Derestricting a Yamaha DT125R 2004

A lad in the factory has just got one of these and is struggling to
find out how to derestrict it. He's quite mechanically minded but can't
seem to find the answer anywhere.

Open to the floor

 

from when I had a dtr 125 I seem to remember there is a rotating
valve in the exhast port and you turn it so that it's open. Or there is
a some other sort of washer there that you can remove. Not sure if you
need to change the carburation at all. ISTR mine blew up on the dual
carriage way, needing a re-bore. quite pokey though.
Simon

 

That makes it shite, not derestricted. The modern ones are restricted in
the engine black box. I remember something about an older DTR black box
on the newer DTR makes the already fitted powervalve work properly
again.

 

From http://www.yamahaclub.com/forums/index.php?showtopic=2553

Might help.

When you say 2004 the following is for the Electric start RE Model!

A new pipe and silenser kit will help below 65mph, however the YPVS is set
to close above this speed and creates an effect of the engine speed dropping
untill you drop a gear.

Take the light housing off and find the wire loom, black rubber housing, the
indicator wires run into it, you will find a green/black wire that is
connected to nothing, get some male connectors for an auto shop with about 2
meters of wire + a ring ended connector (fit wire and connectors, you can
press some of them closed around the wire) and run this under tank and air
box to the main system earth under the old kick start hole (Now a black
rubber blank plate).

This connection allows the power value to fully open to the red line some
11000rpm not close at 8000rpm, note is nothing to do with any rev limiting
system as one do's not exist, however its upto you how you us the bike once
this is done, but 11000rpm is not over the top for a 2 stroke bike in
anycase, (use the best oil and change the gear oil often) at least you can
enjoy the engine, if you intend to keep it in 2nd for ten mins from the
lights thats your problem!

I did the wire fix before exhaust and although the Dep made some diff the
power valve already added some 20mph, the dep sounds good and makes the bike
easyer to lift in the dirt but only added about 8mph!

HTH

 

Was it a 2004 model?

And the rest of your advice is shite as well.

Top tip: give advice only if you're sure of your ground, otherwise all
you cause is noise and possible harm....

 

Ah, well. There's the problem - bottom half of the crankcase is missing,
innit?
--
Dave
GS850x2 XS650 SE6a
I demand nothing of you except that you amuse me.

Folding@Home Team UKRM
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