Is the Zeeltronic worth it?

[Calum]

I skim both the head and barrel.

https://dt125r.co.uk/topic/11/how-to-i-gentle-skim-your-head-barrel

[Strike78]

I've been looking for a new cylinder, and I found an Athena 125 cylinder kit for the DTX and was wondering if anyone here has first-hand experience with it. How does it hold up over time with regular use?

In terms of performance, is it actually worth it compared to the stock Yamaha cylinder, or would I be better off rebuilding an OEM cylinder instead? The price is almost the same.

[Calum]

I mean, Athena make some quality kit to be fair.

I bought their 392cc kit for my RD and the 170 kit for my DTR. I do think they're exceptional value for money though, especially as used units are getting expensive and prohibitively costly to repair.

Have a search on here as some members have bought them in the past.

[HOTSHOT III]

@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 minimal 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 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.

[Strike78]

Sorry for going a bit off-topic from the original post once again.

I've recently come across a brand new 3MB cylinder and I'm considering buying it. Would I need to make any modifications to fit it on my DTX, or is it basically a plug-and-play swap?

Sorry if it's a basic question, but I'm still learning about these engines and I'd rather ask before spending the money. Thanks for your help!

[Calum]

The DTX comes fitted with a 3MB.

It's only the very early 89/88 models that came with the 3BN cylinders.

Otherwise all years ran the same cylinder. Surprising there isn't more availability given how many of them were made etc