No I didn't in the end, only because it wasn't a option for me.

The cam is something I may look at later.
I am close to sea level.
I was running 55,155 jets. White spacer mod. Pod air filter and modded exhaust. This was done prior to the piston.
Lancer is the man to talk to about the tech stuff.
I only installed this piston the other week. So I am still running it in.

The power increase is enormous and I mean ENORMOUS.

paulmarshall wrote on 06/04/13 at 14:46:38:


PaulMarshall:

The power increase is not just because of the change from 94mm to 97 mm.....that gives you a size increase from 652 cc to 695 cc.  This is about a 6% increase in size - so if the stock bike is 30 hp you potentially could just up to 31.9 hp.  The biggest change you might be realizing is the jump from 8.5 compression to something round 10.  This makes the engine much more efficient at the expense of using Premium fuel.

You have been talking about the increase heat......and I am not sure this will increase dramatically.  The bore has increased 6%...but the circumference has only increased 3%.  I don't believe the higher compression ratio will make much difference in heat - as it is the greater expansion ratio that results in more power....not the creation of any substantial increase in the heat produced.      

paulmarshall wrote on 05/01/13 at 12:10:49:


Hey new guy here who has too few posts to start his own thread. I'm looking to rebuild my engine with 97mm Wiseco piston and have cylinder resleeved. I understand that these pistons are quite obscure to find. Is 4597M09700 the correct model number? I have found this exact model number for our bikes on multiple sites that sell Wiseco Pistons. Aside from doing a blanket order of 12 pistons direct from Wiseco I am not 100% sure they are exact ones.

As stated previously in this thread, rather than the bore itself the majority of the power gained is from the increase in compression ratio due to going from a piston that is flat to one that has a dome... this is why i was merely looking at the 95mm bore and wiseco piston...

you get most the benefit, while leaving more cylinder material to sink any extra heat if any at all.

But how about merely truing the surfaces and eliminating the head gasket?  anyone have a calculation on the increase in displacement from ditching the gasket alone?  there must be a bit.

Or is this a bad idea with our aluminum not seating properly after torque?

Then what about decking the head a bit, i could easily do this on my mill.
Anyone have a the numbers to shave for say a 10.5 ratio?

should be starting a new thread?

swedishbiker wrote on 11/20/13 at 01:28:25:


I appreciate the response, but isn't that estimate a bit over simplistic?

The calculation needs to be a factor of the reduction in the size of the combustion chamber, that which is not entirely a continuation of the tubal cylinder, but rather a partial hemisphere.

The trouble in making this calculation really is estimating this partial hemisphere and all the bits it contains...  rather than trouble with merely calculating the reduction in the displacement by removing the gasket itself.

Anyone have the actual displacement measure of the combustion chamber itself?

How does one even make this measure, if it is not supplied in specifications?
I suppose one could use a measured syringe filling the chamber with a liquid...