DT125R FORUM

Calum

Yes your DT will be autolube. If it wasn't... you'd have known by now.

You'll need to keep an on eye on the two stroke level and refill it as it gets depleted.

Calum

Hi Mohamed,

That is a cool looking bike you have there.

I am not too familiar with the newer models as it's not something we get over here and I don't know what performance upgrades are available in your region.

Definitely like to see more of what you do to the bike though!

Welcome to the forum.

Calum

Hello there,

As far as I was aware the Yamaha DT was discontinued in 2007 instead Yamaha makes rhe WR series.

That looks like a cool looking bike though, would love to know more about it.

I take it you're in the Asian market, hence why this is still available. I didn't know that the bike was still being produced there.

I'd almost argue the bike's styling is closer to the 80's LC model vs the earlier 70's model, with the bike using an aircooled design over the liquid cooled variant.

Sorry I can't be much more help than that, still cool bike though!

Calum

@hotshot-iii That's a very cool video and local to me too!

A crated Banshee, wow what a museum piece.

I had no affiliation with the Banshee prior to this build, but what a machine and what an era for motorcycling. All lost to time now and kids these days won't know the joys of machines like that.

Calum

@HOTSHOT-III Yeah and the tuning possibilities for the RD is all thanks to the Americans and the love for the Banshee.

I just think it's amazing that an engine basically designed in the 60s was used competitively all the way up till today.

Wow a Banshee new in crate, that's silly! They command good money now for a Banshee.

Calum

Sadly Imgur is no longer accessible in the UK. So I am not able to see the photo.

But in essence, yes the bullet connector for the loom connects to the neutral switch on the gearbox. So using a spade connector and a wire to go to the bullet connector.

Calum

Wow, it's really sad how long this project takes to come to fruition...

Maybe I'm spreading myself too thin with way too many concurrent projects, maybe it's because for the first time in my life I've been doing stuff other than motorbikes/cars, but in any event December saw lots of time off for me and I was able to drag what I've been accumulating out of the wardrobe and start with some head scratching and engine work assembly.

Banshee/RD 350 Athena 421 Bottom End Assembly

With that all said, this month I took stock of my inventory and I came to realise that I had virtually all of what I needed to close the crankcases up on my Banshee 350 motor, in preparation of assembling the Athena 392 kit.

As some of you may know, there is free performance to be made if you port your crankcase's transfers to match the transfer ports on the cylinders. The Yamaha RD 350/Yamaha Banshee engines are notorious for leaving steps in between the transfers for the bottom end and the cylinders. Since I intend to run the Athena Big Bore Kit, this step is even more exacerbated.

In a nut shell, here I'll be marking out this discrepancy using some Dykem Blue engineering fluid, then scoring a visible outline using my Facom Scribe and then with my die grinder, porting the bottom end to match.

For reference again, the engine cases I bought were brand new direct from Yamaha. As such this gives a good example of how much, unmolested cases need to be grinded away.

You can get a rough idea of what needs to be cut by overlaying the gasket over the bottom end and marking out the material that needs cutting out.

In my cases, I painted on the Dykem Blue and assembled the cylinder to the bottom end. This squished out excess fluid and left a visible line of where the cases meet the cylinder.

Here I've placed a guitar pick into the location of what we need to cut. There is a visible step here that should be machined away using a die grinder.

To ease the cutting process, I've washed away any excess Dykem Blue fluid and scribed a distinct line for where I want to cut up to.

With all the appropriate markings made out, it's time to grab the die grinder and port the bottom end to match.

I'm using a Rounded Tree Shape gold coated carbide burr. It's coarse flute geometry and titanium nitrate coating prevent the flutes from becoming clogged up and essentially cut through the alumiunium like butter.

In only a matter of seconds I've roughly cut out the intended shape.

Care MUST be taken here that you don't go too deep into the trenches. The crankcase walls are pretty thin towards the bottom and therefore care must be taken to avoid porting straight through the cases.

