Decking the head?

[caged]

Hey iv got a 125cc loncin with--- I.R.K, 26mm mikuni carb, 26mm manifold port matched, unifilter, big exhaust and straight through muffler, porter inlet and exhaust ports and a large cam. just wondering who does heavy duty valve springs? Also im thinking of decking the head for a slight compression gain, does anyone no what ratio rise a 10 or 20tho skim will give me? I cant work it out as the engines not at my place atm. cheers

 

[themountain]

Harder springs evoid coilbind and valvefloat with higher rpm....if you got no problem with it yet , you probably don't need them.
What kind of Headgasket do you run?? Maybe a thin copper one will do the trick!!
Decking a head is a risky business

 

[Le|Garage]

the loncin 125cc runs a 52.4mm piston i think. I know there are alot of aftermarket high compression pistons in 52.4mm sizes. Maybe try that? (it's a 13mm pin). Try akunar,tbolt etc. Easier then decking the head imo

 

[Fiddy@norway]

I've fitted a high-comp piston in my loncin 110cc, the 125 and 110 loncin both uses the same 52,4mm piston with 13mm wrist-pin, it, an easy and cheap upgrade which makes an difference over the entire powerband.

 

[caged]

Thanks for all the replys, I have only just got the cam and havnt run it since, i was thinking just shim the springs but i want to avoid coil bind. The reason i wanted to deck the head instead of a piston was because i have access to a machine shop for the next week. I think ill just look at a new piston, akunar should have all that stuff ai? H/D valve springs, copper head gasket and a H/C piston.

 

[themountain]

Probably...but AHP in us have it forsure and they're on christmas sale ...and Mark definately rocks!!
::AHP minis:: | iShock, Honda Trail Bikes, Fast50s, Boyesen, and Sano

 

[Cactus Jack]

Decking the head or using thinner gaskets alters the cam timing slightly and you'll also have to recheck your piston to valve clearances .

Yes , Akunar has all the parts and so does AHP .....