DT125R FORUM

I think EVs for the masses is great. I for one would love an EV, most people don't do much more than 40 miles a day commute, although I just cycle that as my preference.

I've got nothing against EV motorcycling, but it's the weight. It's one of the reasons I don't have a thou or a 600. I was on my RS the other day and for its class, it's fast. Easily will nail the last bike I rode, MT07, in the twisties for sure. You simply can't beat the weight of a well designed two stroke, let alone its simplicity.

That said, they're hardly friendly for the environment. I'm currently working on another project, welded the frame up last weekend and the oil that thing dripped was rediculous!

My issue is, I don't see the motorcyles as the root cause of the problem for climate change. Small CC bikes are hardly the biggest contributor to greenhouse gases.

Nice one, thanks for that suggestion! I’ll give that a go.

Ps. Nice name!

@MadGyver Thank you! 😁

Very cool!

Tip: You can embed the photos by using the ![](https://example.com/location/of/image.png syntax.

They are fuel overflow hoses. Attach a hose like shown on the other side and feed it underneath the bike away from any hot areas.

They're designed to flow gas away from the bike and hot areas should the bike fall over and the tap not be shut off.

Now that the engine is done, I suppose it's best I return back to the frame. I've contacted another local powdercoaters who are able to do the work for me and it'll be dropped off tomorrow. Fingers crossed they do a pucker job this time.

This is it as of yesterday, it hasn't been touched since I got it back from the coaters.

My garage is also very warm as it houses the gas boiler which means it's toasty in there all year round.

Meanwhile I saw this cheeky swinging arm over in Italy for a measily £50...

Now despite already buying and refurbishing an aluminium swinging arm, at no small expense I might add, I do prefer the styling of this arm. I wanted this arm originally, as this is what you'll find on the MX, however the one on the MX uses a special kind of dog bone which I could not source for love nor money. However this one came fitted with the same dog bones that you'd find on the RX/SX/ETX and claims it came off an RX. So I snagged it.

Dimensions wise it all checks out the same as the one I originally bought, so there should be no issues with spacers, clearances or alignment.

It's a lovely bit of kit and a few minutes on a basic polisher shows how good it can come out.

I'll be sending it away for vapor blasting and new bearings have been ordered.

Question is? To polish or not to polish?

I'm looking forward to getting this bike reassembled and back on the road.

@eric74 Fair play for getting on and replacing the tacho drive O-ring. Looking at your pics I'd say the oil is definitely coming from where the cable joins the tacho drive so I'd order the oil seal for this (item 7):

https://www.fowlersparts.co.uk/parts/4083282/dt125r-3py3-1991-999-a/tachometer-gear

Looking at the 4th image you posted up, the plastic breather stub should be right behind the tacho drive about where the old O-ring you mentioned is so it looks like your breather is missing (items 14 and 15):

https://www.fowlersparts.co.uk/parts/4083277/dt125r-3py3-1991-999-a/crankcase

Not sure whether oil would be visibly leaking out of here if it simply wasn't fitted (you never see any oil in the clear tube IIRC) so it may be that someone had the bright idea of plugging the hole with silicone sealant or something similar. Have a poke around here but be careful, if that's what's been done it would be too easy to end up with it disappearing into the crankcase, but if you're patient with the needle nose pliers/tweezers etc. you can remove a wodge of sealant like that from the outside.

A tyre/rim chart I have says up to 80/90-21 is ok,90/90-21 is what I will put when I change tyres.
Don't remember where but someone fitted that size to 1.60-21 rim and had no problem.

@Julius And what type of CDI unit do you have?

But what you're talking about is replacing the whole ignition system, flywheel, pick up, stator and CDI because you don't want to have your RE/X crank rebuilt.

Which PJME do for £40

https://www.pjme.co.uk/acatalog/Yamaha-DT125R-DT125-R-Crank-Rebuild-4121.html#SID=1170

That doesn't make any sense

@Challenger IMG_20240624_214933.png
Hi,
I followed the advice of Spookdog and Stevie Wonder and ordered one in Portugal from Romeu..
is now on its way and can arrive at any moment
in terms of price this was also the best option.
I'm very curious about the sound and performance.

It's doable. I've taken parts from 3 Mikuni 28s.One from my DT,one of a TDR250,one that has oil feed tube don't know what bike and made my current carb.
The one with broken is off,the bent tube is overflow if memory serves.
Chokes are the same.

@dominik22 I take it your pump is not the plunger type?

https://www.youtube.com/watch?v=WwFUzgr2xnA

This is how I set my pump many many years ago. I did not align the lines intentionally just to run a fraction more oil due to the porting work I was running at the time.

Make sure that the air waves are cleared on your bike, you don't seemed to have mentioned this.

So there is nothing nasty blocking your intake solution. A quick, dirty, way to confirm this is to just remove the airbox to carb joiner and take it for a quick run. Sounds like it's running rich, so doing this should cause the bike to lean out. If it's only for a short time it shouldn't hurt. You just want to know if it's getting air.

So check the airbox and renew the filter if you find that removing the boot fixes the issue.

The other common problem is water getting into the exhaust expansion chamber. So cleaning the exhaust is really vital for a two stroke. I've seen this before where a bike was sat for a long time and the exhaust was full of fluid. The bike would refuse to run if this was the case.

That’s absolutely fine, never had a chain cover to begin with. Thanks

@GiannisT No worries 👍 The XT springs/15W oil mod stiffens up the front end quite a bit, to make my YSS shock match the forks I had to up the preload 16mm over the supplied setting and run the rebound on position 29 out of 30. If I'm honest it made the suspension a bit too stiff for off-road (I weigh 145lbs), if I'd had more time I would have experimented with cutting 10mm at a time off the DTR spring spacers to get it just right.

I had Michelin Trackers (road legal MX tyres) fitted all the time I ran this setup so can't comment on street use but it's a pretty easy mod to try and it sounds like you're looking for a stiffer front end, XT springs come up for sale quite a lot because a lot of owners upgrade them (too soft for the 160kg+ XT = a good match for the DTR). Would be interested to hear if it's good for Supermoto, plus if you still want to go the USD route it won't have cost you much to try it!

@HOTSHOT-III alt text

https://dt125r.co.uk/topic/20/yamaha-dt125re-x-stock-exhaust-pipe