I've taken a photo here to give you a clear indication of how deep you'll want to aim to go.

I've gone around and done a rough cut of the desired shape.

I can quickly overlay the gasket to ensure I'm along the right track.

Note: The gasket used here is only a basic indication, there are cases where the gasket protrudes into the transfer ports and as such the gaskets need trimming. Therefore the method described above is preferred to get the perfect shape. This is especially true for ported cylinders.

You can see here a Before/After photo and how now the pick is not being covered by the bottom end transfer ports and now correctly aligns to the cylinder transfers.

The cases need to be thoroughly cleaned throughout to ensure no swarf is left anywhere.

These cases can be ported to quite some degree, since this is only running a mild big bore kit, the extent of the transfers needn't be too significant.

With this out the way, I can now start to assemble the bottom end with all the trick bits I've bought.

Bottom End Assembly

Now that the porting work has been completed and the gearbox rebuilt with a taller first gear, it's finally time to assembly the crankcase halves.

Here the selector drum can be installed along with the dog ears. The selector drum has been modified to aid easier shifting and easier neutral detection. It's a common mod for these engines and involves grinding away at the shift star to make the ramps more pronounced.

The upper crankcase halves have been installed with lightweight titanium studs.

The 4mm Hot Rods crank can be installed, along with the straight cut primary gear. New seals throughout and I also acquired/installed new bearing clips that were allegedly tighter tolerances than the OEM ones. Although upon inspection they look much of the muchness to me.

The gearbox wouldn't be complete without all new bearings throughout, although my bearing was missing the much needed circlip. Luckily I have amassed enough spares in my workshop to salvage a bearing clip from another gearbox.

Here is the gear on the output shaft which was swapped for the 1st gear conversion.

Along with the shift star mod, I've also got a modified detent arm (with roller bearing) and shift lever with the cut outs widened to give greater movement to the shifter mechanism.

All the gears were tested/shifted to ensure correct alignment and engagement.

The shifter mechanism operates on a cam which needs to be aligned prior to sealing. A relatively simple job once you understand what you're looking for, but easy to overlook. Once the alignment has been done, the locking nut can be tightened.

Low profile grade 5 titanium bolts are used to affix the baffle plates and bearing retainer. Everything inside this engine is brand spanking new, since I have been building the engine from scratch.

I've just ordered a Pro Design Billet Stator Plate, not that I'll need it as I plan on running a Zeeltronic ignition system, however it should finish off the bottom end nicely. I also ordered a chinese copy which looked perfectly serviceable.

I also decided to buy the Pro Design Wicked Cool Billet Head to fit onto my Athena Big Bore kit.

I still need to get a clutch basket and clutch plates, then my straight cut gears can all be installed and the bottom end completed. This will have to wait a few months as this is quite an expensive item to acquire.

In order to get the top end assembled I need to ditch the Athena Pistons and order some appropriate ones for the stroker kit.

Carbon Fibre Moulding

On a side project, for the panelling on this machine I want a Carbon Fibre tank guard. This really isn't an necessity and I've merely been messing around with various techniques to try get a feel for how hard it would be.

Initially I started off with a moulding kit, but I ordered an inappropriate amount, failed to fully do the prep work and rushed the process. The result was the mould cracked upon separating.

Next I instead opted to just do a simple design to better understand the technique. Here I designed a part I wanted for the clutch cover in CAD then 3D printed the part to make a mould from.

This too failed as I was unable to separate the mould from the part and as a result the whole thing was scrapped. I was starting to grow impatient and finally I decided I'd directly 3D print the mould and then make a carbon fibre part directly from the mould.

To my surprise, this actually worked out really well (given the low-budgetness of it all), however I was not getting the desired effect. I wanted the lettering to be really pronounced as it is on the original part. However the lettering is feint and is mainly made of the epoxy which fell into the mould and not the carbon fibre.

I refined the approach, this time creating a mould-press to help form the lettering. I wanted to use a red carbon weave to accent the bikes final "Black" colouring.

