3TJ CDI Derestricting

[hawksuspension]

Great stuff stuart

Totaly Recomended mate

[JBlade56]

Hey guys, really old post dug up. Does anyone know if Bendy3 is still doing these CDI mods? Really keen to try and get hold of a kit spec CDI.

[Evilchicken0]

Probably - see if he responds to a Private Message

[JBlade56]

Thanks, I've shot him a PM, see what comes of it.

[Evilchicken0]

No worries - welcome to the forum btw

So you have a 3TJ ??? Track bike ???

[JBlade56]

Thank you kindly. I'm actually an NC30 racer from some years back, down here in Cape Town, South Africa. This was my VFR about midway through its development.


At that stage it had the carbon seat that bolted to the main frame without subframe, carbon tank and carbon fairings. Later I managed to get it running very nicely on NC35 carbs inside a carb enclosing airbox that used the tank as an airbox top with ram air. The tank was cut in half kind of like BDK engineering's FZR tank with fuel in the back and airbox volume up front. I can tell that hadn't come yet from the pictures because I couldn't get the ram scoop out above the radiators so I converted to side mount radiators inside those side vents which freed up space for a nice large air intake up front. You can see my Yamaha connection in that picture, the seat unit started out as a 2003 odd R6 seat and the front fairing I modified a crashed R1 set to fit before moulding. That bike was 148kg on the start line full wet, it ran pretty quickly. If I remember correctly it was running 148/150 jets front and rear vs the stock 112s and with an onboard wideband logger it was running bang on with AFRs. I later progressed to a R6s for our regional and national series which came to an end through injury and financial constraints.

The 3TJ development has come about because a close friend and ex team mate's 600 racing career has met the same financial fate and he's started racing the regional powersport class again for 400cc machines but this class has been opened up to 650cc twins. The 650s are lapping at least a second faster then the fastest a 400 has been around our local track, despite their handling being likened to delivery bikes so we're trying to put together a 3TJ on a slightly small budget that can hang with a 650 at least. Our class has a 65bhp so we don't have to go very mad on the engine side so plans are to hit at the weight, the 3TJ certainly has potential to get well under the 148kg of my old NC30 without that anchor of an engine and we already have some pretty up to date hardware in the form of R6 suspension bolted up to the rolling chassis, hoping to get the bike running soon to get him going in the series early and then carry on working on competitiveness. I'm an electronics engineer by trade so I'm hoping to eventually use the bike as a test bench for some custom engine management and EFI electronics but that can come later.

I haven't heard from Bendy so it seems that avenue is a bust, reckon I'll get a box myself and have a go at it on my own bench. Anyone know what goes into the derestriction? Does the stock box perform when all the stock restrictions are bypassed or is there actually some complicated reprogramming that needs doing? Hoping to get at that higher rev limit and don't really see how you'd get the stock 3TJ box to do that without some kind of programming.

[Evilchicken0]

Well the restriction gets a 0 kmh signal from the speedo, if it doesn't it restricts to 12,500 rpm in all gears. Then the speedo sends a signal at 180kmh and the cdi soft cuts 2 (?) cyldiners, if you still try to go faster it cuts them hard so you slow down.
The cdi uses the same circuit as the "reserve" warning , the side stand cut out and the redline - I think if you doctor the 3TJ CDI it takes out the reserve etc but I can't be sure.

There are urestricted cdi's on the 4DX model, they were official UK imports and didn't have the speed restriction

[aceman]

Having stripped various electrical cabling and components off my 3tj for the track, I discovered I had engineered back in the restriction to 12,500rpm. I had an M Max box, but couldn't remove the restriction even with it plugged back in the loom. I sent my TCI box to Bendy and a few days later I am revving to the red line! Thanks Stuart. Looking forward to my next track day; those extra revs will make all the difference.

[bendy3]

Enjoy

[3TJRob]

Hi guys just re-joined the forum after a 10 year absence!

Have got my 3TJ back up and running. Just before it was long term garaged I purchased a set of 4DX clocks and CDI unit. I've just had a look at derestricting the bike using these parts but the connector blocks on the loom are different to those on these components. Is it worth persevering with this. If so can someone offer some advice on what I need to do next? Or is it easier to just get the cdi derestricted?