DT125R FORUM

Forum patched and updated. Fixed some database corruption issues which was having a knock-on effect with emojis so hopefully they're working now.

Hey All! Due to personal circumstances I will be needing to suspend the DT125R Forum for an indeterminate amount of time. This is an advance notice to say that at some point, in the not to distant future, I will be switching off this forum. My intention is to relocate the forum/database hosting as the current situation is no longer economically viable. It is unclear at the moment as to what the future will be for this forum, but rest assured it will be back online in the fullness of time. I appreciate each and every one of you that contributes to this forum so there is a BIG thank you from me. Take care & keep smoking! Calum

Not sure this is allowed here I have also put it in the tuning section under carbs….. Bought my DTR few month back was lacking power in first and second gear, looked at the carb and it had seen better days so I decided to clean it. Put it back together and it ran the same. It came with a dep pipe so after some research decided to rebuild it with the suggested parts for the dep pipe. Put a 5DP39 needle in, 22.5 pilot jet and 260 main. Started with needle clip on the second from the top and it started well and idled okay but bogs and dies as soon as you put revs on. Since moved the clip to position 3 and 4 and still the same although slightly better. Runs and doesn’t bog with choke on. Another thing is the air screw is making no difference to idle no matter how far out I turn it even though I’ve just replaced that as well. Any help is appreciated TIA

@Calum said: You can measure the coil to see if it's within tolerance, what I was finding was that from cold it would work a treat, but once under load and warmed up, it would fail to fire above 4k RPM. Okay good to know. So even my measurements looks okay to me I thought about that it might not be okay under load anymore. But I didn't want to manipulate any plugs just to measure under load. @Calum said: I've had this before with a faulty ignition coil. These can still be bought brand new from Yamaha and I highly recommend going for genuine coil over an aftermarket one. The aftermarket one I had led me on a wild goose chase trying to figure out the intermittent faul Do you have any link or shop? Thanks

I meant the wiring for the bulbs. Thank you for the picture, the problem was that the diagram I found showed that the brown wires aren't supposed to be connected (brown from the thermometer, oil bulb, neutral bulb), mine showed that the thermometer needed to be connected to the oil bulb and that the neutral bulb brown needed to go straight into the 6pin connector, without connecting to the oil bulb or the neutral bulb. I didn't understand that but the diagram you sent made everything completely clear, thank you!

The most easiest carb to get ahold of is probably a Dellorto PHBH 28mm. Found on restricted RS's, they're widely used and reknowned for being easy to jet. I run a Dellorto VHSA 32mm carb on my DTR. The reason I've gone with this carb, although rarer and harder to find, is that they were factory fitted to the TZR 125 RR Belgarda which effectively ran a DT125RE engine. Which just gave me nice confidence that it was a solid choice to make. One for sale here: https://www.ebay.co.uk/itm/178501570394?_skw=Dellorto+VHSA+32&itmmeta=01M4B4V0QQEPEYJMTHPDP73MJH&hash=item298f85cf5a:g:QzEAAeSwwDVqqknx&itmprp=enc%3AAQALAAAA8GfYFPkwiKCW4ZNSs2u11xCsZ9R43qCdhmBbcO8vd2J2b6UmsaleZzaYCXtHKDFciw7JJKWAv%2BVU1RMnsTcB6BR1oQISPasgAcqE0jvZsRV6c%2FlVyBaJXcN8rrE44oBe2oSQMMj8qAaObD%2Fbe28WiBSFTDYhptWeveTmzxQZ09RFGD7JnvJgWfjWhS4BRVr1FAcIy%2FVPcCRof3cnpiW1FFNAA8NGpOV3g7ZB2Ofvh56ymFldlS74mqGTajYR3fy53FzAnXiqxtqLCFu%2F4or12IxEXL%2B%2BYXIOMAsOoLkx2wRBM6v%2BZd63q%2FuxmzX2SAEqnw%3D%3D|tkp%3ABk9SR4iN7OSiaA Another great carb, albeit harder to tune, is the VHST 28mm. So keeping the size the same as the Mikuni, but this time Flat Slide instead of Round Slide like the PHBH. Remember, bigger is not always better. Going from 28->32 doesn't necessarily mean more performance. Fair enough if you're giving the engine a tune up, but if your plan is to keep it relatively stock, then sticking to 28mm isn't a bad idea.

Also don't forget to change bulb in light cluster for an led Kind regards