But this again was unsatisfactory and I decided to ditch the lettering and call it a day for that idea and just focus on making a singular part.

Although the weave got distorted, the part came out better than I expected.

Sadly, I don't love the result, it actually looks better when the light isn't shining directly on it.

I am happy with how the part has come out, it's done as a budget part and it has worked to a degree.

Undeterred, I've given the moulding process another shot to see if I can fair up better. This time making sure I do plenty of prep work and don't rush it.

Actually pleased to say the moulding has worked! So I now have something that I could potentially make a carbon fibre part from. I know you can get reasonable jobs from this type of setup, I am not looking for perfection here, just something to give the bike a bit of bling would be nice.

Sadly, I ran out of carbon fibre weave to actually progress with this and I'm not sold I want the red carbon/polyester weave, however I've seen you can get red pigments for the epoxy resin which I may give a go with this mould.

Conclusion

Still a LONG way to go, but having the crankcase halves assembled is a huge milestone for this project. I'm hoping that next year I can get the cylinder work completed and the engine closed up. Once this has been done, I'd like a Bitubo steering damper welded to the frame and then the frame and ancillaries can go off for painting. Then it'll be case of rolling the chassis!

Calum

The right attaches go the airbox. It's the main power cable. So the positive terminal for the battery attaches to it.

The one on the left looks like the CDI wires, so attaches to the frame.

Calum

@rich1299 said in Yamaha DT 125 R derestriction:

Hi I’m looking at de restrictions on my 2007 dt 125

Could you possibly tell me what I can do to get more power

Hi @rich1299,

It's literally described in the last paragraph of the post I made.

Zeeltronic ignition system gives a big boost to midrange
DEP system also boost mid range
VForce Reed block
Bigger carb
Athena 170 Kit
Cylinder porting
Head squish adjusting
Lightened flyhweel

Just to give you some ideas...

Calum

Merry Christmas Everyone!

Wishing you all a very merry Christmas and thanks to all that have contributed to the site.

Hope you all have a wonderful day doing whatever it is that you do.

Calum

Calum

@raceraidan Let's just focus on the engine at the moment as I am confused as to what you have. If I don't know the engine, then we're going to be chasing a rabbit down a hole here.

If the engine came from a Gilera originally, then it is not an '89 engine.

It'll be a DTRE motor that was found in Yamaha's later production run.

The reason why this is important is because the flywheel on the last revision of engines is inverted. The cranks are different to compensate for this and then so are the stators. Besides the removal of the kickstarter (which can easily be retrofitted) they are identical crankcases/engines. It's only the aforementioned changes.

Secondly, I am not as familiar with the Gilera side of things, I know the engines are similar to the later DTRE, however the ignition is different.

A few years ago I couldn't get my DTR running right (turned out to be a Chinese ignition coild, swapped it for genuine and all problems went away) and when trying to diagnose an issue, I tried to source an OEM DTRE CDI, as I run Zeeltronic ignition system and have had the misfortune of having a faulty one in the past.

RE ignitions have all but dried up (I never should have sold mine) and the only thing I could get my hands on was a Gilera ignition.

Because the engine's are the same, I thought it was worth a punt, but alas I couldn't even get the engine started with the Gilera ignition and as such we need to understand your engine.

You fitting a random engine into a random frame is not going to help us identify the problem. So we need to understand the parts you have in order to diagnose.

There used to be guru's in field like @scrimsmustang who could tell you the engine year from the engine number, unfortunately I don't know how to resolve that, but I can tell you a lot about the engine from some exterior photo shots and whip the generator cover off and get some pics and I'll tell you some more.

Let's go from there and work our way out.

Also yes, with regards to the side stand switch, these can be a royal pain in the bum. Years ago my brother had a 2001 DTR and something was wrong with the sidestand switch and looping it out wasn't sufficient, I can't remember if he grounded the wire, but whatever it was, you legit couldn't start the engine with the key in the 'On' position, you had to kick it over and switch the ignition from off to on to get it to fire up.

