Derestricting my DT125

[zykezz]

At first i would like to say hello to all Yamaha riders Im Sakari from Estonia. But now to the point, i bought a DT125R (1999) 3MB00 to ride in the town, well my KTM 250 is not for that . The bike is in good condition done 20 000km, starts every time even in cold, best thing is i got it cheap, for 650 euros. To test it i took it on the highway powerd up and damn a restrictor kicked in at 90 kmh. So did my Googleing and got here and read the topic by Airhead (nice work ), that took me to a conclusion its the reed switch that restricts. I did everything like it was sayd in the topic (for the reed switch), took my bike for a ride and the hell, the restrictor was at 50 kmh, did cut it off to test and it was still at 50 kmh. Did but the switch back and the restrictor was at 90 kmh again so im confused now, does the restrictor close circle at a certain speed or open at certain speed and what happens if i connect the two reed switch wires to close the circle, does this take the restrictor off ?

[Benjamin15]

Depending on what time in 99 it is theres different ways of derestricting them here ill copy it over for you 
 

3RM9 THROUGH TILL 3RME , 97 TILL MID 99 MODELS ! 
 

FIRST REMOVE THE EXHAUST SYSTEM AS FOLLOWS , FIRST REMOVE THE RIGHT HAND SIDE SIDEPANEL AND REMOVE THE EXHAUST SECUERING BOLT JUST TO THE LEFT OF THE BOTTOM REAR CORNER OF THE FUEL TANK WITH A 10MM SOCKET OR RING SPANNER. THEN YOU WILL FIND ANOTHER EXHAUST MOUNTING BRACKET ON THE LARGEST PART OF THE EXHAUST, REMOVE THE BOLT SECUERING IT TO THE FRAME ,NOT VIA THE BOLT ON THE EXHAUST ITS SELF REMOVE THIS THE SAME WAY. AFTER YOU HAVE DONE THIS REMOVE THE 2 NUTS SECUERING THE EXHAUST TO THE CYLINDER BARREL MANIFOLD WITH A 12MM SOCKET, THEY MAY BE SEIZED A COULD POSSIBLY TAKE OUT THE ENTIRE STUD, DON’T WORRY IF THEY DO AS THEY WILL SCREW BACK IN NO PROBLEM. THE EXHAUST IS NOW READY DO BE REMOVED, JUST GIVE IT A WIGGLE AND FIRM PULL AND IT WILL COME OFF FAIRLY EASILY. CHECK THE GASKET IS STILL IN THE MANIFOLD OR STILL CONNECTED TO THE EXHAUST ITS SELF AS IT NEEDS TO BE REFITTED WITH THE EXHAUST.

　
WITH THE EXHAUST REMOVE PLACE YOUR FINGER GENTLY INSIDE OF THE EXHAUST PORT TO THE TOP OF THE PORT AND TURN THE IGNITION TO THE ON POSITION SO YOU CAN HEAR THE YPVS MAKE ITS CHECK/CLEANING CYCLE, YOU WILL FEEL THE YPVS MOVE THROUGH ITS CYCLE. WHEN IT FINISHES YOU SHOULD FEEL THE YPVS FLUSH WITH THE TOP OF THE PORT WITH NO OBSTRUCTIONS TO THE TOUCH. IF YOU CAN ITS SET CORRECTLY. “NEVER TURN THE ENGINE OVER WHEN CARRYING OUT THIS PROCEDURE” 

　IF YOU CANT YOU NEED TO AJUST THE YPVS VIA ITS CABLES, THERE LOCATED ON THE LEFT SIDE OF THE CYLINDER BARREL AND SECURED IN THERE POSITION WITH A 9MM LOCK NUT ON BOTH CABLES.

