Temporary power loss VFR800FI '99 - suggestions

Hello fellow Viffers!

A month ago I bought a VFR800FI ('99) in pristine conditions, 30k miles on it (40,000km). All stock except the fact the muffler box has been removed and it has had a pearl white repaint - just love it.

VFR800 LACKING A LIL' LOWER BAND POWER:

Just to put you guys into context, I've ridden my brothers '94 VFR quite a bit, and he has ridden my VFR800 now and we have come to the conclusion: his 750 engine does have more punch on the lower band, however we both agree my VFR800FI seems to takes off after 6000 rpm and seems to have quite a bit more power on the top end. I decided I needed to give my 800 the punch it deserves on the lower band so I went to my mechanic to see what could be done (after crawling all over this forum of course!)

CONCLUSION

- Install muffler box again to get a little back-pressure and gain lower band power (with the consequent loss of hp)
- Get a PC or TFI.
- Reduce front sprocket by 1 tooth (this isn't actually changing the way the engine responds, but physically, you will feel more power over the whole power band
due to mechanical advantage)

WHAT WAS DONE

I decided not to install the muffler box (I want all the HP I can get!) and go for the TFI first, and switch to a PC if I'm not convinced.
-TFI with manufacturers recommended settings
- New 2-1 exhaust connection gasket needed replacing (stock exhaust)

TFI FIRST RIDE IMPRESSIONS:

Picked up my bike yesterday, drove off and felt S%$& after 20 miles. It seemed like I was back on my CBF250!!! No power at all on the lower and mid band, like it struggled to get all the way up to 12500rpm. Throttle response was just not there. "floor" it from stand-still in first gear and it felt like it wasn't pulling at all, like there was a void half way through the accelerator. Was very disappointed after a weeks wait! Also, the V-growl was a little more noticeable than usual.

Went back to my mechanic and was told to bring it back on monday to get it dyno'd and remapped.

Anyway, I decided to pull a few hundred miles in it. And to my surprise, after my second tank of gas (I had a 1/2 tank when i started) my bike was slowly regaining all its punch! It felt like it was gradually coming back to normal. VERY STRANGE! But felt amazing. I thought I would be left with no VFR for the weekend and tad-aaah.... al the power was back.. and there was more of it too!

I've been riding all morning and the bike feels less jerky lower down, and much more agile, throttle response is smoother but there when u need it with no delay. A definite improvement lower down. It wants to power wheelie in first and second (front wheel off the ground about 1 foot). I love it. With passenger on-board it wants to wheelie in 3rd too! I cannot imagine what it will feel like with -1 tooth on the front sprocket.

REASONS FOR POWER LOSS:

- ECU reajusting?
- o2 Sensor problem? - I'm told mine doesn't have, I'll try to check if I can see the plugs today
- Exhaust gasket fitted wrongly (back pressure build up) and burnt out the first 100 miles?
Suggestions?
Can anyone relate?


Anyways, TFI is a definite yes (it is cheap too! 105€!!)


Ride safe and vvvvvvvvvvvvv for ever!


I've attatched a little video of where I usually ride, for your viewing satisfaction

YouTube - VFR750 vs 600RR

 

Was your FI warning light on?

 

Nope... No FI warning light!!