The CB1100 Community Forum

(12-29-2014, 04:57 AM)metallyguitarded_imp Wrote: [ -> ]

(12-29-2014, 04:03 AM)grover_imp Wrote: [ -> ]To the OP, I think you'll find that opinions are somewhat divided on whether modifications to the ECU (reflash or Power Commander) are necessary to accommodate a full exhaust system.

I've seen a member post a dyno run from an unmodified ECU bike running a full exhaust with A/F ratios near bang-on 13:1, and others will attest that their bikes run fine without additional mods. However, I think we can agree that an ECU reflash (the only method that allows timing advances) would allow you to maximize your new exhaust system.

Best of luck with your decision!


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I read that thread with great interest (I'd be more than happy to be able to just slap on an aftermarket exhaust and not worry about changing or adjusting anything regarding the A/F ratios) and went back just now to see if I could find it. If I'm right, you're referring to CIP57's charts and the discussion the two of you had. If so, he wrote:

"Here is what you can expect with a flash and a stock PC5 map installed into your ECU running a full Yoshi. The A/F ratio is almost spot on, running a bit rich on top. The bike runs much cooler with the added fuel."

I read that to mean the numbers he put up were showing the ratios after a reflash and download of a PC-V map while running a full Yoshi. Where it gets confusing is that he writes "stock PC5 map" but then also rights that the "bike runs much cooler with the added fuel." It's unclear what he means by a stock PC5 map - I take that to mean it's one of the pre-programmed maps already available on the PC-V for a Honda CB1100 running a full Yoshi exhaust (which means it is changing the A/F ratio) and not a custom map he or Don developed on their own. This is consistent with his next statement about the effect the "added fuel" has on the temp.

CIP57, if you're reading this, maybe you can clarify.

CIP's ECU was sent to Don, it was not put on Don's Dyno.
Don loaded the PCV map settings into the ECU, I believe there is only one map available from DynoJet fro the CB1100, its with stock exhaust, its loaded on the PCV when you buy it and its the same one available for download.
Changes shown in app below.

Thanks Hiker! This reminds me of another consideration - the different gearing for the 2014. That complicates things some. I'll have to check with Dynojet to see if they've developed a stock map for the 2014. I thought I saw one but now I'm not sure.

(12-31-2014, 04:24 AM)metallyguitarded_imp Wrote: [ -> ]Thanks Hiker! This reminds me of another consideration - the different gearing for the 2014. That complicates things some. I'll have to check with Dynojet to see if they've developed a stock map for the 2014. I thought I saw one but now I'm not sure.

Looking at the chart, seems like they are just going by % throttle and RPM to add fuel, it's not specific to gears...look at top, says for gears 1 thru 5. unless the 2014 has actual engine differences that would effect fuel ratios?

It's that unaccounted for 6th gear that had me thinking. I sent an email to Dynojet this morning asking if the addition of the 6th gear would affect or change the appropriateness of using the stock 2013 map. I got a quick response from a senior product manager who said he wasn't sure and that they've been trying to get a 2014 into their facility. I asked if he'd be interested in a mutually beneficial exchange - me bringing in my CB so they can develop a map in exchange for a PC-V. I told him about the forum, our discussions on the issue, and that I'd share my results, including an honest assessment of any improvements to rideability. He agreed! I'll be riding to Vegas next week to have this done.

Stay tuned (see what I did there?)

I will be waiting for the report.


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cool, than maybe plan a trip to Lancaster, PA for a Dyno run in Don's shop for the ECU flash to be 14 specific :-)
May as well make a full trip out of it!

I hope to chat with a tuner here in town that comes highly recommended by some riders I've been talking to.
I want to find out if I need a re-flash AND a Power Commander. However I don't know if he has a dyno; surely he does.
From my research in the net, there is also a tuner that DOES have a dyno that is located in Tupelo, MS.
A lot of the 'busa guys take their bike to him. Tupelo is just over an hour from here.
I might as well go ahead and place the order with Mr T.

I thought the general consensus was that you didn't need both a PCV and a reflash. As I understand it, the reflash does everything the PCV can do and then some.

(01-01-2015, 06:04 AM)Cormanus_imp Wrote: [ -> ]I thought the general consensus was that you didn't need both a PCV and a reflash. As I understand it, the reflash does everything the PCV can do and then some.

That's good to know Cormanus. That was what I was hoping to determine through replies to my original post, but I'm not very adept at relaying thoughts/questions through my keyboard.
I just sent an email to the tuner in Tupelo and hope to hear back from him in a few days. I'm also about to ask Mr T if he is aware of any quality issues with the Nojima exhausts he has sold. I'm getting pretty psyched over this exhaust!

In the past, typical tuners have had problems with our CB due to the speed and RPM limits on the CB. Can't hit redline in top 2 or 3 gears.
I think they have to do their work in 3rd gear......but what work can they really do if they can't hack into the ECU.....I believe that's all where it needs to be done.
hence the need for a place like Guhl's who can flash our ECU......or a plug-in PCV which can do fuel mixture, but not timing or remove RPM speed limits.......back again to ECU flash.........