Engine revs to the moon after cleaning carbs

[Ola]

I had the carb rack out (in one piece, did not touch sync linkage) and cleaned the bowls, main/pilot jets and pilot screw. As best I could I marked the screws, counted the turns in, then unscrewed them, cleaned and screwed them back in. One of them had the washer and o-ring jammed askew which I might solve my stumble.

Everything hooked up again, a big dose of prime and the baby starts. And revs to 5000. I searched the forum and the common diagnosis is air leak, which might be possible (too dark so I just packed up and went inside) but I'm fairly sure all the boots are in good condition and well set.

I messed a lot with the idle screw with the rack out, but I used a cleam/grime spot on the shaft to realign its previos position.

The engine does this straight from cold, I did not let it run for more than a few seconds as I hate to see a cold engine rev hard. So between air leak, messed up pilot screws, messed up idle screw or mystery option 4, what do you think it is?


There could of course be a bind in the throttle wire or linkage, I inspected as best I could in flashlight conditions but will give it a proper look tomorrow morning. Thanks for any input!

edit to mention: this is a 16v TSCC 750cc engine with stock Mikuni carbs

[Dave8338]

Back the idle screw all the way off so that it dosen't even touch the throttle shaft linkage and try it again.

[Wilee7]

I had the same problem after i cleaned my carbs and when i put them back on the bike the end of the throttle wasn't fully seated in the hole so it caused the valve on the carbs to be opened way more than they should have been. i pulled the carbs back off made sure the throttle was in correctly in place and now it runs like normal. hope that helps

[Ola]

Good tips both, hopefully it's just a sticky linkage.

Bonus pics of the pilot screw with washer and o-ring blocking the sliver of daylight the other three showed:




And 2nd bonus pic of me praying to the Shinto God for advice on how to get these suckers out:

[Skyboy8950]

Ola, that is AWESOME!!!

[Ola]

Yup, I had fitted the throttle cable all wrong.

It seems fine now, but not perfect. Idle hunts a little and the rev speed difference between cold and warm is a bit too big. I will go hunting for an air leak as that seems very likely. The filter side boots are also not fitted as perfectly as I'd like.

Now for a follow up question, rate my plugs!





#4 is definitely lean, but it also has the best fitted boots. Should I give the screw on the right near the engine boot a try?



Is it in or out for richer? (I'm pretty sure it's out)

I'll order Colortune and get myself set up with a good sync tool after summer, I've been spending like a drunk sailor lately.

#2 is pale too, just slightly colored on one side. #3 looks great to me, #1 could be a tiny tad more colored. As always, any input appreciated.

[Zook]

+1 on the plug readings.
If ya can't get them any better I sure wouldn't be concerned.

Out is richer on the pilot screws.