Katana Owners Club U.K.

Hello all,

After about 5 years I'm just replacing the battery (normally well served by the Optimate but now lazy).

Apart from the usual dramas of finding a non standard battery of wrong size rammed into a bent cradle with juxtaposed wiring, I've also come across a little black box about the size of a relay marked it seems with a gold "V" and then in black the word "max". It has 2 pink wires and an earth to battery -ve. The pink wires look to connect into the loom normally on pink loom wires. The box had been neatly cable tied in.

As my bike is an SR is this likely to be a speed limit cancel box? - or is it a simple relay like an indicator relay? - any ideas?

Thx

Barry

sounds like its the starter relay, it boosts the power from the battery to the starter motor on start up

Can you get a couple of photos? With the SR having a couple of different features compared to the SZ/SD versions, it could be something to do with the Speed limiter.

Pink wire is speed related. SR is Japan market so it will cut the revs when the bike reaches 118km/h which is the absolute maximum in Japan.

As it's tie wrapped in and from location then it's going to be an add on item so I don't think a starter relay. Pity that uses Vmax on it as Googling it of course brings up lots of Yamaha info!

I tried looking for a wiring diagram from the SR but failed, as knowing what he Pink wire is would help. Do you think the original pink wire has been cut and then fed in then back out of the box? Could you trace the pink wire?

Was there a speed limiter on those - I thought they were just reduced power?

One thought is something like the TRE (Timing Retard Eliminator). I had one of these on my SV650 and my VStrom 650 has one. Basically they reduced the power in certain gears for noise regulations, so you just trick it into thinking it's in 6th all the time. For an idea on this see https://www.vstrom.info/Smf/index.php/t ... 921.0.html. I guess that is a sort of speed restrictor in a away as it reduces power in certain gears.

Other option is to look at bikes of similar age wiring diagrams as they can be similar. I have a GSX600FW (1998) wiring diagram and it shows a pink wire that goes into something called a "Speed Sensor" that feeds out of the speedo.
EDIT: Just read Fossie's post that came in just before mine! So based on the that and the GSX600FW wiring diagram, that speed sensor seem the most likely.

It's basically wot I sed. Up to 1990 little red warning lights in Japan were acceptable for 80 km//h
But after 1990 a maximum speed was introduced and that is why jap speedo don't go past 120 km/h ....the bike won't go over it.
All jap imports Suzuki have a pink wire from speedo.
Look at the wiring to the 400 into black box and follow pink wire from speedo to black box ...when the speedo reaches the required speed a magnet makes a connection and power is cut until the speedo drops below....again and again .

Because the SR is old school with the original CDI which is just electronic points, another way of telling it power down is required.

If you have a blue speed convertor fitted of course you'd never know as the speedo is unlikely to reach 118 mph.

Thanks all - I have a jap parts manual so I'll see if it has a wiring diagram. The pink wires themselves appear standard only the box looks aftermarket. I don't ride it like an arse but having attempted to rev it out at least once it will go " off the clock" which stops at 120 albeit that performance seems to flatten out dramatically. The SR had a load of changes to make its character different making 95 bhp from new but carbs, airbox, cams and exhaust all played a part. Fossie, what is the blue speed converter you mention?

barryr wrote: ↑

Sun Nov 17, 2019 1:00 am

Fossie, what is the blue speed converter you mention?

It's the device that screws into the speedo first and then speedo cable screws into that so the speedo then reads mph. Of course to mileage will be kph upto that point and then miles after.

https://www.mandp.co.uk/products/kph-mp ... ter-501839

UB

Ah right - thx for that. Not fitted to mine- it has the ubiquitous white mph overlay stuck on the glass.

I've seen a speed limit cancel box on eBay from unicorn as I recall. Pretty sure that's what it is then.