DT125R FORUM

@Calum said: Oh awesome! Congrats on the bike. I've had mine now 16 odd years now! Some great advice here, but I'll just chime in with some alternative idea for food for thought, but it doesn't negate the great advice we have here. Many years ago, I went down the TZR Belgarda route, which effectively ran a DT125RE engine, just modified porting. As a result, I ended up using the carb from that bike, which was a Dellorto VHSA 32mm carb. These are probably easier to find as they're used heavily in the scooter community. I've never had problems with that setup, but I am not convinced that the bike is that rapid (despite all the mods I've done), but maybe I just got used to it. @calum is there more info somewhere regarding your setup? I am very curious regarding your experience of the TZR Belgrada "route"

Hello and welcome to the forum! Tidy looking TDR you have there @hotshot-iii Always heard good things about the TDR250. @scrimsmustang Used to rate them as well.

Hi Calum, the OEM coil I ordered has arrived from Fowlers but the clear autolube pipe I ordered from e bay has not arrived. It is showing as running late when I check the tracking. I do not want to start the bike until the clear oil tube is fitted and bled so I am at the mercy of Royal Mail. Assuming the bike will run the only thing left to do is a couple of bulbs and then it should be ready for its MOT. I will fit a new plug cap similar to the one you show.

@Rallyfinnen ciao, grazie per il tuo post. Anch'io vorrei installare il 230 sulla mia TDR125R per avere più potenza. Rimango in attesa di tuoi cortesi aggiornamenti. Grazie

@Elan-n Don't worry about it, I've done a lot worse! Sometimes you can be so close to the thing you're trying to fix it's easy to miss something. The main thing is you're moving forward

Hi John, Sounds like a lovely little time machine you've got there. Cracking bike and very very reliable, if it's not working, then it'll be something very simple and I am sure we'll be on hand to answer any questions you may have in an attempt to get you on the road again.

Thanks for that info Rallyfinnen

Definitely go the OEM route for sure.

@DTGREENLANER I'd say that's a dry bearing inside the servo somewhere, I think they can be taken apart and the gear train serviced. Never done one myself but it's pretty much a scaled-up RC car servo, just take your time and lay everything out in the order you removed it and you should be all good. Southeast Asia is full of DTRs, DT230 Lanzas etc. and some of those guys repair the servos quite often.

Yeah, I used a Honda CR85 Apico one on mine. I though the YZ 125 ones didn't fit.

@HOTSHOT-III thanks

Not familiar with a 1994 DT175 (I presume this is from the Asia (Far East) market). The oil light will just be for the two stroke. There are no sensors that do gearbox, the most you get is a Neutral Light sensor (if you're lucky). For the gearbox oil, the only sensors you see are with your eye balls and the oil sight glass. I can't 100% say this is the case, but I say it with high confidence that this will be the case. Hopefully that's useful. Calum

Well it looks like I have found the issue... somewhere along the line someone has pikey bodged the front axle and spacers... What should have had the sleeve spacer which has the 1mm wall which slides in to the 17mm ID bearing was clearly lost and someone had inserted a 40mm x 15mm bearing and used a spacer from an older DT in place of the correct one.. The joys of owning an unknown modified bike! So I am now getting a spacer machined up and I should be good to go! It has only been holding me up since before christmas.. so now I can get the wheels fitted, get the bike back to mine and do the final few bits before MOT.. starting to get excited now Picture of the spacer that I should have had below: [image: 1773302928622-spacer.jpg] Versus the spacer that someone had installed and was somehow using.. [image: 1773303198579-shaft.jpg]

Yeah that sounds like a good idea and should be easy to swap the wheels over without too much faff!

Hi, thanks again for the detailed reply and for all the information. I had already heard about the larger snorkel from the DT200/DT230, but I’ve seen that they are very difficult to find. Designing one in CAD could be possible, but I don’t have any experience with CAD programs and I also don’t have access to a 3D printer. Regarding the carbon reeds, I had heard about them before but I’m not sure which ones would be a good option at a reasonable price. I’ve also read that some people install a VForce4 reed block for the Yamaha Blaster on the DT125 with small modifications. However, it’s quite expensive. I did find a cheap copy on AliExpress, but I’m worried that the lower quality materials could damage the engine or even perform worse than the original reed block. The air filter was replaced a few months ago with a TwinAir filter, and the exhaust was also cleaned a few months ago. If I eventually decide to modify those spigots in the inlet port, do you know where I could find a good guide or tutorial to follow?

Cheers @beng1968 . I must admit, I bought 2 more Athena kits sometime after this post was made and can't concur with the opinions here. The casting was spot on and it was very good value for money. Considering it comes with everything you'd need to bolt it onto your engine, I'd say it's good value. I will agree it's not YZ rip roaring performance from stock, and considering the extent of tuning on my DTR, it's still nothing compared to a stock Aprilia RS 125. However, it's not without its merits. The extra CCs give a nice broader range of power, which as I've gotten older I've come to appreciate more (I'm no longer 75kgs wet ). I did take my cylinder to Mick Abbey for further porting and there is still more porting work that I need to do on my setup. It should be a decent bit of kit, when setup properly. The first experience I had was when I loaned my brothers 2001 DTR back in 2010, he'd fitted the Athena kit amongst various other mods, and that went very well. At the time, I went all in on a ported 3MB00P cylinder from the TZR Belgarda and that setup definitely served me well. I haven't been on my DTR for several years now and I am eager to fire it up again to rejudge my opinion.