Members Login
    Remember Me  
Post Info TOPIC: FZR400 3TJ Hacking


Status: Offline
Posts: 2
FZR400 3TJ Hacking

Hello there,

I recently interested on "hacking" a Yamaha FZR400 RR ECU. The bike has  frame  3TJ.

The ECU reads BB7208 3TJ-00. Its based on Hitachi HD6301 or 63701 family MCU. These they differ on speed. Here are the datasheets:

Now these ECUs are restricted somehow. Eg disconnecting the EXUP motor from the harness stops the ECU revving over certain rpm. Same issue with the speedo. The ECU cuts out on 180km and if it doesnt get signal from the tacho directly falls into automatic restirction mode and not going over a certain rpm.

Luckily there were a version of this bike called RRSP. That was the race version of yamaha. On this model Yamaha removed all the restrictions of EXUP, speedlimit on the ECU etc and also lifted the rev limiter to 15400 rpm.  

Some ppl in the UK eg BDK enginnering or some privateers managed to read ***I think***  the eeprom of the RRSP ECU and reprogram a stock 3TJ-00 unit resulting in turning the stock ECU in a race one. Unfortunately they charge a lot of money for it. Your forum its really great!  

I want to find out the how to's here in details and apply this not only to 3TJ-00 ones but 3EN1.2 FZR400s that seems to be exactly same ECUS. Also i will see if by editing the eeprom i can change some parameters on the ECUs eg the rev limiter which at 15400 rpm is a bit too high for this bike.

Now I will post loads of photos and be aware I have programmed MCUs before. However I am not familiar as to what an ECU is equiped for. An MCU i guess for start. But then? Eg usually using the MCUs storage or have a different chip to handle parameters? Eg in my specific case below I would post photos of stock ECU boards  3TJ-00 and also photos of the modified BDK ones (ala RRSP race) . You would see easily looking these pics that amonst others BDK has removed two resistors. Initially I thought he is putting the HD63701 in eprom read/write mode and using some UV and SOIC kind of clip reprograms it with the hex of the RRSP unit.

However now i think its much simpler as ppl like them are usually clueless on electronics. I think the "black" 8-pin chip next to the 2 resistors missing from the modifying "race type" ECUs is a (serial) eeprom and all they do is read/write this supplying 5V to the board.

I will need help from you guys that you know how ECUs are structured to find if I am on the right path.

Kind Regards,

PS: data.jpg is data.pdf the datasheets

PS: Perhaps a section FZR400 will be more appropriate?




Status: Offline
Posts: 1


I just made it on my FZR 400 4DX, but the bike doesn't go further than 12000rpm.
Does it give another restriction on this bike?

Page 1 of 1  sorted by
Quick Reply

Please log in to post quick replies.

Tweet this page Post to Digg Post to

Create your own FREE Forum
Report Abuse
Powered by ActiveBoard