Yamaha TRX850 Enthusiasts Forum

Hi Everyone, now my bike is running well I was checking the Top end speed of my Trx but my speedo cable snapped
what is the normal top speed of a TRX? I am so pleased with the ride now with the Ohlin shocks fitted.
Does anyone know where you can get a MPH conversion for the KMH speedo mine has indicator stickers over the real
ones.

T.C.

When I fitted the Koso dash I recorded a top speed of 360kph
but the realised it was calibrated to count 3 bolts instead of 6..
But it still looks cool when you go to the top speed recorded function..
Depending on front tyre size, (speedo reads a 6km per 100 kph difference with a 70 series),
Gearing and mods to my bike 16/40 with FCR's , bell mouths and free flowing pipes would get me just over 230kph ( std 60 series front tyre)

(speedo reads an extra 6km per 100 kph with a 70 series)

Interesting variation Cobba'. I've yet to check against the GPS but I found the 70 series actually corrected speedo. In theory, a taller tyre should read slower than actual speed.

Motor testing reviews often rated top speed of a standard TRX (17/39 gears) at 218 km/h but I "know of" 225 being seen on the speedo of a completely stock bike in good tune.

Yes your correct Brett,
My mistake, back to front again.. I think I'm becoming lixdecksic
Gear commander gave a 4.4kph difference (placed in 120/60- 120/70 on the rear) but different tyre manufacturers differ in circumference on a 120/70 ( Anything from 1882mm to 1900mm ) so 6kph is a safe margin.

I've seen 225 indicated on my bike, completely stock, down the main straight of PI circuit many years ago.
Standard tyres, gearing, pipes and carbs.
I'm sure it must go faster as I was riding into a head wind and not trying to go flat out.

dicky.

Theoretical top speed at 8000rpm is 235kmh. Given perfect tune, favourable conditions and enough road, I think a stocker should manage it. Though not on any track in Qld.

According to the dyno, my 17/42 gearing topped out at 152mph (244 kmh) bouncing off the rev limited at 9750.

Brilliant info chaps, has anyone tried a little NOS on these TrXs and did the engine stay together with it being a twin,
I suppose it wouldn't like it for long?
Does changing the rear sprocket up two more teeth help the top end much and I suppose it makes the bottom end struggle
too much?

TC

Going up in tooth at the rear makes the bikes speed lower at the same rpm.