84mm pistons for GSX-R/Bandit 1200 ??

[FJD]

Is there a known piston kit with 84mm for these engines, or just the Busa-84mm ?

Have a big block here, might want to punch it out to the max. LA Sleeves says up to 84.5mm on this sleeves is possible.

[Jaydee]

35 minutes ago, FJD said:

Is there a known piston kit with 84mm for these engines

Yes, an 84mm bore is 1301cc on slingshot/bandit.

[FJD]

can´t find a JE kit for 84mm, neither from Wiseco

[no class]

MTC do a 84mm / 1307cc  for gsxr/bandit

[Gixer1460]

It's not a 'normal' bore size - most will use 85 or 86mm for 1340 or 1371cc but if you can find the pistons - why not!

[FJD]

from what i found, there´s two different sleeves for the big blocks - up to 84,5mm and then some which can take 85 or even 86mm pistons.

i have a big block with 83mm psitons (one sleeve an piston broken), and a bare block without liners.

Also just snapped up a JE 85mm kit for just USD 220....soooo will have to order some big liners to go with them me thinks...

Try also to find one 83mm piston to complete the old block then.

[Oilyspanner]

What are you going to do with the head FJD ? - have you got something spicy already ? - a good porting job, big valves and lumpy cams make the big engines work well - will need an extra cooler.

[FJD]

Not  yet, i have GSF head,  ported DOT head here.

Not sure what a Big Valve head would cost me  and who does the work in Austria. 

Any recommendations for valve sizes/make  ?

[no class]

you can cut stock seats that will take 30/26 ( stock 28.5/25 ) or go the more expensive route and have oversized bronze seats installed and cut for 31/27 valves . max valve size for  stock oil cooled head without offsetting the guides .  Kibblewhite ….Ferrea ….are among some of the good quality valves

Edited October 9, 2018 by no class

[FJD]

@no class: good info here - much appreciated !

Are there some known stock Suzuki Bikes which have these valves 30/26 as standard - or only aftermarket  available ?

Like pistonwise - busa in b12 etc.

 

[Oilyspanner]

Good question FJD - have had a look at valve specs before, but couldn't see any 5mm shank valves of the right length - early Hayabusas'  valves have 5mm stems (like ours), but are 33.5 mm standard on the inlets and I don't know their length, or retainer to tip length..... had a look at a valve manufacturers catalogue and didn't see any valves with the same product code, so I don't think there is a straight swap. Even Hayabusa pistons are only a fit, not ideal for a N/A motor, without  some work to up compression and the valve angles are different between the motors, so you have to keep checking valve to piston clearance - but like all things, most things can be made to work !

p.s. - a lot of the litre sports bike valves use thinner valve stems - 4.5 and even 4mm, so it limits possible swaps. There's some ingenious people on here, so there might be some ideas - it does look like special purchase for the valves though.

[FJD]

Yes, came up with the same results while checking online catalogues.

It´s actually quite funny, to mix´n match different parts, but i try to stick with OEM parts, and maintain a budget on the modifications.

Maybe you can fit valves with slimmer stem, when you also change the guides in the head - but i guess this is getting expensive then.

[Gixer1460]

If you are going to the expense (time and money) doing a full on port and flow job inc. valves then valve guide replacement is usual as you are boring and re-cutting the seats so why do it with a wonky guide? As long as a valve stem is longer then new collet grooves can be cut and stem shortened then re-hardened with induction heating and quenching - but for the cost you might as well buy bespoke valves...........how fast can you afford to go?

[Oilyspanner]

Unfortunately G1460 has this right FJD - a good head always costs. A ported head on a big block will have torque from very low and make a lot of it, but it will peak early, which will cut the peak hp - depends what you want/are happy with. It'll be Christmas in a couple of months, have you got an rich relatives !

[FJD]

always these decisions......Big CC numbers, and then decide what do do with it, natural aspiration > big valve head with lumpy cams with revised valve springs.

Or i spare the costs, stick with std valves and go with a turbo to overcome the obstacle of small valve area, just add HD valve springs.

Or i win the lottery, and take both, and shit my pants when riding it then.

I think, i will first dig through all my collected parts to see what i will come up with.

[clivegto]

1 hour ago, FJD said:

always these decisions......Big CC numbers, and then decide what do do with it, natural aspiration > big valve head with lumpy cams with revised valve springs.

Or i spare the costs, stick with std valves and go with a turbo to overcome the obstacle of small valve area, just add HD valve springs.

Or i win the lottery, and take both, and shit my pants when riding it then.

I think, i will first dig through all my collected parts to see what i will come up with.

My 1216cc turbo has a flowed head with big inlet valves makes 260hp with loads of low down grunt as well.