DT125R ARCHIVE

otty · DTR Respected Member

Athena 170cc, stock carb and gaskets (help needed)

otty · DTR Respected Member

Well. I'll try it out and then see what I think cause I already bought it. There's always a way to sell it.

Is there a way to buy only the cilinder gasket?

-- Edited by otty on Monday 22nd of April 2013 06:31:51 PM

otty · DTR Respected Member

Hello,

does anybody know what size jet I need for Athena with stock carb?

Does stock cilinder gasket fit Athena? If yes, then a link for that gasket would be nice aswell. Needs transport to Estonia.

Bike is DT125R year 2000. I have removed the restrictors in exhaust and reedswitch.

Thank you!

tunertom · DTR Senior Member

from what ive read, the 170 kit isnt worth fitting

Calum122 · Guru

And you'll want to earth the green and black wire.

And you'll wnt to remove the bottle on the side of the carb boot.

And you'll want to increase the air flow.

And you'll want a 260-280 main jet if I remember correctly.

And you'll want to throw that Athena kit in the bin. Not worth the money IMO.

But you'll need a 170 Athena Gasket mate.

Next time save yourself £200 and have the original cylinder ported and tuned. MUCH better performance.

Calum122 · Guru

I had an athena kit on my 2001 dtr. Was very disapponted. I know a lot more than i did back then.

Basically you'll find the 170 kit won't rev as high as the 125. If the peak power is above the rpm range then you'll never get it obviously. The way to reach this is to alter the timing. I believe retarding the ignition will allow you to reach the extra horsepower. By how much will need precision. A rolling road. And trial and error.

My dt125 had a 38mm carb on it. Air box drilled out to increase air flow. Either way didnt give me what i expect. An extra 45cc's on a two stroke i was expecting rip roaring powerbands.

Also i now know that an engine is balanced in the factory with the cc's on the top. If you increase the cc's by 49cc in theory you should have to slightly alter the balancing of the bottom end. I don't know how to do this.

There's a lot you need to take into consideration.

For my aprilia rs125 i bought a 160cc polini kit. This kit also supplie a woodruff to alter the timing to correct the under rev issue.

There is LOTS of information flying about. A quick google search will give you far clearer results.

NEV · Guru

Would not a shorter con rod also remedy the problem? actually no scrap that, a dumb idea

-- Edited by NEV on Monday 20th of May 2013 04:01:23 PM

banzairx7 · DTR Newbie

You can use a WR200/DT200 base gasket, The head gasket has to be from Athena. You can use a DT200 head from Yamaha on theAThena cylinder kit then use the DT200 head gasket also.

There is one huge reason the Athena kit doesn't make good power. The port timing is completely wrong. The ports are 3mm lower than they should be and are partially blocked by the piston a BDC. The cylinder needs a 3mm spacer to get the port timing in line. Then 3mm+ needs to be machined off the top of the cylinder to get the squish correct.

Calum122 · Guru

banzairx7 wrote:
You can use a WR200/DT200 base gasket, The head gasket has to be from Athena. You can use a DT200 head from Yamaha on theAThena cylinder kit then use the DT200 head gasket also.

There is one huge reason the Athena kit doesn't make good power. The port timing is completely wrong. The ports are 3mm lower than they should be and are partially blocked by the piston a BDC. The cylinder needs a 3mm spacer to get the port timing in line. Then 3mm+ needs to be machined off the top of the cylinder to get the squish correct.

That seems like a highly technical 1st post lmao.

Well that sheds some light on port timing.

banzairx7 · DTR Newbie

Ha ya. I just found this board. I've been working through a multi year project using the Athena kit on a Derbi GPR125 which shares the same motor as you guys.