So I am weary about the side stand switch.

The oil light I am not worried about as as far as I know, it doesn't loop back into the CDI, but a Haynes wiring diagram will confirm this. If I go into my workshop at some point I will have a look for you.

Calum

Not aware of an '89 DTRE engine.

In the UK the DTRE was from 5-07 where the bike was discontinued, but in France there was some Electric start DTR engines. But I don't know too much about those.

The best thing to do in theae situations when you're lost, is get the bike back to standard. This means fixing the sidestand switch and 'oil sensor switch' (I presume you mean the neutral switch on the bottom of the engine).

These engines are incredibly simple, so it shouldn't take too much head scratching to figure out.

Calum

@matt0084 Yeah, I only say that as it is a known issue where the cables get mis-installed and the servo doesn't operate as intended.

I find that the alignment hole in the cylinder doesn't allow the valve to sit flush in the port. I always align the valve with the exhaust off to guarantee alignment.

Calum

Hi @matt0084,

77MPH sounds pretty decent to me! My DTRE certainly doesn't reach those speeds anymore and I've just about tuned everything on it. I swear when I got the bike bone stock it did 80+ and went off the clocks. But alas, I suspect I've put on weight and so has the bike and that's what I'm left with.

I'm not sure what restrictions Italian models would have had, are they the same as the UK models.

Of course, making sure the YPVS is working is going to be your first port of call. The way I check this to rule out other possibilities, is to align the valve with the exhaust port so that it is flush and then disconnect the powervalve system.

Go and take your bike for a ride. Without the valve you'll notice it's lost all bottom end, but after 6K RPM you should feel the bike come alive and scream to the red line in every gear. This is going to be what your bike would be like if the valve was working (minus the bottom end loses).

If your bike is like this, then you know the issue lies with your valve timing (you've indicated it's reversed so unreverse it).

If your bike is still sluggish and slow, then your problem lies elsewhere.

It's a misnomer about the second bottle on the boot. Please restore this bottle to the air boot, it is not a restriction.

On the DTR engine there is free performance to be gained by flowing the crankcases. If you remove the reed block and look down the inlet port, you will see that the spigots on the bttom of the barrels protrude into the ports. There is around 12mm to be removed from the spigots.

Also, port matching the bottom end to the cylinder is very important. If the crankcase transfers don't match the barrel transfers then you're just dropping performance on the floor.

Sadly both of these free performance improvements require you to dismantle the engine, but worth bearing in mind next time the engine is stripped.

Calum

Hello @matt0084 and welcome to the forum.

Amazing, what a choice for a bike at 17.

Thanks for taking the time to say hello.

Yes, you always have to start somewhere and the DTRE is a great bike to start with. That's where I started out learning about bikes/mechanics all those years ago and then the passion for bikes just spiked!

Calum

@ChuckSR86 Do you have a DTR or a DTX?

or

I must admit, if it's light greenlaning, then you can get away with it on supermoto in the summer?

Anything more hardcore then some knobbley's would be ideal.

For simplicity, I'd be lacing a set of hubs with ally rims for knobbleys. That way you only need to swap the wheels and not the brakes.

Calum

Hey @rhodes5150,

Nice early example which should hopefully be full power.

Best thing you can do with these is to start by getting them full stock. That's a derestricted CDI (yours sounds like it should be), then making sure you've got a working YPVS system which is setup correctly.

If the engine is sweet, then leave it alone for the time being. If it's aged and worse for wear, then getting it rebuilt is the way to go. These engines are incredibly simple and easy to rebuild with no specialist tools required. Can drop the bearings in by using a conventional oven heating the cases up.

Checkout Yamaha DT 125 r derestriction to see what's needed for your bike.

Once you've got the stock motor running sweet, and you still want more power then here are a list of mods I'd do (haven done most of what can be done, experience tells me this is the best order and bang for buck).

