[BFC Scrounge]

88 twin cam carburetor motor. My problem is when motor has been running for a bit and I stop at a light the motor will rev up to 14-1500 rpm. Sometimes it will go down to 8-9 hundred. Had a stock carp then an SnS carb , changed jets, gaskets, and just about everything I can do and it will continue to do it!
so wondering if someone might know what is going on with it.

 

[NCPiper]

What have you eliminated? Have you looked at anything?

Intake leak is where I would start...and most likely the issue.

 

[NCPiper]

I found this:

How to diagnose and fix an intake leak - RevZilla

Intakes leaks suck, literally and figuratively. Here's how to identify them and fix them.

www.revzilla.com

 

[<G Man>]

Not sure what year your bike is, but it sounds like a MM EFI issue that is pretty common, but you said you have a fish instead of EFI.

Why would you change the jets for an idle issue? If this is "just about everything" you can do, that might limit the range of usable answers. Did you really change the carb and still have this same issue before and after the carb change?

 

[BFC Scrounge]

Not sure what year your bike is, but it sounds like a MM EFI issue that is pretty common, but you said you have a fish instead of EFI.

Why would you change the jets for an idle issue? If this is "just about everything" you can do, that might limit the range of usable answers. Did you really change the carb and still have this same issue before and after the carb change?

i changed carbs, jets, idle size , intake gaskets, like i said everything i can think of has been dealt with at least twice to make sure i didnt mess something up the first time.

 

[BFC Scrounge]

What have you eliminated? Have you looked at anything?

Intake leak is where I would start...and most likely the issue.

like I said i've replaced or changed everything from the air cleaner to the intake gaskets at least one.

i changed carbs, jets, idle size , intake gaskets, like i said everything i can think of has been dealt with at least twice to make sure i didnt mess something up the first time.

its a 2005 classic

 

[Hoges]

Just a guess if running stock fuel tap they are vacuum operated so maybe a air leak in hose or diaphragm. also map sensor bad.

 

[<G Man>]

Could the enrichener blade be moving?

 

[BFC Scrounge]

It doesn’t have one. Put on an SnS super on it and still have the same issue as with the stock carb

 

[rootintootin]

Find a book and adjust your throttle and idle cables. One or both of them could be causing this issue. Any little movement of the fork can cause your idle to go up or down.

 

[<G Man>]

Which S&S carb did you put on? Was it a new carb? What tuning procedure did you follow when you installed it?

You say you changed jets. Was that with the S&S? Did you change them as part of a tuning procedure or just random changes hoping for a good result?

 

[<G Man>]

Find a book and adjust your throttle and idle cables. One or both of them could be causing this issue. Any little movement of the fork can cause your idle to go up or down.

Yes, throttle cable seems like a likely suspect since the carb change seemed to make no difference.

So, the question is what happened before this problem started?

 

[Brand'd]

I found this:

How to diagnose and fix an intake leak - RevZilla

Intakes leaks suck, literally and figuratively. Here's how to identify them and fix them.

www.revzilla.com

I've been using this method for years and it's always worked well. I remove the torch tip and stick a length of rubber hose over the tube though. Makes it a better tool.

 

[BFC Scrounge]

Which S&S carb did you put on? Was it a new carb? What tuning procedure did you follow when you installed it?

You say you changed jets. Was that with the S&S? Did you change them as part of a tuning procedure or just random changes hoping for a good result?

Super E read instructions and called them. Didn’t have an answer. So just trying different jets and so worth to see if would make a difference. So far nothing has worked. Every once in a while it will drop on its own and that just makes it all the more strange

 

[Don Dorfman]

This bike has stock ignition?

 

[BFC Scrounge]

This bike has stock ignition?

Yes

 

[WEINERDOGBONE]

Most of these guys are smarter than I when it comes to troubleshooting, but it seems like you've elminated possible fuel issues. I'd probably be interested in testing the speed sensor. A faulty speed sensor can cause strange idle symptoms. In my experience your speedometer may also be off and it can issues with turn signal canceling as well. I don't think every symptom would necessarily be present.