Athena 170 porting
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Hi guys,
So since i had a small oil leak i decided to rebuild my bike from the ground up (frame just got painted, everything is in pierced still).
But I got curious and after some research offered a 170cc kit.When I did the research I saw that the ports are 3mm off for optimal power so i'm wondering if anyone has a guide or some tips to port a 170cc Athena kit to get that little bit extra.
Thanks in advance
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Someone had done it and documented it I thought. Have you had a look on this forum?
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Check this thread out:
https://dt125r.co.uk/topic/2164/ported-athena-170-kit-with-34mm-carb-and-athena-system -
@Calum
Yes i saw this one. The best solution would probably be a spacer but I would prefer a 'simple' porting job. -
@lllDennis A spacer would be far simpler. Run a mill over the top of the barrel and remove a few mm, then add a shim at the bottom.
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@Calum
I'll check it out, don't really have a Mill available. So i'll have to look for someone to do it for me. Spacers are custom build? Or you happen to know if anyone is selling them? -
@lllDennis I'm sure I saw some on eBay a while back.
But that you won't need specialist tools. Buy a sheet of aluminium from eBay of a certain thickness, take the 170 base gasket as a template. Draw around and cut out.
It might not be pretty, but it doesn't have to be perfect. Just enough to act as a spacer. You finish it off with a file and take your time.
With regards to the mill, that is a really standard practice for engineering firms that work with heads for skimming. They'd probably be able to make the bottom spacer too. And will have a good understanding/confidence that what has been done is correct.
I'd want to see the results on the dyno before committing to anything yet though.
Also, you will need supporting mods to take advantage of this.
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@Calum
I got a custom build pipe ready.
Zeeltronic also ready
All the jets for rejettingI am planning to put the bike back together with the new pipe. Go to the dyno.
Change to the zeeltronic, prepare some maps. Go to the dyno
Change to the 170cc and after a solid break in back to the dyno.To get a good idea of what gives the most difference
This is a dyno from my current setup
(Can't get the picture to work though)
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Yeah smart. Sounds great.
Is that figure with the Athena as is?
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@Calum
Stock dt125r with gianelli pipe and silencer.
And the destriction with the wire behind the Dash.She pulls really well. But had a leaky connection between the silencer and pipe which lost a lot of power.
Also had a small oil leak at the shift lever. So decided to rebuild the while bike while waiting on my custom one I ordered from Henriques -
@lllDennis barrel spacers are readily available on eBay for about £10 each in varying thicknesses. Not sure about 3mm but you can use 2 1.5mm spacers.
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@lllDennis That looks really good tbf.
I'd say that's probably better than my Ported 125 DTR with Zeel etc.
I would be interested in seeing how the stock 170 Athena barrel is by comparison.
My RS is very quick, however just looking at the curves on yours, it would have the RS low down. My bike is like unusable below 6K
Pretty sure the powervalve doesn't work either so it tapers off at 10K. Still miles faster than my DT though. -
@markus-w
I'll look into this. Now that i think about it the spacer is not that difficult we have a CNC machine at work to build electrical panels that van do this no problem.
Just have to find a mill now.1mm enough? Or better with 1.5mm, 2mm? I only found 1mm on eBay
.
Honestly I have no idea
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@Calum
I got very lucky. I bought it 6 years ago and looking back it was the deal of a lifetime. By far the best 125 I could've bought. And I got it very cheap -
@lllDennis I read that the port timings were off by 3mm because apparently the barrel was based off a dtr200. How true that is...
Would love to see before and after dyno pulls though. See how the stock Athena compares to a modified one.
Always Originate, Never Pirate!
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@lllDennis i have the Athena 170 kit on mine, I'm happy with performance but I have heard that the ports are 3mm out so was looking to raise it 3 mm with 2 1.5mm spacers and skim the top. They were on eBay must have sold out. but, what I'm now looking into is a long stroke crankshaft and only today BARacing of Portugal have advertised on Facebook 2 new crankshafts that are a direct fit, one is a 53mm stroke which would raise port timing by 2.7mm and other is 54mm so a 3.7mm raise, Standard stroke being 50.3. I read they need to be raised by at least 3mm so I'm guessing the 54 would be best but I have messaged then for advice on this and prices so will let you know if you're interested. probably an expensive way but I'd say by far the best way also would increase cc to about 185.
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@markus-w
That sounds real nice. Please keep me up to date -
@calum said in Athena 170 porting:
@lllDennis I read that the port timings were off by 3mm because apparently the barrel was based off a dtr200. How true that is...
Would love to see before and after dyno pulls though. See how the stock Athena compares to a modified one.
I have compared Athena 170 kit vs 3MB P (and 2RH) cylinders, the only 2 things that's off the athena kit is the piston taller than the stock,the ports are exact copy off the 3MB just a bit wider and the c port is little lower and matches more a 2RH cylinder
The 170 is a mix between the 200cc casing (for the cooling canals and ypvs location) and 125 portmap internally.I searched for a piston that has the dimensions of the 56mm and with bore of 65mm but there is not,only some aftermarket forged that are max 61mm have the right piston height (pin to top).
