho it may need reset........ nice try tho Lucky but even if its wrong ...it may not be.. whats wrong ;D  Brian's guess would seem logical..... but I'm hoping the mech's did what they said and soakd and cleand with air pressure and I don't have to go that deep but if all else fails  :'( ......       I'd be checking the flapper before that tho....... cause he didn't seem to know about that either :o ....and would seem logical. How would you check that? ....I pushed it open to make sure it wasn't stuck....... but how to see if vacuum is working ? ...will it open when reved sitting? can I just unplug line and feel the vacuum to see if its working???   Cracked carb boots seems likely too seeing they are prone to cracking and the carb was removed more than a few times till they could get it to run so who knows.I'll liquid tape  that before I tear into carbs tho thats for sure.       And as for NV ::) the tire was on bike before its long nap and running normal so your guess can be deemed incorrect now :o  ;D but hey maybe once I put this 83 shock on it who knows ;D  

[Brian Moffet]

 Brian's guess would seem logical but I'm hoping the mech's did what they said and soakd and cleand with air pressure and I don't have to go that deep but if all else fails

The emulsion tubes can be reached by pulling the tops off the carbs, They're out there in the open then.  But by then you've already got the tank, the airbox, and pretty much everything else off far enough to pull the carbs.

Brian

[Night Vision]

And as for NV ::) the tire was on bike before its long nap and running normal so your guess can be deemed incorrect now :o  ;D but hey maybe once I put this 83 shock on it who knows ;D   

dang, I should have read the fine print

....If you would like more info before taking a guess let me know....

[ps2/bikevision]

i vote cloged exhaust. Unless you have macs then im wrong.

[Lucky]

it is possable to have synq & pilots off enough to allow the bike to run, but not well. kind of one thing compensating for another.  that's a good example of one problem masking another.

Ina said cloged mains, i said that would kill high rpm,. one or partially clogged mains would allow it to run though. crap in the pilot fuel (under the carbs) is more likely, the holes are smaller, they are at the bottom of the carbs where crap settles.

also, it's probably not something easy to reach, that wouldn't be Vision-like...

you can test the flapper by sucking on the hose. if the flapper moves, it's good.

[kwells]

+1 what lucky said

[Kevin]

Sounds like you are just running on one cylinder.Are both downpipes hot?

[GT @ oh.]

Yes both pipes get hot Kevin.     Lucky.... how many turns might the the pilot setting be off.... I just counterclockwised them 2 turns, backed the idle down (which seemed smoother after turns) and took it for a spin.... some improvement but still not right (was able to give it more throttle) so I backed it another turn listend for change in idle but not much diff.    I'll take it for another spin in a bit .....wanna make sure it will cold start as well as bfore. You are probably right about it being ..easy to get at.. is out of the question

[samsr]

I am going for the emulsion tubes being clogged.  The emulsion tubes have small holes in them which can get gummed up pretty quickly.  The tubes MUST be removed to get them clean.

[Lucky]

Gt:
from an old post of mine:

the way I set the pilots, is that I use 2.5 & 3.5 as starting points if the bike doesn't run.  If the bike runs, then I use that as a starting point.

cap off the YICS

so, assuming the bike runs (carbs installed after rebuilding) get it up to operating tempurature, and adjust each pilot screw, one at a time, first "in" till the bike runs rough, then out till the bike runs rough. set the pilot screw in the center of these 2 points, then out an additional 1/4 turn.

repeat with the other pilot screw.

after setting the pilot screws, synq the carbs & recheck the pilot screw settings, you may need to tweak them.

reinstall the YICS

when your done, take the bike for a test ride & check for a bog. if it bogs a little, turn the pilots in or out 1/2 turn & ride again to test.  sometimes "seat of the pants" gives a good indication of how close you have them.

--Lucky

[Walt_M.]

My guess is that you just don't want to clean your carbs and are hoping there is an easy solution. There isn't. Clean them and move on.

[GT @ oh.]

And the winner is .......Walt  ;D

[YellowJacket!]

Gremlins stuck in  the carbs and chewing on the mains.  ;D

David (needed a study break)