Exhaust System
- Full DEP system
- Really perks up the mid-range punch
- Cuts out significant weight over the stock system
Zeeltronic Ignition System
- Over my DTRE/X (pretty restricted CDI) really punches up the midrange
Carbon Reeds
- I run VForce4 Reed block on my DTR
- But generic carbon reeds can help
- Mileage may vary I'd struggle to tell the difference
Porting work
- Making sure the head/squish is correct is where you'll get the most gains
  - Cheap to get someone to do and can make or break a two stroke
- Having the cylinder done can be more expensive and mileage may vary on this
Athena 170
- I've grown to appreciate the 170 kit
  - It doesn't compare to RS 125 big bore kits or other extreme setups
- Massively increases the mid-range (reducing overrev)
- Makes the ride much easier to live with
- Of course this can also be ported to make additional gains here.

You can do other mods, such as skimming the flywheel. This doesn't give you any more power per se, but allows the power to be obtained faster. This can drastically affect the overall performance though, so sometimes it's best to leave it alone.

Calum

That's a shame.

Cannot you not find another RD 125 LC engine to go into it?

https://www.ebay.co.uk/itm/205474590726?_skw=RD+125+YPVS+engine&itmmeta=01KC275HYWNTSFVH91MXMV4C5S&hash=item2fd73d7006:g:98sAAeSwFkVoHSMO&itmprp=enc%3AAQAKAAAA8FkggFvd1GGDu0w3yXCmi1flawLV8IY1Q%2BrlqkKlic4SXFWM4Bld3oyF05bRU9LUWdscqYhvVTtdOkDY1%2FG3VHo2NDyEqwWMHCxK%2FEnHmUlNOTtyxRChFwHDMDNF4hGFsYNO1%2BMNJrpzoEsKSn51cql8ycAzXLVFuB3lm9gzggENh6xG3wkWaiJYWF%2BPgQC6SlEwBUem7jb9XUrr4v3klWvcQO395O%2BoKhv0EA5leglUnC07mgX2160r8f0UQ0ksnKFzMKYc1uIYwZCBdJ1dkvGS4dePYxAQYLnYPN52YUY2%2FMNGbqYBxafQAv%2BFjefTfA%3D%3D|tkp%3ABk9SR8qflsfgZg

I'm assuming the DTLC and RDLC shared the same motor.

https://www.ebay.co.uk/itm/297655151397?_skw=Yamaha+DT+125+LC+YPVS+engine&itmmeta=01KC27ARB03RWQF3WQ34R07YK5&hash=item454da12b25:g:I7UAAeSwLwxo33bh&itmprp=enc%3AAQAKAAABAFkggFvd1GGDu0w3yXCmi1dScxS26vLr3VUxzzoLKz9MCz6BhUKDd6IJJgX0%2BGOr8YuwtuuVfIyONqKuFIBnfAArFY5FNCepeYi5b5uc3kbel4XOdj%2BzswSkhLKfQgWW9ntz0QB%2BVtvaxZ7cAFCUknzv7XrMRHzyeZAjIvK1OTxi5r3mKqV0B5ZOJoCtR0OKRxBzgJ33j%2FABOqWk4nDl3JIPiW%2FZxhjlbl4YqY54MVwLvB1X0Q1k0cvTloKDsnomN7P3m3yA9SezgGppswLbyMXyb9hp86tgoW1931wr4UzZjpV43PIivf7RHCa%2F5d0h1duFjDOcXl1ZE38zIEz6lsI%3D|tkp%3ABFBM5IWrx-Bm

From what I've heard, the LC engine is more performant than the DTR engine.

Calum

All credits go to @scrimsmustang

3DB1 THROUGH TILL 3RN9 , 88 UNTIL 96 MODEL YEARS !

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.

