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[olly]

Could anyone please confirm the valve to piston running clearances on a std production assembled CVO 103, 253 cams, std cast stroker pistons, 40 thou head gaskets etc,(without me having to clay up the build). I am looking to deck the heads on my motor to raise the compression ratio to 9.5/9.8:1. and was interested to see what I can machine off the heads before I run in to problems

[DCFIREMANN]

You have more room  in there then you can imagine. You can deck 40 with no problem. One thing I am not sure on is the max decking clearence on the stock SE 103 heads. I know 50 is the standard on Evo's but this motor has a very large combustion chamber but also has larger valves. So to anwser your question you will be OK.

Be Safe

THE DAWG

[CVOJOE]

Olly,
What's the petrol situation there, meaning what's the highest octane you can get at the pumps normally ? Forget the pricing issue, I believe you're facing double what we pay here in the colonies.

I'm planning a trip across the pond sometime next year and will be renting a bike for a tour-about of some sort.

I believe DC answered your question on the clearance spot on and it's what I've read.

Cheers [smiley=drink.gif]
Joe

[thechop107]

Olly,
Have never had the opportunity to check piston to valve clearance on a stock 103.  The SE-253 cam has very low TDC lifts though, .119 int/.158 exh.  

The minimum recommended operating clearnance is .060. valve to piston.  This minimum tolerance is assuming valve springs are in top condition and correct for the RPM range of the cam.

Knowing that you're working with a flat top piston, a relatively low TDC cam and a .040 head gasket, I agree with The Dawg, you have plenty of room to tighten things up.  You also have the option of using a .030 head gasket which will help your compression and clean up the squish area too.  This will require less material off the head.  

The only way to know for sure is to break out the clay and bolt the heads on twice.

Hope this helps.

The Chop

[OTIS]

Remember to cut the intake.

                     OTIS

[AUSSIE_FLSTFSE]

I thought I had made up my mind not to touch my engine as I was looking at 5-6K to gain 10 or maybe 15Hp (new heads, pistons & cams).Then I find a thread like this which makes me start thinking about it again.How much is 40 thou off going to raise the comp ratio? will it improve the output by much? 2,3 or even 5Hp?? what about cleaning up the ports or flowing the heads? how much should they flow for good output. Are the 103+ heads that much better & why??

Cheers