DT125R FORUM

Moral of the story from this I can see is More horse power = power maintenance worm with pustion changes probably more regularly Keeping the dep exhaust carbon reeds and sprocket changes seems like the best for performance with out risking blowing pistons more frequently I did see a video on YouTube on how to make two stroked more powerful but with this there was a risk of blowing the engine maybe if you want a fast bike just get a bigger one? I wanted a yz road legal but for daily use I can imagine these get warm and aren't really good for road bikes sure for the track for a couple hours it's all good The dtr is a true work horse in my opinion

Done. Thanks guys

Nice one for that mate thanks for all the info I'll take the break completely off and try see where the leak is actually coming from but I suspect it is the seals will order some genuine ones tonight thank you pal for the tips

Morning guys I just popped of rad cap went for a ride and she's now staying cool cheers guys

@Calum no worries mate. I would take a cad file if you wouldn’t mind sharing will likely send them off to a local machinist. I have a 3d printer as well so could try the cad file on there!

Hi spook need the right fork as i snapped the axel bracket when changing the front tyre getting it ready for its mot

Good morning pal thank you so much the thread on the engine was fine brought a tap and die set and fixed the bolt and it's back o there was In full panic mode how would I go about bolting it on to the engine as at the moment I have one bolt on it and I use that through the exhaust to the engine to bolt it on but the other one you just undo the nut and the bolt stays in the engine how ever the other one the Bolt comes out of the engine sorry if it does not make sense my English is not the best

@mbmO8 This explains the YEIS box between the carb and reed valve better than I can: https://global.yamaha-motor.com/stories/history/stories/0019.html When working around that area it's not that difficult to remove as long as you have a decent pair of pliers to squeeze the clip on top of the reed block, just stuff a rag in the hole until you refit it. The one behind the carb on later bikes, I've never owned a DTR with one of these fitted so maybe someone else can help out explaining this? I see a lot of people blank these off with the lid off a Coke bottle.

Hi all. is there any way to find out my engine year as it says 3py-001. at 1st can't find anywhere to check engine numbers and make of it.

Cheers @HOTSHOT-III

Whoa. Yes, it's a good thing we didn't ordered the wrong parts for my bike. So you're saying i should check the carb?

If the cabling is not messed up the main light runs directly from the stator, doesn't load the battery.

@mbmO8 Nice to hear bud, enjoy

@Hark_Ptooie I found with the Tecno expansion chamber (basically identical to the Athena) it fitted a lot easier using the genuine Yamaha rubber grommet and spacer on the upper mount. The ID of the spacer is quite large and allows a little more movement to line it up than the grommet/spacer supplied..

I am led to believe that the WR125X wheels are Saxxes wheels, not Excel like they were on the DTX. That said, I thought they do fit, but you need the DTX setup etc, so the front brake, forks and spacers. It's not a direct swap for the DTR setup, but it is a very simple swap.

6Nm rings a bell Haynes is invaluable.

@dominik22 I'd start by refitting the airbox snorkel and the stock silencer if you have one. My French '93 4BL ran very well running the jet sizes you mentioned (i.e 240 main) with either a full stock exhaust system or a Tecno expansion/DEP silencer combo but it didn't like the stock expansion/aftermarket silencer combination. Sometimes the tailpipe can affect performance as the stock expansion chamber and silencer are designed to work together; if you change one it can alter back pressure and mess with the pressure waves going backwards and forwards. These evacuate exhaust gases from the cylinder, assist in drawing fresh mixture up through the transfer ports and act to keep the fresh charge from escaping straight out the exhaust port. I never thought the tailpipe alone would affect this but once I tried a brand new DEP silencer on my otherwise stock French '93 4BL with 3NC CDI; it immediately refused to rev beyond 9k. I rode it around for about an hour to eliminate wind direction etc., came home and refitted the stock silencer and straight away it revved to 10k+ again. This is only personal experience, I don't have access to a dyno or anything but it made a big impression on me. A Tecno expansion chamber would probably work well with that Athena silencer. Tecno expansion is identical to the Athena apart from the clearcoat and under half the price. Only downside is the clearcoat melts around the header pipe and is difficult to sand off making your bike look like a Crème Brûlée. If I bought another one now I'd paintstripper it and paint it heatproof black before fitting it. Very good quality pipe for the money, gives a more usable mid-range hit than the DEP which delivers peak HP revs about 600rpm later. https://www.ebay.co.uk/itm/253780922884?gclid=Cj0KCQjwurS3BhCGARIsADdUH5215jUowscJtBepB7NQYPYfR4AeBV1Gu63S4cHFVVEN8aPRotYawA4aAoc7EALw_wcB&_ul=GB&mkevt=1&mkcid=1&mkrid=710-53481-19255-0&campid=5339059258&toolid=10044&customid=Cj0KCQjwurS3BhCGARIsADdUH5215jUowscJtBepB7NQYPYfR4AeBV1Gu63S4cHFVVEN8aPRotYawA4aAoc7EALw_wcB

@Koltin As far as I know all pre-DTRE master cylinders are the same from 1988 until around 2004 so I'd start by comparing part numbers on Fowlers website, look up the part for say an '88, a '96 and your own bike: https://www.fowlersparts.co.uk/?gad_source=1&gclid=CjwKCAjwl6-3BhBWEiwApN6_ks8FnxkMK8pUTlwAmDTt4wZ4GV5FlSqAj_zeubTOZF-qK69xd1CwVxoCpO4QAvD_BwE