Lope idle with new exhaust setup

[jamesf]

I just installed a two brothers slip on and while I was in there I gutted my cat. Sounds excellent now.
Problem I'm having is that the idle is crap now. Its super lopey and rough. I can get it to smooth out if I raise the idle to like 1450-1500 rpm, but then the revs don't drop as quick as I'd like after revving.
Right now I'm running a map I found on sportbikes.net (getting it tuned soon). I find if I lean out the idle mixture quite a bit (from +15 to -5) I can get it to idle steady occasionally, but revving it usually breaks this steadyness and sends it back to being rough.
Covering half the exit of the mufflers stabilizes the idle completely, so this is clearly an issue of the exhaust being too straight through for good flow at idle.
Anyone else experienced this issue with a similar setup? If so, what was your remedy (or did you just leave it)?

 

[twobob1]

It has been mentioned on long de-cat discussion/debate threads that if you have a aftermarket exhaust AND de-cat then its going to change the dynamics too much to run normally without a tune/dyno. I am running a k&n air filter with a scorpion exhaust with the cat and still feel that I'm pushing it a little bit anything more like a decat and its tuning time. It does run a bit choppy sometimes on my idle as if it wants to cut out almost but only sometimes.

 

[FinalImpact]

What fuel controller are you running?

 

[TownsendsFJR1300]

Your mods, will OFTEN make the idle lopey, generally happens until you start adding fuel controllers to make up for the additional air flow...

Had you NOT gutted the cat, you probably would have kept your smooth idle..

I have open Scorp's (no DB killers), everything else stock, (cats still there), idles dead smooth at 1050.

 

[jamesf]

What fuel controller are you running?

Running a PCV.

 

[jamesf]

Your mods, will OFTEN make the idle lopey, generally happens until you start adding fuel controllers to make up for the additional air flow...

Had you NOT gutted the cat, you probably would have kept your smooth idle..

I have open Scorp's (no DB killers), everything else stock, (cats still there), idles dead smooth at 1050.

I have a PCV, and I tried enriching the mixture (already at plus 15) and it didn't seem to help (just made the loping more labored). This makes me wonder if a dyno tune will be able to fix it.

 

[Motogiro]

Some fuel controllers will not allow fuel modification below a specific RPM because of emission laws. Make sure your PCV (Which I think it does) is actually allowing a richer mix at the idle RPM which is where you're experiencing the lope. The FZ6 will lean out a little with Two Bros even when the CAT is retained so at idling without the CAT the engine is seeing a big black hole.
It really needs to be on the tread mill to see what the numbers/ratios are.

 

[jamesf]

Some fuel controllers will not allow fuel modification below a specific RPM because of emission laws. Make sure your PCV (Which I think it does) is actually allowing a richer mix at the idle RPM which is where you're experiencing the lope. The FZ6 will lean out a little with Two Bros even when the CAT is retained so at idling without the CAT the engine is seeing a big black hole.
It really needs to be on the tread mill to see what the numbers/ratios are.

It does allow modification of low rpm values, I can tell because I can elicit a response by changing the parameters, I just can't fix the issue. Hopefully a Dyno tune with a sniffer will sort it out.

 

[kenh]

I am running a Two Bro setup with a cat delete pipe with no modifications required. Runs great and idles around 9. I would proceed with a dyno tune at a local shop to sort it.out. Any modifications must be evaluated on a risk versus reward basis, but if things to far out of whack you will be just chasin' your tail to figure it out. Please post up when you get it sorted out, we really do want you to enjoy the 6. :thumbup:

 

[FinalImpact]

I am running a Two Bro setup with a cat delete pipe with no modifications required. Runs great and idles around 9. I would proceed with a dyno tune at a local shop to sort it.out. Any modifications must be evaluated on a risk versus reward basis, but if things to far out of whack you will be just chasin' your tail to figure it out. Please post up when you get it sorted out, we really do want you to enjoy the 6. :thumbup:

And both of you have earlier bikes (S1).

Have you tried just running the stock map (load zero map) or simply unplug controller from injector and plug injectors directly to ECU.

Do the TB sync with vacuum gauge and set the idle speed and vacuum to spec. See what happens!

 

[jamesf]

And both of you have earlier bikes (S1).

Have you tried just running the stock map (load zero map) or simply unplug controller from injector and plug injectors directly to ECU.

