392cc Athena kit.

[RadarRacing]

Ok slow down. Ive had 6 hrs with this kit. And am rebuilding the bike. And i dont have a dyno so i have no idea what hp its making. Its a very nice improvement over stock. But its not a cubI

 

Thats whqt we keep saying. 6 hours and its time for a rebuild. They really have a peaky powerband and most people I know that have had them and rode them a bit have plqting problems. I dont know why because other athena cyls dont have the same problems. I dont know if its a supplier problem or what but they are very short lived as they come.

[Banshee Climber]

Im going to have pro circuit pipes, 28mm or 30mm carbs, no lid on air box, vf3 reeds, 19cc domes or 20cc domes, +4 timing, and ill be getting a port job. It will be a runner. Theres no doubt in my mind, i will make it so it walks all over stock cylinder ported banshees. I think 34's would be too much for that setup. If he was trail riding?

 

stock cylinders and stock crank banshee i just had built by cameron.

 

[trickedcarbine]

Im going to have pro circuit pipes, 28mm or 30mm carbs, no lid on air box, vf3 reeds, 19cc domes or 20cc domes, +4 timing, and ill be getting a port job. It will be a runner. Theres no doubt in my mind, i will make it so it walks all over stock cylinder ported banshees. I think 34's would be too much for that setup. If he was trail riding?

That should make a fun and snappy little ride. Not sure it would walk all over properly ported stockers. My old Vito's 404 motor ran on 34mm pj's and it was a trail/back road style bike and I think they are ana option worth testing if you are going through the trouble to see what you can get out of it. Not to mention that you can get a pair for a relatively cheap price nowadays.

 

In my opinion, I would say these are a good midrange quality product at a decent price suited for the guy with .080 cylinders that are pretty much done. Not every one needs a big bad totally trick 4 mil. But for the high school kid with minimal dollars and just wants a little more oomph, these are perfect. Yeah you can justify that if you're already spending the money just get a cub, serval, twister, etc. but then if you are doing the cub you might as well do the full reach around with all the goodies. That shit can get expensive and the average trail guy won't justify that. That is where an aftermarket "Replacement Cylinder" like an Athena comes in.

 

Apparrently it is possible to get some good numbers out of these things though. Wicked has some experience with massaging them, and rumor is that Rob at RDZ is using these as his platform to make "Eliminator" cylinders. So I guess if a guy just wants to replace his stock cyls with new unused stuff with out doing a major rebuild, these could be a good ticket. Then if they realize they want more it can be ported

[armyvet]

yeah super old post but i can give my opinion on these first hand.These cylinder rock for the money.Lots of midrange.im sure a cub set up will lay down more peak power and what not but if your into actrual riding and hill climbing and not just draggin then these will fit the bill to the "average' rider.No im not some kid 41 yrs of age and been into banshees for 20 yrs or more.The athena set up is a lot more rdieable than a hogged out stockers with drag porting.Obviously getting a set of stockers trail ported will be cheaper but if one sprang for the whole kit i wouldnt call it a waste of money.plus the nickasil coating will last longer than a steel bore.just shedding a little insight on what i have seen and experienced not what i read on the "internet".While theres a plethora of good info online theres also just as much bullsh** as well lol got fmf fatties and single carb on my athena set up..perfect for my riding.will pull 15t gearing with 20in razr rears

[sprinklerman]

yeah super old post but i can give my opinion on these first hand.These cylinder rock for the money.Lots of midrange.im sure a cub set up will lay down more peak power and what not but if your into actrual riding and hill climbing and not just draggin then these will fit the bill to the "average' rider.No im not some kid 41 yrs of age and been into banshees for 20 yrs or more.The athena set up is a lot more rdieable than a hogged out stockers with drag porting.Obviously getting a set of stockers trail ported will be cheaper but if one sprang for the whole kit i wouldnt call it a waste of money.plus the nickasil coating will last longer than a steel bore.just shedding a little insight on what i have seen and experienced not what i read on the "internet".While theres a plethora of good info online theres also just as much bullsh** as well lol got fmf fatties and single carb on my athena set up..perfect for my riding.will pull 15t gearing with 20in razr rears

Or you could just buy a serval and blow the " as sent" athena kit away.

Shoot..my dad's ported 4mm stockers layed the beat down on 3 ebay athena kits that I know of. And they weren't aggressively ported. In fact, my butt dyno told me they had at least the same amount, if not a wider power dpread.

But glad you like them.

 

Sent from a van down by the river

[Russell Wealthall]

My son bought em after he smoked his stock pistons

I put them on t5 open box jet 360 ran like a cut snake high revs absolutely no bottom or bottom mid jetting was perfect

Pulled off head checked durations ex 189/109 38.5 blowdown couldn't believe it

Just about to bump up transfere to 127 then it should be good

Inlet good size Trans good size and shape unrestricted and tripple port ex why the hell the Trans was so low I can't imagine

[Russell Wealthall]

Run more transfer and it gave a big hit more with good bottom end

Also ran dial a jet and got a noticeable mileage increase had to bore carbs bigger to offset tube restriction

[67banshee01]

I know this is an older thread but has anyone used this kit with a 4mil and porting? I would assume with porting that this big bore kit will be just as good as any other big bore of the same size?

[the benz master]

Just got a set at like 65% off on amazon and decided to look into port timing more closely before using it because a lot of people don't seem to like it. Made the port map and compared to stock cylinders (picture bellow)

 

So basically i think this port timing was never meant to be used with stock stroke. Piston will cover about 2mm of the bottom of the transfer ports when at BDC instead of sitting flush. So the transfer ports are 13% larger than stock but piston is blocking like 16% of the ports so you end up with less area than a stock cylinder... and with the lower port timing well it just won't work on stock crank unless you change the porting/timing. I think the slightly lower transfer port must work out ok with a stroker crank, will have to calculate exact timing it gives out with both strokes.

 

So the facts:

Transfer ports 13% more area than stock

Intake ports are 48% more area than stock

Exhaust port (s) have 42% more area than stock

Lots of material in the cylinder for porting

In 392cc trim this is not bolt on, needs some serious work to make right

You need a +4 stroker crank to make use of these transfer port properly

Casting quality is not good, lots of porosity in the aluminum so lots of porosity in the nikasil coating too. I might get one of the two cylinders re plated before using it. (must be why it was sooo cheap)

 

At 325$ it was a great deal, but anyone paying full price is def getting ripped off and not getting a well engineered/manufactured kit. D

 

[the benz master]

Went ahead to calculate the timing with these measures.

With stock stroke it's 110/188 = 39 blowdown... Makes absolutely no sense at all. Transfers need to be raised at least 10-12deg to yield usable timing. This means raising the transfer ports about 1,8 to 2,1 mm. this would give 120-122/188 and  33-34 deg of blowdown.

With a 4mm stroker crank = 118 /189.5 with 35.75 blowdown. Timing makes a lot more sense.

 

stock cylinders measured out to 113/180... seems a bit low compared to what i've read around here.