Carb question

[Extent]

The accelerator pumps really are only there to keep the bike from bogging down while you're moving and crack the throttle open more.  They don't do anything while the bike is starting or idling, so if you can't keep a steady idle I wouldn't look at the accelerator pumps, it must be something else.

The fuel level in the float bowels should be the same on both, it sounds like you're pretty close, I can look up the exact spec in a bit if I remember.  Whether you've got new or old needle valves doesn't matter, if it's at the wrong level it needs to be fixed.

You might need to clean the carb again.  If it was running better just after you cleaned it the first time but it got worse it sounds to me like a bit of grime that was loosened w/ your first cleaning got out and is now clogging something up somewhere else.

[2002_wrx]

Yeah, that's what I'm wondering...today it wouldn't start again so I'm thinking maybe something else got clogged up. 

When I go to clean it round 2, what else should I do?  I dipped the carbs in Yamalube carb cleaner and tried to get all the passages cleaned out by spraying carb cleaner thru and running copper wires and things thru.  The only thing I didn't pull out were the emulsion tubes - I wasn't even sure if these could come out.

As for adjusting the floats, I'm assuming it will be easier to measure fuel level with the carbs taken apart.  I couldn't really get consistent results measuring from the drains.

Also - probably a dumb question, but are spark plugs for a motorcycle the same size as a car?  Couldn't get my socket to fit for some reason

[fret not]

Spark plugs, there are several sizes.  Different socket for each size.  Get one that fits. ;)

[Extent]

spec is 20mm from the gasket for the drain test, and 36mm from the gasket measuring the float height directly.  both +- 1mm

For your 2nd round just do more of the same.  It's not that you missed anything in your first dip, it's just the softening of the cleaner and the vibration of it being on a running bike again that breaks more bits off to clog up the works.  I just dip, rinse, and spray out everything with compressed air.

[Tiger]

 :) Spark plug socket size for a Vision...18mm

              8).......TIGER....... 8)

[QBS]

Sticking wires into tiny carb passages is generally not a recomended procedure.  Sticking compressed air in, is the recommended procedure.  The emullsion tubes screw out.  Yours are probably plugged.  The float level is best set using the overflow drain spigot and clear tubing process with the fuel petcock set on prime.

[Night Vision]

:) Spark plug socket size for a Vision...18mm

              8).......TIGER....... 8)

a thin wall socket works best

[Cdnlouie]

I'm just going to say this once...there are no shortcuts to cleaning a set of Vision carbs.  Everything has to come apart and be cleaned.  Rust and dirt clogs the passages and results in erratic running.  You must get your tank clean, add a very good filter (finest particulate mesh possible) and then clean the carbs thoroughly as there are no quick fixes (or rarely).  Emulsion tubes just pull out although if they are corroded they require a careful gripping by a good pair of needle nose to get them moving and extract them for cleaning. You don't have much of a lip to grip or try and blow them out with air.

Use a fine stainless steel wire to clean the choke circuit (haven't found anything better to clean corrosion in that very fine hole), and make sure you feel it go through the hole in the bottom as this can be the cause of poor starting.  Make sure you do the jet in the bottom of the carb below the access screw.

Replace all o-rings on the idle screws and ensure they have the correct spring and washer combo, and there are no o-rings jammed in the passage (again from a past life and don't ask me how I know that happens).

And you need to check all jet types, sizes, locations to make sure someone did not screw something up.  Most carburetors have something messed up because someone who did not know what he was doing got to it in a past life.

Much more could be said on this subject, but suffice it to say it requires a bit of experience or very careful reading of many past posts (and from someone who actually knows what they are talking about).

Good luck  :-\

[Night Vision]

well said

[kev10104]

I would listen To Cdnlouie.

[2002_wrx]

Thanks for all the tips guys.  You're really helping me thru this.