NOW LOOK INSIDE THE EXHAUST WERE IT MEETS THE MANIFOLD YOU WILL SEE AN INSERT “SMALL TUBE” SECURED BY 3 SMALL SPOT WELDS, REMOVE THE WELDS WITH A DREMMEL OR DRILL OR ANYTHING YOU HAVE IN YOUR TOOLS TO DO THE JOB, AND THEN REMOVE IT.THAT’S THE EXHAUST DERESTRICTED, REFIT IS THE REVERSE OF REMOVAL !

WITH THE EXHAUST REMOVED YOU WILL NOW BE ABLE TO INSERT YOUR FINGER INTO THE EXHAUST MANIFOLD OF THE ENGINE, DON’T WORRY THERE IS NOTHING SHARP IN THERE TO WORRY ABOUT !

“WARNING” ONLY WHEN THE ENGINE IS COLD AND DO NOT TURN THE ENGINE OVER WHEN CARRYING OUT THIS NEXT PROCEDURE !

DON’T WORRY YOU DON’T NEED TO PLACE YOUR FINGER IN THE MANIFOLD YET, ON THE LEFT SIDE OF THE CYLINDER BARREL YOU WILL SEE A ROUND COVER WITH A 10MM BOLT IN THE CENTRE AND 2 SMALL ALLEN SCREWS EITHER SIDE OFF IT, REMOVE IT , 10MM BOLT FIRST THEN THE 2 SMALL ALLEN SCREWS.

UNDERNEATH THE COVER YOU WILL FIND A SLEAVE WITH A SMALL PEG IN IT THAT SECURES IT TO THE CAP YOU HAVE JUST REMOVED. REMOVE THE SLEAVE AND YOU WILL HAVE ACCESS TO THE “YPVS DIAMOND” WITH A THREADED HOLE IN THE CENTRE WERE THE 10MM BOLT YOU REMOVED SCREWS INTO AND A DOT STAMPED INTO IT !

NOW YOU NEED TO INSERT YOUR FINGER INTO THE MANIFOLD”TO THE TOP”, AT THE SAME TIME SLOWLY ROTATE THE YPVS DIAMOND, YOU MAY NEED PLIERS TO DO THIS ,AS YOU DO THIS YOU WILL BE ABLE TO FEEL THE YPVS ROTATING INSIDE THE EXHAUST PORT, WHEN YOU FEEL IT FLUSH WITH THE TOP OF THE PORT THAT’S IT.

REFIT IS THE REVERSE OF THE REMOVAL. CLEAN THE MATING SURFACES OF THE COVER AND THE CYLINDER BARREL AND REASSEMBLE WITH A LITTLE INSTANT GASKET SEALER. YOUR BIKE IS NOW DERESTRICTED AND READY TO RUN !

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

THE PROCEDURE FOR THE EXHAUST IS IDENTICAL TO THE MODELS PREVIOUSLY COVERED, HOWEVER THE MODELS COVERED IN THIS SECTION HAVE THE SERVO FITTED AS STANDARD TO ELECTRONICLY OPERATE THE YPVS SYSTEM.

TO CHECK THE CORRECT OPERATION AND SETTING OF THE YPVS SYSTEM ON THESE MODELS. WHEN THE EXHAUST IS OFF FOR DERESTRICTION IT ALLOWS VERY ACCURATE CHECKING OF THE YPVS WITH THE EXHAUST REMOVED.

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..

IF IN DOUBT JUST ASK !

ON 3RME ONWARD BIKES , BUYING A CDI FROM GERMANY ETC ON EBAY WILL NOT SOLVE THE PROBLEM AS ALL OF THE EU USE THE SAME RESTRICTED CDI UNIT. THERE IS NO FULL POWER CDI,S FOR THESE BIKES , ITS AN INTERNET FORUM MYTH. EXCEPT FOR THE ONE OR TWO 3RMM BIKES THAT I HAVE CAME ACROSS THAT DON’T SEEM TO BE AS BAD, I HAVE YET TO BE ABLE TO MAKE OUT THE PART NUMBER ON ONE OF THESE THOUGH.

