DT125R FORUM

Glad to have give it a once over Bent oil sump bolt

I use the Athena pipe with the 170 cylinder, it works quite well, and most of the power is in the midrange, even if I can get it to rev higher with modified ignition curve, the torque is in the midrange. I have seen Mick Abbey writing somewhere that the stinger ID needs to be at least 22mm (or was it 23) with the 170 kit, so that is a bit tight at least with the Athena pipe. The black paint seems to hold up quite well on the Athena-branded version.

I recommend Zeeltronic too.

@hotshot-iii @aragian Gawd! I made the mistake of buying a chinese "racing" coil and that caused me so much grief. A fresh DTR rebuild and I was plagued with running issues which I couldn't get my head around. Wasn't until my brother bought his RD 350 and he took it in for a Dyno where the chap refused to run the bike due to the coil and suddenly it hit me!

I found out that the shorter rear axle collar(part numper 90387-202U8) is the same on the Wr200 and Dt. If anyone has that longer collar(part numper 90387-206X8), could you measure its length? And if anyone has a wr200 rear axle, could you measure its length? The rear axle part numbers of the Wr and Dt are almost the same WR axle part numper 3XP-25381-00 DT axle part numper 3BN-25381-00

@Calum Is that undeslung exhaust a custom job? I'm building a DT LC 'X' (supermoto-inspired) and want to run a underslung exhaust on it. I'm thinking a underslung DTR exhaust could fit pretty well, some minor mods will probably be needed though. I have a modified DTR Athena 170 cylinder with cylinder reed, and a Zeeltronic for that engine.

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.

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!

Could be a lot of things.. but everything is probably not as it should be if it's not starting.. What I can think of: -Leaky crank seals -Damaged/leaking reed/intake -Carb issue -Ignition angle off (flywheel key?) Is the spark plug wet? Is there a good suction pulse from the carb when kicking it? With some experience you can feel it if you cover the carb with your hand on full throttle while kicking/cranking the engine. It should not blow, only suck, and the pulse should be 'strong enough'. Old fuel can make it hard to start too.

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.

@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...

Merry Christmas everyone!

@Calum @raceraidan Interesting thread. I once owned a 1998 DT125RE French import which looked identical to a DT125R the same year (pic 1). It had a larger battery and separate toolikt compartment as well as the electric start wiring. [image: 52481614948_a84fb86893_b.jpg] During this time I was fortunate enough to source a Yamaha service manual for this exact model, I still have this and here are some pictures of the wiring diagram. I believe KTM also used this engine/electrical platform for the LC2 125 which they sold a lot of in Germany (I bought 2 or 3 3MB CDI units marked LC2 125 from German breakers, and also some NIP 3MB YPVS servos which had both the Yamaha and KTM part numbers on the packaging (sadly now all sold). During my ownership I tried all these items on the bike and they all just plugged into the loom (same connectors) and worked. I'm pretty certain the (inverted) flywheel and stator were both stamped 3MB. As you can see this model also has a clutch switch which IIRC, with the clutch pulled in, allows you to start the engine in gear even with the sidestand down, but cuts the ignition when you let out the clutch to try and pull away. If you've already looked at the sidestand switch I'd locate this and give it a dose of WD40 etc. as a starting point. Also the two relays (items 12 and 13) are worth a look although I'm not sure how you'd go about testing these. It might be of some help to just get some more and plug them in and try them. Here's a link to the KTM parts fiche; search Google/eBay etc. for the KTM part numbers as well as Yamaha France and you might get lucky with a European breaker as they can be quite diligent with posting up used parts for sale including the original numbers: https://www.trevorpopemotorcycles.co.uk/index.php?main_page=ktm_fiche_finder https://ypec-sss.yamaha-motor.co.jp/ypec/ypec/b2c/html5/app/en_GB/parts-search/index.html?ver=bd30d8f2-88bf-45bf-81ba-b46167a61f3c Here are some pics of the wiring diagram, not sure if the Gilera SC125 used the same electrical platform but hope this helps: [image: 53464155671_38fb444afb_b.jpg] [image: 53463243007_9a4dea8951_b.jpg] [image: 53464293058_21dae26cab_b.jpg]

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!

@ChuckSR86 Do you have a DTR or a DTX? [image: yamaha%20dtx%202006.jpg] or [image: yamaha%20DT%20125%20R%201991.jpg] 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.

RD and DT LC are the same block, but gear ratios differ. RD has a close ratio gearbox and DT has a wide ratio. Close ratio is not ideal if you want to go offroad IMO. Primary drive with clutch and 'middle shaft' length differs in the the LC engines I compared. Definitely get a LC YPVS engine if you go that route, -more usable power than without power valve. I have a DT LC YPVS close to stock, I reshaped the head and installed a Zeeltronic and put in 0,3mm carbon reed petals, the rest is stock. Goes well and has really good midrange torque for a 125. I think the DTR and TZR engines are the same block too, but there is probably the same gear ratio difference, and possibly more I have not tried dropping in a DTR engine in a LC frame (have only one DTR engine and many LC's), but have thought about it. Let us know if you try it!

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.

£300 is a good price. Get them respoked with some stainless steel spokes and powdercoated hubs etc. I ended up running RS 125 wheels on my Yamaha to get it supermoto. But again, that wasn't cheap. By the time you've refurbished them, sure I paid more than £300 all in.

I saw a another post about someone who made a model of it (the original rubber airboot). But he has not been online for over a year :(. I have a 3d printer so its cheaper to print a new boot than but one.