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DT125X Modifications

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Hi guys, i guess theres alot of DT125X owners out there wanting to make their little mopeds pretty and nimble like myself, so i figured prehaps i can help some people out and they can help me and each other...

I have seen many single and confused threads here on the forum asking questions about de-restrictions, modifications, etc...

So to start off i will explain the different mods so far i have come across and try my best to explain them one by one assuming we have got the bike from standard, and what other mods that might be availible for your DT125X.

Exhaust Systems

First off, replacing the standard exhaust on the DT125X not only gives the bike better performance, but often a completely different sound and reduces alot of weight, thus giving the bike more overall noticable speed.

There are many different aftermarket exhausts out there for the DT125X, personally i went with the full DEP system, which was around £280 inc delivery, many websites on the net sell these, a simple case of googling!

The DEP system comes with all relevant info and instructions on how to fit the exhaust, some people may get confused with what to do with the small chrome airflow pipe that fits to the original exhaust pipe, its a simple case of removing the chrome pipe and using the metal bung that DEP supply to fill the tube hole and also the cable tie they supply to hide the dangling tube out of harms way.

The DEP system needs a few mods to fit properly, as the rear tail pipe mounts are not 100% square in my experiance, it needs to be spaced outwards slightly from the fitting to fit into the rear pipe... also some exhaust putty may be needed as the tail pipe does not sit all the way into the rear pipes join.

Before i purchased the DEP pipe, i bought a 'Big0ne' tail pipe from ebay, for around £50... it stated cleary by the seller it was for a DT125X, i tried to fit the pipe & the fittings were way off, and the tail pipes piping was too long to fit into the front standard exhaust and needed to be shortened... they supplied a rubber tube to connect the pipes together, which eventually melted in less than a week SO BE WARNED! this ebay seller is still selling and did not answer to my complaints!

Rev Limiter De-Restriction

Going into the speedo is a four pin connecting block. There are 4 wires going into the block and only 3 wires coming out the speedo side. Just find the Green & Black wire going into the block, clip it to separate it from the block, and strip the end and join a small piece of wire to it (long enough to to join to an earth on the frame). When the Green/Black wire is earthed to the frame this stops the YPVS from retarding over 7000 RPM. The engine should rev freely now.

You can also earth it to the earth wire running from your front indicator by using 2 splicers and a small peice of wire if required.

Snorkle Removal

remove the rubber snorkel off the top of the airbox under the seat. It'll help the air flow and you'll hear the air induction sound.

Please note:

If you are planning to do a lot of muddy, wet greenlaning/offroading then it would probably be best to leave the rubber snorkel on as it would stop the airbox from sucking in any un-wanted objects, otherwise it is pretty well covered once removed and kept safe under the seat.

Modify Inlet Manifold

I havent done this myself, but you will find a tutorial on this web page: http://dtr125.net/tuningf.htm

The tutorial reads:

First you need to remove the carburettor (refer to Haynes Manual). To remove the inlet manifold, unscrew the 4 x 10MM bolts and gently remove the two-stroke oil feed pipe attached to the top of it. And either block the oil feed pipe with something small or just make sure it stays up in the air so no oil leaks out of it. You should now be able to remove the inlet manifold, although it may require a little help to un-stick the manifold gasket from the engine.

inletmanifold.jpg

The square rubber piece attached to the inlet manifold (as shown in the photo) is designed to channel all the air/fuel mixture to the tip of the reed valve block, restricting the flow. To remove this square piece, get a stanley knife and first cut it off flat with the base. Next you need to carefully trim the flat surface so that you get a nice curved surface from the hole to the outside.

reedflat.jpgreedcurved.jpg

When i refitted mine, i used instant gasket paste to ensure a good seal on re-assembly.

Also: When re-assembling, block the hole in the large air bottle (the one that's got a screw holding it to the frame). This is another item that's been fitted to newer DTR's to mess with the air flow. Ideally it would be better to find an older model inlet pipe to replace the one (with the large hole in the left hand side) that's fitted between the airbox and the carburettor. To block the air bottle hole on mine i've used duct tape over the hole (on the bottle)(because duct tape is strong) and refitted the bottle hence blocking the hole. It seemed to have worked.

Make sure the bottle seals in the hole properly with the duct tape on it. I put a square of duct tape over the hole with a strip all the way round the edge to hold it in place.

Other 'easy to do & possible' Mods

-Changing handle bars / grips / mirrors / leavers

-Fitting hand guards

-Decal & Graphic kits

-Tail Tidy Kit made for DT125X includes LED tail plate light

-Smaller / Larger rear sprocket sets to adjust acceleration / top end performance

-Upgrading Piston & head to 175cc big bore kit (around £500 and requires re-jetting)

I have seen photos of DT's with different plastics etc, also i hear of a height / suspension mod where u change to shorter tension bars that fit and control the distance of the swinging arm, to pull the suspension downwards thus making the bike sit higher and apparently more stable with added visability over oncoming obstacles, but i struggle to find these tension bars for sale at all, maybe somone can shed some light on them?