THE WAY TO DO THIS IS TO REMOVE THE COVER SECURED WITH THE 2 SMALL ALLEN SCREWS, WHEN THIS IS REMOVED YOU WILL BE ABLE TO SEE THE YPVS CABLE PULLY WHEEL. IN BETWEEN THE CABLES ON THE PULLY WHEEL YOU WILL SEE A GROOVE ,WHEN THIS GROOVE IS LINED UP WITH THE DOT THAT IS STAMPED INTO THE CYLINDER BARREL BEHIND THE PULLY WHEEL. WHEN YOU TURN THE IGNITION SWITCH TO THE ON POSITION ,AFTER THE YPVS CYCLE FINISHES, IF THE GROOVE IS ALIGNED WITH THE DOT THE YPVS IS CORRECTLY SET FOR FULL POWER OPERATION. IF NOT ADJUST AS REQUIRED. 

PLEASE NOTE THAT SOME BIKES MAY NEED THE YPVS DIAMOND ROTATING 180 DEGREES,IF THE DOT STAMPED ON THE DIAMOND IS AT THE BOTTOM ROTATE THE DIAMOND 180 DEGREES ! 


ONCE CORRECT AJUSTMENT IS GAINED REFIT THE EXHAUST, REVERSE OF REMOVAL, LOCK THE YPVS CABLES INTO POSITION, REFIT THE PULLY WHEEL COVER WITH A LITTLE STANT GASKET SEALER.


NOW FOR THE DIFFICULT PART ON THESE MODELS ! 

AT THE FRONT OF THE 2 STROKE OIL TANK ON SOME OF THESE BIKES YOU MAY FIND A SMALL SILVER/GRAY BOX WITH A FEW WIRES COMING FROM IT, IF YOU DON’T IT’S A BIT LESS WORK FOR YOU. IF YOU DO READ ON. THESE ARE THE WIRES SWITCHING THE CDI UNIT. THERE SHOULD BE A RED, YELLOW, BLUE AND A GREEN.

　

THE RED GOES TO A BROWN AT THE REGULATOR

THE YELLOW GOES TO A RED/WHITE STRIPPED ON THE PULSE COIL BEHIND THE L/H ENGINE CASE.

THE GREEN GOES TO THE RED/WHITE AT THE CDI.

THE BLUE GOES INTO A PLUG FROM WERE THE YELLOW IS COMING FROM.

NOW FOR THE CHANGES, DISCONNECT THE RED AND THE BLUE AND ISOLATE THEM. YELLOW AND GREEN WILL REMAIN, JOIN THEM TOGETHER, THEN JOIN THE REMAINING RED/WHITE WIRE TO EACH OTHER. MAKE SURE EVERYTHING IS PROPERLY INSULATED WITH DECENT ELECTRITIANS TAPE. IF ITS NOT SINKING IN JUST READ IT A FEW TIMES. 

THE BIKE IS NOW DERESTRICTED AND READY TO RUN !　

IF NO SILVER BOX IS FITTED AND THIS MOD CANNOT BE CARRIED OUT SWAP TO A PRE 96 CDI UNIT , HOWEVER YOU WILL STILL SEE A MARKED IMPROVEMENT IN PERFORMANCE BUT PRE 96 CDI UNITS HAVE A HIGHER RPM REV LIMITER.

　

3RME THROUGH TILL 3RMM MODELS , MID 99 TILL 03 MODELS. 

“NO STEERING LOCK BUILT INTO THE IGNITION SWITCH”

THESE MODELS WERE MADE REALLY DIFFICULT TO DERESTRICT BY YAMAHA DUE TO EUROPEAN POWER TO WEIGHT RATIOS AND EMISSIONS LAWS IN EUROPE.

THE ONLY GOOD THING IS THE YPVS NEEDS NO AJUSTMENT “ON 99% OF THEM ANYWAY” BUT CHECK ANYWAY WITH THE METHOD DESCRIBED IN THE EARLYER MODEL SECTION.

REMOVE THE EXHAUST AS DESCRIBED IN THE EARLYER SECTION, THE RESTRICTION IS NOW MORE DIFFICULT TO REMOVE !!! IT IS TO SEMI CIRCULAR PLATES AND A LOT OF WIRE MESH LOCATED IN THE LARGEST PART OF THE EXHAUST. TO REMOVE THEM THE EXHAUST NEEDS CUTTING OPEN WITH A GRINDER OR HACKSAW AND RE WELDING .

