The CB1100 Community Forum

(03-09-2022, 09:40 AM)PowerDubs_imp Wrote: [ -> ]There is no need to have a custom header made- there are a LOT of exhaust options for this bike believe it or not.

There are 4-1, 4-2, 4-4, 4-2-1, 4-2-4 options. Some black, some chrome, some titanium.

You will have to order from overseas and wait- but you would have to wait for custom header anyway.

The cost to have a proper header made- correct lengths, diameter, oil filter access, good welds, good chrome, good fitment... might want to pick an already available option and not risk the quality.

I had a custom sissy bar made for this bike- and had to send it back and have it done again, and it still had issues.

I had a 4-4 made by a supposed reputable exhaust shop for this bike- and the welds look like a 2 year old snuck into the garage while his parents were away and tried welding for the first time- after stopping at the fridge first and downing a 6-pack.

Taking the cat out will always gain a bit of power.

An O2 sensor bypass plug will make even a completely stock bike run better.

A power commander is always the safest thing to do when losing the cat- as it will lean out a bit due to increased airflow.

If you are just wanting sound- why now just do a slip on - much cheaper, easier, and no need to add fuel, but I would still do the O2 sensor bypass plug.

These are nothing but a few cautionary thoughts, after some read-up on each subject, I do not pretend to know better ... Let me know if or where I go astray ...

-> cat out means more air flow in the pipes, but it comes at a price, the ECU doesn't know, and will run the engine with less than ideal air/fuel mixture (not an issue with conventional ignition and carbs),

-> same with a sensor bypass, if you're lucky it runs better at some power/temp/rpm range, certainly not across the board (the idea that - since cats need lambda sensors - without the cat you don't need the sensor, is tricky if not risky)

-> a power commander is nothing but a "different" ECU. I do not doubt that sb could develop, test and tune a power commander optimized for your custom bike and riding, but it ain't cheap, and I have a hard time believing that some of-the-shelf ECU replacement is gonna make you happy.

Unless I am missing major points ... don't fall for stupid marketing scams talking about cheap "power and performance".

j3gq-

#1- correct- the bike doesn't know the cat is gone. But you will gain airflow (while leaning out the mixture)- the bike will still run, and still make more power- just run hotter and chance of detonation.

#2- the o2 sensor on this bike is narrow band, only for emissions- it is the cause of the part throttle twitch when you are in a parking lot, pulling into a driveway. The bypass plug removes that. The cat does NOT need an o2 sensor, and on these bikes it is not set up as such. On cars they have a precat & post cat sensor to compare readings to judge cat functionality. That is not the case here.

#3- a power commander is indeed a piggy back to 'trick' the bike into adding / removing fuel at all the RPM / throttle positions. And adding fuel to modern lean by default bikes does make then run better- smoother, cooler, and more power. Engine tuning isn't magic or super specific- if it was carbs would never have existed- think of the power commander as a carb jet kit- that you tune with your laptop. Or add an auto-tune box and it will do it for you on the new wideband O2 sensor that comes in the kit.

None of that is 'scams' and yes- more power is easy. On any motor. In any vehicle.


m in sc-

Our stock ecu doesn't adjust. It will run- and yea pulling the cat on a stock bike will make more power- but because there is still enough fuel even when going lean to support combustion. In fact- that is WHY lean occurs- the added air burns as much fuel as it can. Doesn't mean it is safe.

Heck- just adding the TSR airbox plate (and yes, I dyno'd it by itself before and after) made the bike run leaner up top than I would recommend without adding fuel.

Well the power commander is on the way i think the consensus that i saw on another thread that the "stock exhaust and Stock Intake" was the best map to start with and powerdubs can you point me in the right direction for the bypass plug? still could not find anything.

Side note the only place that i found that TSR plate was from overseas. The ebay link from the other thread is now dead. Not sure what site to trust but trying to get it here in time for spring!

(03-10-2022, 07:57 AM)bnhanneman_imp Wrote: [ -> ]Well the power commander is on the way i think the consensus that i saw on another thread that the "stock exhaust and Stock Intake" was the best map to start with and powerdubs can you point me in the right direction for the bypass plug? still could not find anything.

Side note the only place that i found that TSR plate was from overseas. The ebay link from the other thread is now dead. Not sure what site to trust but trying to get it here in time for spring!

I looked back at my ebay purchase for the bypass plug I got and the seller does not sell it anymore. I found another one at the following link but I can't vouch for the seller. Looks like they're from Greece.

https://smartmoto-electronics.com/comple...it-ose-214

There may be other U.S. sellers but you will have to dig around a bit.

