Bike reving to 5k, after the overhaul. Help please!

Ok, so I have rebuilt my carbs. New throttle shaft seals and all.
I polished the piston and sanded the bores.
After buttoning up they acted funny. When the battery was low(sat for a month and the battery is due for a change) it barely wanted to run. Mabye around 1k.
I charged battery and now(after starting fluid spray) it reved up to ~5k.
Thought it was the starting fluid, so stoped bike waited and restarted ran for 30-45 secs. Repeated this several times and got the same results.

Now running at 5k means its getting fuel from the pilot jet AND the main, right????
If you guys have any suggestions of what to test I would appreciate it. I am at work and want to make a list of what to check when I get home

My thoughts currently are(with the 5 k rev)
*Throttle cable bound or mixed up (checked this by pushing the throttle holder down and it was down already)
*Float level? I dry set the float levels but have not checked them with fuel.
*Vacuum Leak Any advise of how to check when the rpms are already high?
*Pistons sticking They were clunk tested and when put back together Air was blown into the valve, made it lift and quickly returned.

Any help would be appreciated, just need to throw the "symptoms" out there and see what the causes could be...any carb doctors out there?

**EDIT What if #2 & #3 butterflies were replaced with #2 & #3 butterflies from a parts set? Would that cause the problems I am having?

 

For starts, did you bench sync the carbs when they were off? ONE "hot" carb can cause it to run fast.

Is the throttle quadrant (on the rack, the thing the cable actually wraps around to pull on) hung on one of the fins?

Is the master throttle adjuster (the starwheel) backed all the way off?

Float levels do need to be "fluid checked" but that shouldn't cause your issue. Vacuum leaks will explain erratic high idle but not 'racing' as you describe. It's something simple, approach methodically and you'll find it.

You didn't mix up the throttle and choke cables did you? It has happened before...

 

Diff carb synch bottles instantly tell you of an imbalance and instantly tell you when your are turning the carb synch screw in the wrong direction.

After I bench synched my carbs there was a HUGE imbalance in the 3/4 pair. It required a few minutes of fiddling to balance them. After that the engine was a totally different animal. My problem before the sync was die with throttle and not a race condition as you have.

 

Butterflys are sticking on something, check all the minutiae.

 

check for the clamps that hold carbs to intake boots. Everytime I have put my carbs back on my bike, it does this, and I finally figure out that one of them is holding the throttle up. If the Idle adjustment is backed off all the way, the carbs are bench synched, and the throttle cable is not too tight, then there is probably something else, such as a clamp, bumping the throttle assy. It doesn't take much to make it rev high when idling.
5k isn't bad, lol, mine shot up to the redline last time it did this.

 

When I had done mind I forgot to back off my idle adjustment screw. When I first started mine it when straight to 5grand. It scared me senseless. I tought I messed something up. Then I checked the idle adjustment and backed that thing way off.

 

Did you replace throttle shaft seals? I have seen them cause the exact symptoms you describe.

 

+1 on one of the carbs not closing all the way.

you could put the YICS tool in, and pull the plug boots one at a time to see which carb is sticking open... it might sting a bit.

 

I had the same problem with mine i think the po tried to solve his failing carb problem by cranking up the idle screw soon reaching the end and sold the bike cause he couldn't get it to run ( wish i would have got it before it sat uncovered in his yard for two years) after i cleaned the carbs it ran good but the engine raced without load untill i backed it off! now it's fine.
shaun

 

If your throttle cable and arm are free try pressing the throttle rail to fully close the butterflys. If that helps you could have several issues most already mentioned but mine was the main spring was not positioned correctly. The spring end was not in the proper place which made the spring not close the rail fully (less tension)

 

the throttle seals are new, Just replaced.

throttles are snapping shut

idle screw backed out all the way AND throttle cable removed entirely.

It HAS to be either a horrible sync OR a butterfly getting stuck open.

I will remove this afternoon and re-bench sync and report back soon.

BTW it idles perfectly at 5-6k, steady as it gets. if I push downwards on the sync screws it accually brought it down.
it has to be a sticking butterfly

 

Mine appeared to snap shut too - but I had similar experience to you- when you press the sync screw it helped - so you are on the right path it appears one or more of the your butterflys are not closing. When I examined the carbs I saw the butterflys did not close fully unless I pressed on the rail. I had reassembled as it came apart but careful inspection showed the spring was wrong.

Anyway may not be your problem at all but it sounds very similar. I was convince they snapped close too.

One other thought - you said you replaced 2 of the butterflys. Take a close look at how well they close. I actually swapped 2 of mine during rebuild because they fit better that way.

 

Ok, pulled carbs after work and seems the sync was a bit off.
I have re-bench synced via paperclip method, and also used the light method to great sucess. 8)
I am not sure how "open" the butterflies are to be, but will open them up a way to get an idle outta her. Then bring her back on down.
While I had them down checked the "clunk" of the pistons.
They looked good, but I had nothing better to do so I did a round of 800, 1000 & WD-40 party!! :roll:
They snap to attention with authority. :!:
I am going to re-install tomorrow and see how she runs(its a tad nippy out tonight)
And will report back!!

Afterthought!! I should have searched the forum, as "reving @ 5k" is indicative of butterflies open(bad sync is one explaination of open butterflies)
I guess we all learn something everyday

 

Back that thumb screw right off, Ass. a paperclip gap = 5k. rpm.

 

Pistons clunking= PASS
Throttles closing= PASS
Carbs semi synced= PASS Tough to get sync perfect due to conditions
Enrichment Valves closing= PASS
Throttles seals "Sealing"= PASS Just replaced them(silicone lube too)

Symptoms so far:
Idles @ 1050 relativly well, but revs(and hangs) @ 5K after twisting throttles.
Even if the twist is small.
I back the idle knob out and she dies.

I pulled carbs and "clunked" the piston with spring and needle intact.
They clunked well, and all at the same rate too.
Fluid checked the floats, LOW!!!
A little more than half a bowl, geez why did I not check that before I installed??
Adjusted float height and set to factory spec.

My thoughts are this...
Floats were too low and caused the a lean condition causing the race in RPM
OR
A butterfly is not shutting 100%, but only when they're on the bike??
OR
Idle mixture screw is set too lean, causing me to open the butterflies to get an idle out of her. The "too far open" butterflies come wide open when they are throttled.
But it still does not explain why it hangs @ 5k once they shut.

ANYTHING ELSE I SHOULD CHECK WHILE THEY ARE OFF THE BIKE?
AND ELABORATE THE CHECK PROCEDURE SO OTHERS CAN BENIFIT FROM MY ERROR.
Please :lol:

 

before you take them back off try a real sync with it running, this sounds like something i had one time
another thing i did once as swap the springs on the sync screws, everything worked fine till you hit the throttle then the sync was all messed up again

 

Your sucking air, Ass. check the boots & the vacuum ports.

 

Yes, sounds to be a vacuum leak/sync problem. One thing for sure is that if you have had the carbs off/apart they absolutely need to be synced properly. Bench syncing is only a way to get it to run well enough to do a good sync.
You must first find and repair any vacuum leaks. The best way to find them is with a small propane torch, open the valve and move the torch tip around each carb and intake boot, any rise in rpm indicates a leak. Once they have all been located and repaired then you can sync the carbs correctly.
DO NOT locate leaks by spraying a flammable liquid on a running engine. That is a sure recipe for instant disaster DAHIKT!