I HAVE KNOWN ONE OF THE SEMI CIRCULAR PLATES TO WORK LOOSE BEFORE BY THEMSEVES , SO IF YOU HAVE A RATTLE IN YOUR EXHAUST ITS PROBABLY CAUSED BY THIS.

NEXT REMOVE THE CARB, FIRST REMOVE THE FUEL PIPE, REMEMBER TO TURN THE FUEL TAP TO THE OFF POSITION. LOOSEN THE 2 JUBILEE FASTNERS THAT SECURE THE CARB TO THE INLET MANIFOLD AND AIRBOX RUBBER.

THEN REMOVE THE BLACK PLASTIC BOTTLE THAT IS SECURED TO THE FRAME THAT PUSHES INTO THE AIRBOX RUBBER IN BETWEEN THE CARB AND AIRBOX.

WHEN YOU HAVE REMOVED THE BOTTLE FIRMLEY BUT GENTLEY PULL THE CARB FROM THE RUBBERS FROM THE LEFT SIDE OF THE BIKE. WHEN YOU HAVE THE CARB FREE REMOVE THE 2 CROSSHEAD SCREWS FROM THE TOP AND PULL THE TOP FREE FROM THE CARB AND REMOVE THE SLIDE. THEN PUT THE CARB TO ONE SIDE.

“THIS PART IS IMPORTANT “

NOW REMOVE THE INLET MANIFOLD RUBBER FROM THE CRANKCASES, BY REMOVING THE 4, 10MM BOLTS ,REMOVE THE SMALL BLACK RUBBER 2 STROKE OIL FEED PIPE FROM THE RIGHT HAND SIDE OF THE MANIFOLD AND BLACK IT WITH A MATCH STICK OR SMALL SCREW. THEN CAREFULLY PRISE IT FROM THE CRANKCASES. 

WHEN YOU HAVE THE MANIFOLD FREE YOU WILL SEE A SQUARE RUBBER NOSE PROTRUDING FROM THE BOTTOM OF IT. THIS NEEDS REMOVING , CUT IT OFF WITH A STANLEY KNIFE OR SIMILAR “BE CAREFULL AND WATCH YOUR FINGERS” ONCE THE NOSE IS REMOVED THE HOLE NEEDS CHAMPFERING OUT FROM THE CENTRE OF THE HOLE TO THE EDGE OF THE MANIFOLD TO CREATE A SMOOTH FREE FLOWING FUEL FLOW. IF YOU DON’T FEEL LIKE TACKELING THIS SEND IT TO ME WITH £6 AND I WILL REPLACE YOUR ORIGINAL WITH A MODIFIED ONE.

REFIT IS THE REVERSE OF REMOVAL, USE A LITTLE INSTANT GASKET SEALER . WHEN REFITTING THE BLACK BOTTLE TO THE AIRBOX RUBBER, COVER THE HOLE IN THE BOTTLE WITH INSULATION TAPE BEFORE REFITTING IT. OR ALTERNATIVELY FIT THE RUBBER FROM A PRE 99 MODEL THAT DOES NOT HAVE THE BOTTLE FITTED.

ALSO REMOVE THE RUBBER AIRBOX NOSSLE FITTED TO THE TOP OF THE AIRBOX UNDER THE SEAT TO LET THE BIKE BREATH A LITTLE BIT BETTER. DON’T DRILL HOLES IN THE SIDE OF THE AIRBOX.

