Busa pistons

[davecara]

Been done to death I’m sure but can see anything in the search so...

whats the script with busa pistons? Are Gen2 pistons any good to use? Or is the wrist pin the wrong diameter?

[jameskat]

What are you putting them in?

Gen 1 20mm gudgeon pin, gen 2 18mm gudgeon pin, gsxr1100  20mm gudgeon pin

[davecara]

It’ll be an oil boiler of some description.

If the Gen2 pistons can be taken out to 20mm and still give the same CR as a Gen1 then I’m sorted I think. I can get some Gen2 for practically free and machining done FOC too 

[Cheeky4648]

Gen2 are 18 mm pin as said above but as to boring them to 20mm it would not be feasable as there is only about 10 thou of meat between the top of the pin hole and the oil control ring. So you would have to offset bore them and may then run into probs at the bottom of pin hole. I.e. getting thin and weak. If you need 20mm go with gen1 they will give same comp as gen2. The gen 2 forging is much skinnier than the gen1. 

 

[Paulm]

Got Gen2 in mine but we did change the Conrods to Falcons as well , 

[davecara]

On 12/20/2017 at 8:41 AM, Paulm said:

Got Gen2 in mine but we did change the Conrods to Falcons as well , 

It’ll defeat the object of getting free pistons if I’ve got to buy rods

is sleeving the little end of the rods a viable option? 

Edited December 26, 2017 by davecara

[Gixer1460]

Can't see any reason for not sleeving the rods if machining is FOC as an option.

[davecara]

33 minutes ago, Gixer1460 said:

Can't see any reason for not sleeving the rods if machining is FOC as an option.

That’s the kind of positivity I need!

off to do some research on putting 1127 barrels on my 1052 bottom end....

[nlovien]

can also confirm on fitting bronze sleeves into small ends - done this before with no issues - for sure its got to be done by an experienced shop = tight accuracy tolerances

[davecara]

16 minutes ago, nlovien said:

can also confirm on fitting bronze sleeves into small ends - done this before with no issues - for sure its got to be done by an experienced shop = tight accuracy tolerances

Warm rods, chilled bronze bushes then ream out to correct size once they're pressed in I reckon

[Paulm]

If you’ve gotta sleeve the rods you may as well just buy some Gen1 pistons and put them in.

[davecara]

27 minutes ago, Paulm said:

If you’ve gotta sleeve the rods you may as well just buy some Gen1 pistons and put them in.

Not if the pistons and sleeving are free!

[Paulm]

1 hour ago, davecara said:

Not if the pistons and sleeving are free!

True!

[nlovien]

5 hours ago, davecara said:

Warm rods, chilled bronze bushes then ream out to correct size once they're pressed in I reckon

I haven't done this myself ( had it done) however you got it - the finish ream after installation is key + parallel alignment of the ream relative to the big end

[slingy1157]

Got my gsxr750 short stroke rods bronze sleeved to fit zx10 pistons. No dramas woth it

[davecara]

13 hours ago, slingy1157 said:

Got my gsxr750 short stroke rods bronze sleeved to fit zx10 pistons. No dramas woth it

Nice one Jack, hows your 750 going? Still havent got my EFi'd 750 running yet. Kept losing sync with the crank pulse, it was down to wiring and 3 duff batteries in the end. Gonna get back on with it in the new year

[slingy1157]

16 hours ago, davecara said:

Nice one Jack, hows your 750 going? Still havent got my EFi'd 750 running yet. Kept losing sync with the crank pulse, it was down to wiring and 3 duff batteries in the end. Gonna get back on with it in the new year

Hi dave. The 750 went 1052, then 1157 then sold so i no longer have it. 

But definitely get back to yours and get it sorted. Efi rocks and ironically was the one element that always worked ok on all 3 engines lol

[davecara]

The EFi may well end up on my EFE once Iget my head round it. That'll be 1196cc with these pistons and a Garret T3 hanging off the front

[Duckndive]

6 hours ago, davecara said:

The EFi may well end up on my EFE once Iget my head round it. That'll be 1196cc with these pistons and a Garret T3 hanging off the front

1196cc in an EFE is 76mm bore ....Busa 81mm pistons  gives you circa 1345cc and needs a big block or re-linered stock block

[davecara]

16 minutes ago, Duckndive said:

1196cc in an EFE is 76mm bore ....Busa 81mm pistons  gives you circa 1345cc and needs a big block or re-linered stock block

I’m running an oil cooled 1052 engine in my EFE, can’t afford a proper engine for it!

im currently scrounging 1127 bits though so might end up 1216 yet!

Edited December 27, 2017 by davecara

[nitro]

If I remember right the depth of the dish of Gen1 piston is 2mm and of Gen2 is only 1.5mm. So Gen2 has more CR if you want have same squish. I put Gen2 pistons and rod into my B12 with 1mm spacer and two foot gaskets for original squish. I workes the combuston chamber for less CR.

The Gen2 piston is lighter and also more stabil than the Gen1, because the ringland is 0.2mm thicker and the upper compression ring has is thinner in the inside, so you have more meat of aluminium to transport heat into the center of the piston. That´s all some years ago - I hope I remember right.

[davecara]

I got bored waiting for the Gen2 ones to be given to me, so I bought some Gen1 with rods for not much moolah!

Gonna have a think about which rods to use to get to my desired CR.  Which I also need to have a think about!