CARB BUTTERFLYS slightly OPEN OR just CLOSED on reinstall

I could find no mention of setting the butterfly gap. I have been leaving it open with enough room for a match or safty pin to slide through. Why don't we just use a modified feeler gauge to set the idle with or have I got this all wrong? Am I missing something simple here? I start my bike and the idle jumps to 4500RPMs. How far open exactly am I supposed to have those butterflys? Or how far closed? Or just closed?
Comments appreciated

 

Match or saftey pin is way too big. Use a 1/4 strip of paper or index card to bench sync. Set each carb so there is a slight drag on the paper.
See comments on your other post reguarding this.

 

For all practicality purposes That is how you dry sync the carbs. Just open #3 to a small drill or paperclip. Then set #1to #2. then set the 2,3 combo to #3. That be dry sync. You will adjust the carbs on the bike. So not to worry about butterfly gap at this time.

 

Re: CARB BUTTERFLYS slightly OPEN OR just CLOSED on reinstal

This is not a benchsync question. This is after the benchsync: Open or closed or slightly closed and if slightly closed then what is the measurement of the gap.

 

The engine is idling at 4500RPMs!

 

So you are telling me the gap in the butterflys makes little difference in the high idle. This is not a new problemfor me. I have been troubleshooting this for 3 weeks. I have eliminated most everything but precise float levels which I am trying to call good enough.and I getth ese butterflys correct. I just can't find any information on this topic. Thanks for your output. Have you been at this a while? Still searching for answers.

 

Re: CARB BUTTERFLYS slightly OPEN OR just CLOSED on reinstal

The answer again is that the butterflys should be open the thickness of a piece of paper. If they all are and everything else has been checked then it should idle around 1100 rpm.

If your bike is idling at 4500 rpm then you missed something;
Float levels?
Choke open?
idle mixture?
Bench sync?
Throttle cable?
It is possible you have vacuum leaks also.
Its time to backtrack and revisit some or all of those items.

 

OK, I will bring the float levels up higher as they were low the last time I tried to make them work. Other than that I did not check the distance out on the idle mixture screws and just set them to factory. I had thought I set the butterflies with a paper clip and that caused the idle to go to 5K but apparently not. Thanks guys.

 

The manual will show where to set float heights. This high idle is an easy fix. Turn the idle screw down till it gets the desired idle. Bench sync is with a strip of a buissiness card. Get them all the same. Run the bike and lower the idle with the idle screw. Then sync and color tune . Repeat. Ride and enjoy.

 

1.5 turns out on mix screws for starters. Color tune will help later to get them right.

 

A safety pin or match is way to wide, and will cause a fast idle.

However you only use this method for initial setup anyway.

Forget the actual gap and slow the idle (closing the gap) when the bike is running.

To make it clear, the final throttle adjustment is made with the bike running, there is no gap specification at all.

 

Explain? What does "setting them to factory" mean? How would you know where to set them, when even the "factory spec" is given in number of turns out? You DID remove them, clean the passages and replace the tiny o-rings, right?

This is a tad lean. I'd start at 2 1/2 on the mixture screws.

How "open" or "closed" the butterflies are is inconsequential; what matters is that they move together. The main idle knob should allow them all to fully close when backed off all the way; and you can set it so they JUST start to open before you reinstall. "Barely moved off the stop" should get you in the ballpark, idle-wise, then you adjust via the main knob after you fire the bike up.

As far as using feelers of various sorts to bench sync, I've adapted Polock's method of comparing the position of the butterflies to the tiny "bypass" holes in the top of the carbs throats. The "amount of drag" put on whatever feeler you use is too subjective; you can SEE the tiny holes and get a much more precise bench sync that way.

Just be sure that when the main knob is backed off all the way, the linkage can fully relax and all 4 butterflies close fully.

As for the float levels, you'll have to get them right. NOT "good enough," not with Mikunis. The spec is only ONE millimeter each way; and trust me, it matters.

 

2 1/2 turns out how about that. Learned something new thanx fitz

 

Thank you all. I got her gallopin' fine now. The "DUH" factor in this case. Thank you Fitz for the advice in getting to the idle adjuster by means of the right side. Once I reached in there and turned the idle down it settled down. All hope is restored in the rebuilding of the carbs sinario. It seems to run really nicely at this point but I bought all the gadgets/tools so I will get into that next. And some cheap insurance (one of the great things about bikes is the low overhead).