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Athena 293cc BB kit


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Got one on the way should be here the first week in December.

It will be interesting to compare it to the EG 295.

 

I will test it with stock porting firstly then if it needs some work I can have that taken care of.

 

Early Xmas present to myself :ride:

 

Anyone interested in feedback?

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I would like to hear more about these Athena kits.  I am leaning towards the Athena because I really like the new cylinder casting made for 300cc.  Boring out the stock cylinder seems to be pushing it a little bit.  The 285cc from Max Power sounds like a good deal for a stock cylinder, but those motors are built to run 100+ octane.  I want a pump gas motor.  Please let us know how it goes.  I would really like a 300 that runs like the stock YZ250 but with more every where.  Let's not turn these beautiful BLUE bikes into want-to-be KTM's.

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I'm curious to see how you think it compares to the EG295.

Do you have to machine the cases? I saw a few reviews that said they had to clear the cases for the cylinder to fit.

That would be on the 125/144. 300 is a bolt on.

Obviously I will need to check/set the squish for a comparison.

Will be pretty hard to beat the EG 295 in performance, maybe reliability and ease of set up, maybe not.

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Does the Athena cylinder use the same 72.0mm bore piston as in the EG295?

What's the situation with PV design, and parts?

It utilises a 72mm Athena piston. Not sure yet if there is a replacement from Wiseco

Cylinder comes complete with Powervalve and all parts to install.

I will take some photos before I install it and the porting experts can comment.

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I wonder how much development went into the Athena 293 kit. Did someone design the ports in the Athena big bore with correct configuration to get the most out of the larger 72mm bore?

If you read the HP 300 thread supposedly the main exhaust width above the transfer ports is holding back the potential of the stock YZ cyl bored out to 72mm. The design of the stock booster port mechanism limits what you do with the stock cyl main exhaust port. Also some of the other ports are being almost wiped out by the larger bore and there is not enough material inside the water jacket to allow much cutting on these ports.

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I wonder how much development went into the Athena 293 kit. Did someone design the ports in the Athena big bore with correct configuration to get the most out of the larger 72mm bore?

If you read the HP 300 thread supposedly the main exhaust width above the transfer ports is holding back the potential of the stock YZ cyl bored out to 72mm. The design of the stock booster port mechanism limits what you do with the stock cyl main exhaust port. Also some of the other ports are being almost wiped out by the larger bore and there is not enough material inside the water jacket to allow much cutting on these ports.

The Athena kit is a complete redesign, my engine guy in Aus had a look at mine before  he shipped, he noted everything looked OK, but needed to test ride it first. 

As to the HP300 comments, bottom line is that for all the talk about what he thinks is better, clearly has not worked. My EG 295 rips, his 300 does not, explain that away all you like!

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The Athena kit is a complete redesign, my engine guy in Aus had a look at mine before  he shipped, he noted everything looked OK, but needed to test ride it first. 

As to the HP300 comments, bottom line is that for all the talk about what he thinks is better, clearly has not worked. My EG 295 rips, his 300 does not, explain that away all you like!

Sounds good. I'm anxious to see what you think after riding a EG295 so long. I like the idea of all new cyl and components too. You would think this kit would have more potential vs the stock cyl since it is starting out as a 72mm bore.

 

I was lucky enough to find a used YZ250 cyl with all PV components and a head for just over $100 so I have about $780 in my EG295 plus shipping and have my original 250cc top end too.

 

I agree, My EG295 rips too. Something is not adding up. I know what looks good on a dyno does not always work good in real life riding. In my real world riding I am Not running my motor WOT most of the time so That could be the Big difference as the dyno charts are at WOT ??? All I know for sure is, with my riding style, my EG295 pulls 14/48 gearing better than the stock 250 motor pulled 14/51 gearing. If a gain of 4.4 HP is doing that ,Great!!! it works for me!

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