I have the TSR plate and it really isn't worth it. If you want to make actually power gains from the intake side, purchase an extra pair of stock intake funnels and hone them out to make them bigger. There are quite a few threads on here that talk about it. By then you will probably want add an autotune to your PCV. If you think you may go that route make sure your buddy welds in an o2 bung for you just in case.

(03-10-2022, 07:57 AM)bnhanneman_imp Wrote: [ -> ]Well the power commander is on the way i think the consensus that i saw on another thread that the "stock exhaust and Stock Intake" was the best map to start with and powerdubs can you point me in the right direction for the bypass plug? still could not find anything.

Side note the only place that i found that TSR plate was from overseas. The ebay link from the other thread is now dead. Not sure what site to trust but trying to get it here in time for spring!

No need- the TSR plate only made about 2whp at very high WOT on the dyno.

But also made the intake noise annoying to me- and I'm pretty well deaf after many years in an artillery unit so that's saying something.

If I thought it made any power to be worth it- I'd still have it on, instead of it laying on my garage floor for the last few year collecting dust.

Instead, I would do (and did do) this-

http://cb1100forum.com/forum/showthread....pid=271068


and I with that- I still made 103WHP and 75wtq.




m in sc- no offense- but just because it didn't blow up doesn't make it right. Go put it on a dyno w/ A/f curve and get back to me with the chart.

I promise you more fuel would make it safer, run cooler, and more power. No- it does NOT adjust.

How many dyno runs have you done on this bike? I've done at least 30. With all sorts of parts before and after.

There is a map sensor in the airbox that basically reads the atmospheric pressure and adjusts the entire map plus or minus essentially on a sliding scale.

Airflow changes from part modifications will have different effects at different RPMs that are not addressed by a sliding scale because the map needs to be changed not slid.

Hope that makes sense.


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I never said you were damaging it.

Engines can run a wide range of less than ideal fuel ratios- it takes a pretty extreme in either rich or lean to cause a noticeable problem.

Honda themselves had heat issues when designing this engine- that is part of the reason why even our spark plugs have their own cooling fins. Personally I prefer to cool with fuel as opposed to lean out and create more heat.

Modern fuel injection spray & head design burn so efficiently that plug read is useless.

Your exhaust doesn't put the bike out of the range of where it will run. But the bike doesn't know your exhaust is even there- it does NOT adjust.

Trust me- put a stock bike on a dyno and look at the A/F curve- then take out the cat- redyno and look at the A/F curve. It will lean out. Would be interesting if the cyl head temps were read- as they should increase as the air ratio climbs.

The O2 sensor is narrow band- it only knows 14.6 14.7 and 14.8 - that's it.

Anything else and it is out of range and does not do anything whatsoever. It is for emissions purpose only.

There is no running target AFR- there is only static map injection pulse. Nothing changes other than airbox atmo pressure shifting the whole map up or down completely and simplistically for altitude and air temp- it doesn't change fueling at individual rpm or look at any result and compare to any target- how could it- there is no feedback loop. It's a pre-set dumb system- as are pretty much any other bike, car, etc. That's the entire reason tunes exist- the map actually gets modified- the fueling actually changed.

That's why even a tune- like Guhl or any other tuner- is still only ideal on that bike, with whatever mods on that day. Once he tunes it- adjusts the map to what a/f he wants- it stays there, locked again as a static map. That's what makes the power commander with auto-tune box appealing- it actually has live real time feedback and adjustment with a wide band O2 sensor that looks at ALL the range of A/F ratio in the exhaust in real time for all throttle position and rpm and adjusts based on what target you design the map for. You can even have it tune for each individual gear you are in- as the engine load does change the #'s a bit.

I'm about to take it a step further than anyone else has done on this bike-and run a dual channel autotune box with 2 WBO2 sensors so I can tune the left 2 cylinders separately from the right 2. I don't expect it to make any difference- but I like to play- and look at generated data. I have the parts, and new 4-4 exhaust- just need to get around to installing.

Dubs, that was a very interesting and informative post. Thanks for that explanation!

If anything- I’d love to see what your exhaust valves look like.

For fun- Here is what a shot of one of my projects over 20 years ago- of a 30+ year old car that I converted from an auto to stick shift, from drum brakes to disk, added ABS, added individual throttle bodies, added mechanical variable cam timing, added stand alone programmable fuel injection, aftermarket programmable ignition, aftermarket traction control …. and yea- I added a wide band O2 sensor … over 2 decades ago.





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Alright lets just say you both have extreme mechanical abilities, but appear to disagree on this subject so no sense in hashing it out any further