help modding a 40hp twin yammy

[serious3]

lads i'm looking for a bit of help and advice on a few simple mods i can make to my 40hp yamaha twin (6E9 model). ive had a root around the "normal" outboard forums and the advice is always "if you want more power buy a bigger motor" thing is i'm unemployed so thats out the window!
the motor is on a zapcat (thundercat, dux hammerhead type) and all my mates have the ubiquitous tohatsu 50.
i'm not after huge power id just like it to rev quicker and harder and get a few extra horses, i was thinking of lightening the flywheel for starters then maybe a set of reeds, possibly dumping the choke flaps and upping jet sizes slightly. has anyone else any ideas that can be done on the cheap by a reasonably competant man in a workshop?
thanks in advance!

[DeanFHobart]

Mill the head to get more compression and increase the ignition timing before top dead center for starters. Use a little more oil.

And as you said.... lighten the flywheel some. Balance it.

[serious3]

hallelujah!! a reply to my question that doesn't start with "trade your motor" .... she's running at 135psi at the moment. how much is the norm for milling the head? presume a couple of thou would do it! i'll start with the flywheel tommorrow after i've been out playing and got a base line figure on the gps. thanks for the reply and keep em coming!!

[byrdsperformance@tds.net]

If your saying a couple as in removing (2) thousand's ,
it wont be worth the time an gasket's.

[serious3]

so how much would you remove then?

[curbman]

take 8 to 10 thou

[88workcar]

I would go thirty thousands right off the bat. But before you do anything check the clearance that you have right now. Make sure the head is bolted on with a used gasket and insert a piece of soider in the spark plug hole till it reaches the side wall of the cylinder. Then slowly turn the flywheel by hand till it compresses the soidier. The remove it and mic. the smashed spot to see how thick it is. This should be kept around .030. Any less and you will get into trouble.
Those carbs are plenty big on that engine, but mic them too, the backside, let us know. The reeds stops can be spread open also. If it is the same block I have a few 2 cylinder 60 powerheads here.

[fs5]

so how much would you remove then?

i dunno about the twin cyl 40hp,but over here they skim .060 off the 50hp 3cyl motors.probably best to stick with 88workcar post ,you can always skim it a bit more.

[serious3]

now were getting somewhere! thanks lads! erm daft question 88workcar what do you mean by mic? think that i'm losing something in the translation this side of the atlantic.....!!!
i was actualy thinking about removing the reed stops altogether

[byrdsperformance@tds.net]

These are mechinist's type mesureing tool's.
You will need one of these to check solder or clay once it's squishied out.