Restrictions
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Just wandering what restrictions are on my bike that's easy and quick to sort out I have a 2002 dtr125?
Can anyone help. -
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@smudge1995 The complete guide for derestricting;
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@tunertom I take your point, my DTR had it's stock front pipe cut open and derestricted. I was unable to test for a before and after to feel the difference personally. But it's probably a safe bet that most owners will not go to that trouble and just swap the whole exhaust over for a DEP, Giannelli etc or similar after market exhaust set-up.
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@tunertom Yeah that inlet manifold is a load of tosh, but don't discount Scrim, he knows his shit.
@CYBER-NINJA haha yeah I did chop my exhaust up and removed the cat, but oh my seriously those pipes have some serious weight, so if not for the performance the weight alone is worth swapping out lmao!
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@Calum said in Restrictions:
@tunertom Yeah that inlet manifold is a load of tosh, but don't discount Scrim, he knows his shit.
@CYBER-NINJA haha yeah I did chop my exhaust up and removed the cat, but oh my seriously those pipes have some serious weight, so if not for the performance the weight alone is worth swapping out lmao!
Hi I have his destruction manual and seems mostly since
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Quick answer since I have a 2002 as well (DE03):
1 - Swap expansion chamber (the blobby exhaust bit) to an Athena or something. This was the big thing.
2 - Pull out the reed switch from behind the speedometer. Do not disconnect it or cut any wires, just wrap it in tape and stuff it aside. It detects when the needle gets to ca 80 km/h and cuts ignition there.That should be it, your bike should now rev freely to 9500 rpm and do 120+ km/h.
Also: ensure that the YPVS is working as it should. Remove the round cap on the left side and turn on ignition. It should rotate back and forth a little, then settle such that the groove on top is right over the hole.
Explanation on that last bit: The YPVS switches the port timing between low revs (more torque) and high revs (more power) as the revs increase and decrease. Variable valve timing, you could say.
When you turn on the ignition it rotates back and forth (flips between low and high mode) to scrape off soot. The resting position should be over the hole because they used that hole to fixate the valve in low-revs mode (and turning off or removing the solenoid actuating it) when they restricted bikes, but I believe they stopped using that method after 1998 or something. If it does not rotate back and forth with an audible "bzzt-bzzt" when ignition turns on, your YPVS is not working and stuck in either of the modes.
As for the inlet manifold I did a thorough CFD analysis and found that you cannot improve it. Leave the plastic bottle on, it smoothens out the gas flow. The carburetor should not need anything either, it is likely a Mikuni TM28SS with a 240 µm main jet, which is perfect.
