put it away :lol:

sorry to hijack this thread............................................ ....





























But I cant wait to get to the track:devil::devil:

How big a job ? not as bad as you'd think. Can get big if the crank needs balancing. Getting pistons that match stock weight is the key to preventing this.
Reliability issues ? shouldn't be any. the bottom end is pretty strong.
Additional service costs ? none really.
Why do it ? makes a great engine. 748 buzz with 916 grunt, or more if you spend further on gasflowing, cams etc ;)
A models that cant be converted ? No, it can be carried out on any of them really. The R makes a superb engine.
Benefits ? see "why do it"
Cost ? £1000 ish upwards depending on spec and if crank needs balancing etc.
Can it go back to a 748 ? Yes. If the crank is rebalanced due to new pistons, then it's a little more difficult.
A job you could do ? I can do it, yes :lol:

916 barrels/pistons were/have been used. 2 problems, the barrels are taller and need machining and the pistons are heavier requiring crank balancing.
Sigma's kit uses stock weight pistons, as did my kit. I'll probably not go the route of having any more pistons made as the cost, quantities etc. make it financially difficult having them sat on the shelf for some time.
I'd probably use Pistal pistons, or Sigmas kit.

I'm hoping to get the fuelling sorted on mine soon and see what it's really capable of producing. It had the legs on 999's at brands, but was only doing about 18mpg, the top end is very rich, so there could be more to come ;)
It's a bit more than just a set of big pistons though ;)

mmmmmmmmmmmmmmmm like the sound of this ;)

Why NOT to do it?
Bike is no longer "standard", so unless you pay to put it back before selling, you might have problems.
Using it on the road? Insurance company would need to be informed and might decline to insure it since its no longer standard. You might have to approach a specialist broker.

i had mine done by cjs performance, had a 853 kitted and chris used a bit of his magic and my bike is making 107bhp on the dyno compared to the sigma 853 making 104. im well happy with it, just waiting to get to silverstone next weekend to see what the difference is now its been properly fuelled.

i would recommend it to any 748 owner thats considering it