PEOPLE SELLING THESE OPEN CDI UNITS ON EBAY MAY BE SELLING A FULL POWER 3RMM UNIT BUT I WOULD NOT TAKE A CHANCE ON IT AS THERE MORE THAN LIGHTLY JUST SELLING THE RESTRICTED UNIT AFTER A FULL POWER RETRO FIT CONVERSION.

IF YOU CAN GET A PART NUMBER IF YOUR CONSIDER BUYING AN OPEN CDI FROM EUROPE GET THE PART NUMBER IF POSSIBLE AND CHECK IT WITH THE PART NUMBER ON YOURS IF YOU CAN MAKE IT OUT. OR WITH YOUR LOCAL YAMAHA DEALER AND YOU WILL NO DOUBT FIND ITS IDENTICAL TO THE TYPE YOU ALREADY HAVE.

PRE 3RME BIKE USE A DIFFERENT WIRING LOOM AND THE EARLY TYPE FULL POWER CDI UNITS ARE JUST NOT COMPATIBLE WITH THE LOOM AND YPVS SERVO. SO THE RETRO FIT IS THE ONLY WAY TO GET AROUND IT.

I HOPE THIS HELPS, IF YOU HAVE ANY QUESTIONS JUST ASK, DON’T WORRY JUST TAKE YOUR TIME AND YOU SHOULD HAVE NO PROBLEMS JUST MORE GO !!!

YOU CAN ALSO FIT A SET OF RACING REEDS , BOYESEN OR HY TEC ETC AND A PERFORMANCE EXHAUST SUCH AS A DEP , FRESCO BIGONE OR ARROW ETC AFTER YOUR BIKE IS DERESTRICTED. THESE WILL GIVE MORE TORQUE AND A SNAPPIER THROTTLE RESPONSE.

PERSONALY I WOULD CARRY OUT THE RETRO FIT FIRST ON THE LATER BIKES. THE PERFORMANCE EXHAUSTS ETC WILL NOT MAKE THAT MUCH OF A DIFFERENCE ANYWAY WITH A RESTRICTED ELECTRICAL SYSTEM.

IF YOU WOULD LIKE THE SAME POWER DELIVERY AS THE EARLY BIKE YOU CAN PEG THE YPVS IN THE FULLY OPEN POSITION SO YOU GET THE POWER KICK AT AROUND 6500 RPM. I LIKE THE POWER DELIVERY LIKE THIS MYSELF.

THAT’S ABOUT IT , THANKS AND HAVE FUN.

REMEMBER A SERVICE IS ALWAYS A GOOD WAY TO KEEP YOUR BIKE RUNNING WELL AND THIS IS A GOOD TIME TO CARRY IT OUT, FRESH OIL A NEW PLUG AND A CLEAN AIRFILTER AND AIRFILTER BOX. YOU WILL BE SURPRISED HOW MUCH A DIRTY CLOGGED AIRFILTER WILL AFFECT THE PERFORMANCE OF YOUR BIKE.

DT125RE AND DT125X 2004 ONWARD !

THE NEW MODEL BIKES ARE REALLY STILL MORE OR LESS THE SAME AS THE OLD BIKE EXEPT FOR THE NEW STYE BODYWORK AND THE FITMENT OF THE ELECTRIC START AS OPPOSED TO THE KICKSTART. ITS IDENTICAL TO THE DT230 LANZA THAT’S BEEN AROUND SINCE 96 ALTHOUGH NOT OFFICIALY IMPORTED INTO THE UK BY YAMAHA.

THERE VERY EASY TO DERESTRICT COMPARED TO THE OLDER VERSION.

THERE IS NO REEDSWITCH FITTED ON THESE BIKES , THE EXHAUST HAS NO RESTRICTION AS SUCH FITTED, HOWEVER IT IS FITTED WITH A HOTCAT CATALYTIC CONVERTER THAT IS WORSE THAN THE OLD RESTRICTIONS. IT IS REMOVABLE WITH DIFFICULTY , THE EXHAUST NEEDS CUTTING OPEN AT THE LARGEST PART OF THE EXPANSION CHAMBER TO GET AT IT.

