If you have a 2 into 1 exhaust system are both the front and rear cylinders AFR adjusted during a dyno tune?

 

Yessir.

 

Yes, if the guy knows what he is doing.

 

how?
..

 

Steve, with either a 02 sensor in the pipe or carefull positioning of the afr probe. Some pipes harder than others, but should be doable. When yours is tuned they will have to drill a hole in the baffle most likely...

 

Thanks, I knew about the hole, so they just use a long probe then i guess to get past the seperation between the front and rear pipes then.
I wasn't sure if they maybe had some type of piggyback harness that somehow worked with the existing o2 sensors or something like that that used the existing bungs while leaving the bikes narrow band o2's still operating. Been a couple of years since I've fooled around with any of this so I didn't know if methods had changed or not. Sounds like not.
Thanks

 

We proble your exhaust and yes, you are right, we go past the crossover pipe, I try to get mine as far in as possible to get the best reading. We can't use the stock o2 sensors because they are narrow band and we need wide band ones to tune.

 

So I guess a dyno sheet for a 2 into 1 system would show a combination of both the front and rear cylinders on the AFR graph.
Where as most of the dyno sheets for a 2 into 2 system only shows the AFR for the front cylinder.

 

We only tune 1 cylinder at a time, you could request your tuner to show you the AF from the other cylinder. I always start with the front cylinder, on any bike. When it is fully tuned I mover on to the rear, when the A/F is tuned I start the timing tune, when that is done I run a reference pass and print it. Since the probe is still in the rear cylinder that is what is on their print out. I could give them a refernce pass from the front cylinder, but the HP and TRQ numbers would be off because the rear wasn't tuned in yet. Is any of this making sence?

BTW, each cylinder is tuned independantly in a 2 into 2 system as well.

 

A dyno sheet for 2:1 should show either the rear or front. As long as the pipe has 18 mm bungs I just put widebad sensors in there and just switch the dyno connection from back to front. I will start on the back at 0% TP and work up to 100%, then switch to front cylinder and work from 100% back to 0%. This saves time setting up Winpep as at different TP's I use different rates of step testing. On the '10 models with stock exhaust,12mm narrow bands and lambda based maps you have to tune differently.