Throttle springs are wore out.

OK, I thought I had a mixture problem but after taking the tank off and looking at things it looks like the springs that snap the throttle back on the carbs are wore out. Could this happen. How many springs are there suppose to be? If I hold my finger on the screws that adust the throttle and put pressure on them when I snap the throttle, it goes right back down to Idle. It seems that whatever is supposed to bring it back to idle is wore out. Where do I get these springs or how do I make them work better?

 

I would start by unhooking the throttle cable and checking if the cable itself is sticky. After that I would pull off the carburetors to get a better look. Maybe the throttles are sticky or you have broken/stretched springs. If you need springs/parts, then set up a thread in the buy sell and trade section.

 

I put a new throttle cable on last night and it didnt help. I think my springs are wore out.

 

Are you sure that your carbs just don't need to be synchronized? The screws that adust the throttle and put pressure on them when I snap the throttle" adjust how much the butterfly is open. When you put pressure on them, it will close just a bit more.

I'm not an expert here, but it sounds like a synch issue.

 

The throttle-return springs are all external: they are the four large shiny coil springs that you see wrapped around the throttle-butterfly shaft between the carbs. I doubt very much that they are your problem. If by chance you're correct, you get to pull all the carb bodies off the rack in order to separate the carbs to install new return springs.

The big slinky-like springs inside each carb do not "wear out", nor do they have anything to do with closing the four throttle butterflies that are connected to the right twistgrip. They can be damaged through owner abuse (stretched, stepped on, installed dirty...), but failure due to age is highly unlikely.

The problem you are describing may be as simple as properly routing the cable and having the proper amount of play in it.

My guess is that Fraps is right.

 

The rack needs to be adjusted so that the #-3 Carb is closing down ... the 1, 2 and 4 are adjusted to follow the #-3.

Look at the linkage during a Bench Sync. Back-off the Manual Idle Speed Setting Rod (Between #-2 & #-3) ... until the FINE THREADED END is no longer in contact with the small "Platform Area" on the Carb Linkage that it applies pressure too causing the LINKAGE to move.

Oil the fine threads with Light Machine Oil. Put a dab of grease inside the Rubber Grommet Bushing so the Idle Adjustment Rod will turn with ease.

Watch the TIP (The very end) of the Fine Threaded End screw-in and come into contact with the PUSH PLATFORM on the LINKAGE.

The Butterflys should all be ADJUSTED (In Sync) with the #-3 Butterfly ... Closed SHUT -- when the ROD is NOT in contact with the PLATFORM.

As the ROD is turned IN ... The End touches the Linkage and MOVES the Linkage causing the #-3 BUTTERFLY to MOVE.

Open the #-3 ... By turning IN the ROD, until you can slide the diameter of a RED TUBE from a can of WD-40 between the bottom of the butterfly and the carb body and feel the opening of #-3.

With #-3 Butterfly set Open to the diameter of the RED TUBE ... Set - #-4 to the EXACT Opening of the The RED TUBE Diameter, too.

Set 2 - to - Match 3 & 4.
Set 1 - to - Match 2, 3 & 4.

Now, your Bench Synced.

When you do a Vacuum Sync ...

Set 1 to Match 2
Set 4 to Match 3
Set 2 to Match 3 &4
1 follows 2 when 2 is adjusted.
Synced!

 

Well, I finally know what it means to perform a "bench sync"!! I just vacuum sync'd the carbs and everything runs pristine. Is a bench sync just a base point to ensure the bike starts and runs well enough to perform a vacuum sync??

 

Rick,
So, looking at this picture from Alive's post, would this carb be set with the butterfly closed too much? Or, is it going to be closed once done setting with the red tube, but you are using the red tube only as a guage of sorts?

 

That picture is a SYNC Screw ... Not the IDLE Screw.

Between the 2 and 3 Carb ... Above and to the left of the Starter ... is a Knurl Knob-ended Rod protruding from a bracket which should have a rubber bushing surrounding the Rod.

THAT is the MANUAL IDLE ADJUSTMENT SHAFT.

When you turn that KNURL ... you ADJUST IDLE ... because the ROD pushed on a small PLATFORM on the LINKAGE that causes the WHOLE LINKAGE to move.

Look for the end of the rod. The Ultra-fine threads allow micro-adjusting of the BUTTERFLYS.

Lube and exercise the SYNC Screws for critical adjusting.
Back-off the MANUAL IDLE ROD until #-3 is fully closed.
If 1,2 and 4 impede the movement of 3 ... adjust them open and concentrate on getting #-3 CLOSED.

Trun the Rod and OPEN 3 until the RED TUBE slips between the Butterfly and body with slight drag.
Test the Rod to see that 3 will close when the Rod is turned OUT allowing 3 to close.
Yes?
Open 3 and RED TUBE 3
Reset the others.

Manual Idle Adjustment Rod will control Idle.