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Athena maximum bore size?

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Hi All,

Could i go 96mm bore on my athena using stock stroke?

96mm bore x stock stroke = 453cc

94mm bore x +4 stroke = 462cc

I know 94mm bore is about max on the OEM cylinder, because of possible headgasket issues.

The Athena is said to be different, i think eddies 60HP 485 uses a 95.5mm bored athena.

I'm thinking that would be a plausible alternative to +4mm stroking it in my case. That way i wouldnt have to split cases. Cheaper and easier to DIY.

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Thanks Chooken that what i needed.

In that thread eddie writes:

"using an athena cylinder as a base they are safe to 96mm."

:lol:

As for the 96mm piston:

JE has one, 1:13 comp.

I'd like to keep that to 1:12.5 tops.

Is there anyone out there who knows if the JE 1:13 is spec-ed for E or S (base gasket)?

Would the 453cc be big enough to keep low end TQ with a 41mm FCR?

I'm planning to use my old style Hotcams st2 with this.

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These guys also do a 95.5mm BB...http://www.lukesracing.com/luksr/drz450.htm

So does Milenium, but I've been down that route and have gone through 2 different cyls from them with nothing but head-aches, blown gaskets, coolane/oil mixing, and countless time lost until I finally decided to drop it down to a 434, and all problems miraculously went away...SHould've heeded Eddie's warning sooner....I'm stubborn:bonk::banghead::bonk::cheers::bonk::smirk::bonk::foul::bonk::lol::banghead::):banghead:

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Thanks Chooken that what i needed.

In that thread eddie writes:

"using an athena cylinder as a base they are safe to 96mm."

:lol:

As for the 96mm piston:

JE has one, 1:13 comp.

I'd like to keep that to 1:12.5 tops.

Is there anyone out there who knows if the JE 1:13 is spec-ed for E or S (base gasket)?

Would the 453cc be big enough to keep low end TQ with a 41mm FCR?

I'm planning to use my old style Hotcams st2 with this.

Usually, the comp is given by using one single layer base gasket.

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So does Milenium, but I've been down that route and have gone through 2 different cyls from them with nothing but head-aches, blown gaskets, coolane/oil mixing, and countless time lost until I finally decided to drop it down to a 434, and all problems miraculously went away...SHould've heeded Eddie's warning sooner....I'm stubborn:bonk::banghead::bonk::cheers::bonk::smirk::bonk::foul::bonk::lol::banghead::):banghead:

I must be lucky with my 485..no issues at all...

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I must be lucky with my 485..no issues at all...

very lucky :lol: glad its working for you. It rarely does.

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very lucky :) glad its working for you. It rarely does.

And another 95.5 here that works just fine. :lol:

Some have problems and it's not a great plan. As the odds are you will push head gaskets on a 95mm and larger bore.

But it can be done. I’ll bet I have issues with mine once I start running it in SM trim..maybe not as it’s a 5mm stroker, and does not need to be revved hard to make power.. Time will tell.

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Thanks for the feedback all.

f2 too.

I think Craigo and Marquez are using the OEM as a base to bore.

I'm planning on boring the Athena though.

Should be fine up to 96mm as per Eddie.

And

-Use copperspray on the headgasket

-Torque the nut down to the correct value (not the erroneous one from the manual)

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Thanks for the feedback all.

f2 too.

I think Craigo and Marquez are using the OEM as a base to bore.

I'm planning on boring the Athena though.

Should be fine up to 96mm as per Eddie.

And

-Use copperspray on the headgasket

-Torque the nut down to the correct value (not the erroneous one from the manual)

I have an OEM cylinder with a Millennium Technologies installed, bored, plated liner sized to 95.5mm.

I have just under 80 hours since the head was last off… No issues.

Had only a few hours on it after rebuild and had an unrelated valve train failure.. crappy springs, nothing more.

So since the 5mm stroked, 95.5mm big bore stroker motor using Hot Cam Old style Stage 2 cams, and single layer base gasket... was built 2008..

I’ve had the top end off twice, and none of the three copper coated installed at 43 ftlb head gaskets have been a problem. With the bikes conversion to SM.. higher RPM’s for longer spans at a time are likely.. I will not be surprised if it pushes a head gasket.

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Thanks for the feedback all.

f2 too.

I think Craigo and Marquez are using the OEM as a base to bore.

I'm planning on boring the Athena though.

Should be fine up to 96mm as per Eddie.

And

-Use copperspray on the headgasket

-Torque the nut down to the correct value (not the erroneous one from the manual)

I used the lukes racing 485 stroker kit...now only available as a 480 kit due to Hotcams not doing the +5mm crank any more...

Done 1 piston/rings replacement and now due for another ...No head gasket issues to date...

I may use an extra base gasket this rebuild due to some minor detonation problems..otherwise all good

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