DT125R FORUM

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.

@HOTSHOT-III Does sound interesting, for my long-term Aphrodite project I definitely need to set this up properly. So either I'll be taking it somewhere, or I'll be learning the ins and outs to get it in the right ball-park.

No you don't need to open up the engine all the way. It's just a push rod system, if the clutch cam isn't engaging with the push rod then it might be because the push rod has fallen beneath the cam arm so you're not able to position the cam behind the push rod. I've never had this happen to me personally, I don't recall this being an issue, but the design is very simple so there is very little to go wrong. What commonly happens is that the ball bearing inside the engine can get misplaced, which presents itself in a similar manner as you're describing. But this is not possible without dismantling the engine. In essence what you have can be pictured as below: |_._ The | is the cam that you slot from the top of the engine. When the cable is pulled, it twists the cam which acts on the first pushrod denoted here by _. This is space separated with a ball bearing, denoted by . which pushes a further push rod denoted by _. What might be possible is that you've ended up in situation where you've pulled the cam out and now the setup is like: | _._ The cam is now resting on top of the push rod and is no longer engaged with it. So when you pull the lever, nothing happens. I can't remember whether this is even possible, but if it is then you'll notice the cam is sitting a lot higher outside the engine and would be obvious. I am not sure if the pushrods are under load, but if they're not, then leaning the bike over towards the clutch may cause the rods/ball to move allowing the cam to be lowered appropriately. If that doesn't work, then no it's not a full dismantlement. It's just a case of taking the clutch cover off, and taking the clutch pressure plate off to expose the push rods. Extracting them (by leaning the bike over careful not to misplace the ball bearing) and then inserting the cam in first. BUT I REALLY don't think that's what is happening here. It's probably more likely that the clutch just needs adjusting. I'd recommend referring to the Haynes manual for this.

@HOTSHOT-III damn just did enduro on sunday and the bike shut off instantly its having electric problems im having a very weak spark the bike doesnt turn on at all tried bypassing the killswitch and the kickstand switch no result and now i want to check the pickup coil from the stator im not that good with electrics but im trying my best to find the problem

@Calum ok, thanks, and what about electronics?

I’ve had someone listen to it as in person is obviously way better then a compressed video and think it may be the piston rings

@gary76 i do have the meter but i dont really know how to use it could u help?

That's normal. All DTs are like that. [image: IMG-20251011-114625.jpg]

@HOTSHOT-III Hopefully the issue gets resolved as I don't want to lose the data they're hosting. The important stuff I ought to host here to guarantee it isn't lost.

@HOTSHOT III Thanks for the reply bud yea all good on that front it’s the long pedal travel I don’t like it’s just me and how I like things

Trust me, I love my RS, but the DT is just a solid whip. I now have an RS powered trail bike. Never ridden it, despite having it 4 years.

@Calum https://gilimoto.com.br/products/tanque-modelo-dt-200-r-possibilita-uso-de-aletas?variant=43453664133336 They have IT on ebay too https://www.ebay.com/sch/i.html?sid=gilimoto3402&_pgn=1&isRefine=true&_trksid=p4429486.m3561.l49496

@Calum thank you buddy appreciate

@HOTSHOT-III Thanks bud time to put up for sale now done

Thanks mate, will defo look into the impact wrench. I was just hoping it was going to be a quick easy fix with the bits i already had purchased and was shocked to see it was completely different to what i was expecting. My bike is off road due to an accident and im moving house in the next week so the pressure is on as i have no transport for it. All the best

@HOTSHOT-III Absolutely spot on information here. I've not had the thermostat fail on me, but MY GAWD does my DTR run hot. I am not making this up, my Vespa runs cooler than my DTR. The DTR could seriously benefit from a lower opening thermostat, especially when you tune. I've removed my thermostat and now the DT runs a cool 60 degrees. But you're absolutely spot on about having pressure at the cylinder head. It is stops pockets of stale gas forming causing hot spots on the cylinder head (promoting knock).