DT125R FORUM

Merry Christmas everyone!

@HOTSHOT-III Hopefully the issue gets resolved as I don't want to lose the data they're hosting. The important stuff I ought to host here to guarantee it isn't lost.

@Rat80y The drain bolt stretching is a common thing on the DTR, IMO it's a design feature as if you overtighten it it usually snaps. Whilst being a right PITA to get the clutch cover off and wind out the broken part, it does mean the thread in the crankcase is saved (new crankcases = much more difficult/expensive than taking off an engine cover) so I hope you've ordered genuine from Fowlers (get a load of copper washers as well for future gearbox oil changes). Tightening torque is 15Nm so it's also well worth getting yourself a 1/4" drive torque wrench like this one: https://planetx.co.uk/products/jobsworth-pro-torque-wrench-set-1 There is some truth in both your AI source and what your friend said. In the days of the 12bhp learner restriction, DTRs with the powervalve pinned shut would struggle to rev beyond 6k rpm but properly set up/derestricted/full power it should rev to around 10k.

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

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 .

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.

@Calum That site is known even more year's!!!!!