NEXT REMOVE THE HEADLAMP SHROUD BY REMOVING THE 2 SCREWS/BOLTS ,ONE ON EITHER SIDE OF THE SHROUD. THEN REMOVE THE HEADLIGHT BY REMOVING THE 10MM BOLTS SECUERING IT TO THE BRACKET, UNPLUG THE WIRING CONNECTIONS FROM THE BULBS AND PLACE THE HEADLIGHT TO ONE SIDE. YOU SHOULD NOW BE ABLE TO GAIN ACCESS TO THE BOTTOM OF THE SPEEDO, UNSCREW THE SPEEDO CABLE WITH PLYERS, DISCONNECT THE WHITE PLASTIC WIRING CONNECTOR BLOCK THEN REMOVE THE 2 SPLITPINS SECUERING THE SPEEDO TO THE BRACKET IT SITS ON ”THERE SMALL AND FIDDLY SO TAKE YOUR TIME” WHEN YOU HAVE DONE THIS PULL THE SPEEDO UP FROM THE BRACKET. FITTED IN THE BOTTOM OF THE SPEEDO IS THE BACK LIGHT THAT LIGHTS UP THE SPEEDO IN THE DARK WHEN YOUR LIGHTS ARE SWITCHED ON, AND THERE IS A WHITE PLASTIC INSERT PUSHED INTO THE BOTTOM ALSO, PRISE THIS OUT AND YOU WILL SEE WHAT LOOKS LIKE A SMALL GLASS FUSE. THIS IS THE REED SWITCH. WHEN THIS IS REMOVED YOU WILL NEED TO SLICE THE BLACK PLASTIC SURROUNDING THE WIRES SO YOU CAN FURTHER SEPARATE THE REED SWITCH FROM THE BACKLIGHT. PUSH THE REEDSWITCH THROUGH THE SPEEDOS BRACKET SO ITS FREE. DON’T CUT IT OFF JUST LEAVE IT FREE UNDERNEATH THE CLOCKS. THEN REFIT THE SPEEDO THEN THE HEADLIGHT AND SHROUD ,THE REVERSE OF THE REMOVAL.

THE BIKE IS NOW DERESTRICTED AS MUCH AS THE CDI AND CARB FITTED WILL ALLOW HOWEVER YOU SHOULD NOTICE A MARKED INCREASE IN PERFORMANCE, THE CDI HAS A LOWER REVLIMITER AND THE CARB IS DESIGNED FOR BETTER EMISIONS RATHER THAN POWER. HOWEVER I CAN AD THAT SOME LATE 52 REG AND 03 REG 3RMM MODELS SEEM TO HAVE THE UNRESTRICTED REVLIMITER CDI THESE ARE MARKED 3RM-20 AND RESPOND REALLY WELL TO THESE MODS.EVEN SO AS I HAVE SAID YOU WILL NOTICE A BIG IMPROVEMENT REGARDLESS OF THE CDI THAT IT FITTED TO THE BIKE BUT IF YOU HAVE THE 3RM-20 CDI ALL WELL AND GOOD.

IF ITS STILL NOT ENOUGH THERE IS ONLY ONE WAY TO FULLY DERESTRICT THESE MODELS, AND THAT IS TO RETRO FIT PARTS FROM THE 89 TILL 96 MODELS IF THE POWER IS STILL NOT ENOUGH. 89 3RN1 CDI ARE THE BEST THEY ARE THE MOST POWERFULL EVER PRODUCED WHEN DERESTRICTED. 



PARTS THAT WILL NEED TO BE SWAPPED ARE AS FOLLOWS !

COMPLETE WIRING LOOM

CDI UNIT, EARLYER THE BETTER !!!

REGULATOR/RECTIFIER.

IGNITION SWITCH

LIGHT SWITCHES

STATORPLATE

FLYWHEEL “ ITS WEIGHTED ON 3RME 3RMJ AND 3RMM MODELS” 

CARB

　

3 WIRE YPVS SERVO MOTOR “AS THE 5 WIRE FITTED AS STANDARD IS NOT COMPATIBLE WITH THE EARLY TYPE CDI UNITS“. EARLY 97 98 DT125R TYPE OR ANY TDR 125 TZR 125.

　

　

FITTING OF THESE IS THE ONLY WAY TO GUARENTEE FULL POWER DERESTRICTION ON 99% OF THESE MODELS AS THE EARLY TYPE UNDER FUEL TANK CDI UNIT IS NOT COMPATABLE WITH THE LATER MODEL WIRING LOOM..

　

Edited October 29, 2015 by Benjamin15