Here is a pic of the standard tension bars, i am not too sure of the correct name for this part...

p0508090613.jpg

So i hope this info helps some guys out, i will be sticking around, so any questions just ask and i will try my best to answer :)

P.S - I am NOT responsible if you break your bike! :mellow:

Parts List & prices

Here i will list parts and generic / close prices for specific standard parts for the DT125X as new.

(Parts & prices based on personal experiance with buying / quoting and fitting the listed parts stated)

Speedo Cable - £10

Front Exhaust Unit (standard) - £500

Rear Silcencer (standard) - £100

Complete Exhaust Unit (standard) - £600

High Quality chain & sprocket set - £50

Clear-Glass indicators x 2 per pack - £15

Oil Light Bulb (RED) - £3

Rear tyre (pirelli sport demon) - £100 INCLUDING GARAGE FITTING

Front Tyre (pirelli sport demon) - £70-£80 EXCLUDING GARAGE FITTING

My DTX so far:

p0208091016.jpg

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Thanks for the reply bob-c, i think making them yourself could take alot of time, and special tools would be required to make each 'suspension link' precise, let alone gaining the correct material to make them.

I would have thought these links must be manufactured somewhere, set to precise lengths that coordinate to the rear shock somehow?

Am i correct to think that maybe these links from some of the older model DT's, or the DTR/E model would be shorter as the DT125X sits lower being a supermoto?

Thx.

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Hey is there any chance you could post a picture of the 4/3 wire connecting block for the YPVS mod, Im having a lil trouble locating the right wires. Would be very much appreciated!

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p0208091016.jpg

Hi i have a dtx06 and was wondering where u can get the DTX stickers you have on your swing arm as i want to do this to mine ??

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Guest MaD.VeZ

Don't know if you will get a reply as the post is a little old. But they look like the stickers from the side panels to me, so you can ordered them from any Yamaha dealer.

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Hi there,, I really am needing a answer and ive looked everywhere and i cant find any.. But i also need to know if the DTX Steat will fit on the DTR125 or will it be too short/small?? Do you know anywhere that sell the seat alone?

Hi guys, i guess theres alot of DT125X owners out there wanting to make their little mopeds pretty and nimble like myself, so i figured prehaps i can help some people out and they can help me and each other...

I have seen many single and confused threads here on the forum asking questions about de-restrictions, modifications, etc...

So to start off i will explain the different mods so far i have come across and try my best to explain them one by one assuming we have got the bike from standard, and what other mods that might be availible for your DT125X.

Exhaust Systems

First off, replacing the standard exhaust on the DT125X not only gives the bike better performance, but often a completely different sound and reduces alot of weight, thus giving the bike more overall noticable speed.

There are many different aftermarket exhausts out there for the DT125X, personally i went with the full DEP system, which was around £280 inc delivery, many websites on the net sell these, a simple case of googling!

The DEP system comes with all relevant info and instructions on how to fit the exhaust, some people may get confused with what to do with the small chrome airflow pipe that fits to the original exhaust pipe, its a simple case of removing the chrome pipe and using the metal bung that DEP supply to fill the tube hole and also the cable tie they supply to hide the dangling tube out of harms way.

The DEP system needs a few mods to fit properly, as the rear tail pipe mounts are not 100% square in my experiance, it needs to be spaced outwards slightly from the fitting to fit into the rear pipe... also some exhaust putty may be needed as the tail pipe does not sit all the way into the rear pipes join.

Before i purchased the DEP pipe, i bought a 'Big0ne' tail pipe from ebay, for around £50... it stated cleary by the seller it was for a DT125X, i tried to fit the pipe & the fittings were way off, and the tail pipes piping was too long to fit into the front standard exhaust and needed to be shortened... they supplied a rubber tube to connect the pipes together, which eventually melted in less than a week SO BE WARNED! this ebay seller is still selling and did not answer to my complaints!

Rev Limiter De-Restriction

Going into the speedo is a four pin connecting block. There are 4 wires going into the block and only 3 wires coming out the speedo side. Just find the Green & Black wire going into the block, clip it to separate it from the block, and strip the end and join a small piece of wire to it (long enough to to join to an earth on the frame). When the Green/Black wire is earthed to the frame this stops the YPVS from retarding over 7000 RPM. The engine should rev freely now.

You can also earth it to the earth wire running from your front indicator by using 2 splicers and a small peice of wire if required.

Snorkle Removal

remove the rubber snorkel off the top of the airbox under the seat. It'll help the air flow and you'll hear the air induction sound.

