You starter jets are both blocked by the sounds of it, the one on the carb body and the one in the float bowl. Common problem with none starting tm28,s Very old post but should help people who think these carbs are a nightmare when they have a starting problem with them.

Okay so I think I’ve solved it, if you cut away the tab/loophole that the coolant line at the rear feeds that’s attached to your air box (don’t worry everything still follows it’s original route and looks clean) you can then take off your battery tray and unbolt your air box and remove the whole system air boot included with absolutely 0 effort at all. To refit you simply the procedure in reverse, to fit it it all in you have to approach from the exhaust side and twist All that’s required is you remove your rear exhaust/silencer, rear quarter panels and seat I shit you not, what is usually a 45 minute job with lots of profanity is now a piece of piss

@SpookDog it is a a lot of money yes but they are suppose to be so good, look them up online on the reviews they are suppose to make the performance so much better, also takes the stress out of jetting been wrong on traditional carbs Ect, which I think is a pretty common problem on DTs is carb related problems The whole goal of my project is to build a old school looking two stroke but have a more improved or up to date component structure

@spookdog I’m pretty sure everything’s on the stock set up on the carb although the pilot screw is at 1 and 1/2 turns out I’m planning on doing a top end rebuild and maybe getting the cylinder wall honed if it needs it but I’m gonna keep the standard 56mm bore also putting some boysen reeds in it to make it a bit more responsive my mates got a 1988 model with a hand welded pipe from Portugal and with reeds and no snorkel and I think he went Down to 230 main jet and standard on everything else so I’ll keep mine on the 240 and see what’s it’s like after I’ve done it he said the reeds make it a bit richer so may have to go down a few

@stevie-wonder I would check for massive air leaks around the carb & inlet, also maybe the magneto side oil seal. Especially if the revs are really ring-ting, ting, ting, ting fuel starved sounding...

@skunkno1 I haven't heard of anyone running them but with how much people rate them in other bikes it's worth a try right?

@markus-w good shout, i use it every couple of months so ill give that a try as well.

@kevin Don’t know about Legend... Standard is 5j25 or 5j40. Don’t know if it’ll help you narrow it down? They both go with a Q2 needle valve though (tho the 5j40 is a Q2M)

@spookdog okay mate thank you , will have a play with it

For the carb use 0.5mm gasket paper and be very careful to the details.

The centre is usually a good colour, but it is only the very centre, electrode, ect. The ‘outer ring’ is always black and wet. No matter how it’s ridden. I removed the bottle top plug I have on the carb to filter rubber, to let more air in and the engine ran a lot better. Not proper but better...

@pablo13 said in Anyone got experience with power jets?: The Mikuni website begs to differ "Kit may be installed easily on TM and VM series Motorcycle and Snowmobile carburetors." The carbs that Yamaha use are not the same. They are made by Mikuni but they are made to order. The power jet has no ‘brass screw in’ adjustability. It’s just a casting. There are a few other differences like having heater pipes and lack of air~jet brass screw adjustability...

Actually, scratch that! I don’t think they have the weird angle/tilt to them that the Dtr does. That’s the problem, most carbs are level...

@spookdog Yes, they are used during dyno runs to ensure it's not detonating. I'd imagine it would need to be calibrated to a two stroke due to the smoke it burns.

I’m guessing that people are still running the power jets on their carbs when they state main jet sizes?...

@DtxPower Best jetting for Athena 170 is 300 main jet on the standard Mikuni tm28 carb but with the powerjet blocked off. Just cut the rubber tube in half from the float chamber to the powerjet then block the 2 halves of the rubber tube with a couple of 5mm threaded bolts or similar.

@kevin I want to go with a 2.0 or so. I don’t know the increment’s. I have a 2.5 fitted ATM...

@garth link text As for cleaning it, I admit I usually leave my carb alone as much as possible and leave it for those more experienced then I however cleaning it isn’t too hard. If you can take the carb off yourself then locate someone with an ultrasonic cleaner and Chuck them a tenner, failing that go to your local bike shop. However there are plenty of extremely detailed and fool proof tutorials on YouTube for the DT125R look this, courtesy of my favourite grumpy old git of a DT enthusiast, Frankie. link text

@dtr-nsr Thanks for the input guys. It's a very interesting topic, which will have many viewpoints and will surely be a hot debatable one for many years to come!!!

@theportingmaster Thanks alot , just what i wanted to hear it narrows down the "to buy" list where u running with or without powerjet circuit ?