Racing engine at intersections, stops, etc.

[Chilly Willy]

Hi all,

I've had this happen a couple of times now and it's starting to freak me out a little.  I'll come to a stop at an intersection, pull in the clutch, roll off the throttle, and the engine will rev up all by itself.  I've even taken my hand completely off the throttle while this is happening.  Each time, I just hit the engine kill switch, started back up again, and rode away just fine.

What's going on?

Thanks,

Chilly Willy

[rangerbrown]

choke is sticking sounds like

[Chilly Willy]

Cool.  So how do I fix this?

Chilly Willy

[rangerbrown]

remove seat
remove gas tank
and check cable all the way down to the carbs.

if cable is find then check the carb linkage on carb (remove carb)

[Chris_B]

Sounds more like its running way lean. Check for vaccuum leaks, your mixture screws may need adjusting, or your carbs could be dirty. Or the choke is sticking, but I dont think it would be back to normal after shutting it down and starting it back up if it was the choke sticking/not closing fully.

[Turd Ferguson]

Sounds more like its running way lean. Check for vaccuum leaks, your mixture screws may need adjusting, or your carbs could be dirty. Or the choke is sticking, but I dont think it would be back to normal after shutting it down and starting it back up if it was the choke sticking/not closing fully.

+1

My vote is for lean.

-Turd.

[Chilly Willy]

How do I fix lean?

Chilly Willy

[Chris_B]

Check to make sure the vaccuum line coming off the left carb isnt cracked or poor fitting, make sure the boots arent cracked or dried out, and make sure they form a good seal around the carb and onto the cylinder head. The pilot jets are pretty small and can be clogged fairly easily, taking the carbs off and cleaning them is never a bad idea. Adjusting the mixture screw may fix the problem, in makes it leaner, out makes it richer.

[thirdman]

I had the exact same thing happen to me, and adjusting the mix screws out (richer) fixed it right up. 

[Chilly Willy]

Thanks all,

I'll give it a look and a try. 

Chilly Willy

[Chilly Willy]

I had the exact same thing happen to me, and adjusting the mix screws out (richer) fixed it right up. 

Can I adjust the mix screws without removing the carb from the bike (i.e. how complicated is this process)?

Thanks,

Chilly Willy

[mjn12]

Yep

I use a small flathead bit that you would normally slide into one of those magnetic screwdriver handles (spinner handle, whatever you want to call it). Don't try and put it in any kind of handle, just hold it with your fingers.   It takes a little feeling around and you have to pay attention to the oreintation of the bit to determine how much you are rotating the screw. 

[Chilly Willy]

Cool--how much should I rotate it and when do I know if I've gone too far?  How do I tell when it's "just right"?

Thanks,

Chilly Willy

[Mandres]

I had the exact same thing happen to me, and adjusting the mix screws out (richer) fixed it right up. 

Can I adjust the mix screws without removing the carb from the bike (i.e. how complicated is this process)?

Thanks,

Chilly Willy

It depends on whether the brass caps that come stock covering the mixture screws have been removed or not.  If the previous owner removed the caps you can adjust the carbs on the bike.  If the caps are still there you'll have to pull the carbs to drill them out.

[FearedGS500]

chilly i thought the bike was new ? are you out side of the warrenty date ? if not i'd talk to the stealer and see what they say

[Chilly Willy]

Nope, the bike is just new to me.  It's a 94 with 10 k miles when I bought it. 

Chilly Willy

[scratch]

Here's a picture with the brass caps still installed.  Once you take them out, leave 'em out.
Now, for adjusting, I'd gently screw them in just until they seat lightly, then back them out two full turns and half a turn, or three whole turns, depending on your taste.

[Chilly Willy]

Excellent, thank you!  How do I drill out the brass cap in such a way that I don't damage the screw underneath?  What size drill bit / what depth?  Is this tricky or would I be better off removing the carb from the bike before trying it?

Thanks,

Chilly Willy

[scratch]

You will have to remove the carbs, so you can turn them upside down.  The cap is about 3 or 4mm thick, and there's maybe a mm of space before the screw.  Just drill til you break through and let your reflexes release the trigger.  Wear eye protection.

[RVertigo]

Did this issue JUST start?

'cause you may have pinched a hose or something.