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.

@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.

Hi Glenn welcome to the Forum. It's very quiet on here these days, everything migrated to Meta a long time ago, but I feel the real enthusiasts will remain here Sounds like you've got a wealth of experience with these bikes, almost feels criminal to be breaking them nowadays though, price of them are soaring.

@Strike78 I bought one of those Athena 125cc cylinder kits and was quite impressed with it. The plated bore should deliver better heat transfer into the water jacket and spare A, B and C-spec pistons are also available from Athena specifically for this kit (these literally differ 0.01mm in size to compensate for the plated bore wear over time and so are worth obtaining, @calum I wonder if these are available for your 421 kit?). It eliminates the head gasket issues the DTR is prone to and you also get a brand new powervalve and all mounting hardware so it's ready to bolt on. I can't comment on the performance as I sold the bike shortly after building the engine (which also included a Zeeltronic installation) but the new owner seems very happy with it. Roughly the same cost as repairing a stock cylinder as you say but you do need to factor in getting a one or two spare Athena gasket sets and I'd also be ordering B and C pistons (I think it's supplied with an A piston but do check this) as the fact Athena supply these shows they've really thought about the implications of a plated bore. This is something you need if you want to take the performance of any two-stroke beyond a certain level; you can port the stock cylinder all you want (some of the guys in Portugal even make their own exhaust sub-ports in stock DTR cylinders) but if you can't physically remove the heat from the cylinder, it will just keep blowing up. This is why all modern MX bikes and bikes like the Suxuki RGV250 and Kawasaki KR1-S (both around 60bhp stock) have plated bores. Also the 2MA parallel twin TZR250 (50bhp) was OK with steel liners but the Japan-only 2XT version (an attempt to bring the TZR250 up to RGV/KR1-S levels) had plated bores.

@HOTSHOT-III Ok cheers mate for that, I’ve ordered what you recommended Cheers

Not sure if this will work: https://www.facebook.com/photo/?fbid=10165850989140701&set=g.1650331705410143

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