Is there a definitive solution to the jerky throttle????

[68deluxe]

I just got my bike back from the dealer where they did an oil change. They also updated the fuel map, to the newer 2011 map I think. It is a slight improvement at steady speed riding around 3-4K, need more time to tell.

[ultrachrome]

Originally Posted by mousitsas

seems this guy knows his $hit!

http://www.superduke.net/forum/viewt...hp?f=5&t=10354

It's the air box dummy.

My SMT hunts between 3 and 4k RPM in town. It's not dangerously bad but annoying enough that I'm planning to visit a tuner.

I consider myself a skeptic. I've read several tuning threads and after the first couple I quickly formed a distrust of them. What worked for some didn't for others and some mods seemed like they should be counter productive.

But the thread linked above is the first reasoned and informed 990 tuning thread I've read. The author takes time to patiently explain the issues and suggest a solution. It's pretty dense and the Austrian (no relation) author's syntax is a little off in places so I'm going to reread it a couple of times before proceeding.

[68deluxe]

After a few hundred miles since the update I can tell there is a definite improvement in the bikes behavior. At steady speed, 2nd gear around 25MPH, it is much smoother and nearly less surging. It does seem that the problem got moved up just north of 4K but overall it is a much friendlier bike. Maybe 85 out of 100, bike started at 60/100 so I guess I should be happy. Lets see what happens this winter when the temperatures drop back to human levels.

[Spark01]

Originally Posted by ultrachrome

It's the air box dummy.

My SMT hunts between 3 and 4k RPM in town. It's not dangerously bad but annoying enough that I'm planning to visit a tuner.

I consider myself a skeptic. I've read several tuning threads and after the first couple I quickly formed a distrust of them. What worked for some didn't for others and some mods seemed like they should be counter productive.

But the thread linked above is the first reasoned and informed 990 tuning thread I've read. The author takes time to patiently explain the issues and suggest a solution. It's pretty dense and the Austrian (no relation) author's syntax is a little off in places so I'm going to reread it a couple of times before proceeding.

My SMT is recently remapped per cylinder for the CPR airbox for max power so the air/fuel is around the 1:13,2.
But the O2 sensors are still activated.
If you leave the O2 on then, you always will feel the adjustement that the ecu is doing with a steady throttle on the low rpm's.
Or the air/fuel has to be set in the low rpm's and throttle positions close to the 1:14,7 so the adjustment by the ecu will be very limited.
But it isn't snatchy at all (also not before the remap).

The 2011 map is just a little bit improved for the O2 but i didn't notice any difference between the 2008 akra map and the 2011 akra map.

The only true improvement i made and noticed, was by open up the 2nd throttle plate in the low rpm/throttle postion these should not be lower than 10%.

But the nice thing about a good remap is that the bike doesn't only make more power also the fuel economic is better than before. 1:17,8 (l/km) (41.8 Mile per gallon) was 1:15 (l/km) (35 mile per gallon)

[ultrachrome]

Originally Posted by Spark01

My SMT is recently remapped per cylinder for the CPR airbox for max power so the air/fuel is around the 1:13,2.
But the O2 sensors are still activated.
If you leave the O2 on then, you always will feel the adjustement that the ecu is doing with a steady throttle on the low rpm's.
Or the air/fuel has to be set in the low rpm's and throttle positions close to the 1:14,7 so the adjustment by the ecu will be very limited.
But it isn't snatchy at all (also not before the remap).

The 2011 map is just a little bit improved for the O2 but i didn't notice any difference between the 2008 akra map and the 2011 akra map.

The only true improvement i made and noticed, was by open up the 2nd throttle plate in the low rpm/throttle postion these should not be lower than 10%.

But the nice thing about a good remap is that the bike doesn't only make more power also the fuel economic is better than before. 1:17,8 (l/km) (41.8 Mile per gallon) was 1:15 (l/km) (35 mile per gallon)

Do you have stock mufflers?

You are saying keep the throttle plate open more than 10% at low RPM? Have you considered removing them altogether and if not, any particular reason why?

~

This weekend I tried the airbox mod that highscore illustrated although I did it a little differently. I yanked the snorkel but instead of modifying the access covers, I made new ones with a single hole sized to match the opening that would have been achieved by modifying them.

Alas I screwed it up. After calculating the hole size, I forgot to convert radius to diameter and drilled a 1" hole instead of 2". Easy to fix but I tried it anyway and it definitely made the bike feel different. 3-4k felt smoother but 4-4.5k felt a little jerkier. I'll enlarge the holes to the correct size and ride for a few days and then go back to stock for a sanity check.

Personally, I'd like to start by doing the absolute minimum to the bike for the greatest gain but I do believe I'll be acquiring the CPR filter and a remap with the stock mufflers.