Please note:

If you are planning to do a lot of muddy, wet greenlaning/offroading then it would probably be best to leave the rubber snorkel on as it would stop the airbox from sucking in any un-wanted objects, otherwise it is pretty well covered once removed and kept safe under the seat.

Modify Inlet Manifold

I havent done this myself, but you will find a tutorial on this web page: http://dtr125.net/tuningf.htm

The tutorial reads:

First you need to remove the carburettor (refer to Haynes Manual). To remove the inlet manifold, unscrew the 4 x 10MM bolts and gently remove the two-stroke oil feed pipe attached to the top of it. And either block the oil feed pipe with something small or just make sure it stays up in the air so no oil leaks out of it. You should now be able to remove the inlet manifold, although it may require a little help to un-stick the manifold gasket from the engine.

inletmanifold.jpg

The square rubber piece attached to the inlet manifold (as shown in the photo) is designed to channel all the air/fuel mixture to the tip of the reed valve block, restricting the flow. To remove this square piece, get a stanley knife and first cut it off flat with the base. Next you need to carefully trim the flat surface so that you get a nice curved surface from the hole to the outside.

reedflat.jpgreedcurved.jpg

When i refitted mine, i used instant gasket paste to ensure a good seal on re-assembly.

Also: When re-assembling, block the hole in the large air bottle (the one that's got a screw holding it to the frame). This is another item that's been fitted to newer DTR's to mess with the air flow. Ideally it would be better to find an older model inlet pipe to replace the one (with the large hole in the left hand side) that's fitted between the airbox and the carburettor. To block the air bottle hole on mine i've used duct tape over the hole (on the bottle)(because duct tape is strong) and refitted the bottle hence blocking the hole. It seemed to have worked.

Make sure the bottle seals in the hole properly with the duct tape on it. I put a square of duct tape over the hole with a strip all the way round the edge to hold it in place.

Other 'easy to do & possible' Mods

-Changing handle bars / grips / mirrors / leavers

-Fitting hand guards

-Decal & Graphic kits

-Tail Tidy Kit made for DT125X includes LED tail plate light

-Smaller / Larger rear sprocket sets to adjust acceleration / top end performance

-Upgrading Piston & head to 175cc big bore kit (around £500 and requires re-jetting)

I have seen photos of DT's with different plastics etc, also i hear of a height / suspension mod where u change to shorter tension bars that fit and control the distance of the swinging arm, to pull the suspension downwards thus making the bike sit higher and apparently more stable with added visability over oncoming obstacles, but i struggle to find these tension bars for sale at all, maybe somone can shed some light on them?

Here is a pic of the standard tension bars, i am not too sure of the correct name for this part...

p0508090613.jpg

So i hope this info helps some guys out, i will be sticking around, so any questions just ask and i will try my best to answer :)

P.S - I am NOT responsible if you break your bike! :mellow:

Parts List & prices

Here i will list parts and generic / close prices for specific standard parts for the DT125X as new.

(Parts & prices based on personal experiance with buying / quoting and fitting the listed parts stated)

Speedo Cable - £10

Front Exhaust Unit (standard) - £500

Rear Silcencer (standard) - £100

Complete Exhaust Unit (standard) - £600

High Quality chain & sprocket set - £50

Clear-Glass indicators x 2 per pack - £15

Oil Light Bulb (RED) - £3

Rear tyre (pirelli sport demon) - £100 INCLUDING GARAGE FITTING

Front Tyre (pirelli sport demon) - £70-£80 EXCLUDING GARAGE FITTING

My DTX so far:

p0208091016.jpg

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Hi there,, I really am needing a answer and ive looked everywhere and i cant find any.. But i also need to know if the DTX Steat will fit on the DTR125 or will it be too short/small?? Do you know anywhere that sell the seat alone?

You haven't looked everywhere as i have answered this question before on this forum.

No the seat won't fit, too short and the fixing/mountings are in the wrong place.

Could one be made to fit, yes possibly, but it wouldn't be easy or cheap and would probably require the plastics and tank to be fitted from a DTRE/DTX which would require modding also.

http://www.yamahascooterspares.co.uk/spares/epc2.asp?ModelID=9058&pageID=25 at £145 for a seat i can think of better mods to spend money on.

It would probably be an easier fix to strip and old DTR seat and shape it to look like a DTRE/DTX seat then recover it. Just a thought.

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Hi can you tell me the armpit to armpit measurement laid flat please,many thanks Gerry all would anybody know if the DTX seat 2006 fit on a DTRE 2006 many thanks Gerry

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Sparky, start a freash thread in the offroad section. This thread is ancient. That will stop a lot of answers.

Surely the armpit to armpit thing depends on the arms, not the bar?

Anyho, start a fresh thread. I will lock this one as it does get read, need a reference area,lol.

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