Do the TB sync with vacuum gauge and set the idle speed and vacuum to spec. See what happens!

That is what I was thinking of doing next (the TB sync that is, already tried the zero map).
That raises a question though, with the idle jumping around, how should I set the idle vacuum to spec? Presumably I won't have a stable reading. I suppose I could either set the idle high enough that it smooths out (but then the spec is meaningless), or I could have someone cover the exhaust enough to add the back pressure needed to smooth the idle, but that would probably also change the vacuum level from reality. Anyone got any ideas how to proceed?

 

[TownsendsFJR1300]

You may see one or two cylinders WAY OUT of sync. Adjust those accordingly and get them close.

I doubt the major lope is sync related but a sync certainly can't hurt.

As your not getting very far with adjusting the controller, if you have DB killers, install them (for some back pressure), that should help eliminate the lope.

 

[FinalImpact]

I wasn't saying the sync is the fix, more so the RPM & Desired vacuum when set to spec establishes a pretty close AFR value and that should take care of it.

In short whatever device you use you will be visually averaging the values. And once closer it could lesson the severity of the lope.

Make sense?

For that matter simply go turn them all like a 1/2 or 1 full turn in or out and see if that helps smooth it out. If not, put it back.

 

[FinalImpact]

I wasn't saying the sync is the fix, more so the RPM & Desired vacuum when set to spec establishes a pretty close AFR value and that should take care of it.

In short whatever device you use you be visually averaging the values. And once closer it could lesson the severity of the lope.

Make sense?

For that matter simply go turn them all like a 1/2 or 1 full turn in or out and see if that helps smooth it out. If not, put it back.

 

[jamesf]

Update, I set the vaccum and synced the throttle bodies, helped a little but it's certainly still there. Interestingly enough, while messing with the screws I got the idle to be fully smooth, but the vacuum was way above spec (like 26cmHg), and when I set it back to spec it returned to the lope. Maybe that means I needed to add more fuel than I expected with the PCV.
Anyone have any idea what the effects of running with the vacuum that high above spec would be?

 

[TownsendsFJR1300]

You won't get the vacuum to Yamaha spec's. I'm at sea level and no way will it get close.

Adjust the sync so all are even and running smooth, you won't hurt anything.

As posted earlier, the sync is good for up to about 4,000 RPMs.


*Hopefully, no one messed with the throttle shaft adjustment screw between each of the two throttle bodies..

Re-adjust those puppies!

 

[jamesf]

You won't get the vacuum to Yamaha spec's. I'm at sea level and no way will it get close.

Adjust the sync so all are even and running smooth, you won't hurt anything.

As posted earlier, the sync is good for up to about 4,000 RPMs.


*Hopefully, no one messed with the throttle shaft adjustment screw between each of the two throttle bodies..

Re-adjust those puppies!

I did get the vacuum to Yamaha spec by setting the vacuum of cylinder 1 with a vac gauge and then using the homemade manometer trick to sync the others to cylinder 1.
I'm also at sea level, are you suggesting that I ignore the actual vacuum spec and just get it running smooth and well sync'd regardless of what the actual pressure is?

 

[TownsendsFJR1300]

I did get the vacuum to Yamaha spec by setting the vacuum of cylinder 1 with a vac gauge and then using the homemade manometer trick to sync the others to cylinder 1.
I'm also at sea level, are you suggesting that I ignore the actual vacuum spec and just get it running smooth and well sync'd regardless of what the actual pressure is?

,

YES.

That's exactly what I did to one approx. 8 years ago.

Works fine, plug colors fine, idles smooth (at 1050), approx. 44 MPG around town, runs like a raped ape..

Also, re-check and adjust at approx 4,000 RPMs(no higher-useless anything above).

You'll likely see one cylinder different than the others.
You can adjust that up or down and still get well within spec's at idle. The closer at 4K and idle, the better.


You'll very likely feel and see a smoother engine as well (mirrors actually are visible!).


*I used a Morgan Carbtune however.

 

[TownsendsFJR1300]

Any updates?

 

[FinalImpact]

The baseline info helps. My data logger has an O2 sniffer so you can see the live o2 stats like the AFR.

I recall looking at that, a vacuum gauge and the morgan unit but could never kill the lope after jacking the timing up 6.5° from stock. In short at idle its way over advanced but cleans up at 1150 or so.

The main thing to look for is stalling on hot days after decelerating. If it does you need to richen it up!