Engine rebuild advice please -RACE sv650 curvy

Well guys Im the other side of the planet.I race a class similar to mini twins but with different rules. -I can do what I like to the motor(except exheed 650cc) and exhaust but must use the suzuki factory air box and filter.
Start of this season I contacted JHS racing and they supplied me a "kit"
advance key, stage 2 cams,m4 and dynajet kit.
I got 80rwhp on a dynajet dyno
7 meetings later its now down to 75 rwhp again on a dynojet dyno. yep the rings are getting tired.
Im still running a starter motor and factory loom including factory ignition switch.

Its now basicly end of season with a 3 month layoff -Time to strip the engine down. I know its at least rering time.
SOO--What I want is more power in the motor and lighter weight for the bike but I still need reliability.
Could I have advise as to the next step please

[Sid Squid]

1st thoughts:

Carbs are probably a weak spot.
Getting someone who really knows what thery're doing to flow it, not just rub a riffler about and takeh your money - which it what most places seem to do.
Degree-ing the cams.
Compression.
Better ignition.

[northwind]

I can't swear that Busa pistons will stay within your rules, but they're popular with the US racers when combined with decked heads. I've no personal experience of it myself, but what I've read makes it seem a good option.

The HP drop is more likely to be down to the valves needing re-grinding and re-gapping than the rings. What makes you think the rings are gone?

Were you happy with 80hp??? If so then just get the valves reground and re-gapped. Else if you want more than the 80hp, thengo with what others have suggested.

Originally Posted by northwind

I can't swear that Busa pistons will stay within your rules, but they're popular with the US racers when combined with decked heads. I've no personal experience of it myself, but what I've read makes it seem a good option.

Its better to put High-comp JE or Wiseco if its coming apart, then all the tolerences are correct and you can get a decent bit of compression with the right squish and then maybe higher spec cams with the apropriate valve springs and caps.

with 650 and CV carbs there's not much more you can do keeping it reliable, so weight saving would be the next project

[northwind]

The high comp Wisecos are pretty heavy though... They add as much weight as the Busa pistons remove. Not sure of the JE weight, didn't know they did a higher comp one (I know they do low-comp, for the turbo busas)

Any other ideas guys??

[northwind]

Rocket boosters. JHS has 'em.

Long stroke sleeved down motor to keep 650cc and up the midrange torque, roller bearing mains, polish cases internally, improve crankcase breathing and windage, lightweight generator/total loss, change pickups and run dyna ignition (or motech for ££), over-bore the cv's, electric water-pump temp/rpm variable, thin cam caps to reduce friction..................Where do you stop

I need to keep reliablility in mind