Progress...slow, but steady.  Finished cleaning it all out again today.  Reassembled the bike and with the aid of jumper cables it started right up.  Idled nice and even, all the power is back, no stumble, etc.  It felt great...better than it ever had before when I took it on my first test ride.  However, once the bike started warming up I started getting a little bit of trouble.  I think some of it may be attributed to a semi-dead battery as it hasn't been charged all the way up in nearly a month.   

After fiddling with things a bit, I got some consistent behavior out of the vision.  It will idle on it's own no problem at around 1300ish rpm.  It will even rev to redline smoothly and everything sounds and feels right.  However, if I really punch the throttle, it bogs and almost dies.  It never really stalls out, but feels like it almost does.  However, if I more gradually crack the throttle, it feels fine.

Now, I haven't properly synched the carbs yet.  I basically just used the same settings for the throttle linkage, and have the idle mixture (the ones on the bottom right of the carbs on the left side of the bike) turned out somewhere around 2.5 turns.  Is this bogging due to a poor synchronization?  Or is it likely something more than that?  I'm just wondering if I'll need to tear it all down again and do some more cleaning. 

Thanks everyone  :)

[Night Vision]

.....everything sounds and feels right.  However, if I really punch the throttle, it bogs and almost dies.  It never really stalls out, but feels like it almost does.  However, if I more gradually crack the throttle, it feels fine.

Now, I haven't properly synched the carbs yet.  I basically just used the same settings for the throttle linkage, and have the idle mixture (the ones on the bottom right of the carbs on the left side of the bike) turned out somewhere around 2.5 turns.  Is this bogging due to a poor synchronization?  Or is it likely something more than that?  I'm just wondering if I'll need to tear it all down again and do some more cleaning. 

your next step is to sync the carbs... after that, throw one of these digital tachs on it to fine tune the "mixture screws"

http://cgi.ebay.com/ebaymotors/Hour-meter-tach-sx-KTM-exc-mxc-xc-mx-sxf-250-450-525-65-_W0QQcmdZViewItemQQhashZitem56403a8b87QQitemZ370444766087QQptZMotorcyclesQ5fPartsQ5fAccessories

[Lucky]

NV beat me to the punch, but yes, now that you have it running, synq the carbs. don't worry about the bog 'till you have the carbs dialed in.  also, keep in mind that carb synq, pilot adjustment & idle speed are all interdependent.

go slow, make incremental adjustments, not 1/4 turns at a time.

as far as the bog goes, do you have the updated carb/flapper?

reving under no load conditions will make some of these bikes bog.  there are other things to consider such as amount of engine wear, valve lash, etc.  allways check your progress with a test ride.

put a meter on your battery, what's it charging @ 2500 rpm?

[2002_wrx]

Night Vision -    hehe...sorry for my lack of correct terminology.  Haven't really taken the time to learn the names of everything.  Are these just the pilots?  Or am I throwing out random words I've seen in posts?   ;D

Thanks for the link; I'll get hold of one soon.



Lucky - I'll check what the battery's charging at next time I get a chance.  Think my roommate has a meter - if not I'll swing by the store and pick one up soon.  Yes, according to my understanding I do have the updated carb and the airbox flapper.  

[Cdnlouie]

Sounds like you got something happening there.  The only thing I will add as a thought to these previous good thoughts is that you might need another half turn or so on the rear carb mixture screw (out).  I have found that the rear cylinder seems to enjoy more turns than the front.  If the idle goes up as you turn it out, that's generally a good sign, if not, leave it where it where you have it.

Getting the mixture screws dialed in really depends on getting the bike running decent enough to idle at a proper rpm otherwise it is very hard to tell if you are improving the setting or not.  Getting the carbs synchronized really works hand in hand with this setting, but you have to start somewhere.

Also, spray a bit of carb cleaner around your throttle shafts to check for vacuum leaks (Ie. change in rpm) as that will tell you if they are leaking and leaning out your mixture.

Oh...and check the acclerator nozzles for shooting down the barrels without hitting the throttle plate.  They should just skim by the plate as it opens as well as clear the side of the carb body.

Sounds like you are having fun!