need some carb help from the experts

sparky22

sparky22

New member
Joined
Feb 21, 2008
Messages
43
Age
47
Location
milwaukee
continuing trying to fix my sled stated here

http://www.totallyamaha.net/forums/showthread.php?t=74285

Anyway, think I found the problem. Took the carbs apart finally and found that a screw under the brass cover on the very top of the carb came off the link rod that syncs the 2 carbs together.

It was screw and nut #42 and #43 on the part list here for a 99 vx500c on the carburator page

http://www.yamaha-motor.com/sport/parts/home.aspx

I notice that this nut must be some kind of adjustment to sync the carbs togeher since it is an odd shape and a different type of screw that the carb on the other side is linked by. Im I right on that?

If so how do I adjust this?

Thanks for any help in advance. Think I can finally see some light at the end of this nightmare finally.......
 
Last edited:
if i am following your question correctly, use those screws to set the slide height so each carb is the same. there is probably a spec for set heigth, i dont have that info available. basically what your doing is raising/lowering the slides to sync at a specified height and locking those screws down.
 
snowdad4 said:
if i am following your question correctly, use those screws to set the slide height so each carb is the same. there is probably a spec for set heigth, i dont have that info available. basically what your doing is raising/lowering the slides to sync at a specified height and locking those screws down.
Click to expand...


You got it. Its hard to explain in words.

Is an eyeball adjustment good enough or does it need to be more precise than that.

Also, how can I stop that screw from working loose in the future?
 
Could be wrong here, but I if I remember correctly, at least on the triples, that screw #42, threads into that rod so really you can't adjust it using that.
 
SXlover said:
Could be wrong here, but I if I remember correctly, at least on the triples, that screw #42, threads into that rod so really you can't adjust it using that.
Click to expand...

You are right that screw #42 goes into the rod but the nut/washer #43 goes on the screw firsts and has kinda oblonged shaped bowl on the bottom of it so turning it seems to raise or lower how the screw seats in the rod.
 
Hmm that sounds a little different than the system on the triples. If nobody has an answer for you tomorrow, I'll pop the tops off the set of triple carbs I have on the bench and see if they happen to have anything like that.

Sorry, I don't have an answer for you.
 
its the same concept as the triples. for starters, use the known good side as a reference and adjust the one that moved to match that same height looking through the bore of the carbs. eyeballing may be close enough, i would use a measuring device for verification. i will check for any specified height in the morning. purple loctite would be your friend here if you can find some. next choice would be blue. those twin carbs are the big brothers to the triples and most theories apply. sxlover- when you pop the tops off your triple carbs, it will all make sense.
 
snowdad4 said:
spec is 1.5mm or .059". kind of an interesting read on the procedure to double check synchronization using a vacuum gauge.
Click to expand...

Where do you measure to get this reading? Guessing the gap between the slide and the bottom of the carb bore????
 
snowdad4 said:
spec is 1.5mm or .059". kind of an interesting read on the procedure to double check synchronization using a vacuum gauge.
Click to expand...


Finally have some time to putz with this thing, You say spec is 1.5 mm, but on my carbs the side that is fixed (not adjustable) is at 2mm. Do I match the adjustable side to 2mm or set it to 1.5 per spec?

Or is there a way to adjust even the fixed side that I am not aware of?

Thanks a ton guys!!!!
 
sparky22 said:
Finally have some time to putz with this thing, You say spec is 1.5 mm, but on my carbs the side that is fixed (not adjustable) is at 2mm. Do I match the adjustable side to 2mm or set it to 1.5 per spec?

Or is there a way to adjust even the fixed side that I am not aware of?

Thanks a ton guys!!!!
Click to expand...


Back off the idle adjustment screw until the fixed slide is at 1.5mm or as close as possible to that, then match the adjustable slide to match it as exact as possible[no matter what the measurement is]. The 1.5mm measurement isn't the critical measurement the matching of the two slides to the same position[measurement] is. Once you get the slides matched then just use the idle adjustment screw to set your desired idle speed and your good to go!

Hope that makes sense!

Bob
 
More Info:

I always check if the carb syncronization is correct by slowly opening the throttle while looking into the carb throats.[may need a mirror for this] As you approach full throttle the bottom of the slides will start to disappear at the top of the carb throats. By watching that they all match the top of the throat and disappear at the same time means you have them synced properly.

Works for Me!

Bob
 
sideshowBob said:
Back off the idle adjustment screw until the fixed slide is at 1.5mm or as close as possible to that, then match the adjustable slide to match it as exact as possible[no matter what the measurement is]. The 1.5mm measurement isn't the critical measurement the matching of the two slides to the same position[measurement] is. Once you get the slides matched then just use the idle adjustment screw to set your desired idle speed and your good to go!

Hope that makes sense!

Bob
Click to expand...

Got it.

Should I use a tiny bit of blue loctite on the adjustment screw to keep it from falling out again?

Thanks for the help. Cant wait to see if I can finally get this thing back on the snow.
 
sparky22 said:
Got it.

Should I use a tiny bit of blue loctite on the adjustment screw to keep it from falling out again?

Thanks for the help. Cant wait to see if I can finally get this thing back on the snow.
Click to expand...

I have never had to use loctite on these...I would just ensure you snug the nut up.

Bob
 
Well I got it all back together and she seems to be running great! Wont know for sure if it is finally fixed till be get some snow for a test run but I think I got it. Hopefully something else dont pop up like I have had a few times already.

Thanks for all the help. Would never have been able to do it without you guys and this saves me a big bill from a dealer.
 
You must log in or register to reply here.


Back
Top