rev limiters

[sparkybloke]

Ive just recently had my speedo apart to replace the backlighting lamps and found a black box connected between the wiring loom and the ECU behind the dial. It is not marked with any numbers except saying something in Japanese and M-MAX. i took it out and the bike ran as normal  with maybe better mid range and same top speed, don't know yet what effect on fuel consumption. any ideas on what it is? i was thinking it may increase the rev limit or just change ignition timing advance

[clarkdw]

I can see that one wire is Blue with a red trace but the others are not so visible. What colors are all the wires in and out?
The only Blue with red wire I can see on the schematic is to do with the oil pressure light. Does it still come on with the key on and the bike not yet started?

[sparkybloke]

took some more pics. I cant find corresponding cables in my honda manual 89 - 90 CB-1  hence confusion over what it did! thanx 4 responding

[sparkybloke]

sorry if pics not clear but basically the Honda setup was org+blue to org+blue,brown+black to brown+black and  green to green. I think it is tied up with the engine kill switch wiring along with the sidestand / neutral sw which would seem like a rev limiter but does this mean if you hit max revs the device effectively hits the kill sw? sound a bit risky but I once had a friend who delighted in getting alongside and killing your bike just as he pulled away! this was sometime ago on 50cc mopeds mind you

[clarkdw]

I checked three different wiring schematics. One for 89, one for after 89 and another just listed as for the CB-1. None even show the connector you refer to with the orange/Blue,  brown/blk and green. Sorry I can't be of more help. Maybe it is something specific to the Japanese market bikes that isn't even shown on the English schematics.

On the kill switch note it used to be a practice in racing to reach over and pull in someones clutch handle while at maximum speed on a straight effectively blowing up the competitors engine as it revved to the sky. Don't try this at home folks, we're professionals.

[sparkybloke]

yeah,couldnt find anything in my manual at all,thanx for the racing tip though,the lads down the pub enjoyed it!