Carb recommendation

[kepirok]

Hi Guys!

New owner here, after acquiring my childhood dream bike, I would like to ask for your advice regarding carbs.

My 2002 DT125R has a slighlty ported stock cylinder, a chinese PWK 28, Athena pipes and a mapped ignition system. The bike pulls nicely, however I am very unhappy with the chinese PWK's build quality, it's one fo the REALLY bad ones.
The stock carb I received in a box with the bike in very bad condition, it looks like it's beyond repair

Which carb you would buy for this setup?

Thank you in advance for sharing your thoughts.

[HOTSHOT III]

@kepirok Hi bud,

I'd be looking at repairing your original carb or trying to source a replacement, if your cylinder is slightly ported as you say it shouldn't make much difference. Back in the day two-stroke tuners like Stan Stephens etc. used to wring a lot more power out of these engines, very rarely suggested a carb swap unless going fo a full race, rebuild-every-few-hours spec and in a lot of cases even recommended retaining the stock jetting. If your stock carb is really scabby try soaking it in alloy wheel cleaner for 24hrs.

The OEM DTR carb also has a slightly angled float bowl which means it's horizontal with the carb installed, a useful feature due to Mikuni designing the TM28SS specifically for quite a narrow range of Yamaha bikes. It can be a bit expensive to get one in good condition but the time and aggro saved (your bike will just work) is well worth it. The biggest problem with the TM28SS is the air screw seizing but this can be prevented by a smear of copper grease on the threads when installing it in the carb body (it's also worth doing this on all the other carb screws which retain the float bowl, carb top etc), and always spraying the entire engine/carb/radiator area with WD40 after washing the bike (get the 5 litre size with free trigger spray from a motor factors).

I think your Athena exhaust is the same as the Tecno expansion chamber which I've run on stock carb/jetting with good results. Is your ignition a Zeeltronic? If so they're very helpful and will probably tell you which ignition map works best with the stock carb if you email them.

[Rallyfinnen]

My recommendation would be to keep the carb you have, if somebody has put a lot of time putting together a good setup, and everything is working well. Maybe you could tidy up the carb to make it look nicer.

[Calum]

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.