DT125R FORUM

Well it's possible yours is a hybrid system. So it's actually DTR forks with DTR hubs laced onto excel rims.

Again, it's an old bike so it's possible it's been modified.

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

And they're definitely off a DTX and not the Saxxes from the WRX? https://www.fowlersparts.co.uk/parts/view/93306-20348

Dimensions: 17mm (Internal Diameter) x 40mm (Outside Diameter) x 12mm (Width).

https://simplybearings.co.uk/shop/p5076/SKF-6203-Open-Deep-Groove-Ball-Bearing-17x40x12mm/product_info.html

No sorry that template was to fit DTX wheels/brakes onto DTR forks, you basically want to run the inverse.

It sounds like you need to swap things out anyway since you're running different sized discs, unless you plan on running the larger disc on the DTR wheel (if that's even possible).

For the sake of how easy it is to bleed the brakes, it might just be simpler and less faff to get the brake setup.

Otherwise you need some cardboard and a pen and need to start marking out the plate.

Get it into DXF format and someone will be able to laser cut you the bracket.

The bearing can still be purchased new from Yamaha: https://www.fowlersparts.co.uk/parts/view/9330620226

Part Number: 9330620226

Dimensions: 15mm (internal diameter) x 35mm (external diameter) x 11mm (width).

@hotshot-iii The quality of your builds are so good! Everything looks meticulously laid.

Oh nice!

What bits are you trying to locate? It can be difficult locating genuine panels, there were lots of replica panels being made.

A good source to search is CMSNL for bits.

Sorry you're right, I just read WRX supermoto wheels.

The DT used Excel and the WR used a different manufacturer (saxxes I believe), but I was under the impression they were interchangeable on the DTX front end.

Can you source the DTX/WRX front brake setup? It would mean you could use that template above.

It's always easier just to get the entire front end setup as well.

Yes: https://dt125r.co.uk/topic/1343/dt125-front-brake-caliper-bracket-dimensions/2?_=1772783708212

Opening the airbox has proven to improve performance, but there are a whole raft of lightweight mods you can do here.

Firstly don't just drill holes into the airbox it is true that this can increase performance if done a certain way but it's not what you want.

Instead you could do with fitting the larger snorkel from the DT200/DT230, this keeps turbulence to a minimum whilst improving airflow and to be honest you could just easily design one kn CAD and 3D print this part meaning it's literally cheap as chips.

Secondly on the reed valve, whilst the OEM valves are very good, it's likely they're old/aged and prone to fluttering. Consider fitting some carbon reeds to restore health and improve resistance to fluttering.

Equally, ensure the air filter is in good health as this will stifle performance and ensuring the exhaust is well cleared as well. Gunk in the exhaust really hurts performance.

I know there are limitations with a lot of Yamaha reedblocks and that they seem to often be way over engineered (in a good way) or inadequate. I don't know where the DTR sits here, however I know the DTLC basically ran YZ sizsd reed valves and fell into the former category.

The spigot can be modified carefully with a hacksaw, but it's probably best to follow a guide from a reputable source rather than winging it.

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.

Hello @chalcosoma,

Apologise I didn't get around to replying last night.

You can get away with running some pretty aggressive tyres on the stock rims, my friend once went very savage on his DTR (to the point spokes to breaking left right and center ).

Sadly, I am not that clued up on tyres and availability in the States in general, but I certainly would have thought this wouldn't be a hard problem to solve.

It would be interesting to hear what other people have run in the past as I know quite a few members had TDRs.

What does POS mean?

Is that the parking light or something?

Yeah, I certainly think it's worth a shot. I can't see it making too much difference one way or another

Hi @kristóf,

Mmm, problem indeed. This is worsened by the fact that this carb was only fitted to your year of DT. I don't know what the LC's ran and later models used a 28mm flat slide.

I can't imagine the thickness needs to be spot on, should match what other carbs use for thickness, possibly 0.1mm I'd have thought. See what others recommend though as I've just pulled that figure out of thin air and don't have my verniers handy.

Oh that's really cool!

Well it looks well loved for, it's an appreciating classic that's for sure.

I don't know of anyone who's done that conversion. The common one from back in the day were the Polysport conversions, but they're more enduro so not designed for peak brightness

Oh okay...wow, errmm the KTM one is quite ugly to be fair.

I was thinking you were showing a picture of your bike with it already fitted and was thinking! Yeah that looks sweet.

Your bike looks really tidy to be fair. The DTX/RE headlight is a lot better than the DTR headlight, is there something you're not getting out of the current headlight. Not only does your bike look sweet, but the light should be decent out of it.

I'm sure the KTM LED headlight will be even better though.

Yes, the air leak will definitely not be helped by not plugging up the oil inlet on the manfild, albeit a tiny leak.

Yes the '88 DTR ran the TMS26 carb not the TM28 carb found on all other years.

That said, I am not aware of any other changes. So finding a suitable inlet manifold (probably can still be had new) and the airboot shouldn't be hard. But finding a genuine Mikuni 28mm is trickier.

A split in the carb boot is not ideal, but it won't be the source of your problem. I'd just smear some silicone onto it and allow that to harden.

Crank seals are common causes for air leaks, as well as the gasket on the inlet manifolds (once you sort the oil connector out).

Spray some WD40 around the general vicinity and if the revs drop back to normal then you've found your culprit .

A crack in the airbox won't manifest itself as an 'air leak' as it's before the carb. Obviously you are bypassing the air filter and that's not ideal, but the engine will behave normally as you're not running the engine lean since air will still rush over the carb and pick up fuel.

You can run without the airbox just fine.

But yeah, sourcing a new carb boot would be ideal

3MB-14453-00

That's the part number

Or fit a later dtx/re one and bung the YEIS or source the YEIS.
3RM-14453-00

With the choke on and it being cold, I'd be reluctant to rev it past 6500.

The 2000 models were heavily restrictive, so going over it all and ensuring it's full power and healthy would be where I'd start.

See @scrimsmustang's guide for derstricting.
https://dt125r.co.uk/topic/3492/yamaha-dt-125-r-derestriction

Do a compression test, make sure the engine's healthy. Check all the air ways, that the exhaust is free of water/oil. That the airbox is clear and the filter has been changed. Check the carb and jets make sure that they're all clear and not blocked.

I'd pin the powervalve open for the moment, just to eliminate it from being a problem source. This will drastically reduce power low down, but should rip roar to the red line.