she wants to race when i want to stop

Ive got an 82 seca 750. I recently cleaned the carbs to perfection and put them back on. I was going to check the float levels likes the haynes manual suggests but the fuel release screws at the bottom of the float bowls are stripped out so i cant. Anyhow, I'm trying to synch and once the bike gets warmed up its shooting to 4 or 5 k rpms. idle screw is all the way out and it cant be the throttle cable because the problem sticks even if i disengage the cable from the carb body. Not good, gents, this is my only transportation. What do you guys think?

 

Check for vacuum leaks. Use carb cleaner with the thin tube to be precise and spray around the manifolds, vacuum ports, carb hats etc when bike is running at idle. If you have a leak, it will draw the carb cleaner in and cause your idle to go up.

Also, did you do the clunk test before you put the carbs back on?

 

clunk tested fine. I'll check for an air leak though it wasn't doing this before I cleaned them so im wondering if i did something while cleaning. This is what i get for trying to tune this up to perfection i suppose.

 

the carb boots can be hard to seal completely if they are older and hard, i had this problem when i finished puting the midnight back together, just make sure the clamps are tight, the boots arent cracked, and the carbs are properly seated into the boots.
i had one carb that the boot wasnt seated completely because the boot folded into the lip of the carb and i didnt notice.

 

Sounds like my wife!

 

thanks guys. It's dark now and tomorrow is work. I'll check my seals and keep you posted.

 

Ensure you didn't trap your throttle mechanism under the fins on the head, holding it open.

Did you "bench sync" while you had them off?

Float levels are critical, and unfortunately the "fluid method" is the only true way to check. You can check by measuring (various methods) while they're apart but the fluid test is the only positive way. If you've got one float that isn't shutting off properly or one way low it will torpedo your tuning efforts.

 

You need to get at least ONE float bowl screw out, then use that bowl to set all 4 carbs.
You need to do a running sync.
You probablly have worn, leaky throttle shaft seals. . . (+1 Earz_cd)

 

I'd recommend not doing the fluid method with windshield washer fluid (or don't let is sit anywhere inside the carb overnight) because it crystalized in all the hard to reach places when I did it. I cleaned my carbs real well, passed the clunk test, set the fluid height with windshield washer fluid and had the same problems. Took the carbs apart again and found that EVERYTHING was gummed up by the little crystals from the fluid I thought I cleaned out, and I no longer passed the clunk test. Cleaned them out again, put them back on and the hanging and surging idle were gone.

Also if you have an intake boot leak, look into the bike intertube fix. Cheap and easy.

 

Bot, nothing other than fuel should be used to set float levels.
Supernube, did you break the rack? Have you done a bench sync?

 

Yeah I know that now...but just wanted to pass that along because there are alot of posts on setting the float heights that recommend it for safety reasons, but fuel is def the way to go.

 

Does anybody knows where us the thread for checking the float levels through the screws in the bottom of the bowl?

 

try pushing down on one of the sync screws with your finger, look closely at the sync screw mechanism for something rubbing, like the manifold clamps

 

Checking float levels:

It's quite simple actually. Mount the rack in some sort of fixture so that it is dead level both side-to-side and front-to-back. Attach a piece of clear tubing to the drain hole, and open the screw. Hold the tube up next to the side of the carb and see where the level of fuel in the tube settles. The fuel level in the tube will match the level inside the float bowl. You read the "meniscus" which is the bottom of the "U" shaped configuration the fuel takes in the line.

repeat for all 4 carbs; record results; disassemble and readjust as necessary.

 

bigfitz52- Thanks for the explanation. I was afraid to hear that I have to take the carbs off. Well, I am getting good at it anyway. I think I des-install and install them with all the flaots adjustment in an hour now. I will record the time and let you know.

Thanks again.


Carvall

 

There was a topic on how to set the float heights dry here:
http://www.xjbikes.com/Forums/viewtopic ... art=0.html

It DOES NOT take the place of the clear tube method bigfitz described, but will get you to a good starting point, and will save you time if you are swapping out bowls.

There are a bunch of pics of peoples set up in this thread:
http://www.xjbikes.com/Forums/viewtopic ... rt=45.html

My setup involved a 2x4, a 2x6, 4 wood screws and a snowblower tank.

 

ManBot13-- Thank you!

 

allright. I did what polock suggested and pressed down on one of the synch screws, low and behold, she started to calm down. But what does that mean? Do I have the springs that link the carbs wound too tight? Did I reassemble them wrong? And most important, what do I do now?

 

that means that the throttle butterflys are still open and by pressing down on a adjustment screw you forced one or more of them closed
first thing to check is for interference, make sure nothing is touching the sync mechanism anywhere on any carb
then unhook the throttle cable so that's out of the picture, use your finger to blip the throttle as you do the sync
turn the idle screw in till it touches and you just see #3 linkage move
now start to do a sync, it doesn't have to start to do crude preliminary adjustments (hint, no choke)
you should find something way out of whack, if you do correct it and then try a proper running sync

 

I've been doing some reading, Polock, this is because I didn't bench synch, am I right? Jesus, you skip one little step ... I was also directed to a post about dry setting your float levels. I am it. Let's see if this works.