NO DOUBT THAT WHEN THE BIKE NEEDS ITS FIRST MOT TEST IT WILL NEED THE CAT, SO I WOULD JUST FIT A DEP SYSTEM ETC. OR A DERESTRICTED EARLY MODEL EXHAUST , THERE SLIGHTLY DIFFERENT BUT FIT WITH VERY MINOR MODS. ONE BRACKET NEEDS MOVING AND THE TAILPIPE NEEDS SLEAVING AS THEY ARE SLIGHTLY DIFFERENT DIAMETERS WERE THEY JOIN THE MEET.

ALSO THE INLET MANIFOLD IS RESTRICTED IN THE SAME WAY AS THE 99 TILL 03 MODELS , JUST FOLLOW THE SAME PROCEDURE FOR THIS. SEE THE PREVIOUS SECTION FOR DETAILS.

ALSO FOLLOW THE EARLIER PROCEDURE WITH THE BLACK PLASTIC BOTTLE FITTED TO THE AIRBOX TO CARB RUBBER.

THE MAIN RESTRICTION ON THESE BIKES IS A REV LIMITER BUILT INTO THE CDI UNIT, BUT FORTUNATELY ITS EASILY REMOVED ON THESE MODELS. GOING INTO THE SPEEDO IS A 4 WIRE CONNECTING BLOCK, THERE ARE ONLY 3 WIRES ON THE SPEEDO SIDE OF THE CONNECTOR AND 4 WIRES ON THE LOOM SIDE. FIND THE GREEN/BLACK WIRE ON THE LOOM SIDE OF THE CONNECTOR, SNIP IT FROM THE BLOCK, EXTEND IT AND CRIMP AN EYLET ONTO IT AND EARTH IT TO THE FRAME VIA THE TOP RADIATOR MOUNT BOLT. THAT WILL REMOVE THE REVLIMITER FROM THE CDI UNIT.

CHECK THE YPVS SYSTEM FOR CORRECT AJUSTMENT THE SAME WAY AS DESCRIBED AS FOR PREVIOUS MODELS.

28 TO 33 BHP FOR ALL MODELS !

THERE IS A WAY TO GAIN EVEN MORE POWER FOR THESE BIKES WITH SOME SIMPLE BOLT ON MODS.

THERE ARE COUPLE OF ITALIAN BUILT YAMAHA 125,S THAT USE VIRTUALY THE SAME ENGINE AS THE DT125R. THE TDR125 AND TDR125R BELGARDA, THE TZR125R AND TZR125R BELGARDA THAT WILL DONATE THE PARTS SECOND HAND AND PRETTY CHEAP VIA EBAY ETC.

THEY RUN A CHROME CYLINDER SLEAVE WITH BETTER PORTS AND A BETTER COMPRESION RATIO AND A BIG DELORTO CARB.

IF YOU CAN GET THE FOLLOWING FROM ONE OF THESE BIKE YOU WILL MAKE BIG POWER FOR A DT125R.

CDI

CYLINDER HEAD

CYLINDER BARREL

DELORTO CARB WITH INLET MANIFOLD AND CARB TO AIRBOX RUBBER “INLET AND AIRBOX RUBBERS MUST COME FROM THE TDR,S AS THE AIRBOX IS DIFFERENT ON THE TZR MODELS..

THE CARBS ARE USUALY CALLED “VERGASSERS” IN GERMANY , THAT’S WERE YOUR MOST LIKELY TO FIND THESE BREAKING FOR SPARES ON EBAY ETC.

YOU WONT GET AS MUCH POWER WITHOUT A CDI CONVERSION ON THE MID 99 TILL 03 DT. HOWEVER THE TDR AND TZR CDI,S ARE A STRAIGHT SWAP ON ALL DT,S FROM 89 TILL 99 .

2004 ON DT125RE AND DT125X !