PC5 Surge

[Kc5]

Fred..I always value your input and appreciate your help, but I want to clarify my point. I'm not picking on you, because nearly everywhere you look on the web, it says the bypass screws have little affect above idle and I don't agree. I do 100% agree they have a big influence at 5% throttle and below. I rode around monitoring TPS voltage and logged throttle position and my worst surge was at 3-7% throttle in the 2000-3000 rpm range, so not just freewheeling in neutral. Like you, I had some surge at highway speed, but was even more annoyed with the 2nd & 3rd gear, in town riding (30 mph zones, school zones and other in town traffic) There was another post on here about a guy having the same complaint riding in a military installation and felt his pain.

 

[ionbeam]

... I rode around monitoring TPS voltage

and logged throttle position and my worst surge was at 3-7% throttle in the 2000-3000 rpm range, so not just freewheeling in neutral. Like you, I had some surge at highway speed, but was even more annoyed with the 2nd & 3rd gear, in town riding (30 mph zones, school zones and other in town traffic) There was another post on here about a guy having the same complaint riding in a military installation and felt his pain.

I've done the same thing only I also tapped in and monitored the intake vacuum at the same time. You will find that anytime you are cruising at a steady speed with light load, small throttle opening resulting in high intake vacuum, and roughly 0.75 to 0.9 volts on the TPS there is the strongest urge to surge. The TPS absolutely shows you the throttle plate opening distance.

 

[Fred W]

Thanks to both of you for sharing your first hand experiences. This is evidence that can't be denied. Clearly I (nor anyone else that I know of) do not have all of the answers. We are all just mucking around with these things trying to calibrate them and get them to run the way they should. have from the factory.

Can you imagine an auto that came with the fueling issues that almost every modern fuel injected motorcycle does?

 

[bluesdog]

I thought my '11 was OK out of the box, and put the mildly 'snatchy' throttle and low-speed surge down to my inept throttle hand, and that it was my first experience with a FI bike, coupled with the fact that the bike had 0 miles when I took delivery, and needed running in.

I quickly learned on the forum that the FJR generally had weird fueling problems, and so began messing with the system in an attempt to alleviate or at least mitigate some of them.

To date, I have replaced the PAIR system with WynPro plates; experimented with the Barbarian CO jumper mod; carefully performed the Unauthorized TBS; and installed a PCV/Autotune. I also have Staintune cans installed, which supposedly flow better than the stockers.

I also bit the bullet and purchased an LCD 200, in order to monitor the fueling via the PCV on the fly.

At this time, the throttle no longer feels snatchy, but that may be at least partially due to my just getting accustomed to the bike. The surging has completely disappeared.

I'm running a slightly modified smoothness map, and leaving the autotune on.

As a side note: When I had the injectors serviced last year, the guy doing the test said one flowed a little high, and another a bit low. He said there was typically some variance in stock injectors, and that professional racers would have more evenly matched sets installed. I wonder if this variance between injectors may be more pronounced on some bikes, and if that could in turn affect fueling issues, including throttle feel and surging.

 

[Queensland Ken]

I'm running a slightly modified smoothness map, and leaving the autotune on

If you enable the Autotune, it will temporarily overwrite the map anyhow, it all depends on the A:F ratio you set.

I found out the best practice is to adjust the AF ratio you want, let the Autotune do it's trim and when it's all running great, accept the trim then disable Autotune.

If you encounter large changes in elevation, the Autotune may cause fuelling issues.

The LCD 200 is great, if you can find a museum that has a 1st gen SD card.

 

[bluesdog]

The LCD 200 is great, if you can find a museum that has a 1st gen SD card.

Yeah, that was a royal PITA locating one. The retailer claimed 'any SD card' would work, which was a total lie.

I eventually ordered one direct from dynojet.

I'll follow your advice regarding the autotune. The bike is running great at whatever trims the thing has created.

 

[Queensland Ken]

Yeah, that was a royal PITA locating one.

Lucky I had a mate with an old GPS that had one installed.

Didn't know Dynojet had them, bugger, would have saved heaps of time and effort trying to find one.

I had a few problems down the Aussie Alps, spent a week doing the twisties and the mountain roads.

I really thought the bike had a problem until I thought about what the Autotune was doing and disabled it.

I bought the LCD 200 after that to data log the condition.